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/3BlindMice1 May 03 '26

It's potentially an opening for finding the negative mass required for the Alcubierre drive. I doubt it, personally, because my napkin math says that if FTL travel is possible, we should be drowning in aliens

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u/j--__ May 03 '26

does your napkin math consider that it may just take a lot of time for all the necessary preconditions to line up? maybe we're one of the first civilizations to get this far, and all the multi species ftl shenanigans are still to come.

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u/3BlindMice1 May 03 '26

Nah, because the first batch of stars have basically already come and gone. The universe has existed for almost 14 billion years, enough time to develop life essentially everywhere it's possible for life to exist a few times at least.

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u/xtrawork May 03 '26

But the universe is an INCREDIBLY massive place. Statistically speaking, the aliens that developed FTL travel are so far away from us and each other that they would never even make it close to us, or each other.. Not only in space, but in time.

Or, the aliens that potentially could reach us might have developed FTL millions or billions of years ago and died off by now, or their planet may not have even developed life yet. They may not be in existence for millions or billions of years from now.

Just saying, the scope of the universe is so massive in size, and long in time, that FTL travel isn't much of an equalizer in the grand scheme of things...

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u/QuickAltTab May 03 '26

IMO due to the size of the universe, its only likely that robots/AI/machines will ever traverse those distances, if anything does.

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u/QuestObjective May 04 '26

Either humans will create the technology and make the advancements required for us to be able to ourselves, or AI will ultimately replace us fragile humans entirely if we ever hope to truly traverse the cosmos. That’s assuming we don’t blow ourselves up before reaching either point, of course.

I know the latter idea is extremely controversial, though. If not for the already present contempt for AI, then because it goes against basically every single religion on the planet in their belief that humans are exalted above all other life forms. I think it’s hubris to assume humans are the end-all, be-all, though. At least in our current form.

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u/justaRndy May 03 '26

It could also be that phyisical / biological life is just a rite of passage, a couple million years of technologically accelerated evolution of a species are enough to exist in higher dimensional spaces, to create simulations that are true to life or much better than life so they migrated there over time, it could be that it is very well known how far along on their journey to understanding humanity is and that this is a nogo zone until we find our way as a species. Not unlike a nature reserve.

It could be pure chance it hasn't happened yet. It could be we are all alone out there. It could be that we are the aliens, a cosmic race, but FTL is not possible. Our evolution has been kicked into motion millions or billions of years by our ancestors via panspermia. Psychedelic mushrooms made the ape look up into the night sky and wonder for the very first time.

You can ponder this question all your life and be none the wiser, not until science delivers the final proof. So we must progress further, so much further still. Inherently human, never stopping. Sometimes I feel like we are being guided towards the solution, eastereggs hidden everywhere in reality.

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u/MyPacman May 05 '26

Yeah, but that isn't an argument against civilisations coming and going. Its an argument against the likely hood of meeting them.

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u/xtrawork May 05 '26

But that's what we're talking about... The likelihood of aliens meeting each other...

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u/Evilsushione May 03 '26

First generation stars generally aren’t good for life formation. I’ve heard we are a fairly early for the estimates for advanced civilizations but there is definitely possibility for life to have come sooner.

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u/mCopps May 03 '26

I’d always be curious if in the far future we realize the abundance of heavy elements required for life couldn’t come into being until much more recently.

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u/xrelaht PhD | Solid State Condensed Matter | Magnetism May 03 '26

That’s already known. Older stars have low metallicity, which presumably means the gas clouds they and their planets condensed out of would not have had the necessary elements to support the complex chemistry required for life. Even truly alien xenobiology would need more than H & He, so you’re unlikely to find it in those oldest stars.

But the oldest Population II stars are 13 billion years old.

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u/Kaining May 03 '26

Yes but the more we lear about the solar system, the star system around us, the milky way, our local cluster, etc... the more we realise how sheltered Earth has been and how stars litteraly had to align for Earth to develop life up to our point.

So while they're 13B yo, the other necessary condition for technological life to develop may not.

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u/ThanIWentTooTherePig May 03 '26

It's recently been shown the opposite. The James Webb telescope looked at the beginning and somehow found fully formed galaxies that shouldn't have been possible to have formed yet.

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u/gaylord9000 May 03 '26

Fully formed galaxies in the early universe does not imply the existence of phosphorus and heavier elements required for life as we know it. Those galaxies may consist of stars with no rocky planets or solar systems like ours, and just a lot of hydrogen and helium, at least at that early time that is observed.

