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

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

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.

Yeah, you basically need to launch a new one for every target you want to image.

"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

>we move forward

Do you work in something related to Astro?

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.

Probably even many, because it‘s energetically impractical to stop at the focal point.

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.

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.

True but I'd be more convinced by an argument based on tech and engineering constraints than extrapolating a progress line.

Low hanging fruit is easier to pluck. It might be that we cannot progress much further without consuming so many resources that Earth is left an uninhabitable husk.

I agree totally.

That is precisely why we must transition to space based resource extraction and manufacturing.

There are practically infinite resources at our fingertips on the moon, the asteroid belts and eventually the gas giants.

What we need to unlock this are the means to economically launch a minimum viable self replicating infrastructure into space to take advantage of this.

The feedback loops that will ensue should we succeed will allow us to save Earth ecology, radically transform the human condition, and unlock the ability to explore the universe in ways that we can only imagine.

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.