Astronomers want NASA to build a giant space telescope to peer at alien Earths | Hacker News Reader

Astronomers want NASA to build a giant space telescope to peer at alien Earths

npr.org

63 pointszone41134 comments

This is the decadal survey for astronomy and astrophysics for the 2020s. It's a big deal.

The 1980s decadal survey resulted in the Chandra X-ray Observatory (20 years later). The 90s survey resulted in the Spitzer Space Telescope. The one in 2001 resulted in the James Webb Space Telescope (finally launching next month!). And, the 2010 one pushed forward WFIRST & LSST, both under active development, among other efforts.

Here are some other decadal surveys: https://science.nasa.gov/about-us/science-strategy/decadal-s...

And the details of this one: https://www.nap.edu/resource/26141/interactive/

We'll likely cover this in depth in the next issue of Orbital Index (https://orbitalindex.com).

Here's a draft of the summary that will be in next week's Orbital Index:

Last Thursday, at the request of NASA, the NSF, and other science agencies, NASEM released their astronomy and astrophysics decadal survey for the 2020s. Following a decade of exoplanet discovery, the report’s top recommendation was for development of a space telescope significantly larger than Hubble that could directly image habitable zone exoplanet atmospheres in both IR and optical wavelengths to search for biosignatures. This telescope, to launch in the early 2040s, would be neither HabEx or LUVOIR, two proposed next-generation telescopes, but something in between. They also recommend development of a very high resolution X-ray mission and a far-infrared mission. To enable these efforts, and avoid the delays and overruns of missions like the JWST, they recommend establishing a ‘Great Observatories Mission and Technology Maturation Program’ as a new approach for planning and implementing large missions. “The program would provide early investment in technology development for multiple mission concepts to lower the risks and costs of projects before they become too complex, large, and costly.” Decadal surveys have real impact: the 1980s decadal survey resulted in the Chandra X-ray Observatory (20 years later); the 90s survey resulted in the Spitzer Space Telescope; the 2000s resulted in the James Webb Space Telescope (finally launching next month!); and, the 2010s pushed forward WFIRST & LSST, both under active development. Other recommendations from last week’s release include the development of a regulatory framework to control the impacts of satellite constellations on astronomy; changes to funding to increase research and promote diversity; continued development of ground-based gravitational wave observatories; a focus on multi-messenger astrophysics; program management changes with NSF innovation and facility funding; and, continued investment in large ground-based telescopes, such as the U.S. Extremely Large Telescope (ELT), a next generation ground-based cosmic microwave background experiment, the Next Generation Very Large Array (ngVLA) radio telescope, and the IceCube-Generation 2 neutrino observatory.

I love the idea of using gravitational lensing of the sun from a lagrange point around Jupiter. IIRC it theoretically could image an earth like planet in the region of 1000px x 1000px so you could see continents and weather systems - perhaps even light from large cities.

I watched a great "Cool Worlds" video as well that said you could do similar with atmospheric lensing of the earth from a lagrange point near the moon (although it would filter out some visible light wavelengths and be weather dependant) - but potentially a much cheaper mission: https://www.youtube.com/watch?v=jgOTZe07eHA

This would be going full circle in terms of telescope technology, we started with lenses, moved to mirrors and now back to lenses!

To me these seem like the most exciting missions ever - could define a new epoch for humanity and inspire and excite hundreds of millions of people. I would be very disappointed if this didn't happen in my life.

We went with mirrors because lenses would be astronomical in size (pun intended). So instead of having to figure out how to make an astronomical sized lens, we figured out how to use astronomical objects as lenses.

Seth Shostak of SETI has said that an alien civilization could setup a telescope in an orbit beyond the equivalent of Pluto, using their star's gravitational lensing to detect any Earth electronic activity up to a thousand light years away. Of course they would have to wait on our signals to reach that far out first.

> gravitational lensing of the sun from a lagrange point around Jupiter

How exactly would that help? I thought the focal point of the Sun is around 500 AU away (i.e., not anywhere near Jupiter).

That’s correct there was/is a suggested mission to exploit it which will require to send a telescope to 550 AUs https://en.m.wikipedia.org/wiki/FOCAL_(spacecraft)

Is there some trick to make that work so close to the sun?

Jupiter is 5AU out from the sun, but the solar gravitational lense focal point is 542 AU out.

Pathways to Discovery in Astronomy and Astrophysics for the 2020s: https://www.nap.edu/resource/26141/interactive/.

Full report: https://www.nap.edu/catalog/26141/pathways-to-discovery-in-a...

"This telescope would cost an estimated $11 billion, and could launch in the early 2040's."

So that probably means $20 billion and an early 2050s launch? Still worth it in my opinion.

I know right, about 28 days of Iraq war. I'd have shaved 28 days off that war for a giant space telescope.

ESO’s Extremely Large Telescope Extremely Large Telescope (ELT) starts operations in 2027. One of the science goals is direct imaging of planets.

ELT mirror diameter is 39.3 m (128 ft 11 in)

Obviously they need to keep planning for the next few decades but personally I can't even think about this before I see the JWST has successfully launched and deployed. Something going wrong there would be major setback for all plans. It would be hard to justify betting another $10-20 billion after the last bet went wrong.

Is SETI really the top research priority? Or the scientists' opinion of what will best attract funding?

Mind you, I'm in favor of all of it. This stuff is cheap for the knowledge returned. (And a better investment than the various manned programs. Does the science from ISS or another lunar visit compare with what we're talking about here?)

> Is SETI really the top research priority?

The article talks about searching for life, not intelligence.

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