Hello again. Previously, I've just been posting planetaryscience-related articles, but now I need you to help me with something!
For a while, I've noticed that there's no central, easily-navigable database on comets for people to browse, and if there is one, it's not seen very often. So, I've decided to start working on a 'list of comets by type' on Wikipedia. I've made good progress, getting up to C/1913 R1 as of now, but the progress is continuing slowly, and I'll need your help to help me compile the list!
Here's how you can help:
First, no Wikipedia account is required, but one would be required to receive recognition for it. Minimal HTML experience is required, along with being able to follow basic rules and guidelines:
First of all, I'm getting my work from the JPL Small-Body Database Browser, searching for comets using the search term "C/19*" to search for every non-periodic comet found in 1900. But how do you work?
Well, Here is my main workplace, full of unfinished projects that I should really get around to. Just go start editing the table there, and I'll give some guidelines if you still need help there. Thanks for the help!
I'll be posting about the final 'rings' post on the weekend, so stay tuned!
Friday, March 28, 2014
Thursday, March 27, 2014
not so large now. The rings of Uranus
Continuing from my previous post of the rings of Saturn, we'll keep going out to the last 2 planets with rings: Uranus and Neptune.
First of all, I apologize for the delayed post; I came back late yesterday and didn't have much time, and spent the rest of the day messing around with imgur and writing this: Enjoy!
Uranus's rings, unlike the inner gas giants, are very thin and dim. The ε ring, the brightest of the rings, is only a fraction of Saturns' rings brightness. Despite these obvious differences, we'll list the rings as regular from closest to Uranus to furthest.
The ζ & 1986U2R rings
The rings begin pretty much as soon as Uranus ends. The ζcc ring, the closest of the rings, is one of a couple of extensions of the ζ (Zeta) ring orbiting, in full, between 26,840 and 41,350 kilometers from the center of Uranus (~1,300-15,800 km from the surface.) Aside from being the closest, however, it isn't exactly the brightest. The ring is around 100 times fainter than the brightest ring in the system usually, but is very bright if looked at the right way (no, not like those 3D paintings). Since nearby 1986U2R's discovery in 1986, though, the ring has moved in slightly. These rings are fairly dynamic, unlike Saturn's, changing over the course of mere months or years.
The numbered (4, 5, and 6) rings
Slightly further out from the ζ ring, we find a system of bright, narrow rings elevated slightly from Uranus's equatorial plane. These rings were designated the 6, 5, and 4 rings radiating out from the surface for lack of an appropriate Greek symbol. These rings, unlike the ζ ring, don't have much dust in them.
The α & β rings
These rings are the first of the Greek-lettered rings, but unfortunately not the last. These rings are the 2nd and 3rd brightest after the ε ring, but for some reason don't have any dust in them. They are each about half the mass of the brighter ε ring.
More Greek alphabetics: the η ring, ηc ring, and γ ring
The next few rings on our journey are all narrow and a bit dim, but that doesn't make them any less fun. The η ring is pretty dense, but the ηc ring is more broad and dim. The γ ring is much more eccentric than the other rings, and slightly wider than the η ring.
Done yet? the δc and δ rings, and why not add in the λ and ε, too?
These rings, comprising the outer parts of Uranus's thin section of the ring system, also mark the beginning of the moons. Circling just inside the λ ring is Cordelia, only about 40 km across. Despite its small size, it's still large enough to pack a bit of a punch on the ring, acting as its inner Shepard moon. Furthest out and brightest is the ε ring, also one of the largest in the system. The outer Shepard moon for this ring is Ophelia, larger than Cordelia by only 3 kilometers.
The ν ring
Not last, or least, comes the ν ring. This ring, much dimmer than the other rings, is one of two outer very dusty rings. The ring, discovered in 2003-5, is clearly bordered by the moons Portia and Rosalind (inside and outside respectively.) The ring is much larger and broader than all of the other rings closer to Uranus than it, and doesn't appear to be changing much.
Last, and least, the μ ring
The furthest of Uranus's rings, the μ ring, orbits the planet at more than twice the distance of the ε ring, and also has a few guides of its own: Puck, the largest of the inner moons, orbits on the inner part of the ring, and slightly smaller Mab orbits the ring near the center, where it's brightest. This ring, in unlike the red ν ring, is blue in color, probably made of water ice from minor collisions and/or geysers on Mab, and then slowly traveling inwards until it is picked up by Puck's gravity.
