This is debris from Comet Halley, the most famous of all short-period comets. Dawn this morning was actually the best time to look, but it’s a fairly drawn-out shower, so tomorrow morning should be worth a look-see as well, if your weather is cooperating — though bear in mind that it’s not one of the heavier showers. You might see a handful in a hour, or 25 if you’re very lucky and in a very nice dark sky location. The radiant point of this shower is in the constellation Orion, which is one of the easiest to recognize in the night sky. If you are looking at Orion, and his belt is in the middle with Betelgeuse (the reddish one) to the upper left, the radiant will be up and to the left of there.
It doesn’t look like much, but here, taken by the venerable Mars Exploration Rover Opportunity’s Panoramic Camera is Comet Siding Spring. The speckles you see throughout the image are not stars; they’re just noise. But the stars are there, as streaks. PanCam isn’t really optimized for night viewing. It appears the mission team programmed it to track the comet’s predicted motion, because you can see star trails. The comet itself, meanwhile, is a distinct smudge in the middle of the image. There’s also what might be a meteor towards the bottom of the image, though it could also be noise as well. Still, meteors were expected to be likely during the comet encounter, because its dusty coma was expected to brush the planet’s atmosphere.
It might not look like much (there are better comet images from Earth), but as far as I know it’s the first image of a comet from the surface of another world.
The three NASA orbiters are in good health after the Comet Siding Spring encounter; awaiting word on Mars Express and Mangalyaan/Mars Orbiter Mission and the two landers. It takes a great deal of time for high-quality images to come back, but over the next week all seven of the spacecraft at Mars will report in with their findings, and then the interesting science can begin. ;-)
The view may be more disappointing than hoped; Comet Siding Springs had a nice outburst a few weeks ago, but has been fading since then. And I’ve been watching Curiosity’s raw images; looks like things are still quite dusty, and although it has successfully photographed stars, I wonder if the delicate structure of a comet will come through that? I guess we’ll find out. ;-)
Astronomers around the world are getting to watch an amazing event tomorrow — a very close flyby of Mars by Comet Siding Spring. Normally, this would be just a curiosity (since astronomers have ruled out the possibility of a collision) but this is a very fortuitous time for the encounter — two ground vehicles (Opportunity and Curiosity) and five orbiters (Mars Odyssey 2001, Mars Express, Mars Reconnaissance Orbiter, MAVEN, and Mangalyaan/Mars Orbiter Mission) are all ready to observe. MAVEN is particularly fortuitous; it’s specialized for atmospheric observations, which makes it unusually well-equipped for this chance encounter with a comet’s tail.
Because yes, Mars is expected to pass through the comet’s tail. It’s pretty awesome, and the view from Curiosity in particular should be spectacular. (Curiosity is better equipped for night viewing, since it is nuclear powered and doesn’t need to conserve its batteries overnight.) NASA’s GSFC has released this video highlighting the experience:
It won’t just be the seven vehicles at Mars observing the comet. Other instruments, including the Hubble Space Telescope and STEREO-A, will also be watching, as will ground-based observers here on Earth. Amateurs with larger telescopes (8″ or better) and favorable weather will be able to follow the comet as it approaches and passes the red planet.
I can’t wait to see the pictures. ;-)
And if that weren’t exciting enough, the Orionids are starting up. That’s debris from Comet Halley, and it will peak in a few days. And on Thursday, many of us in North America (not all, alas) will be treated to a very nice partial solar eclipse. It’s a good week!
Update: video of today’s landing is now up!
The first X-37B spacecraft has returned from its second trip into space (third for the program, as there are two vehicles), which lasted a record-setting 675 days, the greatest duration for any reusable spacecraft. It landed at Vandenberg AFB in Florida this morning. This is expected to be its final landing in Florida; the Air Force has leased one of the old Space Shuttle bays at the Orbiter Processing Facility at Kennedy Space Center to be its new home, and future landings are expected to take place on the Shuttle Landing Facility strip. This will be a money-saving move to avoid having to ship it across the entire continent between flights. X-37B is cheaper to move than Shuttle was, but it’s still a substantial expense.
Here’s the video of today’s landing:
Scientists have expected for a long time that water ice might be found in the permanently shadowed recesses of Mercurian craters, but nobody’s ever actually seen any — until now. In Kadinsky Crater, near the north pole of Mercury, the MESSENGER spacecraft has spotted ice. It was able to photograph the ice because although the crater is permanently shaded, it isn’t in complete darkness; reflected sunlight from the crater rim does dimly illuminate it. It’s still very dark, but it’s enough for MESSENGER’s Wide Angle Camera, with the right camera settings.
Water is turning out to be a bit more ubiquitous than we’d realized, even in the innermost parts of the solar system.