How large a space telescope do we need to see exo-civilizations?

RGClark · 2020-09-27 09:53:35

A team of scientists is investigating ways of detecting exo-civilizations aside from just radio signals as with SETI:

JUNE 19, 2020
Does intelligent life exist on other planets? Technosignatures may hold new clues.
by University of Rochester
https://phys.org/news/2020-06-intellige … clues.html

Two methods of detection mentioned in the article are detection from reflected light from solar panels or detection or pollution such as CFCs.

However, even on our planet the number of solar panels would not be such that they would add appreciably to the Earth light. And CFCs presence might be short lived as it has been on our planet, having been banned.

Could we instead detect the light on the night side coming from all the artificial lighting that would be used in a civilization? Some of the photos seen from space of the cities alit at night on Earth have been quite striking:

Aug. 14, 2014
Space Station Sharper Images of Earth at Night Crowdsourced For Science

https://www.nasa.gov/mission_pages/stat … ght_images

How big would a space scope need to be able to see this in the Alpha Centauri system, for example?

Robert Clark

Mars_B4_Moon · 2021-06-01 07:02:56

Mysterious radio burst from space is unusually close—and especially baffling
https://www.nationalgeographic.com/scie … adio-burst

tahanson43206 · 2021-06-01 08:22:02

For Mars_B4_Moon re #2

Thanks for the link to that (to me very) interesting article.

The use of long baseline interferometers to pinpoint the location was particularly interesting.

I would expect that as we (humans) advance, we should be able to establish long baseline equipment at a variety of points in the Solar system.

Coordinating time between widely scattered locations is a challenge, but (I'm assuming) scientists doing this work have addressed the issue, because light time differences even over such a short distance as the diameter of the Earth are a non-trivial problem.

If you (or any member) happen to run across discussion of plans for (or actual projects) to establish Solar system long baseline observatories I'd be glad to see reports here.

(th)

SpaceNut · 2021-06-01 18:41:14

The radio burst have been around for a while now but we have not seen data within them or a repeat of the pattern that one would see if its got data riding on the energy that we receive.

The issue is energy itself spreads and become so low by time it reaches earth it does not matter what data it had on it as its to small to detect.

Mars_B4_Moon · 2021-06-29 13:56:54

CHEOPS unexpectedly detects a unique exoplanet
http://www.eurekalert.org/pub_releases/ … 062821.php

The Hubble Space Telescope's Near-UV and Optical Transmission Spectrum of Earth as an Exoplanet
https://www.osti.gov/biblio/23013321-hu … -exoplanet

Radio again

A Lunar Farside Telescope Could Detect Exoplanets Through Their Magnetospheres
https://www.universetoday.com/151659/a- … tospheres/

SpaceNut · 2021-06-29 20:35:41

From what I remember the chemical signatures for life is looking at these exoplanets to see if signs of life is present.

Mars_B4_Moon · 2021-07-14 06:06:38

More discovery

Four exoplanets discovered oribiting stars 130 light years from Earth .
https://www.abc.net.au/news/2021-07-13/ … /100288402

Mars_B4_Moon · 2022-04-12 06:08:12

Giant space telescopes could be made out of liquid

https://phys.org/news/2022-04-giant-spa … iquid.html

Mars_B4_Moon · 2023-03-22 06:57:29

An Earth with a glowing haze, inappropriate Neon, or excessive artificial lighting even adaptive optics can't fix it and it even goes into space. Light pollution in Hong Kong was declared the 'worst on the planet' in March 2013.In June 2016, it was estimated that one third of the world's population could no longer see the Milky Way, including 80% of Americans and 60% of Europeans. Singapore was found to be the most light-polluted country in the world. Over the past 21 years, China's provincial capital cities have seen a major increase in light pollution, with hotspots along the eastern coastline region.
http://www.pressherald.com/2016/06/11/l … sky-views/
,
http://www.scmp.com/news/hong-kong/arti … rst-planet

LightPollution scientists already say satellites streaking past the Hubble have blocked data and ruined photos. It has been estimated that 83 percent of the world's people live under light-polluted skies and that 23 percent of the world's land area is affected by skyglow. https://www.knowablemagazine.org/articl … goes-night

We have direct images of Exoplanets and TPF would have seen more planets.

'By combining the high sensitivity of space telescopes with revolutionary imaging technologies, the TPF observatories would have measured the size, temperature, and placement of planets as small as the Earth in the habitable zones of distant solar systems.'
https://science.nasa.gov/missions/tpf

Interferometer Terrestrial Planet Finder

Direct images and Astronomical interferometer
https://www.space.com/3820-nasa-planet- … world.html
,
https://www.universetoday.com/140341/wh … t-imaging/
,
https://web.archive.org/web/20161003112 … it/why.php

International Dark-Sky Association

Dark-sky movement

'Astronomers sound alarm about light pollution from satellites'
https://web.archive.org/web/20100706051 … geId=71681

https://web.archive.org/web/20110718102 … rksky.com/

https://web.archive.org/web/20120512033 … l_park.asp

https://www.spacedaily.com/reports/Astr … s_999.html

We’ve Found 5,000 Exoplanets and We’re Still Alone

https://www.theatlantic.com/science/arc … ne/627155/

So far, the search for a truly Earth-like world has turned up empty.

NASA’s Webb Confirms Its First Exoplanet

https://www.nasa.gov/feature/goddard/20 … -exoplanet

I have not seen any new article on long baseline observatories
but every month or so an article pops up about Lunar telescope sites or putting Radio Dish on the far side of the Moon for Observation.

Last edited by Mars_B4_Moon (2023-03-22 07:11:55)

RGClark · 2023-03-30 13:46:32

Mars_B4_Moon wrote:

Giant space telescopes could be made out of liquid
https://phys.org/news/2022-04-giant-spa … iquid.html

Thanks for that. Robert Zubrin wrote about this possibility also:

A Method for Creating Enormous Space Telescopes.
by PAUL GILSTER on MARCH 4, 2021
https://www.centauri-dreams.org/2021/03 … elescopes/

Zubrin notes though the liquid mirrors made on Earth create a parabolic shape of the liquid surface of the mirror via the combination of rotation and the Earth's gravity:

Liquid Mirror Telescope.
https://www.youtube.com/watch?v=Q5Cr9P-Q88Y

That is, you would not get a parabolic shape without gravity. He therefore suggests various methods of creating acceleration to induce a force akin to gravity to get the parabolic shape.

However, this later report suggests in zero gravity the rotation can induce a spherical shape. I believe some telescopes do use a spherical shape of the mirror rather than parabolic for simplicity and cost, so this may still work.

Robert Clark

New Mars Forums

Announcement

#1 2020-09-27 09:53:35

How large a space telescope do we need to see exo-civilizations?

#2 2021-06-01 07:02:56

Re: How large a space telescope do we need to see exo-civilizations?

#3 2021-06-01 08:22:02

Re: How large a space telescope do we need to see exo-civilizations?

#4 2021-06-01 18:41:14

Re: How large a space telescope do we need to see exo-civilizations?

#5 2021-06-29 13:56:54

Re: How large a space telescope do we need to see exo-civilizations?

#6 2021-06-29 20:35:41

Re: How large a space telescope do we need to see exo-civilizations?

#7 2021-07-14 06:06:38

Re: How large a space telescope do we need to see exo-civilizations?

#8 2022-04-12 06:08:12

Re: How large a space telescope do we need to see exo-civilizations?

#9 2023-03-22 06:57:29

Re: How large a space telescope do we need to see exo-civilizations?

#10 2023-03-30 13:46:32

Re: How large a space telescope do we need to see exo-civilizations?

Board footer