etc. etc.
…
okay, i think that's the last of them!
*actually, a lot.
I'll try to keep track more!
Friday, February 28, 2014
02-28-2014 Catchup: Asteroid discoveries
Sorry guys, turns out that I've missed a few* asteroids, but don't have enough time to give the orbital details of each one, but here they are:
The biggest of them all: Saturn's ring system (rings:part 2)
While Jupiter and the ice giants have small systems of rings around them, Saturn's is by far the largest. With over a thousand rings, it is also very elaborate. But only some of the rings are permanent. The main rings are designated with letters A through G, in the order discovered (not from the center of Saturn.) The rings are presented by distance from Saturn, with the main rings bolded.
The D ring:
Width: 7,600 km
Distance: 66,900-74,510 km
Thickness: unknown
Density: unknown
Eccentricity: unknown
Total mass: unknown
The D ring is the closest to Saturn of any of the known rings, and is fainter than any of the other main rings. This ring, unlike the others, has no distinct structure except for a series of faint, evenly-spaced ringlets. The brighter of the rings are designated D68, D72, and D73. In 1980, the rings orbited at 67,000, 72,000, and 73,000 kilometers respectively. However, later images by the Cassini space probe showed that D72 had moved 200 kilometers closer to Saturn and had grown dimmer. It's expected that the disruption was caused by a comet pushing the ring slightly out of its orbit, and it is currently reverting back into its original orbit.
The C ring:
Width: 17,342 km
Distance: 74,658-92,000 km
Thickness: 5 meters
Density: varies from 1.4 g/cm2 (inner edge) to 17 (titan ringlet)
Eccentricity: unknown
Total mass: 1.1 Pentillion kg.
The C ring is slightly brighter and larger than the D ring, and has more detail in it than the D ring. The main structures of it are the Colombo gap, a hole in the ring system, about 77,900 kilometers from Saturn, and, inside that gap, the Titan ringlet. These two structures are likely caused by an orbital resonance with Titan. The ringlet is slightly eccentric, with the end furthest from the Sun pointing towards Titan's location. Another, weirder gap in the rings is the Maxwell gap. This gap is about 87,500 kilometes out, and has a smaller ringlet within it. This ringlet is called the Maxwell ringlet for lack of a better name. While this ringlet has wave-like structures, implying a shepard moon orbiting near it, there has been no moon discovered to create the Maxwell gap and ringlet.
Width: 14,600 km
Distance: 122,170-136,775
Thickness: 10-30 meters
Density: 30-40 g/cm2
Eccentricity: unknown
Total mass: 6.2 pentillion kg
The A ring marks the end of the popular, bright group of Saturn's rings. The ring is also the largest of the main rings. While the ring is mostly devoid of structure in the form of bright and dark rings, it still contains a few gaps and ringlets. The most notable is the Encke gap. This gap, about 133,590 kilometers from Saturn, is the closest ring to Saturn that is caused by a moon in its orbit, which was discovered in 1990. This moon, named Pan, orbits the closest of any 'moon' of Saturn (not including the moonlet S/2009 S1.) Further out, near the outer boundary of the ring, is the Keeler gap. This gap is much smaller than the Encke gap, only about 1/6th the size. This gap is caused by the moon Daphnis which is about 1/4th the size of Pan. Both of these gaps appear to have small, disturbed ringlets within them probably caused by tidal interactions with the moons in them. Other than these two main moons, hundreds of moonlets have been discovered in the ring. These are only a few hundred meters large, and are only seen from their effects on the ring around them. The most-studied of these has the unofficial name "Bleriot".
The Roche Division:
Width: 2,600 km
Distance: 136,775-139,380 km
The Roche Division marks the 'end' to Saturn's main ring system, and is a gap of low-density material between the A and F rings. Around this distance, completely coincidentally, is the Roche Limit. This is the distance from a parent body (in this case Saturn) where a moon of a reasonable size is able to accrete from small particles. The reason the rings drop off significantly here is because most of the rings further out have accreted into small moons already. Anyways, this division is probably caused by the moon Atlas. This moon, about 40*35*19 kilometers across, orbits near the center of this division. It, along with sweeping material out of this area, also forms the F ring. Prometheus, a moon much larger than Atlas, also contributes to the Roche Division, but in an opposite way. This moon pulls material out of the F ring and into the Roche Division. This helps keep the division from being completely devoid of particles, but rather simply a low-density area. Other small moonlets also appear to contribute to it a bit, such as R/2004 S1 and R/2004 S2.
The F ring:
Width: 30-500 km
Distance: 140,180 km
Thickness: unknown
Density: unknown
Eccentricity: 0.0026
Total mass: unknown
Just out of the main ring system orbits a small, faint ring called the F ring. It officially marks the end of Saturn's visible rings and is formed by the shepard moons, Pandora and Prometheus. The ring, despite being small, is the most dynamic ring in the system. This ring is also very irregular because Prometheus passes through the orbit of it, leaving gravitational deviations in it. The main ring seems to consist of 3 ringlets: A large, outer one that is sometimes split apart by Prometheus's gravity, a dimmer, inner one that is often straighter, and a faint once near the center that appears to be a faint 'halo'.
Janus/Epimetheus ring:
Width: 5,000 km
Distance: 149,000-154,000 km
While the F ring marks the end to the visible rings, there are several faint rings orbiting out of the main system. The closest of these is the Janus/Epimetheus ring. This ring, named after the moons that orbit in it, is extremely faint and is about midway between the F and G ring. The ring is probably caused by ejecta from impacts on these two moons.
The G ring:
Width: 10,000-12,000 km
Distance: 168,000-175,000 km
Thickness: 100,000 meters (100 kilometers)
Density: unknown
Eccentricity: unknown
Total mass: unknown.
The G ring is the furthest out legitimately 'bright' ring, and orbits between the F and E ring. The outer edge of the ring is only 10-20,000 kilometers away from the moon Mimas, which likely formed it. Aegaeon, another moon orbiting within the ring itself, is likely formed by the ring, and not vice versa, accreting out of the ring's faint disk.
Methone Ring arc:
Width: unknown, probably small.
Distance: 194,230 kilometers
Caused by the moon Methone, the Methone Ring arc appears to be caused by collisions with the moon Methone, which explains why it's not very bright (see image below).
Anthe Ring arc:
Width: unknown
Distance: 197,665 kilometers
This ring, slightly larger than the Methone ring, was formed by impacts with the slightly-more impacted moon, Anthe. This ring, along with the moon, is in a 10:11 resonance with Mimas, leaving the ring confined to a fairly small space.
Pallene ring:
Width: 2,500 km
Distance: 211,000-213,500 km
This ring is the largest of the lunar rings of Saturn, and is formed by the moon Pallene, which is fairly small, but has many impacts on it, forming the large ring. The ring is about as bright as the Janus/Epimetheus ring.
The E ring:
Width: 302,000 km
Distamce: 181,000-483,000 km
Thickness: 10,000,000 meters (10,000 kilometers)
Density: very low
Eccentricity: unknown
Total mass: unknown
The 2nd outermost of the known rings, and the faintest of the lettered ones, the E ring is one of the dimmest and largest rings of Saturn. The ring begins near Mimas's orbit and ends at that of Rhea, making it span an enormous distance and encompassing everything further than the F ring. Most of the material of the ring seems to come from geysers on Enceladus, which later spreads out around Saturn and occasionally falls to form a blanket on other moons like Tethys, Telesto, Calypso, Helene, and Polydeuces.
The Phoebe Ring:
Width: 9,000,000 km
Distance: 4,000,000->13,000,000 km
Thickness: 2,300,000 km
In 2009, after the Cassini and Voyager probes had finished finding new rings, scientists searching through Spitzer data found a huge ring around the orbit of Phoebe that, if visible from Earth, would be the size of 2 moons. The ring is probably formed by impacts with Phoebe, which doesn't seem unlikely considering Phoebe's extremely cratered surface. The ring, while orbiting Saturn, orbits Saturn on an angle of 27 degrees. The ring likely migrates inwards over time, eventually falling onto Saturn's outer moons, like Iapetus.
The D ring:
Width: 7,600 km
Distance: 66,900-74,510 km
Thickness: unknown
Density: unknown
Eccentricity: unknown
Total mass: unknown
The D ring is the closest to Saturn of any of the known rings, and is fainter than any of the other main rings. This ring, unlike the others, has no distinct structure except for a series of faint, evenly-spaced ringlets. The brighter of the rings are designated D68, D72, and D73. In 1980, the rings orbited at 67,000, 72,000, and 73,000 kilometers respectively. However, later images by the Cassini space probe showed that D72 had moved 200 kilometers closer to Saturn and had grown dimmer. It's expected that the disruption was caused by a comet pushing the ring slightly out of its orbit, and it is currently reverting back into its original orbit.
 |
| The D ring, showing the evenly-spaced ringlets. Credit: NASA/JPL/Space Science Institute |
 | |
| The D ring in 1980 (bottom) and 2005 (top) showing the inward travel of the D72 ringlet (2nd from left) Credit: NASA/JPL/Space Science Institute |
Width: 17,342 km
Distance: 74,658-92,000 km
Thickness: 5 meters
Density: varies from 1.4 g/cm2 (inner edge) to 17 (titan ringlet)
Eccentricity: unknown
Total mass: 1.1 Pentillion kg.