Well, that's it. Hope you enjoyed!
P.S. I made a diagram of the rings:
Enlarged (inner halo rings):
Enlarged (thin, central rings):
Enlarged (v ring and surrounding moons):
Enlarged (μ ring):
First of all, I apologize for the delayed post; I came back late yesterday and didn't have much time, and spent the rest of the day messing around with imgur and writing this: Enjoy!
Uranus's rings, unlike the inner gas giants, are very thin and dim. The ε ring, the brightest of the rings, is only a fraction of Saturns' rings brightness. Despite these obvious differences, we'll list the rings as regular from closest to Uranus to furthest.
The ζ & 1986U2R rings
The rings begin pretty much as soon as Uranus ends. The ζcc ring, the closest of the rings, is one of a couple of extensions of the ζ (Zeta) ring orbiting, in full, between 26,840 and 41,350 kilometers from the center of Uranus (~1,300-15,800 km from the surface.) Aside from being the closest, however, it isn't exactly the brightest. The ring is around 100 times fainter than the brightest ring in the system usually, but is very bright if looked at the right way (no, not like those 3D paintings). Since nearby 1986U2R's discovery in 1986, though, the ring has moved in slightly. These rings are fairly dynamic, unlike Saturn's, changing over the course of mere months or years.
 |
| An image of the 1986U2R ring showing its irregular ring arcs and ever- changing shape. Credit: NASA |
Slightly further out from the ζ ring, we find a system of bright, narrow rings elevated slightly from Uranus's equatorial plane. These rings were designated the 6, 5, and 4 rings radiating out from the surface for lack of an appropriate Greek symbol. These rings, unlike the ζ ring, don't have much dust in them.
The α & β rings
These rings are the first of the Greek-lettered rings, but unfortunately not the last. These rings are the 2nd and 3rd brightest after the ε ring, but for some reason don't have any dust in them. They are each about half the mass of the brighter ε ring.
More Greek alphabetics: the η ring, ηc ring, and γ ring
The next few rings on our journey are all narrow and a bit dim, but that doesn't make them any less fun. The η ring is pretty dense, but the ηc ring is more broad and dim. The γ ring is much more eccentric than the other rings, and slightly wider than the η ring.
Done yet? the δc and δ rings, and why not add in the λ and ε, too?
These rings, comprising the outer parts of Uranus's thin section of the ring system, also mark the beginning of the moons. Circling just inside the λ ring is Cordelia, only about 40 km across. Despite its small size, it's still large enough to pack a bit of a punch on the ring, acting as its inner Shepard moon. Furthest out and brightest is the ε ring, also one of the largest in the system. The outer Shepard moon for this ring is Ophelia, larger than Cordelia by only 3 kilometers.
The ν ring
Not last, or least, comes the ν ring. This ring, much dimmer than the other rings, is one of two outer very dusty rings. The ring, discovered in 2003-5, is clearly bordered by the moons Portia and Rosalind (inside and outside respectively.) The ring is much larger and broader than all of the other rings closer to Uranus than it, and doesn't appear to be changing much.
Last, and least, the μ ring
The furthest of Uranus's rings, the μ ring, orbits the planet at more than twice the distance of the ε ring, and also has a few guides of its own: Puck, the largest of the inner moons, orbits on the inner part of the ring, and slightly smaller Mab orbits the ring near the center, where it's brightest. This ring, in unlike the red ν ring, is blue in color, probably made of water ice from minor collisions and/or geysers on Mab, and then slowly traveling inwards until it is picked up by Puck's gravity.
Well, that's it. Hope you enjoyed!
P.S. I made a diagram of the rings:
 |
| A diagram of Uranus's rings. Credit: Me |
 |
| The inner rings of Uranus Credit: Me |
 |
| The bright, central rings of Uranus. Credit: Me |
 |
| Uranus's v ring and the numerous moons around it. Credit: Me |
 |
| The μ ring in all its boring glory. Credit: Me |
Friday, March 21, 2014
[3-5 days later]
Hey there, guys! I'll be going on vacation for the next few days, and when I get back, I'll be continuing with my dragged-out topic on rings with Uranus! Stay tuned till later, and thanks for still visiting the blog! :D
Tuesday, March 18, 2014
When an asteroid isn't an asteroid: the false alarms of fake asteroids.
