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JWST reveals its first direct image discovery of an exoplanet

(www.smithsonianmag.com)
342 points divbzero | 2 comments | 27 Jun 25 17:44 UTC | HN request time: 0.48s | source
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GMoromisato ◴[27 Jun 25 23:00 UTC] No.44401068[source]▶
In case anyone is wondering, we are (sadly) very far from getting an image of this planet (or any extra-solar planet) that is more than 1 pixel across.

At 110 light-years distance you would need a telescope ~450 kilometers across to image this planet at 100x100 pixel resolution--about the size of a small icon. That is a physical limit based on the wavelength of light.

The best we could do is build a space-based optical interferometer with two nodes 450 kilometers apart, but synchronized to 1 wavelength. That's a really tough engineering challenge.

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GolfPopper ◴[28 Jun 25 00:05 UTC] No.44401398[source]▶
We can do better than that! Using the Sun as a gravitation lens[1], and a probe at a focal point of 542 AU, we could get 25km scale surface resolution on a planet 98 ly away. [2] This would be an immense and time-consuming endeavor, but does seem to be within humanity's current technological capabilities.

1. https://en.wikipedia.org/wiki/Solar_gravitational_lens

2. https://www.nasa.gov/general/direct-multipixel-imaging-and-s...

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GMoromisato ◴[28 Jun 25 00:40 UTC] No.44401520[source]▶
Agreed! This might be easier than an interferometer. You just need a lot of delta-v
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cedws ◴[28 Jun 25 04:18 UTC] No.44402272[source]▶
How do you decelerate once you get there though?
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1. GMoromisato ◴[28 Jun 25 04:50 UTC] No.44402363[source]▶
By “delta-v” I mean propellant budget, not initial velocity. So you spend half your delta-v to accelerate out and the other half to decelerate.

But of course, the initial delta-v costs a lot of propellant because it has to push an almost full tank. By the time we have to decelerate the ship will be a lot lighter.

That’s why you needed a full Saturn 3rd stage to send Apollo to the moon, but just the service module to get back to Earth.

I realize now that “a lot of delta-v” is an understatement. 500 AUs is ridiculously far. To get there in under a century you’d need fission-fraction reactors, well beyond our current tech.

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2. kadoban ◴[28 Jun 25 05:45 UTC] No.44402526[source]▶
> I realize now that “a lot of delta-v” is an understatement. 500 AUs is ridiculously far. To get there in under a century you’d need fission-fraction reactors, well beyond our current tech.

Voyager 1 is 166 AU away, it launched about 50 years ago. So wouldn't we just have to do about twice as well as that, or launch 2 of them in opposite directions? That sounds _very_ hard (Voyager is amazing), but it can't be beyond our current tech, right? We did fairly close to that 50 years ago.