Back on 67P

Philae has found organic molecules on Comet 67P.

Carbon-containing “organics” are the basis of life on Earth and may give clues to chemical ingredients delivered to our planet early in its history.

The compounds were picked up by a German-built instrument designed to “sniff” the comet’s thin atmosphere.

Other analyses suggest the comet’s surface is largely water-ice covered with a thin dust layer.

Very very frozen ice, as hard as sandstone.

And landing where it did may have been useful after all.

After bouncing off the surface at least twice, Philae came to a stop in some sort of high-walled trap.

“The fact that we landed up against something may actually be in our favour. If we’d landed on the main surface, the dust layer may have been even thicker and it’s possible we might not have gone down [to the ice],” said Prof McCaughrean.

The drill apparently didn’t get a sample though, which is disappointing.

A key objective was to drill a sample of “soil” and analyse it in Cosac’s oven. But, disappointingly, the latest information suggest no soil was delivered to the instrument.

Prof McCaughrean explained: “We didn’t necessarily see many organics in the signal. That could be because we didn’t manage to pick up a sample. But what we know is that the drill went down to its full extent and came back up again.”

“But there’s no independent way to say: This is what the sample looks like before you put it in there.”

Pesky science, always refusing to give dogmatic answers.


  1. moarscienceplz says

    Pesky science, always refusing to give dogmatic answers.

    Hey! I know what to do! Let’s pore over a book full of 20-century-old fairy tales until we find some passage that we can torture and twist until it seems to support the conclusions we like!

  2. Crimson Clupeidae says

    The latest is the deuterium isotope ratio is different too (than Earth’s water). Not sure what it means, but it’s interesting!

  3. Kevin Kehres says

    I have long thought this whole “delivered to Earth” thing is a bit of a canard. Obviously, the planets were accumulations of the stuff floating around. Since we see water and organic molecules pretty much everywhere we look, there’s zero reason to believe that there was some mysterious process that “delivered” those things to Earth.

    They were always there, part of what composed the early Earth.

    Of course, the process of accretion took a little while, so that’s not to say that at some point in the process, some big-assed space rocks didn’t crash into the forming Earth. But to think there’s some difference fundamentally between what was there and what crashed into it at various time points seems to me to be something akin to magical thinking. Ice, organics, nonorganics, …everything…all there at the beginning. There’s no need to invoke life-bringing comets.

  4. says

    Kevin Kehres:
    The process of planetary accretion that formed the majority of Earth released a great deal of heat, and did so so quickly that nearly all of the hydrogen- and carbon-rich compounds in that mixture (including water) were boiled off back into space. This thermal history is reflected in the isotopic ratios of those elements that didn’t entirely boil off.
    Most of the current inventory of water and carbon compounds on Earth was delivered to the planet in the last stages of accretion, when there were only smaller bodies impacting the planet at a lower rate. Less intense accretion-induced heating combined with the increased escape velocity of a more massive planet to prevent that material from escaping. There is a large dispute in the planetary science community right now as to where those smaller bodies came from – from the asteroid belt, or from comets.
    The mismatch between the relative amounts of deuterium and regular hydrogen on 67P and on the Earth suggests that the source bodies did not all have 67P-like compositions. However, different groups of comets have different deuterium-to-hydrogen ratios, so the data from 67P by themselves do not resolve the dispute.

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