Face it, You couldn't exactly call astronauts 'clean'.
Space missions, whether manned or unmanned, most always leave debris behind, whether if its when astronomers decide to let a telescope disintegrate in the atmosphere, or if STS-32's external tank had a few pieces break off before tumbling into the ocean.
To tell the truth, we've launched over 8,000 objects into space, and currently have about 1,000,000 pieces of debris in orbit of Earth. Most of these are small, only a few millimeters across, but occasionally some of these are a good 10 feet (3 meters) Across.
So, what does all of this have to do with asteroids? Well, to put it simply, we're sometimes just plain idiots.
On September 3rd, 2002, an amateur astronomer, Bill Yeung, found an asteroid that appeared to be in orbit around Earth. Of course, astronomers were surprised by this, because the only natural satellite in orbit of Earth was the Moon! (see previous post) Of course, they were right. After analyzing the object's orbital path and spectrum, they discovered it to have been S-4B stage of Apollo 12, which was intended to orbit the sun, but a small error in the rocket procedure left the stage in orbit for over 30 years! Soon, however, the rocket left Earth orbit to come near it 40 years later.
Of course, this is nothing new: In 2006, the Catalina Sky Survey discovered an asteroid orbiting outside the Moon's orbit around Earth, and was quickly found to have the spectra of the paint found on Saturn V rockets. This asteroid/satellite has the most stable orbit of any orbiting earth: it has been in a relatively stable orbit for 11 to 13 years!
If you thought all of this was crazy, you're in for a surprise:
Astronomers searching for near-earth asteroids (NEO's) found an 'asteroid' in 2007 that would make a very, very close encounter with Earth. At first they were worried- until they found out it was the Rosetta spacecraft, mistakenly designated 2007 VN84.
While numerous of these encounters have happened, I'm not going to mention them all, and just restate the main point:
We're sometimes just plain idiots.
I hope you found this article informative.
Space missions, whether manned or unmanned, most always leave debris behind, whether if its when astronomers decide to let a telescope disintegrate in the atmosphere, or if STS-32's external tank had a few pieces break off before tumbling into the ocean.
To tell the truth, we've launched over 8,000 objects into space, and currently have about 1,000,000 pieces of debris in orbit of Earth. Most of these are small, only a few millimeters across, but occasionally some of these are a good 10 feet (3 meters) Across.
So, what does all of this have to do with asteroids? Well, to put it simply, we're sometimes just plain idiots.
On September 3rd, 2002, an amateur astronomer, Bill Yeung, found an asteroid that appeared to be in orbit around Earth. Of course, astronomers were surprised by this, because the only natural satellite in orbit of Earth was the Moon! (see previous post) Of course, they were right. After analyzing the object's orbital path and spectrum, they discovered it to have been S-4B stage of Apollo 12, which was intended to orbit the sun, but a small error in the rocket procedure left the stage in orbit for over 30 years! Soon, however, the rocket left Earth orbit to come near it 40 years later.
Of course, this is nothing new: In 2006, the Catalina Sky Survey discovered an asteroid orbiting outside the Moon's orbit around Earth, and was quickly found to have the spectra of the paint found on Saturn V rockets. This asteroid/satellite has the most stable orbit of any orbiting earth: it has been in a relatively stable orbit for 11 to 13 years!
If you thought all of this was crazy, you're in for a surprise:
Astronomers searching for near-earth asteroids (NEO's) found an 'asteroid' in 2007 that would make a very, very close encounter with Earth. At first they were worried- until they found out it was the Rosetta spacecraft, mistakenly designated 2007 VN84.
While numerous of these encounters have happened, I'm not going to mention them all, and just restate the main point:
We're sometimes just plain idiots.
I hope you found this article informative.
Is the Moon alone?- the search for other satellites of Earth
For millenia, from the earliest of civilizations to now, people have looked up into the sky at night, and saw, along with the milky way's faint smudge, and the occasional meteor shower or comet, the only thing in the sky that lit up the night around them: the Moon.
