What does Earth look like from across the Universe? | Hacker News Reader

What does Earth look like from across the Universe?

bigthink.com

30 pointsHooke16 comments

The article doesn't say anything about the sort of sensing technology that would be required to look at the Earth, for example claiming that 'Earth would clearly show itself as a living, inhabited world' to an observer 55m light years away at Messier 87.

Yeah right.

OT: I chose to listen to the article rather than read it. Was slightly amused that the TTS option read the sentence "8MK from Detroit, Michigan" as "8 Malawian Kwacha from Detroit, Michigan"

Would have thought these engines are better able to parse context by now.

This is about Earth's past, not the universe.

It's about the universe as a potential observer of Earth. It takes two.

Basically everyone in our galactic neighborhood with a nice telescope has already flagged Earth as an interesting place to visit.

among how many other interesting places?

We won't know until we have a nice telescope ourselves.

What is a “nice telescope” in this context?

One capable of measuring atmospheric composition or maybe even surface light of exoplanets from whatever necessary distance. JWST lets us do that for nearby stars. Exciting for sure, but I don't think it will give us a large enough sample size to put meaningful bounds on the abundance of life.

I think he speaks of none other but the telescope that is to come after James Webb. A telescope whose merest operational parameters we are not worthy to calculate - and yet astronomers will design it for you. A telescope which can show us the question to the Ultimate answer, a telescope of such infinite and subtle complexity that organic life itself will form part of its operational matrix. And humanity shall take on new forms and go down into the telescope to navigate its ten million year programme. Yes, we shall design this telescope for you, and the astronomers shall name it for you. And it shall be called the [insert name here].

With apologies to Douglas Adams.

Best be mindful of the Streetlight Effect (including when hiring for a position)!

https://en.m.wikipedia.org/wiki/Streetlight_effect

We keep trying to make inferences about what our nice telescopes can see of other planets. Maybe we should build a nice telescope that points at Earth but is on a Voyager-like trajectory. It could keep sending us images of Earth as it gets further away so we can compare those images to what we see of other planets. It would be a our base reference model.

> with a nice telescope

Not sure about that. Given that we've only discovered a thousand or so exoplanets, and that our galactic neighbourhood contains millions of stars that probably mostly have planets, and that we've only recently spotted any that are Earth-like and in the habitable zone, I'd guess that most inhabitants of the neighbourhood have no idea this planet exists.

I think the obsessive focus on alien life is misguided, and a waste of time and money. It's so certain that there is extraterrestrial life that it would add essentially nothing to our knowledge if we found evidence of life on an exoplanet. We couldn't visit them, they couldn't visit us. If we tried to visit an exoplanet, we'd have evolved into something else by the time we arrived.

So my guess is that there is a very short period in the development of civilisation when "people" (including aliens) are interested in space aliens. I suspect it kicks in when "people" first understand that they are living on a spherical planet orbiting a star, and that there are many, many other stars. And I suspect it fades away when they realize that it can never make any difference to anything.

You're underspecifying the nice telescope.

Knowing your environment is essential to survival. It will never be an uninteresting topic to a civilization.

I've always thought it would be a cool science fiction (or maybe reality one day), where someone figured out how to observe the light coming from Earth from 2000 years ago. They would be able to actually view what happened, in even better detail than we can with satellites today. The implications are what makes this interesting. We could prove whether Jesus existed, how certain events went down, all kinds of stuff that would shake current society to the core. Like I said, science fiction.

Catching up with the light that left Earth 2000 years ago may be a challenge... you'll have to hurry!

Unless someone has conveniently left a large mirror 1000 light-years away, so you can stay home and watch the reflection?

I wonder if such an echo might exist at least for RF emissions from Earth?

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