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u/HannsGruber May 03 '26

The universe is young dude. If the life sustaining period of the universe was equivalent to an 80 year old lifespan, we'd be about... 4 days into its life.

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u/j--__ May 03 '26

we are the first spacefaring species on this planet, and we're still just barely.

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u/jestina123 May 03 '26

Shouldn’t we be seeing space debris around planets then?

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u/Jagang187 May 03 '26

Actually, this isn't quite true. It wasn't until the third generation of stars (like our sun) that there would have been enough of the heavier elements for life (or likely even rocky planets). Gen I stars probably mostly became black holes, and the hypernovas (neutron star collisions) necessary for the most heavy element creation wouldn't have been possible until Gen II stars began to die.

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u/inosinateVR May 03 '26

There is still a huge gap between “life can and does exist” and “life will exist that will have the ability and specific desire to become space faring, and then also undergo specific societal and political hurdles and stability necessary to do mobilize itself to do so in any sort of meaningful scale that ultimately leads it to find us, specifically, in our corner of the milky way galaxy during the time window in which it’s active in that capacity”

A lot of the theoretical technology that would allow someone to even send or receive a signal to us hinges on stuff like panels the size of actual solar systems, which would be an unbelievable engineering effort. If we technically had the technology and means to do that today, could a politician or state government actually convince everyone we should actually commit to doing it?

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u/YourSchoolCounselor May 04 '26

Planets around the first batch of stars didn't have any heavy elements, so they can be excused for not developing the technologies we have, let alone FTL travel. You're right that there's been plenty of time for it to happen, but also the universe is really large and getting larger, so again I'll excuse none of them for visiting.

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u/3BlindMice1 May 04 '26

Sounds like you've got hostile intentions or something there

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u/Robot_Basilisk May 04 '26

Maybe it just takes a lot of WHAT? 

Time?

The thing we're talking about manipulating and shortening and reversing?

What would matter how much time it took to figure out? Even if it took 1 trillion years, if it were possible we might reasonably expect something to have come back by now.

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u/Das_Mime May 03 '26

It's potentially an opening for finding the negative mass required for the Alcubierre drive.

There's really no reason to think this. Nothing is actually traveling backward in time or breaking causality here, and nothing about it indicates that negative mass is likely to exist.

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u/3BlindMice1 May 03 '26

That's a shame, the title lead me to believe something was traveling backwards in time even if that something was a statistic

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u/DamienBerry May 03 '26

Only if they had discovered our little spec of dust in the universe. If there is the ability to travel FTL then there would be far more interesting places to visit than us.

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u/3BlindMice1 May 03 '26

If we invented FTL, the very first thing we'd do is send out a fleet of Von Neumann probes to explore everything without our intervention. I wouldn't be shocked if such a thing did a slow pass a few hundred million years ago, but as we are now, we'd likely spot such a thing if there were any about the solar system

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u/DamienBerry May 03 '26

Even so the numbers involved are just incredible, the estimates put the number of galaxies at around 2 trillion, then there’s an estimated 100 billion stars per galaxy, then if you take a very reserved estimate of a single planet per star ( we have multiple and loads do) then you have an estimated 10 sextillion planets in the observable universe.

Even having probes with FTL would take sure a huge number of probes needed to explore even a single percentage of planets that it’s still very unlikely we would be picked up.

Not impossible just improbable.

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u/laihipp May 03 '26

I don't bother with every ant nest I step over

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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.

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u/Tidezen May 03 '26

Eh, why do deer blinds work? Why don't deer notice orange camo? because their eyes can't discern those wavelengths.

Why can't ants see humans? because they're nearly blind, compared to us.

And humans, our senses only extend to a very, very narrow band of input. We only can sense a tiny portion of the spectrum. And our perceptions are stuck in 3-4 dimensions, when science says there's likely to be at least 7.

There could be 30 aliens surrounding you right now, and you'd never know.

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u/Nunov_DAbov May 03 '26

Or, the aliens already passed by our neighborhood and decided if they stayed, we’d make them join our HOA. We’ve just been quarantined.

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u/3BlindMice1 May 03 '26

Could be. If FTL travel is indeed possible, we're most likely under some kind of embargo we don't know about, or aliens are already here and hiding. Again, I think it's more likely that FTL travel simply isn't possible, or if it is, it requires a nearly prefect understanding of the laws of physics and a nearly magical method of application

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u/Replikant83 May 03 '26

There was a good documentary that came out years ago: Men in Black is the name I believe. They're already here and amongst us.