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There’s an image of Europa from Webb in the article.

SoftTalker 3y ago
It's less clear than I'd expected. Is that image deliberately downscaled so as to not reveal the true capabilities of the telescope optics?
- baggy_trough 3y ago
  No, moons are not very big.
- dwaltrip 3y ago
  No, I doubt it. Europa is fairly small and very far away. For reference, the best photos we had of Pluto prior to the fly-by were from the Hubble telescope, and were even grainier.
- mlyle 3y ago
  In addition to moons being big and far away, the specific instrument here (a spectrograph) is not very high resolution-- at least spatially. For each "pixel", it measures the brightness of many wavelengths of light.
- Larrikin 3y ago
  Is this post trying to imply they found aliens and are hiding them?
  - wantoncl 3y ago
    No, just some black monoliths on the surface ;)
- colechristensen 3y ago
  No. JWST is not a spy satellite. Everybody gets the images as measured. Different instruments have different resolutions.
- flangola7 3y ago
  Not reveal the true capabilities? Is this an RPG reference?
- acqq 3y ago
  It's as designed: "Both teams identified the carbon dioxide using data from the integral field unit of Webb’s Near-Infrared Spectrograph (NIRSpec). This instrument mode provides spectra with a resolution of 200 x 200 miles (320 x 320 kilometers) on the surface of Europa, which has a diameter of 1,944 miles"
- TaylorAlexander 3y ago
  Webb has two main instruments and one of them is not very high resolution (but I think it’s the one that gets good spectral data). When you browse the raw Webb images on the nasa website you see a mix of high res and low res images and they are each attributed to one of the two instruments.
- dotnet00 3y ago
  You can probably even find the raw data for the image on one of NASA's sites soon if not already available. This isn't a spy satellite where there's a strategic need to hide the capabilities of the optics. If anything, it's more valuable to show off the capabilities because of how it's somewhat of a prestige project.
- LeifCarrotson 3y ago
  No, they're quite open about the capabilities of the optics (see https://webb.nasa.gov/content/forScientists/faqScientists.html#nircam https://webb.nasa.gov/content/forScientists/faqScientists.ht...). It's just that Europa is very far away. Webb's mirror system has an angular resolution of about 0.1 arcseconds. Earth is currently about 630 million km from Europa (Webb is only 1.5 million km away from earth). Because the sine of theta is approximately equal to theta for values of theta near zero, you can get the diameter of a 0.1 arcsecond cone at x km from Earth by multiplying by 0.00000485 = sin(2pi/3603600). 0.1 0.00000485 * 630000000 = 305 km The article says the pixels are about 320 km, so the math works out pretty close (for astronomy). Those magnificent images of black holes and galaxies that are way more distant, but also way way bigger. This isn't downscaled when you compare it to gorgeous, sharper images like those at [1], a 340 light-year wide multi-image mosaic of the Tarantula Nebula, which is "only" 161000 light years away, that width is 1/500th the distance and Europa's width is 1/20,000th the distance. In space, intuition about distances that you've built up from using your eyeballs on human-scale terrestrial objects just doesn't work, you've got to do the math. [1]: https://www.nasa.gov/feature/goddard/2022/a-cosmic-tarantula-caught-by-nasa-s-webb https://www.nasa.gov/feature/goddard/2022/a-cosmic-tarantula...
  - superhumanuser 3y ago
    This reply is why I love the audience on HN. Thank you for your detailed comment.
  - philomath_mn 3y ago
    For the conspiracy theorists: this is the same reason why we can't just point Webb at the moon and get pictures of the lunar landing sites. In terms of arcseconds of the Webb's FOV, the moon landing site is much smaller than these distant galaxies (which blows my mind just how big those distant "objects" are).
    - ceejayoz 3y ago
      We can image the lunar landing sites with lunar orbiters, though. Footsteps and all! https://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html https://www.nasa.gov/mission_pages/LRO/news/apollo-sites.htm...
- dylan604 3y ago
  Only if your IP address has been listed as suspicious. For the rest of us, we see an non-manipulated image.