Unlike the other planets, however, since the Moon was first studied in detail, it's been known to orbit the Earth (although not exactly found by the same methods, as in the Geocentric model.)
For a slightly shorter time, people have also looked up and wondered if the Moon was accompanied by anything else orbiting the Earth. Here are a few of the more notable discoveries:
The first, and most popular claim of another moon, was in 1846, when Frederic Petit made a 'not-so-tiny' claim of another moon in orbit of Earth. According to him, the moon orbited Earth about every 2 3/4 hours, and orbited only 11.4 kilometers (7.1 miles) off the Earth's surface, based on visual perturbations of the Moon's orbit. While his theory was grounded through research, however, we know this definitely not to be true: First of all, if the moon orbits only 7 miles off the surface of Earth, then here's what it would look like:
Not only this an unrealistic orbit, and not only are the crust deviations in Earth's surface enough to have this place hit Mt. Everest or something else in the Himalayas, but it's so close that not only would it orbit inside the atmosphere, but it orbits low enough that average commercial jets should have collided with it by now.
Even with all these inaccuracies, the asteroid still managed to get mentioned in Jules Verne's Around the Moon.
5 decades later, another astronomer proposed a slightly-more-believable, but also problem-ridden theory: He proposed not one, but a moon with moons orbiting it, orbiting Earth- at 1,030,000 kilometers (640,000 miles) away from Earth, and 700 kilometers (430 miles) wide, that orbits the Earth in 119 days.
Here's the a-bit-more-realistic orbital diagram:
His explanation for why it hadn't been seen before, however, was a bit of a stretch:
He claimed that the moon was very dim, except for an hour when it shines like the Sun. Wouldn't it have been noticed before, however?
Soon, after a prediction that it would become exceedingly bright in February 1898, unsurprisingly missed, the moon was found to be nonexistent.
As if that wasn't enough, he proposed another, slightly larger and closer moon in August 1898. Here's the same diagram with this other moon:
This moon was rejected so predictably and unsurprisingly that the fact that I had to say this fact was pretty much pointless because the moon's nonexistence was already assumed by the reader long before I even started on this long, drawn-out sentence.
While numerous other (fake) moons were proposed during the rest of the early to mid 20th century, let's just move on to ones with more scientific grounding:
Date: February 9th, 1913, 7:00 PM
All over eastern and North America, people are leaving their late-night jobs and returning home, having dinner, and going to bed, in various stages. Over most of the east coast, it's overcast, nothing out of the regular. In Canada and the northern USA, however, it's fairly clear.
Date: February 9th, 1913, 8:50 PM
Most of the Eastern United States and Canada is asleep, with only a few avid astronomers, insomniacs, and night-shift workers awake. The night is still continuing as usual, with nothing special appearing to happen.
Date: February 9th, 1913, about 9:15 PM
A few minutes after the clock hits 9:00, people begin to notice a series of bright fireballs traveling towards them from the northwest. As another minute ticks by, the observers count between 5 and 10 of these fireballs traveling slowly across the sky, taking about 40 seconds to pass by. As more of these go by, more keep coming, bringing the total from 10, to 20, to 30, to 50. By the end of 5 minutes, the observers across the Northeastern USA and southern Canada were nearly done witnessing the procession, but they were just about to be in for the most spectacular part:
Date: February 9th, 1913, about 9:20 PM
The trail is nearly finished, but at the back is a bright, white, huge fireball traveling slowly behind them. While the other fireballs slowed down and sped up, eventually disintegrating, this fireball kept burning brightly for nearly a minute, eventually passing over the horizon, bringing an end to that night 's chaos.
Date: February 10th, 1913, 2:20 AM
Observers jolted awake by the meteors who stayed awake all night to see if anything else would happen were not disappointed: 5 hours later, a dimmer meteor procession came over the area, although not nearly as bright as the original- possibly the debris coming a full revolution around. Based on this, the meteorites were traveling 8,020 kilometers (4,980 miles) per hour, or nearly 2 kilometers per second.
Date: February 10th, 1913, the following morning.
As newspapers and emergency phone lines are piled with reports of 'the end of the world', people struggle to find out what actually happened: Many reported a loud, thundering noise, and many more thought it to be unidentified flying objects.
