* Astronomy

Blobrana · L

RE: Alien ID Chart

Blobrana · L

Astronomers have yet to find an Earth-size planet beyond our solar system, but that hasn't stopped them from modelling what these worlds might look like.
A new catalogue of 14 types of such planets, some fantastical, could help planet hunters spot what has until now remained fictional.
The computer models provide specs for 14 planet types, varying according to mass, diameter, composition and where the worlds could be found in our galaxy. Some are made mostly of pure water ice, carbon, iron, silicate, carbon monoxide or silicon carbide, while others are mixtures of these various compounds.

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Blobrana · L

It is only a matter of time before astronomers find an Earth-sized planet orbiting a distant star. When they do, the first questions people will ask are: Is it habitable? And even more importantly, is there life present on it already? For clues to the answers, scientists are looking to their home planet, Earth.
Astronomers Lisa Kaltenegger of the Harvard-Smithsonian Centre for Astrophysics (CfA) and Wesley Traub of NASA's Jet Propulsion Laboratory and CfA, propose using Earth's atmospheric history to understand other planets.

"Good planets are hard to find. Our work provides the signposts astronomers will look for when examining truly Earth-like worlds" - Lisa Kaltenegger.

Geologic records show that Earth's atmosphere has changed dramatically during the past 4.5 billion years, in part because of life forms developing on our planet. Mapping what gases comprised Earth's atmosphere during its history, Kaltenegger and Traub propose that by looking for similar atmospheric compositions on other worlds, scientists will be able to determine if that planet has life on it, and if so, that life's evolutionary stage.

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