Top Document: [sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9) Previous Document: F.10 Why do we assume that other beings must be based on carbon? Why couldn't organisms be based on other substances? Next Document: Copyright See reader questions & answers on this topic! - Help others by sharing your knowledge This question has taken on increased importance with the discovery of giant planets close to their primary stars. It is thought that these giant planets did not form this close to their host stars but migrated. (See the FAQ entry on the formation of the solar system.) In general, the possibility of migration has alerted (or re-awakened) astronomers to the possibility that a planetary system can change over time. If a giant planet migrates inward from the position at which it formed, it can scatter terrestrial planets. These terrestrial planets might plunge into the host star or be kicked into interstellar space. (Another possibility, though probably even less likely, is for a passing star to disrupt a planetary system.) What would happen if the Earth were kicked into interstellar space? Life on the surface would certainly be doomed as it gets its energy to survive from the Sun. In fairly short order, the oceans would freeze over. However, the Earth is still generating heat by radioactive decay in its interior. Some of this heat leaks out through hydrothermal vents on the floors of the oceans. Thus, the lower levels of the oceans would remain liquid, and the hydrothermal vents would remain active. Organisms that depend only on the hydrothermal vents could survive probably quite happily for several billion years after the Earth was ejected from the solar system. (Indeed, since the oceans will probably boil away in the next few billion years as the Sun's luminosity increases, these organisms might prefer the Earth to be ejected into interstellar space!) For additional reading see "The Frozen Earth" by Adams & Laughlin, <URL: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999AAS...194.1511A > and Stevenson, "Life-sustaining planets in interstellar space?", Nature, v. 400, 1 Jul 1999, p. 32. User Contributions:Top Document: [sci.astro] ET Life (Astronomy Frequently Asked Questions) (6/9) Previous Document: F.10 Why do we assume that other beings must be based on carbon? Why couldn't organisms be based on other substances? Next Document: Copyright Part0 - Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: jlazio@patriot.net
Last Update March 27 2014 @ 02:11 PM
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