Courtesy of some of the people working on the Curiosity rover mission, a Mars weather blog. (Via ![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
striped, who pointed to a related Mars weather page.)
striped, who pointed to a related Mars weather page.)After a discouraging forecast, the sky cleared, and looking out the window a bit after 9 (EST) we could clearly see the eclipse starting. We went outside together shortly before totality. The effect was weird: the moon dimmed a bit more, and then brightened, as clouds drifted away. And then they drifted back. We didn't get the red or orange color the nice people at NASA predicted (based on lack of recent major volcanic eruptions), but we enjoyed the view. There were very few other people out there; some were probably in the park, and it was a cold night.
After a discouraging forecast, the sky cleared, and looking out the window a bit after 9 (EST) we could clearly see the eclipse starting. We went outside together shortly before totality. The effect was weird: the moon dimmed a bit more, and then brightened, as clouds drifted away. And then they drifted back. We didn't get the red or orange color the nice people at NASA predicted (based on lack of recent major volcanic eruptions), but we enjoyed the view. There were very few other people out there; some were probably in the park, and it was a cold night.
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idea_fairy, you should look at today's Astronomy Picture of the Day, if you haven't already. (It's generally cool, but it made me think of you.)idea_fairy, you should look at today's Astronomy Picture of the Day, if you haven't already. (It's generally cool, but it made me think of you.)Hail Eris!
Yes, 2003 UB313, the world some blame for the "demotion" of Pluto, has an official name, and the discoverer found something better than "Xena".
Yes, 2003 UB313, the world some blame for the "demotion" of Pluto, has an official name, and the discoverer found something better than "Xena".
Tags:
Hail Eris!
Yes, 2003 UB313, the world some blame for the "demotion" of Pluto, has an official name, and the discoverer found something better than "Xena".
Yes, 2003 UB313, the world some blame for the "demotion" of Pluto, has an official name, and the discoverer found something better than "Xena".
Tags:
Via a link from New Scientist, I got to a page about Neptune's Trojan asteroids. According to the author, a handful are known, all found in the last five years. One of them, newly discovered, is in an orbit tilted 25° from the ecliptic. Which is to say, 25° from the orbit of Neptune.
As I understand it, all five of Lagrange's special-case solutions to the three-body problem involve two co-planar orbits. In the real world, there's a little slack, just as not all of Jupiter's Trojan asteroids are exactly 60° ahead or behind the planet. But 25 degrees inclination seems like a lot to count as at the Lagrangian points. Does anyone know if someone has done the math for that set of orbits? I can't see how this geometry is stable: right now, 2005 TO74 is at or near Neptune's L4 point, but eventually it's going to be 25 degrees north or south of the ecliptic; with Neptune staying in the ecliptic, and at that orbital radius, we're looking at a couple of hundred millions of kilometers north or south of the L4 point. I thought the reason the Lagrange points are interesting and potentially important is that they're small areas: a body at L4 will be consistently in the same direction, and distance, from the primary.
As I understand it, all five of Lagrange's special-case solutions to the three-body problem involve two co-planar orbits. In the real world, there's a little slack, just as not all of Jupiter's Trojan asteroids are exactly 60° ahead or behind the planet. But 25 degrees inclination seems like a lot to count as at the Lagrangian points. Does anyone know if someone has done the math for that set of orbits? I can't see how this geometry is stable: right now, 2005 TO74 is at or near Neptune's L4 point, but eventually it's going to be 25 degrees north or south of the ecliptic; with Neptune staying in the ecliptic, and at that orbital radius, we're looking at a couple of hundred millions of kilometers north or south of the L4 point. I thought the reason the Lagrange points are interesting and potentially important is that they're small areas: a body at L4 will be consistently in the same direction, and distance, from the primary.
Via a link from New Scientist, I got to a page about Neptune's Trojan asteroids. According to the author, a handful are known, all found in the last five years. One of them, newly discovered, is in an orbit tilted 25° from the ecliptic. Which is to say, 25° from the orbit of Neptune.
