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The Disappearing Universe

Soulskill posted about 5 months ago | from the and-for-my-next-trick dept.

Space 358

StartsWithABang writes: "If everything began with the Big Bang — from a hot, dense, expanding state — and things have been cooling, spreading out, but slowing down ever since, you might think that means that given enough time (and a powerful enough space ship), we'll eventually be able to reach any other galaxy. But thanks to dark energy, not only is that not the case at all, but most of the galaxies in our Universe are already completely unreachable by us, with more leaving our potential reach all the time. Fascinating, terrifying stuff."

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And? (0, Troll)

oldhack (1037484) | about 5 months ago | (#47163267)

Which part of the summary is "news"?

Fascinating, terrifying stuff is news (0)

Anonymous Coward | about 5 months ago | (#47163365)

We'll have to take turns screaming at the terror which will spread over infinity. I'll start AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!

Re:Fascinating, terrifying stuff is news (5, Insightful)

Anonymous Coward | about 5 months ago | (#47163547)

It's not really that fascinating or terrifying, though. "Based on our current understanding, we will never be able to reach certain galaxies." Ok, that's cool. We can't even reach another star system within our own galaxy at the moment, so traveling to other galaxies is a bit moot as is. We also know our understanding isn't complete, so it's entirely possible that something we don't know will allow us to travel to those galaxies.

Seriously, this doesn't feel like news. We've been working at the whole science and technology thing for what...ten thousand years or so? I say give it a million more and see where we are then, instead of cranking out sensationalist doom and gloom articles. Of course, all the doom and gloom articles tell you that we're not going to make it another decade, let alone a hundred thousand decades, so if you really feed into such things, then I'd say your outlook on the universe is far more terrifying than the article at hand.

Re:Fascinating, terrifying stuff is news (1, Insightful)

stealth_finger (1809752) | about 5 months ago | (#47163631)

The sub-headline is enough "Even at the speed of light, you’ll never reach these galaxies." Say you wanted to go to Andromeda, not the closest galaxy but not exactly far on a galactic scale, At the speed of light that's still going to take 2.5 million years to get there, not really what most people would define as achievable, If we want to reach any other galaxy we're going to have to be going a hell of a lot faster than the speed of light.

Re:Fascinating, terrifying stuff is news (3, Informative)

Anonymous Coward | about 5 months ago | (#47163667)

For Andromeda, just wait (very long term stasis recommended) it's comming at us, not sure it's a good thing.

Re:Fascinating, terrifying stuff is news (2)

CaptainDork (3678879) | about 5 months ago | (#47163783)

I understand your reasoning, but I question the math. The time for light to travel from Earth to Andromeda is, essentially, zero (0) seconds. The time for humans to WATCH it do that is 2.5 million years. Recall the Twin Paradox where a person leaves Earth at near light speed, returns, and is way younger. The stay-at-home twin thinks the traveling twin has been gone a long time and the traveling twin says, "Hey. I just left!"

Re:And? (2)

NotDrWho (3543773) | about 5 months ago | (#47163427)

This. They're already unreachable now. And until someone comes along and proves Einstein wrong, they're going to remain that way too.

Re:And? (1)

Anonymous Coward | about 5 months ago | (#47163439)

This is less "News" and more "for nerds"
Though not particularly well read nerds on the topic of the expansion of the universe...

speaks to our inner life (4, Insightful)

Cardoor (3488091) | about 5 months ago | (#47163287)

one of the allures for me (and i think a lot of people intrigued with cosmology) is how we can interpret the findings as a macrocosm for our own personal microcosm of awareness and being.

the fact that seemingly inherent in our physical universe is a doctrine of the futility of outward movement (vis a vis reaching a sense of completion or boundary), to me, points to the individual quest for seeking oneself by focusing internally.

Re:speaks to our inner life (2, Insightful)

Anonymous Coward | about 5 months ago | (#47163349)

one of the allures for me (and i think a lot of people intrigued with cosmology) is how we can interpret the findings as a macrocosm for our own personal microcosm of awareness and being.

the fact that seemingly inherent in our physical universe is a doctrine of the futility of outward movement (vis a vis reaching a sense of completion or boundary), to me, points to the individual quest for seeking oneself by focusing internally.

consider as well that as our galaxy redshifts from many possible planets of life we will never gain the knowledge of the inhabitants of those worlds, and by the same logic they could never invade ours.

speaks to our inner life (0)

Anonymous Coward | about 5 months ago | (#47163813)

I agree.
An expanding universe is the aging mind watching his own fail to time...but the ego, that gets bigger. A black hole is fascinating to a thief, a new star is a proud dad. A shrinking universe to a thinker, is dying. Perpendicular minds think the world is flat, and an inline four engine is economical.

  All in the universe.. its got every answer. Let an idiot describe it for himself.

