The future of the universe will likely feature the birth of billions more Earth-like planets. Photo by NASA/ESA/G. Bacon
BALTIMORE, Oct. 20 (UPI) -- New analysis of data collected by NASA's Hubble Space Telescope and Kepler space observatory suggests most Earth-like exoplanets are yet to be born. Earth-like worlds are defined as rock planets orbiting within their host star's habitable zone, the region in which water might exist in liquid form.
The highly theoretical study isn't proof of the rarity of Earth-like worlds -- in fact, there are likely billions of exoplanets in the habitable zone -- but a primer on the future of star-making and planet formation. Simply put, the universe's evolving galaxies are going to keep making stars and planets for a long, long time.
In tracing the evolution of ancient galaxies, researchers at Baltimore's Space Telescope Science Institute (STScI) were able to show that though the rate of star formation has slowed, there is now much more gas available for star-building than there was when the universe first formed. Their calculations suggest the universe's last star won't turn off the lights for another 100 trillion years -- plenty of time for the birth of billions more Earth-like planets.
Current Earth-like worlds make up just eight percent of the total habitable planets that will form over the course of the universe's lifetime.
"Our main motivation was understanding the Earth's place in the context of the rest of the universe," Peter Behroozi, a planetary scientist at STScI, explained in a press release. "Compared to all the planets that will ever form in the universe, the Earth is actually quite early."
Behroozi is the lead author of the new study, which was published this week in the journal Monthly Notices of the Royal Astronomical Society.
"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-author Molly Peeples of STScI.
Behroozi and Peeples say future planets are more likely to be born in giant galaxy clusters and dwarf galaxies, which, unlike medium-sized spiral galaxies like the Milky Way, haven't already used up their star-forming gas reserves.