As I understand it, all five of Lagrange's special-case solutions to the three-body problem involve two co-planar orbits. In the real world, there's a little slack, just as not all of Jupiter's Trojan asteroids are exactly 60° ahead or behind the planet. But 25 degrees inclination seems like a lot to count as at the Lagrangian points. Does anyone know if someone has done the math for that set of orbits? I can't see how this geometry is stable: right now, 2005 TO74 is at or near Neptune's L4 point, but eventually it's going to be 25 degrees north or south of the ecliptic; with Neptune staying in the ecliptic, and at that orbital radius, we're looking at a couple of hundred millions of kilometers north or south of the L4 point. I thought the reason the Lagrange points are interesting and potentially important is that they're small areas: a body at L4 will be consistently in the same direction, and distance, from the primary.
As I understand it, all five of Lagrange's special-case solutions to the three-body problem involve two co-planar orbits. In the real world, there's a little slack, just as not all of Jupiter's Trojan asteroids are exactly 60° ahead or behind the planet. But 25 degrees inclination seems like a lot to count as at the Lagrangian points. Does anyone know if someone has done the math for that set of orbits? I can't see how this geometry is stable: right now, 2005 TO74 is at or near Neptune's L4 point, but eventually it's going to be 25 degrees north or south of the ecliptic; with Neptune staying in the ecliptic, and at that orbital radius, we're looking at a couple of hundred millions of kilometers north or south of the L4 point. I thought the reason the Lagrange points are interesting and potentially important is that they're small areas: a body at L4 will be consistently in the same direction, and distance, from the primary.
Today's Astronomy Picture of the Day is an entire cluster of mini-comets, each with its own coma and tail; collectively, they are Fragment B of Comet P73/Schwassman-Wachmann 3.
Today's Astronomy Picture of the Day is an entire cluster of mini-comets, each with its own coma and tail; collectively, they are Fragment B of Comet P73/Schwassman-Wachmann 3.
Herein I correct the BBC, just to be polite:
Cruithne is very cool, but it's not a moon. The people who figured out what it's doing are very clear on this, but the BBC messed up, and lots of people are now quoting their error.
Cruithne doesn't orbit Earth--it orbits the Sun, doing weird horseshoes around Earth's orbit. This is one of the weirder known solutions to the three-body problem, one spotted mathematically long before it was observed out there in the real world. Now that they know what to look for, they've found two more asteroids in similar resonant orbits, but haven't published details yet.
See http://www.astro.queensu.ca/~wiegert/3753/3753.html for more information.
Cruithne is very cool, but it's not a moon. The people who figured out what it's doing are very clear on this, but the BBC messed up, and lots of people are now quoting their error.
Cruithne doesn't orbit Earth--it orbits the Sun, doing weird horseshoes around Earth's orbit. This is one of the weirder known solutions to the three-body problem, one spotted mathematically long before it was observed out there in the real world. Now that they know what to look for, they've found two more asteroids in similar resonant orbits, but haven't published details yet.
See http://www.astro.queensu.ca/~wiegert/3753/3753.html for more information.
Herein I correct the BBC, just to be polite:
Cruithne is very cool, but it's not a moon. The people who figured out what it's doing are very clear on this, but the BBC messed up, and lots of people are now quoting their error.
Cruithne doesn't orbit Earth--it orbits the Sun, doing weird horseshoes around Earth's orbit. This is one of the weirder known solutions to the three-body problem, one spotted mathematically long before it was observed out there in the real world. Now that they know what to look for, they've found two more asteroids in similar resonant orbits, but haven't published details yet.
See http://www.astro.queensu.ca/~wiegert/3753/3753.html for more information.
Cruithne is very cool, but it's not a moon. The people who figured out what it's doing are very clear on this, but the BBC messed up, and lots of people are now quoting their error.
Cruithne doesn't orbit Earth--it orbits the Sun, doing weird horseshoes around Earth's orbit. This is one of the weirder known solutions to the three-body problem, one spotted mathematically long before it was observed out there in the real world. Now that they know what to look for, they've found two more asteroids in similar resonant orbits, but haven't published details yet.
See http://www.astro.queensu.ca/~wiegert/3753/3753.html for more information.
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