Republicans attack Obama (-1)

Anonymous Coward | about 5 months ago | (#47163297)

http://www.usatoday.com/story/news/world/2014/06/04/taliban-video-handover/9946647/

The Taliban has released a propaganda video of PFC Bowe Bergdahl's release. As can be clearly seen, the White House claim that they had to act immediately due to his failing health is clearly vindicated. Clearly.

Thus your saviour and idol, the socialist Obama is once again proven to reign supreme over Republican lies and deciet.

Long live the homeland! Long live king Obarky!

Re:Republicans attack Obama (-1)

Anonymous Coward | about 5 months ago | (#47163371)

If only George W Bush had been elected for a third time! We would all be saved!

Re:Republicans attack Obama (-1)

Anonymous Coward | about 5 months ago | (#47163397)

George W Bush, crypto socialist and progressive enabler of the statist, no indeed, more Bush would have been about as bad as an Obama regime win.

It is liberty we want, liberty for the citizens, all of them, the citizens that is.

Show me a party that supports the rule of law, low taxes and constitutional protections agianst tyrannical government, this is something we all can support.

George W Bush is none of those things.

You are welcome.

Re:Republicans attack Obama (-1)

Anonymous Coward | about 5 months ago | (#47163375)

Curse you Republican loving Slashdot editors downmodding my post! You fail to support the all powerful Owebama, you must hate socialism and communism! You are nothing but rich capitalist pig-dogs that hate women and ghey people.

Do not fret you Republican loving evil-doers, your fate will be determined not by the citizens at the voting booth, or by the public purchasing items hawked by your capitalist web sight, but it will be determined by the IRS! Yes, they will get you good with taxes! And audits! Until your little Republican brains freeze from all the maths you must do to fill out your forms! Yes the Obama regime has super powers, much like superman, with the IRS, and the EPA! Is there a wetland near your server farms? Farms must have water, and then the EPA will get you bad, yes the EPA and the IRS are coming for you Republican loving haters of socialism, the poor, the imigrants, the women and teh gheys, yes we know Republicans hate all of these people and hate Obama most! So beware.

Re:Republicans attack Obama (-1)

Anonymous Coward | about 5 months ago | (#47163619)

So the administration had time to notify the parents and book a flight from Idaho for the Rose Garden fiasco, but couldn't notify Congress?
Yeah, they just forgot.

Maybe now, but (0)

Anonymous Coward | about 5 months ago | (#47163311)

Unreachable with current technology perhaps, but who knows about the future?

Re: Maybe now, but (1)

Anonymous Coward | about 5 months ago | (#47163461)

So he thinks that using the hypothetical limits of current technology with no hypothetical constraints wouldn't be good enough. Only 200 years ago we only had horses for transport, this fella wouldn't make an imaginative writer.

Re:Maybe now, but (2)

michelcolman (1208008) | about 5 months ago | (#47163585)

The problems are a bit deeper than "we don't have the technology to do it". If we would be able to break these theoretical speed limits, this would automatically imply we would also be able to travel through time or at the very least send messages into the past. That would create a whole bunch of problems for concepts like causality, free will, grandfather paradox, etcetera. Not entirely impossible, I agree, but unlikely nonetheless.

Re:Maybe now, but (0)

Anonymous Coward | about 5 months ago | (#47163911)

Unreachable with current technology perhaps, but who knows about the future or the past?

FTFY.

Re:Maybe now, but (4, Funny)

93 Escort Wagon (326346) | about 5 months ago | (#47163981)

Unreachable with current technology perhaps, but who knows about the future?

The future, Conan?

Have some faith (0)

Anonymous Coward | about 5 months ago | (#47163325)

This guy has very little faith. Yes the human race doesn't get along very well but we build great shit. We still have a lot of time to figure out the universe. He is talking about the speed of light, I'm thinking wormholes, warp drives, hyper space. If we can't figure out how to keep this universe together or move to a new universe in a few billion years than hey we still had a few billion years of existence; that's not bad.

Re:Have some faith (3, Insightful)

jellomizer (103300) | about 5 months ago | (#47163489)

"I'm thinking wormholes, warp drives, hyper space."
All of which are are unproven theories. And could be proven to be impracticable (needing an energy the size of a star E stills equals MC^2) or impossible, or dangerous aka destroying the universe.

It may be the Speed of Light is the Speed limit that we cannot break.

In a world where Science Fiction is still fiction, and these wormholes, warp drives, and hyper space are meant as plot devices to move your characters into the story conflict of dealing with something alien. You find that these plot devices are made especially for weekly serial TV or movies with Sequels as you want to keep the same characters time and time again.

Now that said, it doesn't mean we should stop space exploration or trying to break the limits. Even if we could get a fraction of the speed of light say 1/10th the speed of light. We could travel our own solar system as well the sailors of old traveled the oceans. Generational ships can bring us to stars that are within 10 light years of year, and come back to earth without too much diversion of evolution.

Even without having to jump galaxies there is so much in our little neighborhod that we haven't explored.

As per Douglas Adams:
Space is big, I mean really big, you won't believe how mind boggling huge it is. You think it is a far way to the chemist? That is just peanuts to space, listen!

