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What material could lenses and mirrors be made off that is not glass.. just so we do not throw rocks up the well
by Log_out_ 2y ago
What material could lenses and mirrors be made off that is not glass.. just so we do not throw rocks up the well
- gavinsyancey 2y agoWell, the JWST mirrors are made of beryllium
- rqtwteye 2y agoI guess it's not a good idea to lick them.
- dylan604 2y agoI was thinking the same thing. The beryllium is just the support structure. It's the coating of gold specifically for the spectrum JWST is built for, so why not coat the beryllium with a different material for other parts of the spectrum?
- itishappy 2y agoThat's exactly what they do! https://www.edmundoptics.com/knowledge-center/application-notes/optics/metallic-mirror-coatings/ https://www.edmundoptics.com/knowledge-center/application-no...
- ThrowawayTestr 2y agoSome telescopes are made using a big spinning dish of liquid mercury.
- AlgorithmicTime 2y ago[dead]
- johndunne 2y agoYup, these mirrors can only point directly up (zenith telescope). Any adjustment off horizontally to the earth deforms the curve of the mirror. Some liquid mirror telescopes exist today to track space debris. Cheap and useful.
- ortusdux 2y agoMembrane mirrors show promise: https://physicsworld.com/a/membrane-mirrors-take-off-for-use-in-large-space-telescopes/ https://physicsworld.com/a/membrane-mirrors-take-off-for-use...
- FredPret 2y agoFor low-frequency radiation, I wonder if you could build a big and light radio dish in orbit
- dylan604 2y agoWhy not do something similar to VLA instead. So rather than a single "big and light" dish in orbit, you make a constellation of smaller dishes that equal a single larger dish? We know SpaceX is more than capable of that kind of deployment.
- lizknope 2y agoI think the scientists don't think it is worth it. The reason we need the James Webb telescope in space is because the infrared wavelengths it studies are absorbed by the Earth's atmosphere. We can observe a lot of the radio spectrum from ground based telescopes https://en.wikipedia.org/wiki/Atmospheric_window https://en.wikipedia.org/wiki/Atmospheric_window https://en.wikipedia.org/wiki/Radio_window https://en.wikipedia.org/wiki/Radio_window https://en.wikipedia.org/wiki/Radio_telescope#Radiotelescopes_in_space https://en.wikipedia.org/wiki/Radio_telescope#Radiotelescope... > Since 1965, humans have launched three space-based radio telescopes. The first one, KRT-10, was attached to Salyut 6 orbital space station in 1979. In 1997, Japan sent the second, HALCA. The last one was sent by Russia in 2011 called Spektr-R. https://public.nrao.edu/ask/are-there-space-based-radio-telescopes/ https://public.nrao.edu/ask/are-there-space-based-radio-tele... > There have been a few radio telescopes launched into space over the years, most with the purpose of linking with ground-based radio telescopes to form an array with very long baselines (distances between antennas). One such recent project, which ceased operation just a few months ago, is RadioAstron. I don’t believe that there are any currently-operating radio telescopes in space, though.
- namibj 2y agoOne use would be to hide behind the moon to block interference from Earth, at the L2 point in the earth-moon system. Use a laser to, say, a repeater at L4 or L5, and from there further to either LEO or directly the surface.
- itishappy 2y agoMirrors can be made out of just about anything: glass, metal, ceramic, polymer, wood, you name it. The mirror itself is just a reflective coating (typically gold, silver, or aluminum), and it can be as thin as a few nanometers. The trick is shaping it and convincing it to hold that shape, which is why we currently use rigid materials like glass and metal. Something inflatable might work, but more likely we'll just stick with lightweight metals like JWST's beryllium mirrors. However, there's already a lot of rock up there. Asteroids are numerous and big. What's the concern adding more?
- deleted 2y ago[deleted]
- piker 2y agoGiven the reference to “the well”, it’s likely the parent was referring to mass.
- johndunne 2y agoGiven the hexagonal layout of JWST's beryllium mirrors, future telescopes could 'just' increase the size of the mirror by launching multiple payloads of these mirrors and aligning them in space to form one giant layout. It doesn't seem much of a stretch beyond the complexity and single points of failure NASA managed to hurdle with JWST. How hard can it be? ;-)
- deleted 2y ago[deleted]
- bell-cot 2y agoAre you concerned with glass shattering if hit by orbital junk? If so - impacts at orbital velocities tend to create plenty of debris regardless.