If Earth has a twin somewhere out there, NASA should find it.
That's the takeaway from a once-in-a-decade report that sets the priorities for astronomy over the next decade. In order to find such Earth-like exoplanets, NASA should build a big, fancy new space telescope, the report states.
Every 10 years, the National Academies of Sciences, Engineering, and Medicine advise government agencies, such as NASA and the National Science Foundation, as to what research objectives astronomers should prioritize in the coming decade, Space.com reported. The advisors released their latest report on Thursday (Nov. 4) and highlighted three major research priorities: to better understand the nature of black holes and neutron stars; to investigate how galaxies form and evolve; and to identify "habitable Earth-like worlds" and biochemical signatures of life in other planetary systems.
On this last point, Fiona Harrison, a Caltech astrophysicist who co-chaired the committee, told NPR, "The most amazing scientific opportunity ahead of us in the coming decades is the possibility that we can find life on another planet orbiting a star in our galactic neighborhood."
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The committee recommended that, to find such planets, NASA should build a telescope that dwarfs the Hubble Space Telescope and comes equipped with infrared, optical and ultraviolet sensors. The telescope would also carry a coronagraph, a telescopic attachment designed to block out direct light from a star so that nearby objects can be seen, Axios reported; otherwise, faint exoplanets might be obscured by the light of a neighboring star that shines 10 billion times brighter than they do.
The telescope would cost an estimated $11 billion to build and would (ideally) launch in the early 2040s, Axios reported.
With such a telescope, "you're not going to see continents on the surface of the planets … we'll see distinct little dots," Bruce Macintosh, an astrophysicist at Stanford and a member of the committee, told The Atlantic. Then, by analyzing the light reflected off the exoplanet, scientists could figure out the chemical composition of its atmosphere. Atmospheric evidence of oxygen, methane and water could hint at the presence of life on the planet, although astronomers would need to rule out other explanations for these chemical signatures, such as volcanic activity.
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"When we see the first hint of life out there in the universe and see the fingerprints of life in a distant world, humanity's place in the universe is fundamentally changed," John O'Meara, committee member and chief scientist at the W. M. Keck Observatory, told Axios.
A decade ago, such a mission would have been considered "a little bit pie in the sky," Jonathan Fortney, a planetary scientist at the University of California, Santa Cruz and one of the members of the committee, told The Atlantic. But as of today, scientists have identified more than 4,500 exoplanets, about 160 of which are rocky, like Earth.
With the ability to discover and analyze the atmospheres of far-off worlds, "we have a route to being able to start to answer the question, 'Are we alone?'" Rachel Osten, an astronomer with the Space Telescope Science Institute who served on the committee, told NPR.
Originally published on Live Science.