Re:Have some faith (0)

Anonymous Coward | about 5 months ago | (#47163543)

These ideas aren't simply from fictional books, TV, & movies. Though I'm sure those mediums inspired many theories that now exist from theoretical physicists and the like.

Re:Have some faith (1)

bhagwad (1426855) | about 5 months ago | (#47163797)

Wormholes ok, they at least have a theoretical framework in modern science. Warp drives...well if you're talking about moving a space bubble relative to space itself. But since when did "hyperspace" become even a remotely scientific theory?

FTL or Wormhole Travel (1)

Anonymous Coward | about 5 months ago | (#47163337)

Ignored as even a remote possibility as the author labels it sci-fi fantasy.

We can always hope that some type of controlled wormhole, or spacetime-bending faster-than-light travel can save us, but there’s no evidence that such an innovation—despite our best science fiction dreams—can ever be practically realized.

How open-minded and hopeful the author is...

Re:FTL or Wormhole Travel (0, Insightful)

Anonymous Coward | about 5 months ago | (#47163389)

Perhaps he's a trifle more educated than you are?

Re:FTL or Wormhole Travel (0)

Anonymous Coward | about 5 months ago | (#47163455)

This Guy! [scienceblogs.com]

Re:FTL or Wormhole Travel (0)

Anonymous Coward | about 5 months ago | (#47163519)

That's awesome! Except for the blackface, ew.

Re:FTL or Wormhole Travel (2)

stealth_finger (1809752) | about 5 months ago | (#47163751)

Perhaps he's a trifle more educated than you are?

Why, did he study custard and jelly with a minor in cream?

Re:FTL or Wormhole Travel (0)

Anonymous Coward | about 5 months ago | (#47163971)

That's against the law in most US states!

Re:FTL or Wormhole Travel (1)

Will.Woodhull (1038600) | about 5 months ago | (#47163843)

I've met people who have been educated beyond the level of their intelligence. Are you one of them? Is the author of the post that triggered this discussion one of them? What proof can you offer for your opinion on these questions?

Re:FTL or Wormhole Travel (0, Insightful)

Anonymous Coward | about 5 months ago | (#47163441)

And yet the author says that galaxies are receding from us at greater than the speed of light. Now maybe he means that in a specific reference frame where we are going one direction at .51 c and another galaxy has an exactly opposite vector at .51 c - but he still says receding from us at greater than the speed of light. So he allows that greater than the speed of light is possible...

Re:FTL or Wormhole Travel (2)

Bengie (1121981) | about 5 months ago | (#47163505)

You can't move through space faster than c, but space can move or expand faster than c. The space between us and some distant galaxies is greater than c, meaning, we could never get to them, even at the speed of light. Some galaxies have been measured to have red-shifts past 2c. Even if you were a photon, they'd still be moving away from you at c, which is hard to understand because a photon does not experience time.

Re:FTL or Wormhole Travel (0)

Anonymous Coward | about 5 months ago | (#47163731)

From my not-a-physics-guy perspective, your post looks a bit weird. c is a velocity, so how can you say that the space (=distance) between us and x is >c? It seems like you are conflating two quantities here.

Not saying you are wrong but perhaps you could explain it.

Re:FTL or Wormhole Travel (1)

Anonymous Coward | about 5 months ago | (#47163875)

If i remember correctly (crucify me if you will), c is a physical constant, not a velocity, meaning it needs no direction to satisfy it's meaning. (probably not how you say it).
But i do know Space itself is expanding, the analogy i usually hear is of a balloon being inflated; pick a point on the balloon, and relative to that point everything is moving away, further away parts of the balloon are carried away faster it seems, when in reality there's "new" space being created all the time. (This has no effect on gravitationally bound systems, which confuses me considering the whole universe, i would think, is a gravitationally bound system). I am not a scholar, say what you may. (correct me)

Re:FTL or Wormhole Travel (5, Interesting)

michelcolman (1208008) | about 5 months ago | (#47163807)

It's a bit more complicated than that. General relativity allows you to pick any reference frame, even one that is bent, stretched or distorted in some other way, and do your calculations in that reference frame.

You could pick a "normal" reference frame that obeys the special theory of relativity: speed of light constant everywhere, nothing can go faster, etcetera. Nothing wrong with that, but this turns out to be impractical: we have to pick some place to consider as the center of the universe (for example some place in our immediate neighborhood), and then find that the rest of the universe is moving away at very high speeds, approaching (but not exceeding) the speed of light. This means those galaxies are shrunk in the direction of their motion (Lorentz contraction) and time passes more slowly for them (time dilation). The further you "look" (the infinitely quick kind of looking which you can only do inside a theoretical model, not having to wait for light to get here so we can actually see stuff), the more things are shrunk and the slower time is ticking. At a distance of the speed of light ("c") times the age of the universe, things approach the speed of light and time is passing so slowly that the Big Bang is only just happening right now. In this way of describing the universe, with these coordinates the universe actually fits in a finite sphere around us.

