Comet probe sends back some fascinating science

WASHINGTON: We know Rosetta’s Philae lander was meant to do scientific analysis of the comet it landed on – and that, despite an early death because of landing complications, it delivered data from all of its planned experiments.

But why are scientists so interested in Comet 67P/Churyumov Gerasimenko’s composition, and how will they go about unlocking its secrets?

The Conversation has a great explainer on the subject. Here are the highlights.

Comets might be the key to figuring out our planet’s origins. These days we know living things always come from other living things. We know flies are hatched from eggs laid by other flies, for example, and they don’t emerge spontaneously from spoilt meat.

But at some point, life must have started from something that wasn’t life; a process called abiogenesis. Organic molecules must have somehow shown up on Earth and allowed life to begin, but we aren’t sure how.

The comet impact theory is one explanation. It’s possible that billions of years ago, comets carrying organic molecules from other parts of the solar system hit Earth, leaving the building blocks of life behind.

And if comets didn’t seed our planet for life, they were still there in the early days of the solar system – and the organic molecules locked away in their ice could give us clues as to what else might have gone on at the time.

Philae needs to figure out if the comet’s molecules are left paws.

Chemists refer to molecules as either left or righthanded – just like your left and right hands, these molecules are identical mirror images of each other.

Life on Earth uses left-handed molecules exclusively. But why?

From The Conversation: “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).”

So it’s important scientists find out whether comets have left-handed molecules as well – something one of Philae’s instruments is designed to analyse. – Washington Post

PICTURE: EPA Comet 67P/CG photographed from an altitude of 3km by the Philae lander during its descent to the surface of the celestial body earlier this month.