The C ring is slightly brighter and larger than the D ring, and has more detail in it than the D ring. The main structures of it are the Colombo gap, a hole in the ring system, about 77,900 kilometers from Saturn, and, inside that gap, the Titan ringlet. These two structures are likely caused by an orbital resonance with Titan. The ringlet is slightly eccentric, with the end furthest from the Sun pointing towards Titan's location. Another, weirder gap in the rings is the Maxwell gap. This gap is about 87,500 kilometes out, and has a smaller ringlet within it. This ringlet is called the Maxwell ringlet for lack of a better name. While this ringlet has wave-like structures, implying a shepard moon orbiting near it, there has been no moon discovered to create the Maxwell gap and ringlet.
 |
| The C ring, showing the Titan gap (right) with the ringlet visible on the outer edge of it. The Maxwell gap is visisble at the upper right corner as a dim area outside the broad, fairly bright ring, and then a small, bright ringlet. |
The B ring:
Width: 25,500 km
Distance: 92,000-117,580 km
Thickness: 5-10 meters
Density: 20-100 g/cm2
Eccentricity: unknown
Total mass: 28 Pentillion kg
Of all of Saturn's rings, the B ring is definitely the brightest, largest, and most massive of any of them. It seems to have a wide range of ringlets and objects, but no apparent gaps. While most of the ring is flat, however, the outer edge of the ring also appears to be full of small moonlets up to 2.5 km across. Among other formations, the ring also appears to have small clouds of dust, called 'spokes, in it. This is confusing, because previously the rings had been believed to be created by gravity alone, but the regular appearance of the spokes doesn't seem to follow the theory. The current explanation for them is that small electric charges in them pushes them slightly away from the rest of the ring (similar to how 2 magnets will repel each other if faced the same direction against each other.) The rings also appear to be seasonal, appearing during Saturn's 'spring' and 'fall' equinoxes. While the ring doesn't appear to have any shepard moons, in 2009, while analyzing Cassini data, scientists found a moonlet about 400 meters in diameter. The moon was given the designation S/2009 S1.
The Cassini Division
Width: 4,700 km
Distance: 117,580-122,170 km
Thickness: 20 meters
Density: 18-20 g/cm2
Eccentricity: unknown
Total mass: unknown, probably around 0.05-0.3 pentillion kg
While Saturn's B ring is the most massive, on the contrary, the Cassini Division, which is right outside it, is the most noticeable gap in the system. It is named after Giovanni Domenico Cassini, who discovered it in 1675. With only a 90x magnification, it's possible to view the gap. However, at the time, the gap appeared to be completely devoid of matter, but today's telescopes show it to have some dust inside of it, including a couple of real 'gaps'. The more notable of these is the Huygens gap, at around 117,700 kilometers out. It marks the beginning of the Cassini division, and appears to be caused by a 2:1 resonance with Mimas (it orbits twice for every orbit of Mimas.) Inside of this gap is a small ringlet called (surprise surprise) the Huygens ringlet. The smaller of these gaps is located at about 121,000 kilometers from Saturn, and is called the Laplace gap. This gap doesn't appear to have any direct cause for its formation except that it is near the outer boundary of the ring. It, unlike most other gaps, doesn't have any known ringlet within it and has no moon causing it to be there, leaving astronomers puzzled.
The A ring:Total mass: 28 Pentillion kg
Of all of Saturn's rings, the B ring is definitely the brightest, largest, and most massive of any of them. It seems to have a wide range of ringlets and objects, but no apparent gaps. While most of the ring is flat, however, the outer edge of the ring also appears to be full of small moonlets up to 2.5 km across. Among other formations, the ring also appears to have small clouds of dust, called 'spokes, in it. This is confusing, because previously the rings had been believed to be created by gravity alone, but the regular appearance of the spokes doesn't seem to follow the theory. The current explanation for them is that small electric charges in them pushes them slightly away from the rest of the ring (similar to how 2 magnets will repel each other if faced the same direction against each other.) The rings also appear to be seasonal, appearing during Saturn's 'spring' and 'fall' equinoxes. While the ring doesn't appear to have any shepard moons, in 2009, while analyzing Cassini data, scientists found a moonlet about 400 meters in diameter. The moon was given the designation S/2009 S1.
 |
| The outer B ring, showing the small moonlets embedded in it. Credit: NASA/JPL/Space Science Institute |
 |
| S/2009 S1's discovery image. Note the long shadow despite the fairly small moon to cast it. Credit: NASA/JPL |
Width: 4,700 km
Distance: 117,580-122,170 km
Thickness: 20 meters
Density: 18-20 g/cm2
Eccentricity: unknown
Total mass: unknown, probably around 0.05-0.3 pentillion kg
While Saturn's B ring is the most massive, on the contrary, the Cassini Division, which is right outside it, is the most noticeable gap in the system. It is named after Giovanni Domenico Cassini, who discovered it in 1675. With only a 90x magnification, it's possible to view the gap. However, at the time, the gap appeared to be completely devoid of matter, but today's telescopes show it to have some dust inside of it, including a couple of real 'gaps'. The more notable of these is the Huygens gap, at around 117,700 kilometers out. It marks the beginning of the Cassini division, and appears to be caused by a 2:1 resonance with Mimas (it orbits twice for every orbit of Mimas.) Inside of this gap is a small ringlet called (surprise surprise) the Huygens ringlet. The smaller of these gaps is located at about 121,000 kilometers from Saturn, and is called the Laplace gap. This gap doesn't appear to have any direct cause for its formation except that it is near the outer boundary of the ring. It, unlike most other gaps, doesn't have any known ringlet within it and has no moon causing it to be there, leaving astronomers puzzled.
 | ||||||
| The Cassini Division is visible at the center of this image, with the Huygens gap visible to the right, and the ringlet on the outer edge of it. The Laplace gap is also visible near the outer edge of the division, showing the obvious lack of a ringlet within it. Credit: NASA/JPL/Space Science Institute |
Width: 14,600 km
Distance: 122,170-136,775
Thickness: 10-30 meters
Density: 30-40 g/cm2
Eccentricity: unknown
Total mass: 6.2 pentillion kg
The A ring marks the end of the popular, bright group of Saturn's rings. The ring is also the largest of the main rings. While the ring is mostly devoid of structure in the form of bright and dark rings, it still contains a few gaps and ringlets. The most notable is the Encke gap. This gap, about 133,590 kilometers from Saturn, is the closest ring to Saturn that is caused by a moon in its orbit, which was discovered in 1990. This moon, named Pan, orbits the closest of any 'moon' of Saturn (not including the moonlet S/2009 S1.) Further out, near the outer boundary of the ring, is the Keeler gap. This gap is much smaller than the Encke gap, only about 1/6th the size. This gap is caused by the moon Daphnis which is about 1/4th the size of Pan. Both of these gaps appear to have small, disturbed ringlets within them probably caused by tidal interactions with the moons in them. Other than these two main moons, hundreds of moonlets have been discovered in the ring. These are only a few hundred meters large, and are only seen from their effects on the ring around them. The most-studied of these has the unofficial name "Bleriot".
 | ||||
| The Encke Gap is visible, showing a small ringlet with 'knots' caused by previous gravitational interactions with Pan. Credit: NASA/JPL/Space Science Institute |
 | |
| The Keeler Gap with Daphnis in it, showing 'waves' caused by its interaction with the rings. The shadows give a general impression of height relative to the moon itself. Credit: NASA/JPL/Space Science Institute |
 |
| The Moonlet Bleriot is visible at center bottom in this image, causing small waves in the ring around it, and a partial ring around its orbit. Credit: NASA |
Width: 2,600 km
Distance: 136,775-139,380 km
The Roche Division marks the 'end' to Saturn's main ring system, and is a gap of low-density material between the A and F rings. Around this distance, completely coincidentally, is the Roche Limit. This is the distance from a parent body (in this case Saturn) where a moon of a reasonable size is able to accrete from small particles. The reason the rings drop off significantly here is because most of the rings further out have accreted into small moons already. Anyways, this division is probably caused by the moon Atlas. This moon, about 40*35*19 kilometers across, orbits near the center of this division. It, along with sweeping material out of this area, also forms the F ring. Prometheus, a moon much larger than Atlas, also contributes to the Roche Division, but in an opposite way. This moon pulls material out of the F ring and into the Roche Division. This helps keep the division from being completely devoid of particles, but rather simply a low-density area. Other small moonlets also appear to contribute to it a bit, such as R/2004 S1 and R/2004 S2.
 | ||||
| The Roche Division and Atlas are visible here, along with the F ring and the Encke and Keeler gaps. Credit: NASA |
Width: 30-500 km
Distance: 140,180 km
Thickness: unknown
Density: unknown
Eccentricity: 0.0026
Total mass: unknown
Just out of the main ring system orbits a small, faint ring called the F ring. It officially marks the end of Saturn's visible rings and is formed by the shepard moons, Pandora and Prometheus. The ring, despite being small, is the most dynamic ring in the system. This ring is also very irregular because Prometheus passes through the orbit of it, leaving gravitational deviations in it. The main ring seems to consist of 3 ringlets: A large, outer one that is sometimes split apart by Prometheus's gravity, a dimmer, inner one that is often straighter, and a faint once near the center that appears to be a faint 'halo'.
 | |||||
| A straightened-out composite of the F ring, showing the extreme tidal disturbances in it. Note that the inner ring appears to travel within the main ring about 2/3rd to the right of the image. Credit: NASA/JPL/Space Science Institute |
Width: 5,000 km
Distance: 149,000-154,000 km
While the F ring marks the end to the visible rings, there are several faint rings orbiting out of the main system. The closest of these is the Janus/Epimetheus ring. This ring, named after the moons that orbit in it, is extremely faint and is about midway between the F and G ring. The ring is probably caused by ejecta from impacts on these two moons.
 | |
| Saturn's outer ring system, showing the Janus & Epimetheus ring about midway between the F ring (bright, outer ring) and the G ring (shown) Credit: NASA/JPL/Space Science Institute |
Width: 10,000-12,000 km
Distance: 168,000-175,000 km
Thickness: 100,000 meters (100 kilometers)
Density: unknown
Eccentricity: unknown
Total mass: unknown.