That's a perfectly valid set of coordinates, but I think you'll agree it's not very practical. So physicists invented the cosmological model: imagine a bunch of clocks everywhere in the universe, flying at the same speed as the expansion of the universe (i.e. the same speed as average galaxies in that neighborhood) and ticking at whatever rate the local clocks are ticking at (not synchronized to ours). We define time at any place in the universe as being whatever is indicated by those clocks, not ours. So in effect we change the very definition of simultaneity, moving things from the future into today simply by changing the labeling. Also, imagine measuring sticks available everywhere in the universe, but just like the clocks flying at the same speed as the local expanding universe. To measure distances, we use those sticks instead of our own.

If we now measure everything using local (Lorentz-contracted) sticks and local (time-dilated) clocks, the universe looks completely different. It is truly infinite, the same age everywhere, and distant objects are no longer flat Lorentz-contracted pancakes but look the same as objects in our neighbourhood. Note that this is not a different universe, it's the same one but with different labels stuck onto objects.

Now, with this set of coordinates, it turns out that rays of light don't travel at a fixed speed "c" relative to us, but relative to the local clocks and sticks we used to define the coordinate system. It is still true that nothing can go faster than (local) light, i.e. you cannot overtake a ray of light, but a distant object certainly can move away from us faster than the speed of a ray of light in our neighbourhood. And if some alien over there were to try and shoot a laser beam our way, that light would never reach us because it is traveling towards us at the speed of light relative to the local "space" which is moving away from us faster, like a cosmic conveyor belt. Note that this conveyor belt is not real, it's just a product of our mathematical trickery refefining distances and times.

Of course you might wonder what happens to that alien laser beam in the first coordinate system, where rays of light all travel at the same speed relative to us. Well, in that system, the aliens don't exist yet because time in that part of space is moving very slowly (and has been moving slowly ever since the big bang). And since that part of space is still accelerating away from us ever faster and closer to the speed of light, local time comes to an asymptotic halt before the aliens ever get a chance to shoot that laser.

"Space itself" is just whatever we define it to be. By changing coordinates, we can move things from the past into the future or even into "never". It doesn't matter, it's just math(s), the end result is that we will never see that laser and we will never be able to reach that galaxy either.

Re:FTL or Wormhole Travel (0)

Anonymous Coward | about 5 months ago | (#47163823)

So not a problem at Warp 2 then (8x the speed of light, depending on the episode).

The point of FTL is to make traveling places take as long as the plot requires. If FTL is possible then it does not matter if where you are going is also traveling FTL as long as your FTL drive is better.

Re:FTL or Wormhole Travel (4, Informative)

bhagwad (1426855) | about 5 months ago | (#47163829)

The speed of light in a vacuum is always c. It doesn't matter if you're moving at 0.9c. If you shine a torch of light ahead of you, it will still move at speed "c".

What is meant here however is that there is no limit to how fast space itself can expand. So say we have two ends of a ruler 1 meter apart. After a while, space itself would expand meaning that the ruler will now be longer than what it was. There is no theoretical limit to how fast this can happen. It can be greater than c.

After a while, the space between the nucleus and electrons or within the nucleus itself will become too large, ultimately ripping apart for the fabric of reality itself.

terrifying? (1, Insightful)

stenvar (2789879) | about 5 months ago | (#47163353)

Really, folks, you need to stop being terrified by everything.

Re: terrifying? (5, Funny)

140Mandak262Jamuna (970587) | about 5 months ago | (#47163415)

Actually this theory says the number of things that could terrify you is disappearing fast. So instead of being comforted by this fact, they are being terrified of running out of things that could terrify them. Universe does seem to be weirder than what you can imagine, indeed!

Re:terrifying? (2, Insightful)

Anonymous Coward | about 5 months ago | (#47163449)

Seriously. Dark energy is hypothetical.

Heard it all before. Earth is flat, humans flying is impossible, break the sound barrier and you die, yadda, yadda...

Re:terrifying? (5, Insightful)

Shadowmist (57488) | about 5 months ago | (#47163753)

Seriously. Dark energy is hypothetical.

Heard it all before. Earth is flat, humans flying is impossible, break the sound barrier and you die, yadda, yadda...

If you don't understand the difference between a line of uninformed idiots who kept saying "You can't have a rocket in space because there would be nothing to push against", displaying complete ignorance of Newton's laws, and the limits which are the consequence of well-reasoned scientific models such as C being an absolute limit of material acceleration, then you flat out don't understand the difference between a scientific approach and simply drawing limits out of your butt.

Re:terrifying? (0)

Anonymous Coward | about 5 months ago | (#47163945)

You can't kill your own grandfather before he had children...

Re:terrifying? (1)

Jeremy Erwin (2054) | about 5 months ago | (#47163681)

Imagine how many quadrillions of intelligences exist in a galaxy the size of the milky way. Imagine how many of them will be destroyed by relativistic jets [nationalgeographic.com]

Re:terrifying? (1)

StripedCow (776465) | about 5 months ago | (#47163907)

If they are really intelligences, they would be gone before the jet starts spraying.

