An artist’s impression of the innumerable Earth-like planets that have yet to be born over the next trillion years in the evolving universe. Credit: NASA / ESA / G. Bacon (STScI)
Earth came early to the party in the evolving universe. According to a new theoretical study, when our solar system was born 4.6 B years ago only 8% of the potentially habitable planets that will ever form in the universe existed. And, the party won’t be over when the sun burns out in another 6B years. The bulk of those planets – 92% – have yet to be born.
This conclusion is based on an assessment of data collected by NASA’s Hubble Space Telescope and the prolific planet-hunting Kepler space observatory. “Our main motivation was understanding the Earth’s place in the context of the rest of the universe,” said study author Peter Behroozi of the Space Telescope Science Institute (STScI) in Baltimore, Maryland,
The data show that the universe was making stars at a fast rate 10 billion years ago, but the fraction of the universe’s hydrogen and helium gas that was involved was very low. Today, star birth is happening at a much slower rate than long ago, but there is so much leftover gas available that the universe will keep cooking up stars and planets for a very long time to come.
Kepler’s planet survey indicates that Earth-sized planets in a star’s habitable zone are ubiquitous in our galaxy. Based on the survey, scientists predict that there should be 1 billion Earth-sized worlds in the Milky Way galaxy at present, a good portion presumed rocky. That estimate skyrockets when you include the other 100 billion galaxies in the observable universe. This leaves plenty of opportunity for untold more Earth-sized planets in the habitable zone to arise in the future. The last star isn’t expected to burn out until 100 trillion years from now. That’s plenty of time for literally anything to happen on the planet landscape.
The researchers say that future Earths are more likely to appear inside giant galaxy clusters and also in dwarf galaxies, which have yet to use up all their gas for building stars and accompanying planetary systems. By contrast, our Milky Way galaxy has used up much more of the gas available for future star formation.
The observational evidence for the big bang and cosmic evolution, encoded in light and other electromagnetic radiation, will be all but erased away 1 trillion years from now due to the runaway expansion of space. Any far-future civilizations that might arise will be largely clueless as to how or if the universe began and evolved. http://hubblesite.org/newscenter/archive/releases/2015/35
Recent Comments