Using images of comet Holmes gathered from a Yahoo! image search, astronomers have calculated the comet’s orbit.
Colors of the Wind
Comets don’t have strong magnetic fields, so how do they create a magnetosphere that resists the solar wind?
Easy Being Green
Yes, comet Lovejoy is really green, and its all due to the molecules in its tail.
Lovejoy
This year starts off with a naked eye comet known as Lovejoy (or C/2014 Q2, for those who like to be specific). It’s a long period comet first observed by Terry Lovejoy back in August. The comet isn’t particularly bright, being just within naked-eye range at magnitude 5. But it happens to be near the celestial equator, and even near the constellation Orion, so it is widely observable. Most people will require a small telescope or pair of binoculars to see it, but it isn’t difficult to find.
A Comet’s Tale
Results are starting to come in from the Rosetta mission, including a new article in Science on the composition of water on the comet 67P/C-G. The results support the idea that Earth’s water didn’t come from cometary bombardments.
Song for a Comet
So we’ve sent a spacecraft into space, put it in orbit near a comet, landed on it with a smaller probe, and listened to the comet’s song. What an amazingly human thing to do.
A Holmes Mystery
In 2007 Comet Holmes gained notoriety when it suddenly brightened from magnitude 17 to magnitude 3 in about two days. This made it visible to the naked eye under clear dark skies. The coma (the cloud-like feature surrounding the icy/rocky nucleus) expanded by a factor of four by the end of October, and this once faint object began to look like a traditional comet. We aren’t exactly sure why.
Lost Comet
This week comet Siding Spring (also known as C/2013 A1) made a close approach to Mars. It’s not a particularly bright comet, but it was close enough for the Opportunity rover to take an image of it from the martian surface. Think on that one just a bit. We have robots on Mars doing comet photography now. At closest approach, Siding Spring was about 140,000 km from the center of Mars. If it had made a similar pass by Earth it would have been about half the distance to the Moon.
Orbital Dynamics
If you ever happen to meet someone who does this kind of orbital logistics, shake their hand and say thanks. Without their work our spacecraft wouldn’t arrive at their destination, and we wouldn’t have the opportunity to do some awesome science.