As for dark matter, that is probably just intelligences shielding off their stars with energy-collecting spheres.

All of them (0)

Anonymous Coward | about 5 months ago | (#47163357)

Maybe someone else will some day be able to reach at least one other galaxy, but all of them are unreachable to us. We can't even get to another star in our galaxy.

Universe expanding faster than the speed of light? (0)

Wycliffe (116160) | about 5 months ago | (#47163359)

How can that be? I thought nothing could go faster than the speed of light.
Or does the universe not have to obey it's own rule?

Re:Universe expanding faster than the speed of lig (1)

bunratty (545641) | about 5 months ago | (#47163393)

Nothing can travel through space faster than light. But space can travel as fast as it likes. This is the idea behind warp drive [wikipedia.org] .

Re:Universe expanding faster than the speed of lig (3, Informative)

X10 (186866) | about 5 months ago | (#47163417)

How can that be? I thought nothing could go faster than the speed of light.
Or does the universe not have to obey it's own rule?

We're talking about expansion of space itself, not about a body traveling in that space.

Re:Universe expanding faster than the speed of lig (1)

Culture20 (968837) | about 5 months ago | (#47163431)

Well, space is a whole mess of nothing. If nothing can travel faster than the speed of light, no reason it can't expand faster than the speed of light. Also, that's faster than light where "faster" is measured in spacetime. Stretch the spacetime and light travels differently than it did.

Re:Universe expanding faster than the speed of lig (1)

rtb61 (674572) | about 5 months ago | (#47163533)

Likely the more correct statement is the maximum speed of light is the speed of gravity. So there are quite few particles that travel faster than the speed of light. Now when it comes to reaching other galaxies, seriously who really cares, there is just so much of this galaxy to explore, even living to really ripe old age of 10,000 earth orbits and travelling really fast from sun to sun, there are so many places, likely so many species and societies to explore, even allowing only 1 luna orbit at each location, let alone travel time, likely you won run out of 'interesting' places, just like our own, to explore just in this galaxy. All you need to do is slip on by gravity.

Re:Universe expanding faster than the speed of lig (1)

wonkey_monkey (2592601) | about 5 months ago | (#47163685)

Likely the more correct statement is the maximum speed of light is the speed of gravity. So there are quite few particles that travel faster than the speed of light.

I think you missed a few logical steps out there. Also, the names of these faster-than-light particles would be good to know.

Re:Universe expanding faster than the speed of lig (1)

StripedCow (776465) | about 5 months ago | (#47163921)

Also, the names of these faster-than-light particles would be good to know.

They are called "tachyons".

Re:Universe expanding faster than the speed of lig (0)

Anonymous Coward | about 5 months ago | (#47163837)

Alas the interesting places will stop being interesting after about a day as they just become clones of Earth based locations, rows of Starbucks going on to infinity.

Not so quick (5, Insightful)

Anonymous Coward | about 5 months ago | (#47163383)

Physics graduate student here, and I'd just like to bring something into context before any ./ readers begin an existential crisis.

We don't *KNOW* anything about the dark matter/energy hypothesis yet. They are not well accepted theories like (classical) gravity or electromagnetism, but rather the best answer to questions we don't have any other way of approaching.

Warning: if you subscribe too heavily to these ideas now, you'll be way, way off base later when science starts finding better answers to the accelerating universe and other open questions. This stuff is great for discussion about philosophy and science fiction, but it is far from well accepted science.

Re:Not so quick (3, Insightful)

NotDrWho (3543773) | about 5 months ago | (#47163487)

From every description I've heard of "dark energy" it sounds like a kind of place-filler variable for something--as in, "This equation only works if we put in X, but we have no idea what X is."

Re:Not so quick (1)

thrich81 (1357561) | about 5 months ago | (#47163959)

Maybe so, but that's almost exactly the same situation as when neutrinos were hypothesized to make the equations of some nuclear decays balance out.

Re:Not so quick (1)

Bengie (1121981) | about 5 months ago | (#47163531)

I was under the impression that Dark Matter and Dark Energy were completely unrelated. I was also under the impression that Dark Matter, whatever it is, is somewhat well accepted because of our understanding of electromagnetism, and that we know there is mass, but we also know it does not interact with photons, and we haven't detected any interactions with normal matter.

Re:Not so quick (1)

HiThere (15173) | about 5 months ago | (#47163675)

We aren't even sure that they're unrelated. If gravity needs to be redone, the change might include both of them (or parts of both of them), e.g.

OTOH, coming up with something better than "We can't actually see anything causing these effects, but we see these effects..." is quite difficult.

Re:Not so quick (1)

Bengie (1121981) | about 5 months ago | (#47163849)

We see this effect in hundred million light year wide voids in space. Visibly empty, we can see galaxies way way off in the background, yet LARGE amounts of gravitational lensing, and we know that it's not caused by black holes.

