Posts Tagged ‘comets’

Hang On, Philae!

Posted by Zoe on 12th November 2014 in Exogeology, Main Page

Could you land on a comet? Normally, the force of gravity holds a lander to the surface of a larger body, like a planet or a moon. The less mass an object has, the less gravity pulls you toward it. Comets are small. Gravity won’t do you a lot of good, so you would need to hang on tight.

That’s what Philae is doing. The European Space Agency (ESA) sent a spacecraft named Rosetta to Comet 67P/Churyumov–Gerasimenko, and Rosetta carried a dishwasher-sized probe called Philae, which was to land on the comet. The comet is about the size of a mountain, which may seem big, but think how small a mountain is in comparison to a planet! The Philae lander had to come equipped with screws in its feet and harpoons to grasp the surface.

Philae detached from Rosetta early this morning (09:03 GMT, 02:03 Arizona time) and began its descent. Curiosity had seven minutes of terror landing on Mars, but Philae took seven hours from separation to landing. At 16:03 GMT, ESA heard from the little lander. Philae had successfully touched down! But remember those harpoons? They didn’t work. Philae is clinging on by the screws in its feet, but it’s there.

Philae's view of the comet. Courtesy ESA.

Philae’s view of the comet. Courtesy ESA.

Philae will photograph and analyze the comet for the next two and a half days. If it gets enough sunlight for power, it can keep going for an “extended phase” lasting until March 2015—four whole months of comet science! After that, the comet will be closer to the sun and Philae will probably be too hot to work. Comet 67P/Churyumov-Gerasimenko will also heat up as it gets closer to the sun, so we might be able to see it active, with ices sublimating (turning from solid to gas) and creating the tails of gas and dust comets are famous for. Maybe the most exciting reasons to study a comet up close are that we get to see way, way back in history, and we get to learn about the far, far off outer solar system. Here’s wishing Philae just the right amount of sun.

Is landing on a comet even possible? Yes, but it’s tricky. Hang on tight, Philae!

More information:

Rosetta main website

Rosetta blog

Comet 67P/Churyumov-Gerasimenko

Timeline, instruments, and and landing details from Emily Lakdawalla

Bad Astronomy’s coverage, part one and part two

NPR story

ESA’s photographs

 

The Search for the Unknown

Posted by Petra on 6th April 2010 in Petra's Blog

As I said before, part of being an exogeologist is getting to explore! From the bright Sun and its flares, to the outermost reaches of the Oort cloud, exogeologists get to see it all! The most exciting part is discovering new things about unexplored places.

Moons are some of the most diverse objects; some are like planets with volcanoes and atmospheres, and others are like asteroids with odd shapes and cratered surfaces. Titan has a thick and hazy atmosphere, which just makes me wonder, “What’s down there?”

Exogeologists like myself decided that Titan was a good place to explore. The Cassini-Huygens mission was and is set to explore and study Saturn and Titan. The Huygens lander detached from the Cassini spacecraft and landed on Titan. It found that there is water ice on Titan, the atmosphere is made of methane and nitrogen, and there even seems to be an underground ocean of liquid water! How cool! Literally, because Titan is so cold being so far from the Sun.

Speaking of being cold and far from the Sun, exogeology is also used for studying Kuiper Belt objects, or KBOs. The most famous KBO is Pluto, the famous dwarf planet. Just let me call it a dwarf planet for the purposes of this one blog, okay? :) Pluto and other dwarf planets are mostly made of rock and ice, like asteroids. We don’t have many good photographs of Kuiper Belt objects, so that’s one thing that I’d like to do in the future: take pictures of KBOs.

The most mysterious places to see are exoplanets, planets orbiting other stars! There are planets of all shapes and sizes out there, and exogeologists are finding more all the time! It rocks that there are other solar systems!

No matter where you look, you just might find something new and exciting! Exogeology ROCKS!