The G ring is the furthest out legitimately 'bright' ring, and orbits between the F and E ring. The outer edge of the ring is only 10-20,000 kilometers away from the moon Mimas, which likely formed it. Aegaeon, another moon orbiting within the ring itself, is likely formed by the ring, and not vice versa, accreting out of the ring's faint disk.
.jpg/800px-Aegaeon_(2008_S1).jpg) | |
| The central G ring, with Aegaeon (bright dot) orbiting within the brightest segment. The image was taken over 10 minutes. Credit: NASA/JPL/Space Science Institute |
Width: unknown, probably small.
Distance: 194,230 kilometers
Caused by the moon Methone, the Methone Ring arc appears to be caused by collisions with the moon Methone, which explains why it's not very bright (see image below).
 | |||
| Image of Methone, showing blatant, obvious lack of impact craters. Credit: NASA/JPL-Caltech/Space Science Institute |
Width: unknown
Distance: 197,665 kilometers
 |
| The Anthe Ring arc is visible, with Anthe being the bright 'star' near the end of it. |
 | |
| The discovery of Anthe (red square). Note how Mimas appears significantly brighter than the rest of the moons. Credit: NASA/JPL/Space Science Institute |
Pallene ring:
Width: 2,500 km
Distance: 211,000-213,500 km
This ring is the largest of the lunar rings of Saturn, and is formed by the moon Pallene, which is fairly small, but has many impacts on it, forming the large ring. The ring is about as bright as the Janus/Epimetheus ring.
 |
| The moon Pallene. Credit: NASA/JPL/Space Science Institute |
Width: 302,000 km
Distamce: 181,000-483,000 km
Thickness: 10,000,000 meters (10,000 kilometers)
Density: very low
Eccentricity: unknown
Total mass: unknown
The 2nd outermost of the known rings, and the faintest of the lettered ones, the E ring is one of the dimmest and largest rings of Saturn. The ring begins near Mimas's orbit and ends at that of Rhea, making it span an enormous distance and encompassing everything further than the F ring. Most of the material of the ring seems to come from geysers on Enceladus, which later spreads out around Saturn and occasionally falls to form a blanket on other moons like Tethys, Telesto, Calypso, Helene, and Polydeuces.
 |
| The E ring, showing Enceladus's silhouette and its effects on the ring. The bright dot directly below it is a geyser erupting near its south pole. Credit: NASA/JPL/Space Science Institute |
Width: 9,000,000 km
Distance: 4,000,000->13,000,000 km
Thickness: 2,300,000 km
In 2009, after the Cassini and Voyager probes had finished finding new rings, scientists searching through Spitzer data found a huge ring around the orbit of Phoebe that, if visible from Earth, would be the size of 2 moons. The ring is probably formed by impacts with Phoebe, which doesn't seem unlikely considering Phoebe's extremely cratered surface. The ring, while orbiting Saturn, orbits Saturn on an angle of 27 degrees. The ring likely migrates inwards over time, eventually falling onto Saturn's outer moons, like Iapetus.
 | |
| The Phoebe Ring in infrared, comparing the size of Saturn to its extent. Credit: NASA/ESA/STScl/AURA |
 | |
| Image of Phoebe, showing heavily-cratered surface. Credit: NASA/JPL/Space Science Institute |
Wednesday, February 26, 2014
02-26-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
- Discoveries:
- None
- Events:
- None
- Births:
- 1928 (86 years ago)- Anatoly Filipchenko, a Russian cosmonaut on Soyuz 7 and Soyuz 16, is born in Davydovka, Russia.
- 1958 (56 years ago)- Susan J. Helms, an American astronaut on STS-54, STS-64, STS-78, STS-101, STS-102, and STS-105, is born in Charlotte, North Carolina.
- Deaths:
- None
Coming up later today:
I'll be finishing up Saturn's Rings guys! I promise this time, later today!
Tuesday, February 25, 2014
02-25-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
- Discoveries:
- None
- Events:
- None
- Births:
- None
- Deaths:
- None
Monday, February 24, 2014
02-24-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
I honestly don't know. Probably Saturn's rings, just keep waiting.
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
- Discoveries:
- 1916 (98 years ago)- 25D/Neujmin is discovered by Grigory Neujmin.
- Events:
- 2011 (3 years ago)- Space Shuttle Discovery launches for the last time before being decommissioned on March 9th.
- Births:
- 1967 (47 years ago)- Brian Schmidt, an Australian astrophysicist who studied supernovae types, is born in Missoula, Montana.
- Deaths:
- None
I honestly don't know. Probably Saturn's rings, just keep waiting.
Sunday, February 23, 2014
02-23-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
- Discoveries:
- None
- Events:
- 1987 (27 years ago)- Supernova 1987a, the closest supernova for over 400 years, explodes in the Large Magellanic Cloud, killing a few obscure alien civilizations.
- Births:
- 1583 (431 years ago)- Jean-Baptiste Morin, a French astronomer who attempted to solve the longitude problem by calculating the distance of the Moon, is born in Villefranche-sur-Saône, France.
- 1928 (86 years ago)- Vasily Lazarev, a Soviet cosmonaut who flew on Soyuz 12 and Soyuz 18a, is born in Poroshino, Russia.
- 1929 (85 years ago)- Jaan Einasto, an Estonian astrophysicist who helped discover the large-scale structure of the universe, is born in Tartu, Estonia.
- 1949 (65 years ago)- Marc Garneau, a Canadian astronaut who was on STS-41 G, STS 77, and STS-97, is born in Quebec City, Canada.
- 1959 (55 years ago)- Clayton Anderson, an American astronaut on STS-117 who participated in ISS expedition 15, is born in Omaha, Nebraska.
- Deaths:
- 1855 (159 years ago)- Carl Friedrich Gauss, a German astronomer who is responsible for a number of Astronomical contributions, including the prediction of Ceres' orbit after being recently discovered, dies in Göttingen, Germany.
Coming up later today:
It's the middle of the night! What did you expect me to make? Saturn's ring system will be a more extensive article than the usual, and is still under construction.
Saturday, February 22, 2014
02-22-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
Rings of the Solar System 2: Saturn's rings.
None today
Comet discoveries:
None today
Today's astronomy anniversaries:
- Discoveries:
- 1928 (86 years ago)- 30P/Reinmuth, a periodic comet with a period of 7.33 years, is discovered by Karl Reinmuth.
- Events:
- None
- Births:
- 1796 (218 years ago)- adolphe Quetelet, a Belgian astronomer who founded the Royal Observatory of Belgium, is born in Ghent, Belgium.
- 1824 (190 years ago)- Pierre Janssen, a French astronomer who discovered Helium on the Sun, is born at age 0.
- Deaths:
- None.
Rings of the Solar System 2: Saturn's rings.
Friday, February 21, 2014
If you like it so much, why not put a ring on it: the rings of the Solar System, from past to future part 1
In 1610, when Galileo turned his newly-invented telescope towards saturn, he observed what appeared to be 'ears' around it. After further observations of the planet, he concluded them to be 2 satellites orbiting the planet closely. Later, in 1616, he noticed the objects to have disappeared, making him confused. While it certainly was odd, he'd accidentally found an interesting formation- a ring system. Since his initial discovery of them in 1611, and their recognition as rings in 1655, rings have been found orbiting all of the other gas giants, including Jupiter. Recent visits by spacecraft have allowed us to learn more about these objects, how they formed, what they're made of, and what will happen to them. Here are the different planets' ring systems, including past and future ones.
The inner planets:
While none of the rocky planets have rings currently, it's likely that a couple of the planets had/will have rings at some point in their life.
Earth:
Earth (obviously) doesn't have any natural satellites or rings other than the Moon (as far as we can tell), and it's likely there weren't for a fairly long time. However, Earth's violent history says otherwise. Early in Earth's formation, a planetesimal the size of Mars collided on an angle with Earth, throwing debris from both planets' crust and mantle into orbit, leaving Earth slightly smaller today than it used to be. While this material eventually coalesced into the Moon, it stayed in orbit for a few million years, long enough for it to become a ring system. The total mass of the ring system was about 15% of Earth's. After a while, half of this mass left Earth's orbit or collided with it, and the other half became 2 moons. As the Moons' gravity affected one another, they slowly 'squished' into one another, with the smaller moon forming a thicker layer of crust on the far side of the current Moon. This was probably one of the slowest collisions in the history of the Solar System.