They are nearly 100% certain that there is galaxy amounts of invisible mass in these voids that cannot be seen. We can't detect dust of any kind, we can't detect black holes, yet we can detect huge amounts of mass. At this point, it is a fact that there is invisible mass.

Is it the cause of the strange observation of galactic rotations? We're not sure, but we know it would almost perfectly match up with the observations.
1) We know there is "Dark Matter", whatever it is
2) We are not sure if Dark Matter is the cause of our observed high speed outer arm orbits in galaxies, but it would be a nearly perfect fit

Dark Matter is a 60 year old concept that has only recently be all but confirmed, The addition of Dark Matter into Universe simulations also fixed the issues we've been having.

Re:Not so quick (0)

Anonymous Coward | about 5 months ago | (#47163903)

> we haven't detected any interactions with normal matter.

We do have ways to that may direct ways detect Dark Matter - Looking for the heat generated when they zoom through cryogenic detectors. I believe these are starting to produce results.

Re:Not so quick (0)

Anonymous Coward | about 5 months ago | (#47163573)

Totally. Presenting all this as fact is super lame.

I'm not a physicist, but my impression is that dark energy is a made up thing to hold the good theories together. I buy all the quantum weirdness because it's proven. Dark energy may or may not exist, i've heard nothing to sway me either way. I honestly think that the dark energy thing will turn out to be something very cool that sheds light on interstallar/galactic travel.

At the top it talks about travelling at near light speed. Exploring the universe won't happen at light-speed, way too slow, and that effectively makes the whole piece moot. We all know that you can't go faster than light in a drag race, it's up to the physics heavies to sort us out some good tech. That Alcubierre dude has the right idea.

Re:Not so quick (1)

31415926535897 (702314) | about 5 months ago | (#47163839)

I agree with you there, but any time I try to start the discussion with scientists at Fermilab, I've run into brick walls. They all have bought into dark energy as if it were as secure as our understanding of gravity.

Perhaps where you work it's not as well accepted, but in the little corner of the real science world I know, dark energy is some kind of science gospel.

Re:Not so quick (0)

Anonymous Coward | about 5 months ago | (#47163935)

I find it somewhat annoying and somewhat sad that for so many people who "Science!" around here that this had to be explained.

Re:Not so quick (1)

BlackPignouf (1017012) | about 5 months ago | (#47163937)

+1

Am I missing something? (0)

Anonymous Coward | about 5 months ago | (#47163391)

"But not if our Universe is accelerating. If something is receding from us right now at more than 299,792.458 km/s—faster than light speed—and it’s accelerating too, how could anything reach it?"

Isn't c the upper bound of speed in our universe?

Re:Am I missing something? (1)

Jesrad (716567) | about 5 months ago | (#47163479)

Yup. At "worst" in an accelerating universe the galaxies would be receding from us at speeds that would tend asymptotically to 'c', but never at 'c' nor above.

Re:Am I missing something? (1)

wonkey_monkey (2592601) | about 5 months ago | (#47163695)

Nope. Distances between objects can increase faster than c because space is expanding.

Re:Am I missing something? (1)

wonkey_monkey (2592601) | about 5 months ago | (#47163817)

Although perhaps under such circumstances concepts like "receding" and "moving" become a bit more ambiguous than we're used to.

Re:Am I missing something? (1)

Shadowmist (57488) | about 5 months ago | (#47163821)

Yup. At "worst" in an accelerating universe the galaxies would be receding from us at speeds that would tend asymptotically to 'c', but never at 'c' nor above.

You haven't begun to imagine the worst. see my post above.

Re:Am I missing something? (1)

bhagwad (1426855) | about 5 months ago | (#47163891)

Space itself is expanding and there is no limit to how fast that can happen. It can be at 1000 times the value of c if necessary.

Re:Am I missing something? (2)

Xelios (822510) | about 5 months ago | (#47163493)

It's not that the thing itself is flying away from us at c, it's that all the space in between us and that thing is expanding. Naturally the further away it gets, the more expanding space there is between us and the thing, the faster the thing appears to be receding from us.

In this system nothing is moving faster than the speed of light but the effect is the same: a spacecraft trying to reach that galaxy would need to overcome all the expanding space between, and that would require a speed greater than c. In fact, at that point even light from that galaxy would not reach us anymore, putting it outside our cosmological horizon. [wikipedia.org]

Disclaimer: I may not know what I'm talking about. This should really be in my sig.

Re:Am I missing something? (0)

Anonymous Coward | about 5 months ago | (#47163691)

thank you. that was very well put.

it all boils down to principles similar to the horizon, as you say. they are very neat concepts, and with the scales involved (of both time and space) it's a pretty good little game to try and conceptualize/visualize. they could have written a great article about it, instead we get disingenuous arm waving. the 'oh noes!!' crap is getting so goddamn boring. report honestly or take your clickbait and go away.

