In the Hunt for Alien Life, Most Earth-like, Habitable Planets Have Yet to be Born

As the hunt for alien life continues, researchers have come to a somewhat interesting revelation. It turns out that many Earth-like planets have yet to be born; scientists have found that Earth came early to the party in the evolving universe, and that about 92 percent of habitable planets have yet to be formed.

"Our main motivation was understanding Earth's place in the context of the rest of the universe," said Peter Behroozi, one of the researchers, in a news release. "Compared to all the planets that will ever form in the universe, the Earth is actually quite early."

The Hubble Space Telescope has given astronomers galaxy observations that chronicle the universe's star formation as galaxies grew in the distant past. In fact, data from Hubble reveal that the universe was making stars at a fast rate about 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, but because there is so much leftover gas the universe will continue creating stars and planets for a long time to come.

Kepler's planet survey actually indicates that Earth-sized planets in a star's habitable zone are ubiquitous in our galaxy. Based on the survey, scientists predict that there would be about 1 billion Earth-sized worlds in the Milky Way galaxy, and a good portion of those are presumed to be rocky. This leaves plenty of opportunity for more Earth-sized planets in the habitable zone to arise in the future.

In fact, Earths are more likely to appear inside giant galaxy clusters and in dwarf galaxies, which have yet to use up all of their gas for building stars or accompanying planetary systems. In contrast, our Milky Way galaxy has used up much more of the gas available for future star formation.

These latest findings show that when it comes to finding other Earths, we may be in for a long wait. IT seems as if most habitable planets will arise in the future.

The findings are published in the journal Monthly Notices of the Royal Astronomical Society.

Related Stories

The Hunt for Alien Life Becomes Easier with New 'Habitability Index' for Exoplanets

Earth-like Planets Near Dim Stars May Have Magnetic Fields and Life

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).