Mars:
While it's unlikely Mars originally had a ring system, it probably will in only 50 million years. This may seem like a long time, but, for comparison, the solar system is about 4,600 millions years old. Anyways, Mars's moon, Phobos, is the only moon that orbits faster than the planet itself. Because of this, Mars is slowing down Phobos's orbit, causing it to become closer to Mars by a centimeter per year. This means that by 3000 AD, it will be 10 meters closer. Eventually, as it spirals inward from its current distance of 9234-9517 Kilometers, it will eventually pass an imaginary location called the Roche limit. This area is the location relative to a body where any orbiting object will have such great a gravitational difference that the object will be pulled apart. For Phobos, it will pass the limit when it becomes closer than 5450 kilometers away, in about 50 million years. Once this happens, the satellite will be pulled apart into a ring around Mars. This just goes to show you that nothing in the Solar System is permanent.
The outer planets:
Right now, the planets with rings currently around them in our solar system are Jupiter, Saturn, Uranus, and Neptune. Saturn's are by far the most extensive, with Uranus having loose rings, Neptune having even looser ones, and Jupiter having only a few, but fairly dense, rings, around it.
Jupiter:
Until Voyager 1 passed by Jupiter in 1979, the only known planets with rings were Saturn and Uranus. The Voyager 1 images weren't very detailed, but later images by the Voyager 2 and Galileo probes showed the structure of the rings. These are the rings from closest to furthest from the planet:
Halo ring:
The halo ring orbits Jupiter the closest, at only about 100,000 kilometers. It's not very massive, and is the dimmest of the rings in the system, only visible in infrared. It's also the thickest, being nearly twice as thick as the second-most, the Thebe ring.
Main ring:
The brightest ring in the system, the Main ring has a mass of 100,000,000,000 to 10,000,000,000,000,000 Kilograms, making it the most massive ring, too. Despite its mass, it's also the thinnest of any of the rings, only 6,500 kilometers wide. The ring appears to have a shepard moon, Adrastea. A shepard moon is a moon who, through its gravitational pull, keeps a ring bounded to an area instead of spreading out further. The only visible detail in the ring is a notch near the orbit of Metis. Because of this apparent association, it has been named the Metis notch. Apart from this notch, the ring doesn't show much detail except a sharp decrease in brightness outside of it.
Amalthea gossamer ring:
While the Halo ring and the Main ring form the main rings of the system, the Amalthea gossamer ring and the Thebe gossamer ring are very faint rings outside of it that appear to be more like haloes of material than 'rings' in the strict sense. The Amalthea gossamer ring is named after the moon Amalthea, which appears to be the shepard moon for the outer part of the ring. The ring is 53,000 kilometers wide, and 2,000 kilometers thick. It doesn't have any visible features, and is only visible at 5-10x light sensitivity.
Thebe gossamer ring:
The faintest of the rings in the Jupiter system is the Thebe gossamer ring. Named after Thebe, it's fainter than all of the other rings, only visible at 20x light sensitivity. The ring is 97,000 kilometers wide and 8400 kilometers thick. Despite its name, however, Thebe isn't actually a shepard moon of it. The ring has been seen to continue past the moon. It's thought that the ring is formed by dust from impacts on Thebe, which are probably unusual, and therefore leaving the ring fairly not-dense.
Phewph! It seems that this ring article is taking longer than expected, so i'm going to split it into two or three parts. Tomorrow, I'll cover Saturn's ring system, and if I have time, Uranus and Neptunes. Stay tuned till then!
The inner planets:
While none of the rocky planets have rings currently, it's likely that a couple of the planets had/will have rings at some point in their life.
Earth:
Earth (obviously) doesn't have any natural satellites or rings other than the Moon (as far as we can tell), and it's likely there weren't for a fairly long time. However, Earth's violent history says otherwise. Early in Earth's formation, a planetesimal the size of Mars collided on an angle with Earth, throwing debris from both planets' crust and mantle into orbit, leaving Earth slightly smaller today than it used to be. While this material eventually coalesced into the Moon, it stayed in orbit for a few million years, long enough for it to become a ring system. The total mass of the ring system was about 15% of Earth's. After a while, half of this mass left Earth's orbit or collided with it, and the other half became 2 moons. As the Moons' gravity affected one another, they slowly 'squished' into one another, with the smaller moon forming a thicker layer of crust on the far side of the current Moon. This was probably one of the slowest collisions in the history of the Solar System.
Mars:
While it's unlikely Mars originally had a ring system, it probably will in only 50 million years. This may seem like a long time, but, for comparison, the solar system is about 4,600 millions years old. Anyways, Mars's moon, Phobos, is the only moon that orbits faster than the planet itself. Because of this, Mars is slowing down Phobos's orbit, causing it to become closer to Mars by a centimeter per year. This means that by 3000 AD, it will be 10 meters closer. Eventually, as it spirals inward from its current distance of 9234-9517 Kilometers, it will eventually pass an imaginary location called the Roche limit. This area is the location relative to a body where any orbiting object will have such great a gravitational difference that the object will be pulled apart. For Phobos, it will pass the limit when it becomes closer than 5450 kilometers away, in about 50 million years. Once this happens, the satellite will be pulled apart into a ring around Mars. This just goes to show you that nothing in the Solar System is permanent.
The outer planets:
Right now, the planets with rings currently around them in our solar system are Jupiter, Saturn, Uranus, and Neptune. Saturn's are by far the most extensive, with Uranus having loose rings, Neptune having even looser ones, and Jupiter having only a few, but fairly dense, rings, around it.
Jupiter:
Until Voyager 1 passed by Jupiter in 1979, the only known planets with rings were Saturn and Uranus. The Voyager 1 images weren't very detailed, but later images by the Voyager 2 and Galileo probes showed the structure of the rings. These are the rings from closest to furthest from the planet:
Halo ring:
The halo ring orbits Jupiter the closest, at only about 100,000 kilometers. It's not very massive, and is the dimmest of the rings in the system, only visible in infrared. It's also the thickest, being nearly twice as thick as the second-most, the Thebe ring.
 |
| The Halo ring in infrared- the bright yellow line is the Main Ring. Credit: NASA/JPL-Caltech |
The brightest ring in the system, the Main ring has a mass of 100,000,000,000 to 10,000,000,000,000,000 Kilograms, making it the most massive ring, too. Despite its mass, it's also the thinnest of any of the rings, only 6,500 kilometers wide. The ring appears to have a shepard moon, Adrastea. A shepard moon is a moon who, through its gravitational pull, keeps a ring bounded to an area instead of spreading out further. The only visible detail in the ring is a notch near the orbit of Metis. Because of this apparent association, it has been named the Metis notch. Apart from this notch, the ring doesn't show much detail except a sharp decrease in brightness outside of it.
 |
| The Main ring. The faint dust visible inside is the Halo ring, and the dim- mer part in the middle is the Metis notch. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
While the Halo ring and the Main ring form the main rings of the system, the Amalthea gossamer ring and the Thebe gossamer ring are very faint rings outside of it that appear to be more like haloes of material than 'rings' in the strict sense. The Amalthea gossamer ring is named after the moon Amalthea, which appears to be the shepard moon for the outer part of the ring. The ring is 53,000 kilometers wide, and 2,000 kilometers thick. It doesn't have any visible features, and is only visible at 5-10x light sensitivity.
 |
| The Gossamer rings, with the Amalthea ring's edge being visible as a slight decrease in brightness 2/3 to the left of the image. Credit: NASA/JPL-Caltech |
The faintest of the rings in the Jupiter system is the Thebe gossamer ring. Named after Thebe, it's fainter than all of the other rings, only visible at 20x light sensitivity. The ring is 97,000 kilometers wide and 8400 kilometers thick. Despite its name, however, Thebe isn't actually a shepard moon of it. The ring has been seen to continue past the moon. It's thought that the ring is formed by dust from impacts on Thebe, which are probably unusual, and therefore leaving the ring fairly not-dense.
 |
| An image of the rings of Jupiter, showing the gradual decrease in brightness further away from Jupiter. |
Phewph! It seems that this ring article is taking longer than expected, so i'm going to split it into two or three parts. Tomorrow, I'll cover Saturn's ring system, and if I have time, Uranus and Neptunes. Stay tuned till then!
02-21-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
None today
Comet discoveries:
C/2014 C3 (NEOWISE)
Type: Halley-type comet
Perihelion: 1.712-1.872 AU
Aphelion: 1.66-29.606 AU
Eccentricity: 0.62-0.969
Period: error-60.2 years
Last perihelion: January 3rd, 2014
Next perihelion: September 22nd, 2039
Today's astronomy anniversaries:
Ring of the solar system (I'm working on it right now!)
None today
Comet discoveries:
C/2014 C3 (NEOWISE)
Type: Halley-type comet
Perihelion: 1.712-1.872 AU
Aphelion: 1.66-29.606 AU
Eccentricity: 0.62-0.969
Period: error-60.2 years
Last perihelion: January 3rd, 2014
Next perihelion: September 22nd, 2039
Today's astronomy anniversaries:
- Discoveries:
- None
- Events:
- 1972 (42 years ago)- Luna 20, an unmanned Russian sample-return mission, successfully lands on the Moon.
