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Two galaxies aligned in a way where their gravity acts as a compound lens

(phys.org)
268 points wglb | 2 comments | 16 Nov 24 16:48 UTC | HN request time: 0s | source
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ck2 ◴[16 Nov 24 18:30 UTC] No.42158113[source]▶
Fund the SGL Telescope!

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

replies(1): >>42158166 #
dmix ◴[16 Nov 24 18:36 UTC] No.42158166[source]▶
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.
replies(3): >>42158333 #>>42158395 #>>42159127 #
skykooler ◴[16 Nov 24 18:55 UTC] No.42158333[source]▶
Yeah, you basically need to launch a new one for every target you want to image.
replies(2): >>42158794 #>>42159135 #
1. Tomte ◴[16 Nov 24 19:58 UTC] No.42158794[source]▶
Probably even many, because it‘s energetically impractical to stop at the focal point.
replies(1): >>42161460 #
2. skykooler ◴[17 Nov 24 02:19 UTC] No.42161460[source]▶
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.