• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

How galaxies can travel faster than the speed of light

Page 3 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.
silverpig said:
It's no more real than a bird either.

It's one that everyone in the universe can agree on from wherever they are by performing the same experiment. I don't know how someone in andromeda is going to measure the frame of reference of you sitting at your desk.
Click to expand...

What you are doing is going to confuse people into thinking that there is an absolute frame of reference. You perform your experiment and I perform mine we can transform the results into what ever frame we want.
 
ElFenix said:
the more interesting question is if expansion is happening at the subatomic level
Click to expand...

Insert joke about continuously expanding Americans here.

But that does add an extra mindfuck to the equation. An equation already made up of a minefield of mindfucks.

The universe expands...empty space gets bigger...so what constitutes empty space? Atoms are mostly empty space...they have other forces holding clumps of them together, yeah; but there is also some kind of force acting upon pretty much everything in the universe, even if it's just the weakest of gravitational fields causing the most miniscule of tweaks to the way something moves.

Does the answer lie in chemical bonds? I.e. the earth, all it's organisms, ect, are not subject to universal expansion...nor anything in its atmosphere, I guess...but the vacuum of space that surrounds us is? Or is that also an exception due to the giant black hole that we're spiraling around*?

*Into? I wanna say into. Do astrophysicists, cosmologists, and the like have any solid predictions for how galaxies could end? Or is it a moot point because all the stars burn out first?
 
phucheneh said:
The big bang didn't have a location. It created everything. The big bang is all around you. D:

I made the analogy to a balloon and Paul did a good job of correcting it...the rubber is 'spacetime,' and it keeps growing, with everything moving apart. Like if you drew a bunch of dots all over the balloon to represent galaxies...as the balloon expands, everything gets further apart. And the dots get bigger, but we'll pretend they don't...or, wait, should they? Is expansion happening on a galactic level, as well?

I was thinking not, because of the other forces binding all the galactic crap together. And there are of course other forces at play on an intergalactic level, too, but I think the video in the OP touched on that.
Click to expand...

That isn't making much sense at this point.

Then again I'm not sure how much we understand 'the big bang'.

And especially anything before the big bang.

I'd think you could reverse objects by time and speed to a 'location' for the big bang.
 
Craig234 said:
That isn't making much sense at this point.

Then again I'm not sure how much we understand 'the big bang'.

And especially anything before the big bang.

I'd think you could reverse objects by time and speed to a 'location' for the big bang.
Click to expand...
The Big Bang was the thing that generated the possibility of time and spatial coordinates as we know them, so it can easily mess with people's minds.
 
Craig234 said:
That isn't making much sense at this point.

Then again I'm not sure how much we understand 'the big bang'.

And especially anything before the big bang.

I'd think you could reverse objects by time and speed to a 'location' for the big bang.
Click to expand...

Space as we know it did not exist then, imagine it as the entire universe exploding with super pressurized super heated plasma, expanding and cooling.

Some interesting stuff if you want further reading here-

http://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis

http://en.wikipedia.org/wiki/Supernova_nucleosynthesis

http://en.wikipedia.org/wiki/R-process

http://en.wikipedia.org/wiki/Cosmic_ray_spallation

It's kind of trippy to think about the origins of various matter.

And of course we know little of it, the big bang happened a really long time ago. We have some good guesses though.
 
Last edited:
I have mentioned it multiple times before, but for anyone who knows even less about this stuff than I do but wants to learn something...or just likes interesting TV...watch 'Wonders of the Universe.' BBC-produced, airs on the Science Channel sometimes. There's also a previous 'Wonders of the Solar System,' but it doesn't deal with principles that are, well, more universal. Like the Big Bang, formation of matter and different elements, gravity, ect.

Brian Cox takes these complex things, and explains them in a such a simple way that it makes you feel kinda dumb for not knowing it or at least grasping it more fully. Some of it might be a little TOO basic, but it's still interesting. It's kinda like Top Gear meets astrophysics.
 
disappoint said:
It isn't. There is no expansion of space happening for gravity bound objects. Galaxies are not expanding, the spacetime between them is.
Click to expand...

But how do you draw the line?

Aren't the Milky Way and Andromeda bound by gravity?

edit: LOL, I just posted in another thread why people didn't just use Wikipedia before asking silly questions (in that particular case, about a conceived perpetual motion device). Whoops, guess I shoulda followed my own advice.

https://en.wikipedia.org/wiki/Metri...nsion_of_the_universe_felt_on_small_scales.3F

Specifically states that space between the two mentioned galaxies is not expanding.
 
Last edited:
It wasn't a silly question but I'm glad you found it on Wikipedia. I hadn't read it on there. I learned it watching a Lawrence Krauss lecture.
 
A great analogy I once read that made it easier to understand was to think of a balloon as the universe and dots drawn on it as galaxies. As you inflate the balloon, the dots are still where they are but the distance from one dot to another gets farther away from each other. The rate of inflation is this expansion that is happening faster than light.
 
disappoint said:
It isn't. There is no expansion of space happening for gravity bound objects. Galaxies are not expanding, the spacetime between them is.
Click to expand...

Well, the expansion of space is happening for gravity bound objects, but it just doesn't matter because gravity overcomes it, so these things stay stuck together.

If the expansion of the universe continues to accelerate, gravitationally bound galactic clusters will eventually fly apart. After a while, galaxies themselves will fly apart, then solar systems, then stars, planets, and people.

If the rate of expansion accelerates with no end, even atoms could be ripped apart.
 
Neato. I struggled with the galaxies becoming unobservable part for a bit though.

Also if galactic expansion does not occur on a subatomic level, why are we able to observe the redshift in light? Would it not be unaffected? Or is that getting into the whole light is "not quite matter, not quite energy" thing?
 
Videos like that are the dark holes of youtube--where the comments are full of intelligent, thoughtful ideas, and can never escape to the rest of youtube.
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top