- Births:
- 1964 (50 years ago)- Mark and Scott Kelly, two identical twins who were both astronauts on STS-108, STS-121, STS-124, STS-134, and STS-103, STS-118, Expedition 25/26 (Soyuz TMA-01M) respectively, are born in Orange, New Jersey.
- Deaths:
- 1788 (226 years ago)- Johann Georg Palitzsch, a German astronomer who recovered Comet Halley after Edmond Halley predicted its return in 1758, dies at age 65.
- 1938 (76 years ago)- George Ellery Hale, an American astronomer who invented the Spectroheliograph and has an asteroid, Lunar crater, and Martian crater named after him, dies in Pasadena, California.
Ring of the solar system (I'm working on it right now!)
Thursday, February 20, 2014
02-20-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
None today
Comet discoveries:
P/2014 C2 (STEREO)
Type: Parabolic comet
Perihelion: 0.489-0.534 AU
Aphelion: N/A
Eccentricity: 0.459-1.541
Period: N/A
Last perihelion: February 18th, 2014
Next perihelion: N/A
Today's astronomy anniversaries:
- Discoveries:
- 1999 (15 years ago)- (26375) 1999 DE9, a nearly-spherical trans-Neptunian object about 450 kilometers in diameter, is discovered by Chad Trujillo and Jane Luu.
- Events:
- 1965 (49 years ago)- Ranger 8 impacts the moon after successfully looking for Apollo landing sites.
- 1986 (28 years ago)- Mir, the world's first space station, is launched into orbit by Russia.
- 2013 (1 year ago)- Kepler-37b, the smallest known extrasolar planet (a bit larger than the Moon), is discovered by the Kepler telescope.
- Births:
- 1948 (66 years ago)- Andrew Fabian, a British astronomer who researched galaxies' black holes and X-ray sources, is born in Britain.
- Deaths:
- 1771 (243 years ago)- Jean-Jacques d'Ortous de Mairan, a French astronomer who discovered M43, or de Mairan's nebula, dies in Paris, France.
- 2013 (1 year ago)- David S. McKay, an American astrobiologist who studied the possibility of life on Mars based on Martian meteorites like ALH 84001, dies at age 76.
I'm not sure I'm doing anything, but I might work on the rings article I talked about yesterday.
Wednesday, February 19, 2014
02-19-2014 Astronomy anniversaries and new asteroids (now with comets, too!)
Asteroid discoveries:
None today
Comet discoveries:
P/2014 C1 (TOTAS)
Type: Encke-type comet
Perihelion: 1.585-1.802 AU
Aphelion: 2.653-6.459 AU
Eccentricity: 0.266-0.65
Period: 2.059-8.981Years
Last perihelion: December 20th, 2013
Next perihelion: June 30th, 2019
Today's astronomy anniversaries:
The rings of the solar system: What formed them, their physical characteristics, and their eventual demise.
None today
Comet discoveries:
P/2014 C1 (TOTAS)
Type: Encke-type comet
Perihelion: 1.585-1.802 AU
Aphelion: 2.653-6.459 AU
Eccentricity: 0.266-0.65
Period: 2.059-8.981Years
Last perihelion: December 20th, 2013
Next perihelion: June 30th, 2019
Today's astronomy anniversaries:
- Discoveries:
- None
- Events:
- 1960 (54 years ago)- China launches its first sounding rocket, the T-7.
- 2002 (12 years ago)- the Mars Odyssey begins mapping Mars in infrared.
- Births:
- 1473 (541 years ago)- Nicolaus Copernicus, a Polish astronomer who suggested that the Earth revolved around the Sun and not the other way around- is born in Toruń, Poland.
- 1932 (82 years ago)- Joseph P. Kerwin, an American astronaut on Skylab 2, is born in Oak Park, Illinois
- 1952 (62 years ago)- Rodolfo Neri Vela, a Mexican astronaut on STS-61-B, is born in Chilpancingo, Mexico.
- Deaths:
- 1553 (461 years ago)- Erasmus Reinhold, a German astronomer who made a large catalog of stars and followed the geocentric theory, dies in Saalfeld, Germany
The rings of the solar system: What formed them, their physical characteristics, and their eventual demise.
Tuesday, February 18, 2014
Comets, Centaurs, and Damocloids- oh my! an introduction to the Solar System's wide range of comets of all shapes and sizes.
Since antiquity, comets have flown past Earth towards the Sun to the awe and wonder of observers. Early on, they associated the comets with significant events, like in 43 BC, when Caesar's Comet graced the skies. As the name implies, the Romans took it as a reminder of the dead Julius Caesar, who died the year before. By the 1800s, however, people began to understand more about what comets were and how they worked, and began to study more about them. They found several periodic ones, many of which come by occasionally today. (Although some of them were subsequently lost or disintegrated, like 3D/Biela (Comet Biela), which broke into 2 pieces after the 1852 encounter and probably disintegrated later, or 5D/Brorsen (Comet Brorsen), which was last seen in 1879 after patchy observations of it.) While most of these comets have predictable orbits, their orbit often intersects with Jupiter, leading them to often change their orbit. This happened with comet 9P/Tempel (Tempel 1) in 1881, when a close approach to Jupiter lengthened the period of it from 5.68 to 6.5 years. But while the comets you see are the most common type, though, there are some different types of comet that are created by gravitational interactions with Jupiter, close approaches with the Sun, or even interactions with other stars!
First of all, while most comets are unrelated objects of completely different orbits, some all have similar orbits because they originated from another comet long ago. One of these groups of comets is called the Kreutz Sungrazers. This group is thought to be descended from a huge comet that came to Earth in 326 AD. The comet came unusually close to the sun (between 0.001 and 0.01 AU.) Later, it broke into 2 fragments that came on orbits back into the Solar System. These fragments came back in 1100 and 1106 respectively. The first comet broke further into what would later be C/1843 D1, C/1880 C1, and C/1887 B1. Meanwhile, the second comet, the larger piece, fragmented into many more comets than the first, with C/1882 R1, C/1945 X1, C/1963 R1 (Comet Pereyra), and C/1970 K1 (Comet White-Ortiz-Bolelli) being a few of its pieces. Now, comets with similar orbits appear to come near the Sun every few years now, making them the largest comet group in the Solar System.
Sometimes, close encounters with Jupiter will cause comets to enter brief orbits around it, sometimes colliding with it. The most famous example of such an encounter was Comet Shoemaker-Levy 9, which entered an orbit around Jupiter between 1960 and 1970. The comet later fractured and collided with the planet. This doesn't usually happen, however. Often, Jupiter will simply change the orbits of the comets, leading them to become Jupiter-family comets, a group of comets whose aphelion is near where Jupiter orbits.
While those are the regular 'unusual' types, there are a few more odd objects which are truly odd!
Extinct comets are simply comets that have run out of all of their ice. After numerous orbits around the Sun, they've burned off all of the H2O they had to offer. A few suspected extinct comets are 3552 Don Quixote, which will have a close encounter with a windmill or two in the next hundred years, 14827 Hypnos which seems to be sleeping right now, and 2101 Adonis, a particularly young asteroid. This type of comet is hard to find, because it's difficult to tell if an asteroid used to have ice it burned off, or if it was an asteroid the entire time, so it's likely there are several asteroids that used to be comets that we don't know about yet.
A sort of 'extinct comet' orbits further out. Named after 2060 Chiron (a centaur in Greek Mythology), Centaurs are comets that were thrown out of their orbit near the sun, and orbit in the inner Kuiper Belt and between Uranus and Neptune. These comets, unlike extinct comets, have a lot of ice still in them to burn off, but orbit too far away from the sun for this ice to vaporize and form a tail. This group has many members, including 10199 Chariklo, the largest known Centaur, and 7066 Nessus.
In between these two groups exists a type of comet called a Damocloid. Named after 5335 Damocles, these are believed to be extinct Halley-type comets. Many objects belong to this group, with semi-major axis ranging from 2 AU (2009 HC82) to over 1200 (2013 BL76 (article by me!)) These are different from extinct comets in that they have extreme orbits that make them more Halley-type or even long-period comets. Speaking of long period comets, let's get on to one of the weirdest type of comet.
Interstellar comets are-well- comets that aren't from the Solar System at all! Like rogue planets, they wander interstellar space, sometimes being pulled into a hyperbolic orbit by another star. These types of comets are rare, and there aren't any likely comets in the Solar System that could be one. Usually, this type of comet has an extreme eccentricity of 1.2 or greater (anything smaller than 1 is a recurring orbit, but 1 or greater is a parabolic orbit, or an orbit where the object won't come back again.) No comets of eccentricities of more than 1.1 have been found, making it unlikely any are interstellar comets. However, gravitational perturbations could easily disrupt their orbit. The only way to know for sure is measuring a comet's spectrum. Comets with odd emission lines, and, therefore, different chemical makeups, probably came from another star. However none of these have been found yet.
