Amateur finds moon orbiting comet in Rosetta archive

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In mining the Rosetta archive of images of Comet 67P/C-G, an amateur astronomer has discovered a twelve-foot-diameter chunk of material that had broken from the comet and was in orbit around it.

Modelling of the Rosetta images indicates that this object spent the first 12 hours after its ejection in an orbital path around 67P/C-G at a distance of between 2.4 and 3.9 km from the comet’s centre. Afterwards, the chunk crossed a portion of the coma, which appears very bright in the images, making it difficult to follow its path precisely; however, later observations on the opposite side of the coma confirm a detection consistent with the orbit of the chunk, providing an indication of its motion around the comet until 23 October 2015.

While it is not really unusual for their to be small objects in the coma of the the comet, orbiting it, this is apparently the largest so far found. That they missed it initially is also not surprising, considering the amount of data they were gathering in such a short time.



  • MDN

    Parachutes are really hard. This documentary about the Mars Exploration Rover mission recounts how they suffered a catastrophic failure in their first parachute test, and then encountered even more problems when studying fixes in a NASA wind tunnel.

    The test failure bit starts at 22:45, and the wind tunnel fix testing at 33:00.

    The wind tunnel they are using is the 80 X 120 at NASA Ames Research Center in Mountain View California. This is a wind tunnel with a test chamber that is 80 feet tall X 120 feet wide that can simulate up to about 180MHP, where they have tested things like real twin engine/70 passenger turboprop aircraft with the engines running for stability in high crosswind landing conditions (the kind of stuff you don’t want to really test in flight).

    Facilities like these are national assets that deserve a lot more recognition then they get because they just aren’t that sexy in the grand scheme of things. But for problems like this you just can’t figure it out with computer modeling and such, because parachutes live in the realm of turbulent flow, and computer codes simply suck at that, even on our most modern and largest super computers. But we’re lucky, because the Greatest Generation built this tool and many others like it, proved the value of empirical engineering with programs like Apollo, the SR-71, and countless others, and left us the tools to keep solving these problems.

  • MDN: I think you posted this comment in the wrong thread.

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