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Fund the SGL Telescope! https://www.universetoday.com/149214/if-we-used-the-sun-as-a-gravitational-lens-telescope-this-is-what-a-planet-at-proxima-centauri-wou

by ck2 2y ago

Fund the SGL Telescope! https://www.universetoday.com/149214/if-we-used-the-sun-as-a-gravitational-lens-telescope-this-is-what-a-planet-at-proxima-centauri-would-look-like/ https://www.universetoday.com/149214/if-we-used-the-sun-as-a... Seriously, we could build that, it's at the limit of our tech but if it was either we walk on the moon again or build SGL, I'd pick SGL

dmix 2y ago
I made this comment before but someone on HN made a good argument is way harder than it sounds and given it's size/cost/function it'd basically have to point in one direction, it's not like an easily moveable telescope you can scan around with.
- skykooler 2y ago
  Yeah, you basically need to launch a new one for every target you want to image.
  - Tomte 2y ago
    Probably even many, because it‘s energetically impractical to stop at the focal point.
    - skykooler 2y ago
      The neat thing about a how an Einstein ring works is that you don't need to stop, because rather than there being a focal point, there is a focal line, moving directly outward from the Sun. This means a probe could spend potentially decades imaging the same target on its outward path, if it had sufficient power.
  - Voultapher 2y ago
    I'd think to make it practical you'd have to have kind of (semi-) automatic space based assembly infrastructure that builds them and launches them. Launching these probes individually seems like it would be impractical. Building that infrastructure wouldn't be easy at all and I don't see that happening in the next 50 years.
- ck2 2y ago
  "way harder than it sounds" is how we move forward walking on the moon was beyond our limits when it was announced JWST was insanely hard and almost cancelled a few times, look at it now
  - moralestapia 2y ago
    >we move forward Do you work in something related to Astro?
  - dleary 2y ago
    This is true, but also, keep in mind that the JWST was insanely hard and almost cancelled a few times :) The SGL would be much, much harder than the JWST would be, and the JWST was already stretching our capabilities. The SGL needs to be 650AU away from us. Voyager 1 and 2 are currently 165AU and 120AU away. The JWST is 0.01 AU from us. And you can only look in one direction after the probe finally gets into position. Once you're 650AU away, it's not really feasible to move "sideways" far enough to look at something else.
    - Teever 2y ago
      The ratios between 650AU, 165AU, and 0.01AU are somewhat moot. In 1957 Sputnik 1 had an apogee of ~900km from the Earth. By 1969 NASA was sending rockets ~385000km to the moon. By 1979 Voyager 1 & 2 were reaching Jupiter ~5AU from Earth. We went from 900km to 5AU in 22 years. If SpaceX achieves their stated goals of lowering $/kg to orbit and rapid re-usability with Starship it will unlock things like asteroid/lunar mining and space based manufacturing which will allow the construction of the kind of infrastructure needed to make distances like 650AU achievable in reasonable time frames.
      - hehehheh 2y ago
        True but I'd be more convinced by an argument based on tech and engineering constraints than extrapolating a progress line.
      - paulryanrogers 2y ago
- deleted 2y ago
  [deleted]

by ck2 2y ago

dmix 2y ago

I made this comment before but someone on HN made a good argument is way harder than it sounds and given it's size/cost/function it'd basically have to point in one direction, it's not like an easily moveable telescope you can scan around with.

skykooler 2y ago
Yeah, you basically need to launch a new one for every target you want to image.
- Tomte 2y ago
  Probably even many, because it‘s energetically impractical to stop at the focal point.
  - skykooler 2y ago
    The neat thing about a how an Einstein ring works is that you don't need to stop, because rather than there being a focal point, there is a focal line, moving directly outward from the Sun. This means a probe could spend potentially decades imaging the same target on its outward path, if it had sufficient power.
- Voultapher 2y ago
  I'd think to make it practical you'd have to have kind of (semi-) automatic space based assembly infrastructure that builds them and launches them. Launching these probes individually seems like it would be impractical. Building that infrastructure wouldn't be easy at all and I don't see that happening in the next 50 years.
ck2 2y ago
"way harder than it sounds" is how we move forward walking on the moon was beyond our limits when it was announced JWST was insanely hard and almost cancelled a few times, look at it now
- moralestapia 2y ago
  >we move forward Do you work in something related to Astro?
- dleary 2y ago
  This is true, but also, keep in mind that the JWST was insanely hard and almost cancelled a few times :) The SGL would be much, much harder than the JWST would be, and the JWST was already stretching our capabilities. The SGL needs to be 650AU away from us. Voyager 1 and 2 are currently 165AU and 120AU away. The JWST is 0.01 AU from us. And you can only look in one direction after the probe finally gets into position. Once you're 650AU away, it's not really feasible to move "sideways" far enough to look at something else.
  - Teever 2y ago
    The ratios between 650AU, 165AU, and 0.01AU are somewhat moot. In 1957 Sputnik 1 had an apogee of ~900km from the Earth. By 1969 NASA was sending rockets ~385000km to the moon. By 1979 Voyager 1 & 2 were reaching Jupiter ~5AU from Earth. We went from 900km to 5AU in 22 years. If SpaceX achieves their stated goals of lowering $/kg to orbit and rapid re-usability with Starship it will unlock things like asteroid/lunar mining and space based manufacturing which will allow the construction of the kind of infrastructure needed to make distances like 650AU achievable in reasonable time frames.
    - hehehheh 2y ago
      True but I'd be more convinced by an argument based on tech and engineering constraints than extrapolating a progress line.
    - paulryanrogers 2y ago
deleted 2y ago
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