Life on Exoplanets

[Slim]

https://www.cam.ac.uk/stories/strongest-hints-of-biological-activity

I suppose most people have heard this news story about a chemical being discovered in the atmosphere of a distant exoplanet. On Earth, dimethyl sulphide is produced by marine microorganisms.

But what I find nearly as amazing as the idea of life on other worlds is the method used to analyse the atmosphere - it's called Transit Spectroscopy. When an exoplanet passes between its star and a telescope's line of sight, a fraction of the star's light passes through the planet's atmosphere. The way it's filtered is analysed using a spectrometer and this can be used to reveal if specific molecules are present.

I find that amazing, that there's enough information in a star's light to analyse the atmosphere of one of its planets. But the method is only viable for a small set of exoplanets - those where the telescope (in this case the JWST), the planet and its star line up exactly.

It's 124 light years from Earth so the analysis is actually of the atmosphere of the exoplanet as it was in 1901.

It's only since the '90s that we've known for sure that exoplanets exist.

[The Picnic Wasp]

I share your fascination for this extraordinary field of science, but I can't help but feel a nagging sense of disappointment about the probable futility of it all. It seems so unrewarding that such human excellence will achieve very little for our species. Detecting molecules in atmospheres trillions of miles from us increases my sadness and frustration that we cannot look after our own.

[Slim]

Just a fantasy really but imagine a sample of the organisms of that world, if they do exist, could be brought to Earth.

Every living thing on Earth is descended from a single microscopic cell that existed around 3.5-3.8 billion years ago. Every fish, chimp, spider, tree, blade of grass, dandelion, hippo, pigeon etc etc.

We're all related. But these things warped here in a test tube somehow wouldn't be. They'd be the first life we've ever known that isn't part of our billions-years-old family tree. Every organism we've ever known shares fundamental similarities because they all descended from that same microscopic blob.

So what might be different? Well we'll probably never know, not in my lifetime anyway.

[Slim]

Imagine that it escaped from a laboratory somewhere .. just a bit of green gunk on someone's shoe .. and it thrived

[Nick]

I assume this light is many years old and the pond slime may now be full on Xenomorphs.

[The Picnic Wasp]

If it's the same or similar molecules detected as produced by marine organisms on Earth, then perhaps the idea that life is spread around the cosmos by hitching a ride could be plausible. Intelligent apes might already be ruining that planet too, although I suppose pollution would be more readily detected

[Thenop]

Imagine that it escaped from a laboratory somewhere .. just a bit of green gunk on someone's shoe .. and it thrived

Invasion of the body snatchers springs to mind.

[David L]

I wouldn't get too excited at this stage. An astrophysicist has just been interviewed on Newsnight and was a bit sceptical, downbeat even. She basically said it's down to the way you interpret the stats. Apparently, the team behind this have made discoveries before and, once analysed by peers, they've been found to be incorrect.
I think this may be more of a "can we have some more money" story.

[Slim]

"we certainly know it can occur in absence of life. Whether we can ever get as much as we've seen here is another question"