Current analysis shows that the procession could have been the orbital decay of a temporary satellite captured by the Earth, or possibly even the last remnants of a temporary ring around Earth! However, we may never know exactly what did cause it.
Jump forward 93 1/2 years, and in Tuscon, Arizona, at the Catalina Sky Survey telescope, astronomers find a new asteroid, designated 2006 RH120, that is unlike any other asteroid found before:
It was a moon of Earth.
The asteroid, 3-6 meters across, typically orbited the Sun near Earth, but in September of 2006, made a very close approach to Earth and was captured into orbit of it.
By June 2007, however, perturbations by the Moon and Earth threw the asteroid back into orbit of the Sun, where it is now.
Here are a couple of other honerable mentions that don't really count as 'satellites' exactly:
In 2010, the WISE team found a Trojan asteroid- an asteroid that orbits near a planet's Lagrangian points, where they can have a stable orbit without gravitational pushes and pulls from another planet- designated 2010 TK7. These sort of bodies are common around Jupiter and Saturn- but this one was found near Earth. It is the first, and only asteroid to be a Trojan of Earth, although it doesn't exactly 'orbit' Earth, it shares an orbit with it around the Sun.
Then there's the slightly-more complicated type of minor planet, called a quasi-satellite. These asteroids orbit the Sun at the exact same amount of time as Earth, but don't share an orbit. Currently, there are 5 of these: 3753 Cruithne (see image below), 2002 AA29, (164207) 2004 GU9, (277810) 2006 FV35, and 2010 SO16. All of these asteroids will probably move out of this orbit soon, but for the moment technically 'orbit Earth'.
So, to summarize: Searches for other moons around earth have mostly turned out not to be very fruitful, and while some objects may get into temporary orbits of Earth, most never stay. While Mars may have two, Jupiter may have over 60, and many more orbiting other planets, Earth will always have a single, special satellite that we call the Moon.
Unlike the other planets, however, since the Moon was first studied in detail, it's been known to orbit the Earth (although not exactly found by the same methods, as in the Geocentric model.)
For a slightly shorter time, people have also looked up and wondered if the Moon was accompanied by anything else orbiting the Earth. Here are a few of the more notable discoveries:
The first, and most popular claim of another moon, was in 1846, when Frederic Petit made a 'not-so-tiny' claim of another moon in orbit of Earth. According to him, the moon orbited Earth about every 2 3/4 hours, and orbited only 11.4 kilometers (7.1 miles) off the Earth's surface, based on visual perturbations of the Moon's orbit. While his theory was grounded through research, however, we know this definitely not to be true: First of all, if the moon orbits only 7 miles off the surface of Earth, then here's what it would look like:
 |
| Badly/quickly-drawn picture of Earth showing the proposed orbit of the satellite to-scale (Top) [MS paint ftw] |
Even with all these inaccuracies, the asteroid still managed to get mentioned in Jules Verne's Around the Moon.
5 decades later, another astronomer proposed a slightly-more-believable, but also problem-ridden theory: He proposed not one, but a moon with moons orbiting it, orbiting Earth- at 1,030,000 kilometers (640,000 miles) away from Earth, and 700 kilometers (430 miles) wide, that orbits the Earth in 119 days.
Here's the a-bit-more-realistic orbital diagram:
 | ||
| Diagram showing the Earth, and the orbit of the Moon (to scale) and
the orbit of the 2nd proposed moon, twice as far away.
|
He claimed that the moon was very dim, except for an hour when it shines like the Sun. Wouldn't it have been noticed before, however?
Soon, after a prediction that it would become exceedingly bright in February 1898, unsurprisingly missed, the moon was found to be nonexistent.
As if that wasn't enough, he proposed another, slightly larger and closer moon in August 1898. Here's the same diagram with this other moon:
 |
| Diagram showing slightly-smaller orbit of the 3rd moon. |
While numerous other (fake) moons were proposed during the rest of the early to mid 20th century, let's just move on to ones with more scientific grounding:
Date: February 9th, 1913, 7:00 PM
All over eastern and North America, people are leaving their late-night jobs and returning home, having dinner, and going to bed, in various stages. Over most of the east coast, it's overcast, nothing out of the regular. In Canada and the northern USA, however, it's fairly clear.
