10 HN users recommended this explainer9 months2020–2025score 11.5
Years with an HN recommendation, 2007–2026
HN strongly recommends it as the clearest, best-illustrated explanation of the solar gravitational lens idea, and links it whenever exoplanet imaging comes up.
Explains the proposed NASA JPL plan to use the Sun as a gravitational lens, sending solar sail craft to its focal region to image an exoplanet's surface. It covers the distances involved, how imaging with the Sun would work and the mission design.
“It's got some great graphics and visualisations, and is accessibly narrated.” (HN, 2024)
You CAN use for more than 1 target, you just need to reposition the telescope a bit. See [1], is a great great video on the subject. I can't recommend enough [1]: [this video]
Great explanation of solar gravitational lens imaging.
The whole concept is that we should launch a fleet of them every few months. Very lightweight semi-autonomous smart lightsails with some optics. The first fleet helps targeting the second, and all those who come after them. [this video] (already linked by a sibling comment, but yes, can't recommend this enough!)
Fleet of lightsails with optics imaging exoplanets.
This is the space project that most excites me and the one I most hope we solve in my lifetime. Much more interesting than Mars (not that you can't do both). This video on gravitational lensing blew my mind [this video] What do you think the odds are of if it being done IRL?
Mind-blowing explanation of gravitational lensing for exoplanet imaging.
Forget Earth gravitational lenses, let's use the sun: [this video] (The whole video is great.) This setup could resolve the surfaces of exoplanets with its ~100 billion magnification. JPL is investigating.
Explains using the sun's gravitational lens to resolve exoplanet surfaces.
Forget everything else, we need to build THIS : [this video] A telescope array that can use our sun's gravitational lens would enable us to resolve the surfaces of extrasolar planets. We could resolve surface features as small as 10 km across at a distance of 100 light years. JPL is actively investigating this. It's incredibly promising.
Shows a solar gravitational lens telescope array resolving exoplanet surface features.
Christian Ready made a great video on his Youtube channel, Launch Pad Astronomy, about NASA's plans for a solar gravitational lens. It's got some great graphics and visualisations, and is accessibly narrated. I was inspired and learnt a lot of new ideas. [this video] (23 minutes)
Accessible 23-minute video with great graphics on NASA's solar gravitational lens plans.
There is a very high quality video about how Solar Gravitational Lens could be used to map exoplanets, and full explanations about the images reconstruction and engineering challenges: [this video]
Covers exoplanet mapping, image reconstruction and engineering challenges in depth.
Plan to photograph an exoplanet 25 light years away with 25km per pixel resolution (2020) This is fascinating. There is a plan to directly photograph exoplanets by sending a series of telescopes 500+ AU in the opposite direction of what we want to photograph and using the sun as a gravitational lens. We send out waves of these small telescopes to get pictures at various focal planes. This video has a good description of the paper: [this video]
Good description of the paper on imaging exoplanets via the solar lens.
This video linked by another commenter explains it quite well: [this video] Basically, it's possible to generate an image of an exoplanet, but "retargeting" the telescope(s) to observe another object is not feasible. So you'd better make sure the target that the mission will focus upon is actually worth the attention it gets - but there are other planned telescopes that will be capable of generating data that will allow selecting potential candidates.
Explains well how exoplanet imaging works and why retargeting is infeasible.
And hopefully some day we'll build a solar-gravitation lens to look at the surface of one of these exoplanets: [link] ...with a very interesting video that someone made on that paper: Someone also made an interesting Youtube video of the concept: [this video]
Interesting video of the solar gravitational lens concept.
> A maintenance-free power source capable of lasting the 200 or so years it would take to make it to 542 AU It wouldn't take nearly that long. The proposal is to use solar sails. There is a nice video about the details on YouTube: [this video]
Details solar sail approach to reaching the solar lens focal region.
A recent video talking about what it could take to get high resolution imagery of exoplanets. The video title is a bit hand wavy, but it basically involves using the sun as a gravitational lens: [this video]
Using the sun as gravitational lens for exoplanet imaging.
Its so interesting to watch this technology evolve, life and uncut. Its almost as if every other day another milestone is revealed. Especially as its a tech that one doesn't work with (mechanical engineering / rocket motor engineering etc). Looking forward for all the great space missions that will be made possible by this (europa, enceladus, more comet missions & many more space-telescopes), not so much for humanity becoming multi-planetary, as the scientific value is lower imo. E.g. a great project: [this video]
I heard about this fascinating idea of using the gravitational lensing of our own sun to image the surface of exoplanets: [this video] It wouldn't look like any telescope you might have ever seen. Once we have a candidate exoplanet we want to take a picture of we would launch a flock of free-flying solar-sail propelled satellites in such an orbit that they get yeeted away from the sun on a trajectory opposite of the target exoplanet. They would travel to the "focal plane" of the sun's gravitational lens where the exoplanet's light is smeared to a ring around the sun which they collaboratively capture. Probably one such a pass wouldn't be enough, so we would need to send such flocks multiple times, like waves following on each other. What I love about the plan is that it is both super scifi, yet we already have all the components to make it happen if we want to.
Fascinating idea of imaging exoplanet surfaces using sun's lensing.
That seems to exemplify design by committee. So we'll learn that Uranus has 37% more lightning than we previously thought. I'd much rather see a Europa lander. Better yet, a Europa melt-though-the-ice probe. A solar gravitation lens for exoplanets [1] study fleshed out. A Venus blimp thingy. Mars polar lander. Something with more vision. [1] [this video]
Solar gravitational lens as a more visionary mission.
The Solar Gravitational Lens is very neat but with current propulsion technology it would take a very long time to get the satellites into position. [this video]
Solar gravitational lens, though limited by propulsion.
This is fantastic, thank you! > and finally direct imaging isn't currently feasible for G-type stars like our sun. > Radial velocity requires about two orders of magnitude better detectors, astrometry requires about one order of magnitude more sensitive instruments, > direct imaging at resolutions that'd require a leap in technology and capabilities. Any wild guess for when we'll be able to build these? [this video] [link] Is this feasible at all?
That is awesome. I'm looking forward to seeing the results of unscrambling the ring to see what the galaxy behind looks like. Hopefully someday we will be able to use a solar gravitation lens to look at neighboring exoplanets: [this video] [link]
Video list and Hacker News comment labels from HackerTube (prompted by @karpathy), released under ODC-By 1.0, built on the open-index/hacker-news archive. Hacker News data is provided by Y Combinator; comments remain the work of their authors. Video titles, channel names and thumbnails belong to their creators and are shown via YouTube. HackerTube Watch is an unofficial edition. Data export of 2026-10-31.
Plays via YouTube's privacy-enhanced embed
20 Hacker News comments
From the HN archive; up to 20 kept per video, favoring different commenters. Recommendations first.
Citations, criticism and jokes
Read more