tl;dr From the linked article: "The biosignature detected on K2-18 b is a molecule called dimethyl sulfide, a smelly substance that on Earth is produced only by living organisms."
A question I’ve always had is, assuming we do pick up very strong signatures or signals of life very far out, would it ever make sense (or, is it even possible) to create a ginormous optical telescope in space that could attempt to take pictures at a resolution that would be the next best thing to being there?
How big would it have to be in order to get a Google Earth resolution on a planet many light years away?
> How big would it have to be in order to get a Google Earth resolution on a planet many light years away?
If you're ok to settle for a lower resolution, then a couple hundred astronomical units. Surprisingly, this may actually be feasible by using the sun as a gravitational lens. It would just take a lot of time to get the light collecting instrument in position at the focal point.
To use the Sun, the focal point would have to be situated about 542 AUs. Certainly not impossible, and the resolution would be quite good, good enough to see surface details of an exoplanet.
That's one approach to use the sun as a gravitational lens for looking at exoplanets. There's another approach that instead of one big telescope sends a series of much smaller telescopes, small enough that light sails would be effective for getting them to where they need to go.
Here's a PBS Space Time episode [1] that talks about this general topic, and then about the series of smaller telescopes approach.
Google Earth resolution? You'd need satellites in low orbit around that planet.
For taking images from earth, the resolution would depend on the size and distance of the planet. Within a couple hundred light-years a $10b starshade spacecraft may be able to get a 30px by 30px optical image.
The physics are pretty limiting.
(this is all from memory, I worked as an engineer at an astrophysics institute for 8 yrs, but left that job almost two years ago, so the raw numbers are a bit rusty)
Consider that only last year they managed to image a star to a resolution greater than a single point, and that a planet is much smaller and much fainter. "Ginormous" doesn't quite convey the size of the aperture you'd need.
Update: Experts are pushing back against the Spectator's reporting — including one source quoted by the magazine who says her remarks were taken out of context.
I love the Spectator for its writing (I've been a subscriber for over 30 years), but I would never believe any news reporting that might creep in. It's like a 200 year old blog for conservatives (which I am not) who write about whatever they feel like.
For example: Boris Johnson is a meretricious nitwit but the magazine while he was editor was probably at its best since I've been reading it. You can imagine reading it would be a lot of fun but would you actually believe anything you read?
I do like to imagine that there's almost certainly intelligent extraterrestrial life in frame in at least one of the JWST photos... Depending on what you plug into Drake's, I suppose.
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[ 3.4 ms ] story [ 78.5 ms ] threadhttps://news.ycombinator.com/item?id=37468342 (135 comments)
From Ars, 3 days ago, a more cautious article: https://arstechnica.com/space/2024/01/no-the-james-webb-spac...
i thought the webb was a telescope, not a smelloscope
https://i.redd.it/v453jfa9nky01.jpg
How big would it have to be in order to get a Google Earth resolution on a planet many light years away?
If you're ok to settle for a lower resolution, then a couple hundred astronomical units. Surprisingly, this may actually be feasible by using the sun as a gravitational lens. It would just take a lot of time to get the light collecting instrument in position at the focal point.
https://news.stanford.edu/press-releases/2022/05/02/gravity-...
Edit: the Stanford press release says that without exploiting gravitational lensing, "we would need a telescope 20 times wider than the Earth".
Here's a PBS Space Time episode [1] that talks about this general topic, and then about the series of smaller telescopes approach.
[1] https://www.youtube.com/watch?v=4d0EGIt1SPc
For taking images from earth, the resolution would depend on the size and distance of the planet. Within a couple hundred light-years a $10b starshade spacecraft may be able to get a 30px by 30px optical image.
The physics are pretty limiting.
(this is all from memory, I worked as an engineer at an astrophysics institute for 8 yrs, but left that job almost two years ago, so the raw numbers are a bit rusty)
Having 'Been there, Done that', I speak from personal experience.
For example: Boris Johnson is a meretricious nitwit but the magazine while he was editor was probably at its best since I've been reading it. You can imagine reading it would be a lot of fun but would you actually believe anything you read?