Re:Am I missing something? (2)

Shadowmist (57488) | about 5 months ago | (#47163811)

"But not if our Universe is accelerating. If something is receding from us right now at more than 299,792.458 km/s—faster than light speed—and it’s accelerating too, how could anything reach it?"

Isn't c the upper bound of speed in our universe?

is the upper bound of acceleration through space. Think of it this way. acceleration of a point through the 3d graph of space IS limited to C. But the lines of the graph itself that define the 3d location of things in space are accelerating from each other... the farther they are from each other the farther they recede. There is no limit to that recessional velocity. You will get to a point where acceleration being fixed simply can't keep up with the recession, so you'll never reach those parts., nor will light from those parts reach your position. Vice versa applies here. We're receding at a speed greater than light from those areas. We're not feeling relativity effects because we're moving WITH OUR SPACE

I'm surprised that no one has yet mentioned the ultimate consequence of this recessional acceleration. Eventually the regions where this shows as an effect become smaller and smaller. Galaxy super clusters, then clusters, then galaxies fly apart, and that's when the effect really accelerates, shortly there after, solar systems, stars, planets, and ultimately even the atoms that once composed you and I fly apart as even as the recessional lines of space, accelerated by dark energy rip our observable universe down to a literal NOTHING. So the other end of the Big Bang becomes a Big Rip. Look it up.

Wormholes + a flat universe (4, Interesting)

TrollstonButterbeans (2914995) | about 5 months ago | (#47163419)

Much of the idea of wormholes came from the idea that universe might be spherical in topography --- like a hypersphere --- and a wormhole could poke through the hypersphere to create a shorter distance than even a line segment from Point A to Point B.

http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question35.html
http://en.wikipedia.org/wiki/Shape_of_the_universe

But measurements are looking like the universe is flat.

You never know what scientific discoveries the distant future could hold, but at the moment it looks bleak for the concept of wormholes since the universe doesn't seem to be a hypersphere at all.

Re:Wormholes + a flat universe (5, Interesting)

TeethWhitener (1625259) | about 5 months ago | (#47163687)

Space appears flat on a global scale, but locally, it is highly curved around massive objects, especially around objects like black holes. Nothing we've observed so far strictly prohibits our universe having some sort of locally nontrivial topology like a wormhole. Keep in mind, also, that our observable universe is what appears globally flat. If cosmic inflation is right (and it's looking like it probably is), the actual extent of the universe could easily be 20-30 orders of magnitude larger than what we see, in which case, the universe could be highly curved on those scales and still appear quite flat to the best ability of our observations.

Re:Wormholes + a flat universe (1)

Anonymous Coward | about 5 months ago | (#47163941)

You are basically assuming we know almost everything about the Universe. The idea that this is true is laughable.

We do not have enough information to make that declaration as anything more than an informed guess.

Among other things, surfaces that appear flat in short distances can be curved in huge distances. The plains of Kansas are a simple example. As we have no estimate of the real size of the universe - only an estimate of the size of the OBSERVABLE universe, such assumptions are worthless.

Dark Energy BS (0)

Anonymous Coward | about 5 months ago | (#47163443)

Everything is moving away from everything faster and faster.
Thought experiment: Remember when the comet hit Jupiter?
Before it hit, it broke apart and stretched out. Imagine you are living in that comet traveling through space.
It suddenly breaks apart. How many comet diameters away from Jupiter was it, when it broke up?
So, you do not see Jupiter that many more times away than you have ever looked before.
Each part of the comet is pulling away from every other part faster and faster.
That would also explain why the universe as a whole is not a spinning disk, like most other structures within the universe.

Slowing down? (1)

itscompiling (1166229) | about 5 months ago | (#47163509)

Honest question here, I thought the expansion was still accelerating. Is it or it's really slowing down as the summary says?

Re:Slowing down? (1)

Roxoff (539071) | about 5 months ago | (#47163555)

According to empirical science you are correct, expansion of the universe is accelerating. If the reporter can't get the simplest bits right, how can we trust what they say about the complicated stuff. I'll file this one under 'load of old bollocks'.

Re:Slowing down? (0)

Anonymous Coward | about 5 months ago | (#47163629)

No, the summary says that it is not the case.

So, yes, the expansion is accelerating.

Good (0)

Anonymous Coward | about 5 months ago | (#47163515)

That means we're out of their reach.

It's not expanding (1)

zakeria (1031430) | about 5 months ago | (#47163551)

it's running away from Windows 8

Re:It's not expanding (2)

swb (14022) | about 5 months ago | (#47163705)

Or Beta.

Terrifying (1, Insightful)

gmuslera (3436) | about 5 months ago | (#47163581)

Odds are pretty high that we will never reach the next star, worrying about the next galaxy is a bit too much

Re:Terrifying (1)

Greyfox (87712) | about 5 months ago | (#47163609)

If the expansion continues, one day a walk to the chemist will be too much!

All hope is lost (4, Funny)

NEDHead (1651195) | about 5 months ago | (#47163583)

Now I'll never find the missing socks

StartsWithPromotingHisOwnSite (1)

Anonymous Coward | about 5 months ago | (#47163591)

Is anyone else tired of Slashdot constantly posting the submissions of people promoting their own websites?

