"Diamond" Planets May Have Hosted the First Life in the Universe

Friday, 10 June 2016 - 2:27PM
Astrobiology
Friday, 10 June 2016 - 2:27PM
"Diamond" Planets May Have Hosted the First Life in the Universe
Since 2005, astronomers have been talking about a theoretical kind of planet- called a carbon or "diamond" planet- which may have been host to early lifeforms. Now, a little over ten years later, astronomers at the Harvard-Smithsonian Center for Astrophysics announced a new study suggesting that the first potentially habitable worlds might have been composed mostly of graphite, carbides, and diamond.

Opening quote
"This work shows that even stars with a tiny fraction of the carbon in our solar system can host planets," lead author Natalie Mashian of Harvard's astrophysics department, said in a statement. "We have good reason to believe that alien life will be carbon-based, like life on Earth, so this also bodes well for the possibility of life in the early universe."
Closing quote


The primordial universe consisted mostly of hydrogen and helium, and lacked the chemical elements necessary for life as we know it. Only after the first stars exploded into supernovae did planet formation, and subsequently life, become possible. 

Mashian and her PHD thesis advisor Avi Loeb examined a particular class of ancient stars known as carbon-enhanced metal-poor stars, CEMP for short. "These stars are fossils from the young universe," said Loeb. "By studying them, we can look at how planets, and possibly life in the universe, got started."

Although lacking in heavier elements that can be found in our sun, CEMP stars have more carbon than would be expected given their age. This abundance of carbon would influence the formation of a planet that - from a distance- would be difficult to tell apart from more Earth like worlds. However, upon closer examination, astronomers would find these carbon-based planets to be enveloped in methane and carbon monoxide.

Mashian and Loeb think that the search for these planets might be accomplished using the transit technique - a technique that involves looking for a tiny dip in the light of a star as an unknown planet passes in front of it.

Whether or not these planets are actually out there is questionable but, as Mashian puts it, "We'll never know if they exist until we look."
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Space
Astrobiology

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