Science is SO Awesome!

Explainer: What Philae Did In Its 60 hours on Comet 67P | IFLScience.

So what did rhe lander actually do?  Analytical chemistry.

Although chemical molecules can be right- or left-handed, all those on earth are left handed.

Many molecules come in one of two forms, known as stereoisomers, which chemists designate as left- or right-handed. These two forms are identical apart from the fact that they are mirror images of each other.

Your hands are a perfect analogy. Structurally, they are the same except for the fact that you can’t superimpose one on the other. And so it is with stereoisomers.

Explainer: What Philae Did In Its 60 hours on Comet 67P | IFLScience

Does the same hold true for comets?

Strangely, life on Earth is based entirely on left-handed molecules. It is perfectly possible to make the right-handed versions, but life just doesn’t. Where this preference for left-handedness comes from is a mystery. One theory is that the bias came from within the chemistry of comets. In the comets, right-handed molecules may have been preferentially destroyed by a combination of sunlight (to provide energy to trigger chemical reactions) and liquid water (with which the organic compounds could react).

Philae’s COSAC instrument is designed to sniff away at the comet’s organic contents and figure out whether they look like the building blocks of life and, importantly, whether the comet contains the same preference for lefty chemistry as Earth-bound life.

Second, it will determine (or try to) whether the comet came from detritus in our solar system, or from somewhere else.

A given element is defined by the number of protons in its nucleus. For example carbon always has six protons. However the number of neutrons can vary giving rise to carbon-12 (six protons and six neutrons), carbon-13 (with seven neutrons) and carbon-14 (with eight neutrons). All these different variations are known as isotopes. The ratio of these isotopes in any given body will vary depending on its origins. And since the material in the solar system came from more or less the same place, the isotopic carbon ratios for the Sun, the Earth and asteroids are pretty much the same.

But comets might be different, in fact remote measurements of comet Hale-Boop suggest that it may be an extra-solar alien. The problem is there were large uncertainties in these readings, so we can’t be sure of their accuracy. By sending the Ptolemy instrument to the surface of a comet this should all be resolved, as its isotopic measurements are meant to be as accurate as those performed on Earth, and the solar or alien origins of Comet 67P can be confirmed.

So where did this comet come from?  The lander will try and help us figure it out.  And, just maybe, it will shed new light on our origins.

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