It's less clear than I'd expected. Is that image deliberately downscaled so as to not reveal the true capabilities of the telescope optics?

baggy_trough 3y ago
No, moons are not very big.
dwaltrip 3y ago
No, I doubt it. Europa is fairly small and very far away. For reference, the best photos we had of Pluto prior to the fly-by were from the Hubble telescope, and were even grainier.
mlyle 3y ago
In addition to moons being big and far away, the specific instrument here (a spectrograph) is not very high resolution-- at least spatially. For each "pixel", it measures the brightness of many wavelengths of light.
Larrikin 3y ago
Is this post trying to imply they found aliens and are hiding them?
- wantoncl 3y ago
  No, just some black monoliths on the surface ;)
colechristensen 3y ago
No. JWST is not a spy satellite. Everybody gets the images as measured. Different instruments have different resolutions.
flangola7 3y ago
Not reveal the true capabilities? Is this an RPG reference?
acqq 3y ago
It's as designed: "Both teams identified the carbon dioxide using data from the integral field unit of Webb’s Near-Infrared Spectrograph (NIRSpec). This instrument mode provides spectra with a resolution of 200 x 200 miles (320 x 320 kilometers) on the surface of Europa, which has a diameter of 1,944 miles"
TaylorAlexander 3y ago
Webb has two main instruments and one of them is not very high resolution (but I think it’s the one that gets good spectral data). When you browse the raw Webb images on the nasa website you see a mix of high res and low res images and they are each attributed to one of the two instruments.
dotnet00 3y ago
You can probably even find the raw data for the image on one of NASA's sites soon if not already available. This isn't a spy satellite where there's a strategic need to hide the capabilities of the optics. If anything, it's more valuable to show off the capabilities because of how it's somewhat of a prestige project.
LeifCarrotson 3y ago
No, they're quite open about the capabilities of the optics (see https://webb.nasa.gov/content/forScientists/faqScientists.html#nircam https://webb.nasa.gov/content/forScientists/faqScientists.ht...). It's just that Europa is very far away. Webb's mirror system has an angular resolution of about 0.1 arcseconds. Earth is currently about 630 million km from Europa (Webb is only 1.5 million km away from earth). Because the sine of theta is approximately equal to theta for values of theta near zero, you can get the diameter of a 0.1 arcsecond cone at x km from Earth by multiplying by 0.00000485 = sin(2pi/3603600). 0.1 0.00000485 * 630000000 = 305 km The article says the pixels are about 320 km, so the math works out pretty close (for astronomy). Those magnificent images of black holes and galaxies that are way more distant, but also way way bigger. This isn't downscaled when you compare it to gorgeous, sharper images like those at [1], a 340 light-year wide multi-image mosaic of the Tarantula Nebula, which is "only" 161000 light years away, that width is 1/500th the distance and Europa's width is 1/20,000th the distance. In space, intuition about distances that you've built up from using your eyeballs on human-scale terrestrial objects just doesn't work, you've got to do the math. [1]: https://www.nasa.gov/feature/goddard/2022/a-cosmic-tarantula-caught-by-nasa-s-webb https://www.nasa.gov/feature/goddard/2022/a-cosmic-tarantula...
- superhumanuser 3y ago
  This reply is why I love the audience on HN. Thank you for your detailed comment.
- philomath_mn 3y ago
  For the conspiracy theorists: this is the same reason why we can't just point Webb at the moon and get pictures of the lunar landing sites. In terms of arcseconds of the Webb's FOV, the moon landing site is much smaller than these distant galaxies (which blows my mind just how big those distant "objects" are).
  - ceejayoz 3y ago
    We can image the lunar landing sites with lunar orbiters, though. Footsteps and all! https://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html https://www.nasa.gov/mission_pages/LRO/news/apollo-sites.htm...
dylan604 3y ago
Only if your IP address has been listed as suspicious. For the rest of us, we see an non-manipulated image.