Comets are an interesting astronomical phenomenon, and are both beautiful and odd. And, even if the comet is from our own Solar System, you could say that comets are truly 'out of this world'!
 |
| Tempel 1 while it's not out-gassing. Credit: NASA/JPL/University of Maryland |
 |
| A diagram of the Kreutz Sungrazers' fracturing. Credit: Sekanina, Zdeněk; and Chodas, Paul W. |
Sometimes, close encounters with Jupiter will cause comets to enter brief orbits around it, sometimes colliding with it. The most famous example of such an encounter was Comet Shoemaker-Levy 9, which entered an orbit around Jupiter between 1960 and 1970. The comet later fractured and collided with the planet. This doesn't usually happen, however. Often, Jupiter will simply change the orbits of the comets, leading them to become Jupiter-family comets, a group of comets whose aphelion is near where Jupiter orbits.
While those are the regular 'unusual' types, there are a few more odd objects which are truly odd!
Extinct comets are simply comets that have run out of all of their ice. After numerous orbits around the Sun, they've burned off all of the H2O they had to offer. A few suspected extinct comets are 3552 Don Quixote, which will have a close encounter with a windmill or two in the next hundred years, 14827 Hypnos which seems to be sleeping right now, and 2101 Adonis, a particularly young asteroid. This type of comet is hard to find, because it's difficult to tell if an asteroid used to have ice it burned off, or if it was an asteroid the entire time, so it's likely there are several asteroids that used to be comets that we don't know about yet.
A sort of 'extinct comet' orbits further out. Named after 2060 Chiron (a centaur in Greek Mythology), Centaurs are comets that were thrown out of their orbit near the sun, and orbit in the inner Kuiper Belt and between Uranus and Neptune. These comets, unlike extinct comets, have a lot of ice still in them to burn off, but orbit too far away from the sun for this ice to vaporize and form a tail. This group has many members, including 10199 Chariklo, the largest known Centaur, and 7066 Nessus.
In between these two groups exists a type of comet called a Damocloid. Named after 5335 Damocles, these are believed to be extinct Halley-type comets. Many objects belong to this group, with semi-major axis ranging from 2 AU (2009 HC82) to over 1200 (2013 BL76 (article by me!)) These are different from extinct comets in that they have extreme orbits that make them more Halley-type or even long-period comets. Speaking of long period comets, let's get on to one of the weirdest type of comet.
Interstellar comets are-well- comets that aren't from the Solar System at all! Like rogue planets, they wander interstellar space, sometimes being pulled into a hyperbolic orbit by another star. These types of comets are rare, and there aren't any likely comets in the Solar System that could be one. Usually, this type of comet has an extreme eccentricity of 1.2 or greater (anything smaller than 1 is a recurring orbit, but 1 or greater is a parabolic orbit, or an orbit where the object won't come back again.) No comets of eccentricities of more than 1.1 have been found, making it unlikely any are interstellar comets. However, gravitational perturbations could easily disrupt their orbit. The only way to know for sure is measuring a comet's spectrum. Comets with odd emission lines, and, therefore, different chemical makeups, probably came from another star. However none of these have been found yet.
Comets are an interesting astronomical phenomenon, and are both beautiful and odd. And, even if the comet is from our own Solar System, you could say that comets are truly 'out of this world'!
02-18-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries:
2014 CS14
Discoverer: unknown
Type: Outer Main Belt asteroid
Semimajor axis: 3.398 AU
Perihelion: 2.077 AU
Aphelion: 4.72 AU
Eccentricity: 0.389
Period: 6.26 Years
Inclination: 11.135 degrees
Today's astronomy anniversaries:
2014 CS14
Discoverer: unknown
Type: Outer Main Belt asteroid
Semimajor axis: 3.398 AU
Perihelion: 2.077 AU
Aphelion: 4.72 AU
Eccentricity: 0.389
Period: 6.26 Years
Inclination: 11.135 degrees
Today's astronomy anniversaries:
- Discoveries:
- 1930 (84 years ago)- Pluto is discovered by Clyde Tombaugh (see today's post).
- Events:
- 1977 (37 years ago)- the shuttle Enterprise is carried on a Boeing 747 on its 'maiden flight'
- Births:
- None
- Deaths:
- 901 (1113 years ago)- Thābit ibn Qurra, and Iraqi Astronomer who estimated the length of the year to be 365 days, 6 hours, 9 minutes, and 12 seconds (only about 15 minutes off!) dies in Baghdad
- 1957 (57 years ago)- Henry Norris Russell, an American astronomer who worked with Ejnar Hertzsprung to make the Hertzsprung-Russell diagram, dies at Princeton, New Jersey.
the Hertzsprung-Russell diagram Credit: atlasoftheuniverse.com
Coming up later today:Comets, Centaurs, and Damocloids- oh my! The different ice-covered bodies of the Solar System.
A 'small' delay (sorry, guys): Why isn't Pluto a planet? An introduction to the Kuiper Belt and Pluto's demotion.
Just to make one thing clear at first:
Pluto's discovery was pure coincidence. The discovery of it was pretty much an accident on the part of Percival Lowell. But what exactly was this mistake, or who is Percival Lowell? Well, I'd better start from the beginning.
After Neptune was discovered in 1846 by a series of conflicting observations, which is another story, Astronomers noticed that, according to their observations, Uranus and Neptune's orbits seemed to shift slightly, which led astronomers to believe that there was another planet further out than Neptune. Over the years, this came to be popularly known as Planet X.
Meanwhile, while this was happening, astronomers had begun to realize that some comets were on periodic orbits that could be predicted to a fairly good accuracy. The most famous was Halley's comet, displaying a huge tail, to the awe of observers around the world, every 75.3 years. After this was found, astronomers began to calculate the orbits of other comets, finding many comets with fairly short periods. However, as they began to calculate the orbits, they noticed that some appeared to take much longer to go around the Sun. People began to wonder where they came from, how they got here from so far away, and why they appeared to- in some cases- be making a single orbit around the Sun before being flung into deep space. In 1950, a man named Jan Oort proposed that the comets came from an area far away from the Solar System, where numerous icy bodies orbited the Sun in very, very slow orbits. Occasionally, gravitational interactions between these bodies would catapult one onto a new orbit. Most of the time, they flew out of the Solar System, but sometimes it send them hurtling on parabolic orbits straight towards the sun. Today, this theoretical cloud of bodies is called the Oort cloud in his honor.
Astronomers thought that Planet X was from the inner Oort cloud, and that it sometimes came on an elliptical orbit to where Uranus and Neptune's orbits were. One of them, named Percival Lowell, was especially determined to find this planet. He spent the last few years of his life making calculations based on the observed discrepancies in the ice giants' orbits, and searched for the planet based on these calculations. Although he, oddly enough, actually did find Pluto in his images, he deemed it too small to be the object he was looking for and went on. Lowell never found the planet he was looking for, but the search for Planet X was not over.
A few decades later, in Burdett, Kansas, Clyde Tombaugh was working on telescopes, aspiring to a career as an Astronomer. He built his own telescopes and used the images from his telescopes to draw maps of Mars and Jupiter. After sending these images of the Lowell Observatory, they recognized his passion and talent, and hired him to look for the long-saught planet.
Tombaugh looked repeatedly in the area predicted by Lowell, searching for any sign of movement. He worked long hours in the observatory, comparing photographic plates. Finally, on February 18th, 1930, Lowell was looking at a couple of plates taken the previous month, and finally found the planet. Astronomers around the world celebrated the new discovery, and quickly began to propose names for it. The final name, however, came from an unlikely place. Venetia Burney, a girl only 11 years old, heard about the planet's discovery, suggested the name Pluto to her mother. After her mother gave the idea to the astronomers at the Lowell observatory, it was soon decided to be chosen because Pluto was the Roman god of the underworld, who had the ability to turn invisible. Plus, the first two letters of it were Percival Lowell's initials.
Pluto had a name, and the search for Planet X was complete, but it didn't end there. Astronomers making further, more detailed observations of Uranus and Neptune noticed that the observed wobbles in their orbits was only a result of bad observations. This meant that the calculations that led to the discovery of Pluto were only a mistake, and Tombaugh was just extremely lucky to find Pluto near the incorrectly predicted spot.
Meanwhile, astronomers made mass estimates of Pluto to see just how large it was, and more observations of it brought the mass from 1 Earth in 1931, to 0.1 Earths in 1948. By 1976, the estimate had dropped to 0.01, or only 1/100th Earth's mass. Meanwhile, other object in the area began to be discovered. In 1977, astronomers found a Centaur, or a frozen comet, called 2060 Chiron. It orbited from 8 to 18 Astronomical units out. While this wasn't as far out as Neptune or Pluto, it was only the second recent discovery of its kind. However, in 1992, (15760) 1992 QB1 was discovered with an orbit taking it from 40 to 47 AU out. this meant that it orbited as far out as Pluto! This led astronomers to question Pluto's special role as a planet, but observations showed the asteroid to be only about 1/9th the size of Pluto. The designation sticked.
This wasn't for long, however. In 2003, astronomer Mike Brown discovered 136199 Eris, which, due to observations, was found to be more massive than Pluto, by about 0.0007 Earths. This may not seem like much, but Pluto's mass was only 0.0028 that of Earth's. This was the only thing astronomers needed to finally demote Pluto's position.
