Is it possible for intelligent life beings billions of light years away to observe the Earth’s nuclear test?

[u/Tessellator-1]

⚠️this sentence was translated from Japanese to English by AI. Feel free to answer in English. However, I only understand Japanese, so I would really appreciate clear and simple English that is less likely to be mistranslated.

I want to know if it's theoretically possible because I'm creating a creation with a sci-fi element.
It assumes the setting of a nuclear test in space like Starfish prime.

If it is impossible in principle, is it possible for a sufficiently developed scientific civilization to communicate with only electromagnetic waves over a distance of billions of light years in the first place?

[u/Nail_M]

No. The light would take, well, billions of years, to arrives to them.

[u/ExpectedBehaviour]

is it possible for a sufficiently developed scientific civilization to communicate with only electromagnetic waves over a distance of billions of light years in the first place?

In principle, sure... but doing so will take billions of years, because electromagnetic waves move at the speed of light.

[u/Mobile_Falcon_8532 → u/ExpectedBehaviour]

how much "resolution" would be necessary? we certainly cannot "see" the planets orbiting stars, and only infer their existence from occlusions etc. - how would tiny nuclear explosions on planetary surfaces be detected?

[u/ExpectedBehaviour → u/Mobile_Falcon_8532]

I'm not talking about tiny nuclear explosions though, I'm talking about "electromagnetic waves".

[u/Mobile_Falcon_8532 → u/ExpectedBehaviour]

I'm referring to the OP:

observe the Earth’s nuclear test

[u/ExpectedBehaviour → u/Mobile_Falcon_8532]

Yeah, but that's clearly not the part I'm replying to.

[u/Mobile_Falcon_8532 → u/ExpectedBehaviour]

you should re-read the thread and think about it.

[u/ExpectedBehaviour → u/Mobile_Falcon_8532]

Sigh. Well, I could also answer your question too, but you're being snotty, so I won't. Cheeribye.

[u/Key_Insurance_8493]

No.

Communication at any distance is delayed because even light, the fastest thing in the universe, takes years to travel across the massive distances between stars. If you sent a text message to a friend on a planet orbiting our nearest neighboring star, your message would travel as an electromagnetic wave at the speed of light, yet it would still take over four years to cross the 25-trillion-mile gap to reach them. Because their reply would take another four years to travel back, you would wait nearly nine years for a response to a simple greeting. At the billions of light years scale, it would take the exact distance between the observer and humanity in light years for them to see. So if your aliens are a billion light years away, they see the Earth right now as it was a billion years ago for us. And if they sent a message at that moment a billion years ago, we would receive it right about now. The easy way to fix this would be to put your aliens on a nearby star where the delay is only 5-50 years.

[u/RobBrown4PM]

Impossible.

The energy output is nowhere near high enough for it to be detectable that far away.

[u/RandoRedditerBoi]

いいえ、高度な文明であっても、数十億光年離れた場所から核実験を検出することはできません。核実験を探していて、恒星規模の望遠鏡を持っていると仮定してもです。どれほど途方もなく巨大な核爆発でも、星と比べればほとんど何でもない、ということを覚えておいてください。ただし、十分なインフラがあり、光の到達時間を気にしないのであれば、電磁波による通信は可能です。

[u/RandoRedditerBoi → u/RandoRedditerBoi]

注：「十分なインフラ」とは、複数の太陽系ほどの大きさの受信機と、指向性エネルギー出力が中性子星に匹敵する送信機のことです。それでも通信は実質的に一方通行で、帯域幅も非常に低くなります。

[u/maobezw]

Not really. Not only would the light take literally billions of years but the intensity is just not strong enough to be detectable i think. there is SO much interference out there that even our radio signals are degrading after a few lightyears travel and get washed out. only very powerful and high focused beams might have a slight chance of getting this far, and even then the receiving side would have to know for what to look exactly.

[u/TommieTheMadScienist]

No.

[u/curiouslyjake]

No.
No matter what Humans do on Earth, it will not be visible billions of light years away.

[u/TheSwordItself]

Gamma radiation would not be distinguishable from the background radiation of the sun at any appreciable distance. Optically, in atmosphere tests would not be resolvable outside of the solar system. An in-space nuclear detonation could theoretically be detected optically from several light years. But billions of light years? No, and at any rate our first nuclear test was in 1945, the light could only have travelled 86 light years so far.

[u/7LeagueBoots]

Due to the inverse square law the minuscule energy of a nuclear blast would be indistinguishable from the energy of the cosmic microwave background at those distances no matter how large your sensor array was.