N/T (0)

Anonymous Coward | about 5 months ago | (#47163593)

That's why my car disappeared! It wasn't stolen, it just redded out!

Re:N/T (0)

Anonymous Coward | about 5 months ago | (#47163719)

This is why I only buy purple cars. They last longer before they 'disappear'.

I just wish I could buy a car that was primarily UV colored...

Dark energy not necessarily real (0)

Anonymous Coward | about 5 months ago | (#47163601)

It's completely hypothetical. It's a placeholder for unexplained data and formulae that is a convenient fit. We'll know the real answer in about 25,000 years ( which is enough time to get meaningful measurements of the expansion of the universe )

sounds like a song (0)

Anonymous Coward | about 5 months ago | (#47163637)

Our whole universe was in a hot dense state,
Then nearly fourteen billion years ago expansion started. Wait...
The Earth began to cool,
The autotrophs began to drool,
Neanderthals developed tools,
We built a wall!! We built the PYRAMIDS!
Math, science, history, unraveling the mysteries,
That all started with the BIG BANG!

BANG!

Galaxy as a universe (0)

Anonymous Coward | about 5 months ago | (#47163851)

I've always thought that essentially galaxies are mini (!) universes, as the distances between them are so staggering as to be permanently out of our reach. Even individual stars are so far apart (even in binary systems!) as to make space travel in the Sci-Fi sense permanently unworkable.

http://www.astronomycafe.net/qadir/q306.html

Hopefully this will change in the not too distant future but expect evolutionary not revolutionary changes.

Can you imagine designing a vehicle to last 18,000 years? What if it gets there and we have nobody here to listen to it. You cannot command it remotely as even light would take 4.5 years to get to it.

Someone prove me wrong. Please.

Relativity says cannot receed faster than c? (0)

Anonymous Coward | about 5 months ago | (#47163861)

Okay, I know almost nothing about relativity, but as I understand matters, the speed of light is the maximum possible speed; if you had two cars, rear bumper to read bumper and they both then moved foward at the speed of light, each we see the other car receeding at 1x the speed of light, *not 2x*. The rate at which time passes will have changed, for this to be so.

As such in the article, I see this;

"If something is receding from us right now at more than 299,792.458 km/s—faster than light speed—and it’s accelerating too, how could anything reach it?"

And it seems to me this cannot be true. NOTHING can be receeding from us faster than light speed. A photon (and other massless particles) will receed AT the speed of light, even if we are in turn moving away from them at the speed of light.

Re:Relativity says cannot receed faster than c? (0)

Anonymous Coward | about 5 months ago | (#47163969)

Relativity says cannot receed faster than c?

The galaxies are faster than C because they use an ugly assembler hack.

Too early to make these asumptions (0)

Anonymous Coward | about 5 months ago | (#47163897)

We're still thinking too linear, everything is in reach.

Foolish (0)

Anonymous Coward | about 5 months ago | (#47163913)

Given current technology we can never leave our own galaxy, let alone reach another.

Given future technology whose limitations we don't know make this article total bull.
Basically this article assumed that we would discover how to to everything we can almost do now - specifically antimatter fueled STL spaceships combined with solar sails, and life extension technology. But failed to even consider that we might discover NEW ideas - and new technologies with new capabilities.

I am not saying we will find FTL travel method - but they are assuming we won't which is foolish.

There are several theoretical ways to get around the FTL issue, chief among them negative mass (thereby negating the relativistic limits). Not to mention the possibility of artificial or natural shortcuts "wormholes". Given our such limited understanding of Dark Energy and Dark Matter is totally reasonable for us to laugh at the ridiculous anti-innovation assumptions of this article.

Re:Foolish (1)

mknewman (557587) | about 5 months ago | (#47163955)

The problem is that even with FTL speeds things are still too far apart. Assume you could do 10*C it would still take 3000 years to the center of the galaxy or 10,000 years to the outskirts of Andromeda. 100*C and you are still into many multiple lifetimes of travel just to get there. The distances are so great as to be unapproachable.

If the universe were a hypersphere.... (0)

Anonymous Coward | about 5 months ago | (#47163931)

... then let us consider all of the points on the the hypersurface of the sphere. For the sake of argument, we shall always measure the distance between two points on the hypersurface as the shortest distance between them as measured along the hypersurface.

Now, if this hypersphere were expanding in radius at a fixed rate, then all points that are on the hypersurface of the sphere would recede from eachother at some fixed rate that is a linear function of their distance from eachother at some other point in time since the big bang. If the hypersphere were growing in radius at a speed = c, then any points on the hypersurface that are exactly as far apart from eachother as the radius of the hypersphere at any given moment would always be receding from eachother at speeds exactly equal to c. Objects which are closer would recede from eachother at speeds Not that I'm saying that's how things actually are, of course.... but I think it's interesting how well it lines up with observation.

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