In 2006, the International Astronomical Union decided to revise the classification of what a planet was. First, a planet must orbit around the Sun, not another planet. This means moons can not be planets. Second, a planet must be massive enough to make itself into a sphere. Semispheres like Vesta couldn't be planets even if they did fulfill the final requirement. This was that the object must have enough gravity to clear any objects with a significant mass of it out of its orbital path. While pluto fulfills the first two, it doesn't fulfill the third.
Simultaneously, astronomers created the classification of Dwarf Planet. These bodies have the first two requirements fulfilled, but not the third. Today, there are 6 of these: Ceres, Pluto, Haumea, Makemake, Eris, and Sedna. Many more objects in the Kuiper Belt are suspected dwarf planets.
Despite its current status as Dwarf Planet, Pluto has had arguably one of the most interesting histories of any of the planets in the Solar System, and is more than worthy of this title, if not being an official Planet. But, no matter whether it's classified as a Dwarf Planet, regular one, or anything else around the Sun, it was simply a matter of pure coincidence that lead to the discovery of the (almost) 9th planet...
Do you think Pluto should have been a planet?
After Neptune was discovered in 1846 by a series of conflicting observations, which is another story, Astronomers noticed that, according to their observations, Uranus and Neptune's orbits seemed to shift slightly, which led astronomers to believe that there was another planet further out than Neptune. Over the years, this came to be popularly known as Planet X.
Meanwhile, while this was happening, astronomers had begun to realize that some comets were on periodic orbits that could be predicted to a fairly good accuracy. The most famous was Halley's comet, displaying a huge tail, to the awe of observers around the world, every 75.3 years. After this was found, astronomers began to calculate the orbits of other comets, finding many comets with fairly short periods. However, as they began to calculate the orbits, they noticed that some appeared to take much longer to go around the Sun. People began to wonder where they came from, how they got here from so far away, and why they appeared to- in some cases- be making a single orbit around the Sun before being flung into deep space. In 1950, a man named Jan Oort proposed that the comets came from an area far away from the Solar System, where numerous icy bodies orbited the Sun in very, very slow orbits. Occasionally, gravitational interactions between these bodies would catapult one onto a new orbit. Most of the time, they flew out of the Solar System, but sometimes it send them hurtling on parabolic orbits straight towards the sun. Today, this theoretical cloud of bodies is called the Oort cloud in his honor.
Astronomers thought that Planet X was from the inner Oort cloud, and that it sometimes came on an elliptical orbit to where Uranus and Neptune's orbits were. One of them, named Percival Lowell, was especially determined to find this planet. He spent the last few years of his life making calculations based on the observed discrepancies in the ice giants' orbits, and searched for the planet based on these calculations. Although he, oddly enough, actually did find Pluto in his images, he deemed it too small to be the object he was looking for and went on. Lowell never found the planet he was looking for, but the search for Planet X was not over.
A few decades later, in Burdett, Kansas, Clyde Tombaugh was working on telescopes, aspiring to a career as an Astronomer. He built his own telescopes and used the images from his telescopes to draw maps of Mars and Jupiter. After sending these images of the Lowell Observatory, they recognized his passion and talent, and hired him to look for the long-saught planet.
Tombaugh looked repeatedly in the area predicted by Lowell, searching for any sign of movement. He worked long hours in the observatory, comparing photographic plates. Finally, on February 18th, 1930, Lowell was looking at a couple of plates taken the previous month, and finally found the planet. Astronomers around the world celebrated the new discovery, and quickly began to propose names for it. The final name, however, came from an unlikely place. Venetia Burney, a girl only 11 years old, heard about the planet's discovery, suggested the name Pluto to her mother. After her mother gave the idea to the astronomers at the Lowell observatory, it was soon decided to be chosen because Pluto was the Roman god of the underworld, who had the ability to turn invisible. Plus, the first two letters of it were Percival Lowell's initials.
Pluto had a name, and the search for Planet X was complete, but it didn't end there. Astronomers making further, more detailed observations of Uranus and Neptune noticed that the observed wobbles in their orbits was only a result of bad observations. This meant that the calculations that led to the discovery of Pluto were only a mistake, and Tombaugh was just extremely lucky to find Pluto near the incorrectly predicted spot.
Meanwhile, astronomers made mass estimates of Pluto to see just how large it was, and more observations of it brought the mass from 1 Earth in 1931, to 0.1 Earths in 1948. By 1976, the estimate had dropped to 0.01, or only 1/100th Earth's mass. Meanwhile, other object in the area began to be discovered. In 1977, astronomers found a Centaur, or a frozen comet, called 2060 Chiron. It orbited from 8 to 18 Astronomical units out. While this wasn't as far out as Neptune or Pluto, it was only the second recent discovery of its kind. However, in 1992, (15760) 1992 QB1 was discovered with an orbit taking it from 40 to 47 AU out. this meant that it orbited as far out as Pluto! This led astronomers to question Pluto's special role as a planet, but observations showed the asteroid to be only about 1/9th the size of Pluto. The designation sticked.
This wasn't for long, however. In 2003, astronomer Mike Brown discovered 136199 Eris, which, due to observations, was found to be more massive than Pluto, by about 0.0007 Earths. This may not seem like much, but Pluto's mass was only 0.0028 that of Earth's. This was the only thing astronomers needed to finally demote Pluto's position.
In 2006, the International Astronomical Union decided to revise the classification of what a planet was. First, a planet must orbit around the Sun, not another planet. This means moons can not be planets. Second, a planet must be massive enough to make itself into a sphere. Semispheres like Vesta couldn't be planets even if they did fulfill the final requirement. This was that the object must have enough gravity to clear any objects with a significant mass of it out of its orbital path. While pluto fulfills the first two, it doesn't fulfill the third.
Simultaneously, astronomers created the classification of Dwarf Planet. These bodies have the first two requirements fulfilled, but not the third. Today, there are 6 of these: Ceres, Pluto, Haumea, Makemake, Eris, and Sedna. Many more objects in the Kuiper Belt are suspected dwarf planets.
Despite its current status as Dwarf Planet, Pluto has had arguably one of the most interesting histories of any of the planets in the Solar System, and is more than worthy of this title, if not being an official Planet. But, no matter whether it's classified as a Dwarf Planet, regular one, or anything else around the Sun, it was simply a matter of pure coincidence that lead to the discovery of the (almost) 9th planet...
Do you think Pluto should have been a planet?
Monday, February 17, 2014
02-17-2014 Astronomy anniversaries and new asteroids
Asteroid discoveries (it seems some astronomer was very active tonight.):
2014 CK14
2014 CK14
Discoverer: unknown
Type: Hungaria asteroid
Semimajor axis: 1.9 AU
Perihelion: 1.66 AU
Aphelion: 2.14 AU
Eccentricity: 0.126
Period: 2.62 Years
Inclination: 18.927 degrees
Discoverer: unknown
Type: Hungaria asteroid
Semimajor axis: 1.845 AU
Perihelion: 1.703 AU
Aphelion: 1.987 AU
Eccentricity: 0.077
Period: 2.51 Years
Inclination: 20.306 degrees
Discoverer: unknown
Type: Hungaria asteroid
Semimajor axis: 1.91 AU
Perihelion: 1.589 AU
Aphelion: 2.23 AU
Eccentricity: 0.168
Period: 2.64 Years
Inclination: 23.953 degrees
2014 CN14
Discoverer: unknown
Type: Hungaria asteroid
Semimajor axis: 1.906 AU
Perihelion: 1.672 AU
Aphelion: 2.14 AU
Eccentricity: 0.123
Period: 2.63 Years
Inclination: 26.228 degrees
2014 CO14
Discoverer: unknown
Type: Main Belt asteroid
Semimajor axis: 1.775 AU
Perihelion: 1.685 AU
Aphelion: 1.865 AU
Eccentricity: 0.051
Period: 2.36 Years
Inclination: 24.49 degrees
2014 CP14
Discoverer: unknown
Type: Hungaria asteroid
Semimajor axis: 1.881 AU
Perihelion: 1.748 AU
Aphelion: 2.014 AU
Eccentricity: 0.071
Period: 2.58 Years
Inclination: 23.735 degrees
2014 CQ14
Discoverer: unknown
Type: Mars-crosser asteroid
Semimajor axis: 2.384 AU
Perihelion: 1.573 AU
Aphelion: 3.194 AU
Eccentricity: 0.34
Period: 3.68 Years
Inclination: 25.295 degrees
2014 CR14
Discoverer: unknown
Type: Mars-crosser asteroid
Semimajor axis: 2.466 AU
Perihelion: 1.652 AU
Aphelion: 3.28 AU
Eccentricity: 0.33
Period: 3.87 Years
Inclination: 27.165 degrees
Today's astronomy anniversaries:
Discoverer: unknown
Type: Hungaria asteroid
Semimajor axis: 1.906 AU
Perihelion: 1.672 AU
Aphelion: 2.14 AU
Eccentricity: 0.123
Period: 2.63 Years
Inclination: 26.228 degrees
2014 CO14
Discoverer: unknown
Type: Main Belt asteroid
Semimajor axis: 1.775 AU
Perihelion: 1.685 AU
Aphelion: 1.865 AU
Eccentricity: 0.051
Period: 2.36 Years
Inclination: 24.49 degrees
2014 CP14
Discoverer: unknown
Type: Hungaria asteroid
Semimajor axis: 1.881 AU
Perihelion: 1.748 AU
Aphelion: 2.014 AU
Eccentricity: 0.071
Period: 2.58 Years
Inclination: 23.735 degrees
2014 CQ14
Discoverer: unknown
Type: Mars-crosser asteroid
Semimajor axis: 2.384 AU
Perihelion: 1.573 AU
Aphelion: 3.194 AU
Eccentricity: 0.34
Period: 3.68 Years
Inclination: 25.295 degrees
2014 CR14
Discoverer: unknown
Type: Mars-crosser asteroid
Semimajor axis: 2.466 AU
Perihelion: 1.652 AU
Aphelion: 3.28 AU
Eccentricity: 0.33
Period: 3.87 Years
Inclination: 27.165 degrees
Today's astronomy anniversaries:
- Discoveries:
- None*
- Events:
- 1965 (49 years ago)- Ranger 8 launches to go to the Moon and take pictures of the Sea of Tranquility to find a suitable landing site for the Apollo missions.
