←back to thread

First images from Euclid are in

(dlmultimedia.esa.int)
1413 points mooreds | 4 comments | 21 Oct 24 20:15 UTC | HN request time: 0s | source
Show context
lefrenchy ◴[22 Oct 24 02:20 UTC] No.41910562[source]▶
It's just so crazy to me to see a galaxy 420 million light years away. That is so much time for what we're seeing to have changed. I presume life can form within that window given the right conditions, so to some degree it just feels a bit sad that the distance is so great that we can't actually see what may exist in this moment that far away
replies(4): >>41910744 #>>41911556 #>>41911815 #>>41911840 #
vasco ◴[22 Oct 24 02:51 UTC] No.41910744[source]▶
In another way it's really cool to be able to "see the past" even if all we see is always the past. At this level it is like a super power. If only some aliens had put a mirror somewhere far so we could see ourselves too. Or multiple mirrors at different distances.

With enough mirrors and light bouncing around the size of the universe itself can be a "storage media" of the past with different photons all around carrying "how this location looked X years ago". "All" you have to do to know what happened is find the right photon to see whatever it is you want to see.

replies(4): >>41910803 #>>41910868 #>>41911511 #>>41911560 #
1. grahamj ◴[22 Oct 24 03:13 UTC] No.41910868[source]▶
You don't need mirrors, you just need to get in front of the photons. A time machine or warp drive will do :)

Also the past is the only thing you can perceive, there effectively is no now.

replies(1): >>41914760 #
2. densh ◴[22 Oct 24 14:38 UTC] No.41914760[source]▶
Is there a science fiction universe that explores a hypothetical warp drive that lets you travel very far relatively quickly, but the travel is only possible with simultaneous backwards time travel that's proportionate to the distance traversed? So you can hop across star systems but can't do a roundtrip A -> B -> A without significantly shifting time from the point of view of A backwards (irreversibly from the point of view of the traveler).
replies(2): >>41916313 #>>41930853 #
3. grahamj ◴[24 Oct 24 00:59 UTC] No.41930853[source]▶
Consider:

- I leave Earth and travel 1ly at speed c

- I arrive one year later

- An Earth telescope will see the destination as it was when I left

- It will take another year to see me arrive

So in a way that's already happening because I'm traveling quite quickly - twice as fast as it seems from Earth's perspective - and I arrive in what appears from Earth to be the past.

replies(1): >>41944958 #
4. densh ◴[25 Oct 24 13:15 UTC] No.41944958{3}[source]▶
Relativity is so hard to wrap you head around.