Rare Earth: Why Complex Life is Uncommon in the Universe
Language: English
Pages: 338
ISBN: 0387952896
Format: PDF / Kindle (mobi) / ePub
What determines whether complex life will arise on a planet, or even any life at all? Questions such as these are investigated in this groundbreaking book. In doing so, the authors synthesize information from astronomy, biology, and paleontology, and apply it to what we know about the rise of life on Earth and to what could possibly happen elsewhere in the universe. Everyone who has been thrilled by the recent discoveries of extrasolar planets and the indications of life on Mars and the Jovian moon Europa will be fascinated by Rare Earth, and its implications for those who look to the heavens for companionship.
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Is unlikely that any of the stars in these galaxies could have Earth-like planets because the heavy elements to build them were not yet abundantly available. We thus may be seeing images of the prebiotic Universe. Another insight gleaned from the Hubble Deep Field is that older galaxies seem to have more irregular shapes than newer galaxies. From 30% to 40% of the most distant galaxies (and hence of the the oldest galaxies) are unusual or deformed compared to those nearest our own galaxy. The.
Take place, and entered the arenas of religion, ethics, and science fiction. Science has progressed since the publication, yet nothing we have read or discovered in the years since has caused us to change our minds. One of the most remarkable developments has been the continual discovery of new planets orbiting other stars (the count is now over 100). While this shows that planets are common, it also shows how complex and varied planetary systems are, and how difficult it is to make a stable.
Carbon/nitrogen-rich solids were too volatile and had no means of efficiently forming solids in the warm inner regions of the nebula. Thus Earth has only trace amounts of these volatile components, compared to bodies that formed farther from the sun. An excellent example is the case of the carbonaceous meteorites, thought to be samples of typical asteroids formed between Mars and Jupiter. These bodies contain up to 20% water (in hydrous minerals similar to talc) and up to 4% carbon. The bulk of.
Volatile-rich planetesimals from the outer regions of the solar system into the inner solar system, the realm of the terrestrial planets. Even today, material from the outer solar system impacts Earth. Most of the mass is in particles a quarter-millimeter in diameter that are derived from comets and asteroids. These materials carry not only carbon, nitrogen, and water but also relatively large amounts of organic material, as was first proved when extraterrestrial amino acids were discovered in.
Of projections, much like steps on a ladder, made up of the distinctive DNA bases adenine, cytosine, guanine, and thymine. The term base pair comes from the fact that the bases always join up in the same way: Cytosine always pairs with guanine, and thymine always joins with adenine. The order of bases on each strand of DNA supplies the 56 ward_Text_001-334 3/10/03 13:29 Page 57 Life’s First Appearance on Earth language of life; these are the genes that code for all information about a.