4 ms·

Dumb question. Why can’t we focus on a single exoplanet, look for mountains, grass, buildings? Why am I so stupid but isn’t this the obvious thing to do?

whatshisface 4y ago
There aren't telescopes big enough to do that.
- anewpersonality 4y ago
  - capableweb 4y ago
    > Seeing a bunch of pretty nebulae with artificial colorimg is no longer inspiring, it looks like it could have come out of DALL-E Yeah, that's totally how science works! You can't confirm/reject any theories based on pictures that a AI generates, but I guess you'll tell me that "sure we can" with some more hyperbole.
  - throwaway4aday 4y ago
    If you're not inspired by these images and the accompanying detail on why they are being taken (especially the exoplanet spectroscopic surveys) then you just aren't thinking hard enough about them.
ceejayoz 4y ago
We can, and do. They're so far away that even our largest telescopes see only a few pixels. Examples: https://en.wikipedia.org/wiki/File:HR_8799_Orbiting_Exoplanets.gif https://en.wikipedia.org/wiki/File:HR_8799_Orbiting_Exoplane... https://en.wikipedia.org/wiki/File:Beta_Pictoris_b_in_Motion.webm https://en.wikipedia.org/wiki/File:Beta_Pictoris_b_in_Motion... When Hubble looked at Pluto, it was a low-detail blur ("The Hubble raw images are a few pixels wide"), and that's within our solar system. https://esahubble.org/images/opo1006h/ https://esahubble.org/images/opo1006h/ Remember, the first exoplanet was detected in 1992, and not by imaging; prior to that we didn't even know if they existed at all. JWST's planning started in 1996.
sephamorr 4y ago
There is a fundamental physics limit at play here: the diffraction limit is linear with the aperture diameter and gives an upper bound on the resolution of a telescope. Having a longer exposure doesn't help - that's for resolving very faint objects (more light collected -> higher signal-to-noise). To resolve a building-sized object on an exoplanet, regardless of its intensity, we'd need a telescope the size of the solar system. There are some proposals to use the gravitational lensing of our sun to create such a telescope, but those projects are decades at least from implementation.
- anewpersonality 4y ago
  This is a good answer, though incredibly depressing
- m0giddo 4y ago
  Here's an example of one of the proposals: https://en.wikipedia.org/wiki/FOCAL_(spacecraft) https://en.wikipedia.org/wiki/FOCAL_(spacecraft)
throwaway5752 4y ago
Maybe the link changed, but the 5th link down the page, "July 12, 2022 Release ID: 2022-032", is "Webb Reveals Steamy Atmosphere of Distant Planet in Exquisite Detail ", link is https://webbtelescope.org/contents/news-releases/2022/news-2022-032?Collection=First%20Images https://webbtelescope.org/contents/news-releases/2022/news-2...
- anewpersonality 4y ago
  Thats a spectograph
  - ceejayoz 4y ago
    Yes, and if we do a spectral analysis on a small rocky exoplanet and find a bunch of oxygen, that tells us a lot more exciting information than the 2x2 pixels you might get from an image of it.
dougmwne 4y ago
It’s because those planets are incredibly far away. The distance is so huge, there is no way to even picture it. It would be a single pixel on any telescope we could conceivably build. What we can do though is measure the chemical composition of their atmospheres. This could be very interesting if we found some hallmarks of life on a rocky planet.
worker_person 4y ago
Need a really big mirror, like size of planet to start with. Another neat idea is to use the Sun as a gravitational lens. But you you would need it put it way past Pluto to get proper focus. So maybe another hundred years to get tech and resources to that point. https://www.space.com/earth-like-exoplanet-imaging-with-sun https://www.space.com/earth-like-exoplanet-imaging-with-sun
pkaye 4y ago
How much details we can see if based on the wavelength of light and the diameter of the telescope. And if you worked it out, the telescope diameter would have to be enormous. https://calculator.academy/diffraction-limit-calculator/#f1p1|f2p0 https://calculator.academy/diffraction-limit-calculator/#f1p... However gravity can bend light so there is some thought of using the sun as a lens. However the observation would have to be pretty far away from our sun so its just wishful thinking in our lifetime. https://www.freethink.com/space/gravity-telescope https://www.freethink.com/space/gravity-telescope For now the best we will have to see a dot on image via coronagraphy and maybe understand more about the exoplanet through spectroscopy.

