A new theoretical study suggests Earth is actually an early bloomer, and 92 percent of the habitable planets that will ever exist are yet to be born.
A team of researchers came up with the fascinating new theory after looking at data collected by NASA's Hubble Space Telescope and the planet-hunting Kepler space observatory, NASA's Goddard Space Flight Center reported.
"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, "Compared to all the planets that will ever form in the universe, the Earth is actually quite early."
Using this data, the researchers created a "family album" of galaxies, which outlines the history of star formation. The findings suggest the universe was making stars at a fast rate about 10 billion years ago, but had very low levels of hydrogen and helium gas to work with. Since then star birth has significantly slowed down, but there is so much leftover gas left that the universe will likely remain productive for a long time.
"There is enough remaining material [after the big bang] to produce even more planets in the future, in the Milky Way and beyond," said co-investigator Molly Peeples of STScI.
Researchers have estimated there are currently about one billion Earth-sized planets in the Milky Way, and a great number are likely rocky. The hunt is now on for these types of planets orbiting within the habitable zone of their host stars. The researchers believe future Earth-like planets are more likely to pop up within galaxy clusters and in dwarf galaxies. Our own Milky Way has used up a great deal of its gas, making the prospect of future star births less likely.
"A big advantage to our civilization arising early in the evolution of the universe is our being able to use powerful telescopes like Hubble to trace our lineage from the big bang through the early evolution of galaxies. 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," the researchers concluded.