Date: February 9th, 1913, 8:50 PM
Most of the Eastern United States and Canada is asleep, with only a few avid astronomers, insomniacs, and night-shift workers awake. The night is still continuing as usual, with nothing special appearing to happen.
Date: February 9th, 1913, about 9:15 PM
A few minutes after the clock hits 9:00, people begin to notice a series of bright fireballs traveling towards them from the northwest. As another minute ticks by, the observers count between 5 and 10 of these fireballs traveling slowly across the sky, taking about 40 seconds to pass by. As more of these go by, more keep coming, bringing the total from 10, to 20, to 30, to 50. By the end of 5 minutes, the observers across the Northeastern USA and southern Canada were nearly done witnessing the procession, but they were just about to be in for the most spectacular part:
Date: February 9th, 1913, about 9:20 PM
The trail is nearly finished, but at the back is a bright, white, huge fireball traveling slowly behind them. While the other fireballs slowed down and sped up, eventually disintegrating, this fireball kept burning brightly for nearly a minute, eventually passing over the horizon, bringing an end to that night 's chaos.
Date: February 10th, 1913, 2:20 AM
Observers jolted awake by the meteors who stayed awake all night to see if anything else would happen were not disappointed: 5 hours later, a dimmer meteor procession came over the area, although not nearly as bright as the original- possibly the debris coming a full revolution around. Based on this, the meteorites were traveling 8,020 kilometers (4,980 miles) per hour, or nearly 2 kilometers per second.
Date: February 10th, 1913, the following morning.
As newspapers and emergency phone lines are piled with reports of 'the end of the world', people struggle to find out what actually happened: Many reported a loud, thundering noise, and many more thought it to be unidentified flying objects.
Current analysis shows that the procession could have been the orbital decay of a temporary satellite captured by the Earth, or possibly even the last remnants of a temporary ring around Earth! However, we may never know exactly what did cause it.
Jump forward 93 1/2 years, and in Tuscon, Arizona, at the Catalina Sky Survey telescope, astronomers find a new asteroid, designated 2006 RH120, that is unlike any other asteroid found before:
It was a moon of Earth.
The asteroid, 3-6 meters across, typically orbited the Sun near Earth, but in September of 2006, made a very close approach to Earth and was captured into orbit of it.
By June 2007, however, perturbations by the Moon and Earth threw the asteroid back into orbit of the Sun, where it is now.
Here are a couple of other honerable mentions that don't really count as 'satellites' exactly:
In 2010, the WISE team found a Trojan asteroid- an asteroid that orbits near a planet's Lagrangian points, where they can have a stable orbit without gravitational pushes and pulls from another planet- designated 2010 TK7. These sort of bodies are common around Jupiter and Saturn- but this one was found near Earth. It is the first, and only asteroid to be a Trojan of Earth, although it doesn't exactly 'orbit' Earth, it shares an orbit with it around the Sun.
Then there's the slightly-more complicated type of minor planet, called a quasi-satellite. These asteroids orbit the Sun at the exact same amount of time as Earth, but don't share an orbit. Currently, there are 5 of these: 3753 Cruithne (see image below), 2002 AA29, (164207) 2004 GU9, (277810) 2006 FV35, and 2010 SO16. All of these asteroids will probably move out of this orbit soon, but for the moment technically 'orbit Earth'.
 | |
| Diagram showing the orbit of Cruithne coinciding with the orbit of Earth Credit: Various, including the Celestia program, GDFL, and Wikipedia user Jecowa. |
So, to summarize: Searches for other moons around earth have mostly turned out not to be very fruitful, and while some objects may get into temporary orbits of Earth, most never stay. While Mars may have two, Jupiter may have over 60, and many more orbiting other planets, Earth will always have a single, special satellite that we call the Moon.
Monday, March 17, 2014
Back from the dead
Hey guys, sorry for not posting on the blog for a while. After learning how many asteroids the IAU finds every single day (about 50!), I've been discouraged from posting them, so will continue the blog now without posting those, and, due to timing issues, I'll probably miss a scheduled post now and then (as I've demonstrated before) but at any rate, the blog is not going to die like this, with me to see it here. Don't worry guys, life will continue as usual here with another post late today or early tomorrow.
stay tuned for more updates from the blog that came back from the dead! ;)
stay tuned for more updates from the blog that came back from the dead! ;)
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