Answers to a question about extraterrestrial life

[Buzz Bloom]

TL;DR Summary

Today's APOD (Astronomy Picture of the Day)
contained a reference providing answers to the question:
How will humanity first discover extraterrestrial life?

Today's APOD (Astronomy Picture of the Day)

https://apod.nasa.gov/apod/ap200428.html​

contained a reference providing answers to the question:

How will humanity first discover extraterrestrial life?​

The reference is

https://apod.nasa.gov/apod/ap200429.html.​

The title of the reference is

100th Anniversary of the Shapley - Curtis Great Debate.​

Sixteen scientists answered the question. A majority of them gave similar answers saying something close to the following:

Chemical signature from the interior of an icy moon.​

A few answers added Mars to the above. The second most common answer were variations of biosignatures from extra-solar planets not too far away in the Milky Way. A few answered that Seti will do the job. One very strange answer was that we will need to find and use a means of faster-than-light communication.

 

[BillTre]

I favor Mars. Easiest to access.

Another answer that I heard a while ago on a Sean Carroll podcast was that detectable artifacts of an advanced technological civilization would include satellites and space probes.
Not sure how to find them, but if found they would have obvious implications.

 

[sunrah]

How will humanity first discover extraterrestrial life?

Most likely through the characterisation of exoplanet atmospheres. With sufficient spectral resolution it should be possible to identify biomarkers such as nitrous oxide which is associated with bacterial origin (SPECTRAL EVOLUTION OF AN EARTH-LIKE PLANET).

I mean a single telescope can survey 1000s of worlds, but a space probe can usually only survey part of one world, so statistically-speaking exoplanet characterisation represents a better use of resources in answering the question of whether extrasolar life (and therefore extraterrestrial life) exists. Of course we must still explore our solar system, but the first real indication of whether life is plentiful or not is likely to be extrasolar in my opinion.

 

[DrStupid]

Most likely through the characterisation of exoplanet atmospheres. With sufficient spectral resolution it should be possible to identify biomarkers such as nitrous oxide which is associated with bacterial origin (SPECTRAL EVOLUTION OF AN EARTH-LIKE PLANET).

That leads to the next question: How long will it take until somebody suggests an abiotic origion of these markers?

 

[sunrah]

That leads to the next question: How long will it take until somebody suggests an abiotic origion of these markers?

https://en.wikipedia.org/w/index.php?title=Nitrous_oxide&action=edit&section=27
From wikipedia "Most of the N2O emitted into the atmosphere, from natural and anthropogenic sources, is produced by microorganisms."

You can go against precedence if you like.

 

[DrStupid]

From wikipedia "Most of the N2O emitted into the atmosphere, from natural and anthropogenic sources, is produced by microorganisms."

The reference [L.L.Sloss, "Nitrogen Oxides Control Technology Fact Book"] doesn't seem to include exoplanets.