whatshisface 4y ago

There aren't telescopes big enough to do that.

anewpersonality 4y ago
- capableweb 4y ago
  > Seeing a bunch of pretty nebulae with artificial colorimg is no longer inspiring, it looks like it could have come out of DALL-E Yeah, that's totally how science works! You can't confirm/reject any theories based on pictures that a AI generates, but I guess you'll tell me that "sure we can" with some more hyperbole.
- throwaway4aday 4y ago
  If you're not inspired by these images and the accompanying detail on why they are being taken (especially the exoplanet spectroscopic surveys) then you just aren't thinking hard enough about them.

ceejayoz 4y ago

We can, and do. They're so far away that even our largest telescopes see only a few pixels. Examples: https://en.wikipedia.org/wiki/File:HR_8799_Orbiting_Exoplanets.gif https://en.wikipedia.org/wiki/File:HR_8799_Orbiting_Exoplane... https://en.wikipedia.org/wiki/File:Beta_Pictoris_b_in_Motion.webm https://en.wikipedia.org/wiki/File:Beta_Pictoris_b_in_Motion... When Hubble looked at Pluto, it was a low-detail blur ("The Hubble raw images are a few pixels wide"), and that's within our solar system. https://esahubble.org/images/opo1006h/ https://esahubble.org/images/opo1006h/ Remember, the first exoplanet was detected in 1992, and not by imaging; prior to that we didn't even know if they existed at all. JWST's planning started in 1996.

sephamorr 4y ago

There is a fundamental physics limit at play here: the diffraction limit is linear with the aperture diameter and gives an upper bound on the resolution of a telescope. Having a longer exposure doesn't help - that's for resolving very faint objects (more light collected -> higher signal-to-noise). To resolve a building-sized object on an exoplanet, regardless of its intensity, we'd need a telescope the size of the solar system. There are some proposals to use the gravitational lensing of our sun to create such a telescope, but those projects are decades at least from implementation.

anewpersonality 4y ago
This is a good answer, though incredibly depressing
m0giddo 4y ago
Here's an example of one of the proposals: https://en.wikipedia.org/wiki/FOCAL_(spacecraft) https://en.wikipedia.org/wiki/FOCAL_(spacecraft)

throwaway5752 4y ago

Maybe the link changed, but the 5th link down the page, "July 12, 2022 Release ID: 2022-032", is "Webb Reveals Steamy Atmosphere of Distant Planet in Exquisite Detail ", link is https://webbtelescope.org/contents/news-releases/2022/news-2022-032?Collection=First%20Images https://webbtelescope.org/contents/news-releases/2022/news-2...

anewpersonality 4y ago
Thats a spectograph
- ceejayoz 4y ago
  Yes, and if we do a spectral analysis on a small rocky exoplanet and find a bunch of oxygen, that tells us a lot more exciting information than the 2x2 pixels you might get from an image of it.

dougmwne 4y ago

It’s because those planets are incredibly far away. The distance is so huge, there is no way to even picture it. It would be a single pixel on any telescope we could conceivably build. What we can do though is measure the chemical composition of their atmospheres. This could be very interesting if we found some hallmarks of life on a rocky planet.

worker_person 4y ago

Need a really big mirror, like size of planet to start with. Another neat idea is to use the Sun as a gravitational lens. But you you would need it put it way past Pluto to get proper focus. So maybe another hundred years to get tech and resources to that point. https://www.space.com/earth-like-exoplanet-imaging-with-sun https://www.space.com/earth-like-exoplanet-imaging-with-sun

pkaye 4y ago

How much details we can see if based on the wavelength of light and the diameter of the telescope. And if you worked it out, the telescope diameter would have to be enormous. https://calculator.academy/diffraction-limit-calculator/#f1p1|f2p0 https://calculator.academy/diffraction-limit-calculator/#f1p... However gravity can bend light so there is some thought of using the sun as a lens. However the observation would have to be pretty far away from our sun so its just wishful thinking in our lifetime. https://www.freethink.com/space/gravity-telescope https://www.freethink.com/space/gravity-telescope For now the best we will have to see a dot on image via coronagraphy and maybe understand more about the exoplanet through spectroscopy.