OUR SUCCESSORS can see NEW neighbour solar systems containing myraid of EARTH like PLANETS in FUTURE--- as only 8% of the universe’s habitable worlds have formed so far.

Only 8% of the universe’s habitable worlds have formed so far

NASA/ESA/G. BACON (STSCI)

There are likely hundreds of millions of Earth-like planets in the Milky Way today, but that’s a small fraction of the number that may form throughout the universe in the future, a new study suggests.
       Using data from the Hubble Space Telescope, researchers estimated the rates of past star and planet formation in the universe, which is now about 13.8 billion years old. They then combined that information with data from previous surveys that estimated the amounts of hydrogen and helium left over from the big bang that still haven’t collapsed to form stars. At the time our solar system formed about 4.6 billion years ago, only about 39% of the hydrogen and helium in our galaxy had collapsed into clouds that then evolved into stars, they say. That means that the remaining 61% is available to form future solar systems that may include Earth-like planets in their habitable zones, the researchers report online today in Monthly Notices of the Royal Astronomical Society. In the universe as a whole, the researchers suggest, only 8% of its original starmaking gases was locked up in stars by Earth’s first birthday. The rest will, over the remaining trillions of years of the universe’s lifetime, coalesce into stars whose solar systems will contain a myriad of Earth-like planets in their habitable zones.


On the history and future of cosmic planet formation

Peter Behroozi★ and Molly S. Peeples★
Abstract


We combine constraints on galaxy formation histories with planet formation models, yielding the Earth-like and giant planet formation histories of the Milky Way and the Universe as a whole. In the Hubble volume (1013 Mpc3), we expect there to be ∼1020 Earth-like and ∼1020 giant planets; our own galaxy is expected to host ∼109 and ∼1010 Earth-like and giant planets, respectively. Proposed metallicity thresholds for planet formation do not significantly affect these numbers. However, the metallicity dependence for giant planets results in later typical formation times and larger host galaxies than for Earth-like planets. The Solar system formed at the median age for existing giant planets in the Milky Way, and consistent with past estimates, formed after 80 per cent of Earth-like planets. However, if existing gas within virialized dark matter haloes continues to collapse and form stars and planets, the Universe will form over 10 times more planets than currently exist. We show that this would imply at least a 92 per cent chance that we are not the only civilization the Universe will ever have, independent of arguments involving the Drake equation.

© 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Ref:
http://news.sciencemag.org/space/2015
http://mnras.oxfordjournals.org