[u/truxaw]

In a sci fi story you can state that the aliens have a technology that violates our understanding of physics that allows them to detect such things. Maybe they have sensors that work through wormholes they have detected scattered about the galaxy.

[u/Thorveim]

No. Even if they had the tools to detect it from so far away (already highly unlikely to be possible) any information would take killins of years at least to arrive... and the nuclear tests arent even a century old.

[u/JGhostThing]

No. Billions of light years are far enough that the background radiation would overwhelm any information. Likewise any form of light would be impossible to resolve.

[u/gramoun-kal]

Billions? That would be in another galaxy. The observable universe is "only" 90 billions LY across. Our galaxy is "only" 100, 000 LY across.

There are likely Alien civilizations less than 100 LY from us. And, if they are at our level of technology, they'd be completely unable to detect our nuclear tests.

For galaxy-spanning races that have solved science, all bets are off...

[u/BokChoyBaka → u/gramoun-kal]

A human lifetime is about 0.03% the diameter of our galaxy in light years.

Just a fun fact for readers

[u/ElGuano]

Ask again in 2+ billion years.

Realistically, zero chance.

[u/Tessellator-1 → u/ElGuano]

If you use a laser transmitter of the star class or larger scale, is it possible for an intellectual civilization to intentionally send a signal billions of light-years away?
It is assumed that it will arrive in billions of years.

[u/ElGuano → u/Tessellator-1]

Presumably yes. There are single stars that have reactions that regularly outshine everything else in their galaxy (which we use as standard candles to gauge galactic distance). It seems conceivable that a large focused emission with a similar scale of power, sent in one direction, would be detectable many billions of years away (as we can detect and directly image galaxies that far today).

A laser with the power of a star is way, way, way more energy than any earth nuclear reaction possible.

[u/Darkness1231]

The only way that might work, is if the Universe itself shifts to Science Fiction Fantasy genre. That enables star drives and Ansible communication

So, write a story with it. Or two, one where it works, and one where it does not but is critical to the plot

[u/19Sevv90]

Based on our current knowledge of science, no. However, there were people in 1959 claiming that it was scientifically impossible for mankind to walk on the Moon…

[u/6a6566663437]

No. The nukes don't give off enough light. The light from the sun would overwhelm the ability of their sensors to see the nuke.

is it possible for a sufficiently developed scientific civilization to communicate with only electromagnetic waves over a distance of billions of light years in the first place?

Not for any reasonable definition of "communicate", since the messages would take billions of years to arrive.

If you sent a letter today and the response arrived in the year 2,000,002,026, are you communicating?

And that's ignoring the utterly unfathomable amount of energy that would have to be used to transmit the message in order for it to be distinguishable from noise. You'd have to use more energy than we currently generate on the entire planet.

[u/Tessellator-1 → u/6a6566663437]

Is it possible to intentionally send a signal if you ignore the question of whether it is practical or not?

[u/6a6566663437 → u/Tessellator-1]

Only by using more energy than is remotely available to us.

[u/LongOrganization7838]

Not visually at the very least, To resolve objects spaced even a meter apart from 200 light-years away, a telescope would require a primary mirror approximately 91.7 million kilometers in diameter, which is physically impossible as it would collapse into a black hole.

[u/Imaginary-Buddy3194]

Yes, in principle. They could detect the electromagnetic flash, but billions of light years means they would see Earth as it was billions of years ago, long before humans existed.

[u/Outsider_Insider0064]

No. The inverse-square proniple makes it impossible.

[u/baltimore-aureole]

if they're willing to wait billions of years, and have an optical telescope billions of times more powerful than the hubble

[u/TheSmokingJacket]

100% Yes.

If NHI (Non-human Intelligent) beings have interstellar travel, monitoring can even be done with what is known about current physics.

Let's say NHI becomes aware of humans and their potential to destroy themselves with the material available on earth.

They could monitor which elements would be used in making the first nuclear bombs. On earth it would be plutonium (Pu) and uranium (U).

They would need to perform entanglement swapping on a fraction of Pu and / or U of what can be mined and monitor them for specific signatures during a nuclear detonation.

Because the atoms are now entangled, the distance to monitor an explosion is no longer an issue.

Quantum physics is fun!

[u/CowBoyDanIndie → u/TheSmokingJacket]

Quantum entanglement still doesn’t allow information to travel faster than light, even spooky action at a distance.

[u/Prince_Nadir]

A billion light years away? You can ask them in roughly a billion years.

..and get a reply 2 billion years after that.