An eye-opening new study indicates that we aren't the first Earth, and probably won't be anywhere close to the last.
Researchers have found in a surprising new study that Earth is actually a pretty early planet, and many more like it will be formed.
This theoretical study, based on an assessment of data from NASA’s Hubble Space Telescope and the Kepler space observatory — the latter of which was specifically built for finding planets — states that only 8 percent of potentially habitable planets that will ever form existed when our Solar System first came into being some 4.6 billion years ago, according to a Phys.org report.
That means a whopping 92 percent of planets that may be potentially habitable or Earth-like still haven’t been born.
Peter Behroozi, who was the study author and works at the Space Telescope Science Institute (STScI) in Baltimore, said that the research team was trying to understand where Earth fits in with the rest of the universe, and they found that Earth is a very early planet.
The research team looked out the history of star formation as galaxies grew in size over billions of years, looking at the rate at which the universe is making stars. They found that the universe made stars at a pretty fast rate at about 10 billion years ago, but it didn’t involve a very large percentage of the hydrogen and helium gas in the universe, which are the building blocks of new stars.
So that means that while star birth isn’t happening at the frenetic pace that it was at the beginning of our universe, there is a huge amount of leftover gas, meaning that the universe will keep on cranking out new stars — and thus, new planets — for a very, very long time.
Earth-like planets are actually pretty common already, with probably many of them in our own galaxy — perhaps as many as 1 billion Earth-sized planets, most of them rocky. Multiply that by 100 billion galaxies and you have a lot of potential candidates for life.
Any future formation of Earth-like planets is likely to happen outside of our galaxy, however, as the Milky Way has used up most of its gas for star formation. As a result, most of these formations will probably happen in giant galaxy clusters and dwarf galaxies with lots of leftover gas.
Scientists put out a news release on the study, which can be found here.