4 HN users recommended this explainer5 months2020–2025score 5
Years with an HN recommendation, 2007–2026
HN people point to it as an excellent explanation of using Earth's atmosphere or gravity as a lens in astronomy threads.
David Kipping presents his proposed Terrascope, a telescope that uses Earth's atmosphere as a lens to achieve enormous magnification. He covers the history of telescopes and his path to the idea, plus Sol-scope and Jupiter-scope variants.
You can pretty much make a telescope as large as you'd like, depending on your technological level. Hypothetically, you can use gravitational lensing to make a telescope via the sun! It's rather unfeasible at our current level of rocketry, but in time, maybe! Article: [link] You can also use Earth's atmosphere as a lens too! It's an amazing video: [this video] Going even crazier, I can imagine we could some day use a massive black hole as a giant telescope.
Using Earth's atmosphere as a lens for telescopes.
I love the idea of using gravitational lensing of the sun from a lagrange point around Jupiter. IIRC it theoretically could image an earth like planet in the region of 1000px x 1000px so you could see continents and weather systems - perhaps even light from large cities. I watched a great "Cool Worlds" video as well that said you could do similar with atmospheric lensing of the earth from a lagrange point near the moon (although it would filter out some visible light wavelengths and be weather dependant) - but potentially a much cheaper mission: [this video] This would be going full circle in terms of telescope technology, we started with lenses, moved to mirrors and now back to lenses! To me these seem like the most exciting missions ever - could define a new epoch for humanity and inspire and excite hundreds of millions of people. I would be very disappointed if this didn't happen in my life.
Cheaper atmospheric lensing mission using Earth from a lagrange point.
An excellent video on this: [this video] Earths atmosphere and weather affects this sort of telescope IIRC and will filter out some lightwaves but seems like a much easier win
You might be interested in this video which talks about using the Earth's gravity to create a telescope with a lens roughly the size of the Earth (a terrascope): [this video] They also have a follow up video about using Jupiter to create a jovoscope and there's also more about creating a telescope using the sun (although since the sensor would need to be so far away from the Sun, we would essentially need to launch a different spaceship for each target that we tried to image).
Need many images to superimpose them into a single computed image. David Kipping has a great video on it [this video] We would need a train of probes being sent in a row because there is a limited amount of time they will pass through the focal area.
Great video on imaging with Earth-lens focal region.
personally, hearing this makes me happy, can't wait till it's built. Has anyone heard of terrascopes? (telescopes using celestial bodies) [this video] if it is workable, it sounds fantastical but probably not something I'd see in my lifetime either way
Introduces terrascope idea of using Earth as a telescope.
Yeah, that sounds similar to the idea of the Terrascope. I think the positioning of drones for the sun might be so wide to be infeasible for the next century. (Like, the drones would have to be in the Kuiper belt) I haven't watched this YT video recently, but I think he also touches on a Sol-scope and a Jupiter-scope [this video]
Covers terrascope plus Sol-scope and Jupiter-scope ideas.
good old Space Time has a pretty good video on this [link] and it might even be possible and more feasible to use planets [link] and even earth [this video] as lenses
Not quite, if I understand it correctly. This is like chapter ~one of book one (if you skip over the tangential Chinese politics stuff that I didn't understand on my second read either), so not really a spoiler. In the book it's some magic amplification that happens inside the sun, not based on a physical effect we've actually observed in real life as far as I know. In this case, it's about gravitational lensing (when using the sun) and additionally atmospheric refraction (when using the earth; terrascope). I'm also not sure we could use this, as in 3BP, to send anything. What this does is collect light rays coming in essentially parallel and focus it on a line along which we can place a detector. If we emit from somewhere along that line, it would be scattered as a ring the size of the lens (the earth or sun, in the examples, plus whatever altitude we use to avoid clouds or corona) because the rays are basically parallel from there. At least, that's my guess. I didn't understand even what my high school teacher tried to explain about lenses so this is speculation based on a drawing I saw in the terrascope video linked elsewhere in the thread ( [this video] ).
I think Tipping of the Cool Worlds youtube channel did a video that we can just use earth for the gravitational lensing and that would be far cheaper [this video]
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