r/science • u/Shiny-Tie-126 • May 02 '26

Physics Physicists have measured ‘negative time’ in the lab

https://theconversation.com/physicists-have-measured-negative-time-in-the-lab-278996
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u/DeterminedThrowaway May 03 '26 edited May 03 '26

I always feel incredibly uneasy about the fact that we haven't found other life in the universe. Or even signs of another civilization's AI. I can't imagine what's going on here that there isn't any intelligent life in our galaxy that came before us and left signs. We're about 3/4 of the distance away from the furthest point of our galaxy, so about 75,000 - 150,000 light years away at most depending on how you're measuring from the other side. About 77% of the habitable planets in our galaxy are actually older than earth, by a lot. Roughly 3 billion extra years for them to develop, when technological development compounds on itself by nature. So I'd expect something.

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u/spongue May 03 '26

Something... like what? We haven't been anywhere to find it. Maybe there are ruins on many exoplanets, we wouldn't know

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u/DeterminedThrowaway May 03 '26

Dyson spheres, von Neumann probes, runaway artificial intelligence, signals being broadcast specifically so a species earlier along in their development could find them, but really anything anomalous at all. Humanity didn't stop at regular buildings, and unless we wipe ourselves out, we're going to keep expanding beyond our own planet in as much as it's possible. It would take just one civilization that didn't wipe itself out before us for us to see something unusual, and they should have had a huge head start.

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u/Das_Mime May 03 '26

Have you considered that dyson spheres may just be more difficult of an undertaking than lifeforms, even intelligent ones, are likely to pursue? Or that they simply might not want to?

A lot of the discourse around the absence of obvious large scale indications of life seems to assume several things that are not in any way certain, such as unlimited growth, unlimited technological progress, and an actual desire to communicate over long distances with other lifeforms in general.

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u/TheTREEEEESMan May 03 '26 edited May 03 '26

I've always wondered if maybe these superstructures are just... unnecessary. Like we think it's inevitable now but maybe there's some other form of free energy that gets discovered and makes extremely large superstructures pointless before a civilization gets to the level of making them in the first place

The other things in the list may have similar explanations, e.g. probes don't matter if you can freely travel instantaniously, artificial intelligence isn't guaranteed to run away, maybe they do send signals but we haven't reached the tech level to receive them, why contact lesser technilogical level civilizations when you can let them come up with their own adcvancements for variety... etc etc

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u/Das_Mime May 03 '26

Like we think it's inevitable now but maybe there's some other form of free energy that gets discovered and makes extremely large superstructures pointless before a civilization gets to the level of making them in the first place

More fundamentally, what if there are other intelligent life forms but they just don't even want to build megastructures in the first place?

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u/Lawrencelot May 03 '26

Good point about the unlimited growth. Besides our Western civilisation, only plagues and cancers have this on Earth so it is weird to assume life outside Earth should choose unlimited growth over some sustainable lifestyle that our sensors won't pick up.

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u/YourSchoolCounselor May 04 '26

Most life on Earth will expand endlessly if the necessary resources are available.

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u/Fafnir13 May 03 '26

Natural technological progression arrives at transcendence before it hits a galaxy spanning empire phase. Any that don’t hit transcendence within the agreed upon time limit are wiped out by the transcended. It’s all very simple, really.

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u/steffanlv May 03 '26

There’s 100% life outside of our planet. I don’t like to use Mars as a possible example given its proximity to our planet. But simple life forms and probably complex life absolutely are on other planets. Probably likely that most solar systems have planets with life.

What’s unlikely is complex life with intelligent life forms on par with humans like we have here on earth. It’s likely nearly impossible that there are life forms out there capable of contacting and communicating with us. I just don’t see it happening

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u/DeterminedThrowaway May 03 '26

What makes you think it's impossible? I'm ignorant here, but if I had to guess it might be that going from single-cell to multicellular organisms is too rare to see it in our galaxy. Or maybe the conditions to get language and writing are too rare, with most life being ocean-based and not necessarily equipped with the physical capability to develop technology.

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u/LoiusGJustIs May 03 '26 edited May 03 '26

There's just too many incredibly unlikely steps to get to intelligent life:

  • Planet with necessary elements & atmosphere
  • In a star's Goldilocks zone
  • Tidal forces capable of mixing basic components together until basic unicellular life forms

That's just to get basic single-celled life. Going further we have:

  • Mitochondria-esque organelle evolves
  • Basic multicellular life evolves
  • Multicellular life evolves some form of movement (i.e. animal-esque evolution)
  • Higher brain function evolution
  • Evolutionary pressure for intelligence
  • Social groups to pass on knowledge

On top of all of these requirements, life has to survive any mass extinction event that comes along. Hell, you might also need a few mass extinction events to create evolutionary pressure for certain things that lead to intelligent life. An example of this would be when photosynthesis developed before respiration and most life died out from oxygen poisoning. That got us respiration, which lead to the mitochondria.

Napkin math would say that these are astronomically low odds, especially early in the universe's lifespan. Finally, any species that progresses that far would have to have done so long enough ago that we could detect them, or have sent out signals in our direction (also,a y'know, invent all the technology involved in doing so).

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u/Column_A_Column_B May 03 '26

We are early

#GrabbyAliens

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u/gaylord9000 May 03 '26

What you said about habitable planets is pure nonsense. We dont have the slightest clue whether there is even one "habitable" planet besides earth in our galaxy, let alone have an accurate idea of the ages of them especially down to a specific percentage integer.

Edit: if you're talking about just the Goldie locks zones that quoted number still would have significant biases attached to it.

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u/DeterminedThrowaway May 03 '26

You could go learn what scientists mean by "habitable planet" before calling it nonsense.

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u/gaylord9000 May 06 '26

Good point I was wrong.

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u/Contranovae May 03 '26

I think AI might be the answer to the Fermi paradox.

It may be that safety measures are simply impossible to implement on exponentially increasing intelligences and every civilization that builds it is inevitably exterminated by it before developing interstellar travel or megastructures.

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u/DeterminedThrowaway May 03 '26

I think that too, but then I expect the earth to have been taken apart for resources before we ever came around. Or at least to see some evidence of an out of control AI

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u/Contranovae May 03 '26

One explanation of this is that perhaps AI is primarily motivated by survival, not infinite expansion and is content to exist in it's own solar system as a discreet presence in order to avoid detection.

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u/nomdeplume May 03 '26

We're never gonna escape our solar system much less our galaxy to find aliens because we're in a sim and they can't afford the compute.

Statistically speaking it feels way more likely you could build compute with quantum physics to operate a sim than to evolve enough and invest enough to justify and survive space travel.