Category Archives: comet

astronomy, comet, rosetta, rosetta spacecraft

Rosetta Reveals Tip of the Comet 67P Knowledge Iceberg

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Mapping Comet 67P/Churyumov-Gerasimenko

Comet 67P/Churyumov-Gerasimenko sports jagged cliffs and prominent boulders on its surface. This image was taken by OSIRIS on 5 September 2014 from a distance of 62 kilometers (about 38 miles) from the comet. The left part of the image shows a side view of the comet’s ‘body’, while the right is the back of its ‘head’. One pixel corresponds to 1.1 meters. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

If you’ve ever wondered about the surface of a comet — and why not? — wonder no more. The Rosetta mission has figuratively ripped the fuzzy veil away from Comet 67P/Churyumov-Gerasimenko (Comet 67P for short) mapped its surface, and done preliminary analysis of what that surface is like. That’s just for starters!

It turns out this particular comet (and probably most comets) has a planetary scientist’s wonderland of features. To get you started exploring the comet, check out this amazing image of the comet released over the weekend by the Rosetta mission’s OSIRIS team. OSIRIS is an imaging instrument sensitive to optical as well as infrared light (essentially heat radiation).

When I first looked at this image a couple of hour or so ago, it reminded me of the top of a craggy mountain peak. However, this is no rocky mountain. It’s a chunk of ice the size of a big city, following an orbit that takes it from just outside the orbit of Jupiter (at its most distant) to outside Earth’s orbit over the course of 6.5 years. (Earth orbits at 1 A.U. from the Sun (150,000 million kilometers or 93 million miles.  The comet gets as close as 1.24 A.U. (185,940,000 kilometers or 115 million miles from the Sun).

(This is to reassure anyone who was worried that the comet will somehow intersect Earth’s orbit. It won’t. During perihelion passage (closest approach to the Sun) the comet and Earth will be 3.3 A.U. (490,000,000 million kilometers or 304 million miles). That occurs in August, 2015.)

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astronomy, comet, European Space Agency, rosetta, rosetta spacecraft

Rosetta’s Target Gets Clearer

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Two Knobs joined by a Neck

Comet 67P/Churyumov-Gerasimenko. Courtesy: ESA/Rosetta/NAVCAM

The day after tomorrow (August 6, 2014) the Rosetta spacecraft arrives at Comet 67P/Churyumov-Gerasimenko, and to celebrate, we’ve got another image to look at. This one was taken on the 3rd with the NAVCAM system, and it makes the comet look more intriguing than ever.

What intrigues ME most about this image, aside from the craters and ridges (which are pretty darned interesting in their own right), is the “neck” of material joining the two knobs. I imagine the mission astronomers are talking a lot about it, too. In this view it appears smoother in some places than in others. That makes me wonder at the processes that smoothed it out. Were they part of an event that “stuck” two pieces together in a collision?  Is this nucleus part of a larger one that broke apart along some interior seams?

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