Comets could hold the secret of how life began on Earthby Frank Close / December 12, 2013 / Leave a comment
Comet Ison: “We still know relatively little about comets. So when a new one appears, there is a unique opportunity to study these fossil relics”
“Comets are like cats: they have tails and do what they want.” This piece of astronomical folklore was confirmed once again as the “comet of the century”—Comet Ison—or formally “C/2012 S/1” hurtled towards the sun in the past few months with the promise of being “brighter than the full moon.”
The hype, however, omitted some important facts. First, on 28th November, when the comet was expected to be as its brightest and most visible, the sun was in direct line of sight between the comet and the Earth, rendering Ison invisible. Second, as a comet is an icy dirtball, or a dirty iceball, it had almost literally a snowball’s chance in hell of surviving its close encounter with the sun. Third, the very rarity of a bright comet, which has come towards Earth from the “Oort cloud” deep in space, made it very difficult to predict what would happen.
On 29th November, astronomers waited as the remnant emerged from behind the sun, to see what, if anything, had survived. Initial fears were that the heat had destroyed the comet. But then images from the Soho satellite showed that something had emerged from the opposite side of the sun, and was following Ison’s orbit. Reports of its death may have been greatly exaggerated. Although there was no real hope of Ison being a brilliant sight visible to the naked eye, an enthusiast with a telescope could see it both in the early morning and evening skies during its progress through the constellations.
Although this was not the visible sensation once anticipated, for professionals it is a rare opportunity to learn about the origins of the solar system, and perhaps even life itself.
We still know relatively little about comets, so when a new one appears there is a chance to study these fossil relics from the birth of the solar system. Some astronomers have suggested that comets, which showered down on the newborn Earth, seeded life. If so, then comets such as Ison should contain elements essential for life’s building blocks: carbon, nitrogen and oxygen, in complex combinations, that could seed amino acids.
Astro-biologists have been measuring the spectral emissions of Ison to…