- 1996 (18 years ago)- NEAR Shoemaker launches to go to asteroid 433 Eros.
- Births:
- None
- Deaths:
- 1600 (414 years ago)- Giordano Bruno, an Italian friar, philosopher, mathematician, poet, and astronomer, who followed the Copernician theory, and went as far as to say that there were many other stars, and that the Sun was just one of them, and that there are many planets orbiting those stars, which have other, extraterrestrial beings living on them- dies of being burned at the stake for heresy. :P
*Sorry about missing yesterday's article. My computer was being slow and I spent the entire afternoon running a complete bug scan. I'll try to write the article in full today.
Coming up later today:
See yesterday's 'coming up later'.
Sunday, February 16, 2014
02-16-2014 astronomy anniversaries and new asteroids
2014 CJ14
Discoverer: Pan-STARRS 1- Haleakala observatory
Semimajor axis: 1.454-1.469 AU
Perihelion: 1.143-1.149 AU
Aphelion: 1.768-1.786 AU
Eccentricity: 0.214-0.218
Inclination: 10.957-11.189 degrees
Period: 1.757-1.783 Years
Absolute magnitude: 21.04
Diameter: ~200 meters
Today's Astronomy anniversaries:
Why isn't Pluto a planet any more? An introduction to discovery of the Kuiper belt and Pluto's demotion!
Discoverer: Pan-STARRS 1- Haleakala observatory
Semimajor axis: 1.454-1.469 AU
Perihelion: 1.143-1.149 AU
Aphelion: 1.768-1.786 AU
Eccentricity: 0.214-0.218
Inclination: 10.957-11.189 degrees
Period: 1.757-1.783 Years
Absolute magnitude: 21.04
Diameter: ~200 meters
Today's Astronomy anniversaries:
- Discoveries:
- 1948 (66 years ago)- Miranda, a moon of Uranus, is discovered by Gerard P. Kuiper.
- Events:
- None
- Births:
- 1698 (316 years ago)- Pierre Bouguer, a French Hydrographer and Astronomer, who has a crater on Mars, the Moon, and an asteroid named after him, is born in Le Croisic, France.
- Deaths:
- 1531 (483 years ago)- Yohannes Stöffler, a German Astronomer, who taught Mathematics and Astronomy at the University of Tübingen for a brief time, dies of the plague.
Why isn't Pluto a planet any more? An introduction to discovery of the Kuiper belt and Pluto's demotion!
Saturday, February 15, 2014
Daily Topic:
Every day, in the afternoon (evening for some people), I'll be adding a topic on a controversial or interesting thing in the Solar System. At the end, I'll leave a question or idea for people to think and discuss about in the comments section. I hope you find it both interesting and informative at the same time.
The first image can be easily recognized as a diffraction spike caused by a nearby star, planet, or even Mars itself. However, the second image appears to be a shadow of something. Most UFO enthusiasts agree that it's a cylindrical UFO, but it could also be the shadow of an asteroid or the satellite itself from an angle. Nevertheless, the dissapearance of Phobos II hasn't been explained successfully. Beyond the mysterious disappearance, Phobos has an unusually low density for an asteroid, which could be because it's a large space ship orbiting Mars. This idea was proposed in 1958 by Iosif Samuilovich Schlovsky, but later generally accepted not to be true due to fact that measurements that brought the theory up turned out to be false through more detailed measurements. And, at any rate, there's still something that the UFO conspiracy theorists try to avoid explaining even more than the government supposedly does: Why on Earth would an advanced alien species build an obviously conspicuous satellite to orbit Mars yet put so much effort into destroying any satellites to study it?
No matter what the cause of the lines on Phobos are, whether it be crater chains, fractures, or UFOs, it's certainly an interesting topic to discuss. But what do you think is probably the most likely cause? Post your thoughts below. :)
Stay tuned for future posts tomorrow! :D
Every day, in the afternoon (evening for some people), I'll be adding a topic on a controversial or interesting thing in the Solar System. At the end, I'll leave a question or idea for people to think and discuss about in the comments section. I hope you find it both interesting and informative at the same time.
First in line
the mysterious 'scratches' on Phobos
 | ||
| A visualization of the 'lines' on Phobos. Credit: NASA |
Of all of the moons in the Solar System, you'd be hard-pressed to find an odder moon than Phobos. Not only does it have a controversial origin and the largest crater in ratio to moon size in the Solar System, but it has a series of mysterious lines traveling parallel across its surface. The origin of them is controversial, but here are a few of the leading theories, including evidence for and against them.
The most widely accepted theory is that the lines are crater chains, or a group of related impact craters caused by larger bodies' gravity pulling apart the impacting asteroid or comet.
 | |
| Enki Catena, a crater chain on Ganymede. Credit: JPL/NASA |
The lines do appear to be made up of separate strings of craters, with slight separation between them sometimes, but most of the lines are straight and all appear to come from the same side. How could that have happened?
It works similar to why we only see one side of the Moon at any one time. Phobos, along with many other satellites in the Solar System, is tidally locked with Mars, meaning that it always shows the same face. This also means that one side will always be facing 'forwards' and one side will always be facing 'backwards'. That means the forward side will most likely get more crater impacts than the backward side. The current theory is that temporary satellites caught by Mars's gravity will sometimes break apart and impact Phobos, leaving impact lines on the surface. This is the most widely accepted, but here are a few more explanations:
Another theory is that the impact that made Stickney crater, a crater on the side of Phobos, should have nearly shattered the moon, leaving only tiny pieces in a ring around Mars. However, it obviously didn't, so it's possible that the lines are actually cracks in the surface that later got filled with a layer of dust on Phobos, making them appear more like lines than cracks. This seems to hold true in that measurements by the Mars Express satellite show Phobos to have a fairly low density of 1.88 grams per cubic centimeter. For comparison, Saturn has a density of 0.687 g/cm3, and Earth has a density of 5.515 g/cm3. Based on the density, it's likely that about 30% of the moon is hollow. While that seems fairly accurate, if the cracks originated from Stickney's impact, they would probably originate from that, but observations show that the lines don't originate from Stickney. However, while this makes it less likely for that theory to be true, it doesn't prove it wrong. More observations are still needed.
The last theory (you knew this was coming) is that Phobos is actually an artificial satellite created by extraterrestrials. The lines appear to straight to be naturally-created, and many missions directly to Phobos have failed. For instance, the Russian probe Phobos II was sent to Phobos in 1988-1989, with a mission to send a lander to study the planet. However, slightly before it was set to send the lander down, it suddenly lost connection. Right before, though, it sent 2 interesting images of the area around it.
The last theory (you knew this was coming) is that Phobos is actually an artificial satellite created by extraterrestrials. The lines appear to straight to be naturally-created, and many missions directly to Phobos have failed. For instance, the Russian probe Phobos II was sent to Phobos in 1988-1989, with a mission to send a lander to study the planet. However, slightly before it was set to send the lander down, it suddenly lost connection. Right before, though, it sent 2 interesting images of the area around it.
 | |||
| The last image taken. Credit: Soyuz program |
 | ||||
| The 2nd last image taken. Credit: Soyuz program |
The first image can be easily recognized as a diffraction spike caused by a nearby star, planet, or even Mars itself. However, the second image appears to be a shadow of something. Most UFO enthusiasts agree that it's a cylindrical UFO, but it could also be the shadow of an asteroid or the satellite itself from an angle. Nevertheless, the dissapearance of Phobos II hasn't been explained successfully. Beyond the mysterious disappearance, Phobos has an unusually low density for an asteroid, which could be because it's a large space ship orbiting Mars. This idea was proposed in 1958 by Iosif Samuilovich Schlovsky, but later generally accepted not to be true due to fact that measurements that brought the theory up turned out to be false through more detailed measurements. And, at any rate, there's still something that the UFO conspiracy theorists try to avoid explaining even more than the government supposedly does: Why on Earth would an advanced alien species build an obviously conspicuous satellite to orbit Mars yet put so much effort into destroying any satellites to study it?
No matter what the cause of the lines on Phobos are, whether it be crater chains, fractures, or UFOs, it's certainly an interesting topic to discuss. But what do you think is probably the most likely cause? Post your thoughts below. :)
Stay tuned for future posts tomorrow! :D
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