It's big out there

Brogan

🦶 Leg end
Staff Member
Fascinating.

I've seen a few videos with similar content, but nothing down to 10[sup]-35[/sup]m and not interactive like that.
 
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The Pits

Harumph. Again.
Valued Member
I thought that was fascinating.

I was pleasantly surprised to see Wolf 359 make an appearance, although currently without the wreckage!!
 

Bill Boddy

Professional layabout
Contributor
The part about the expanding universe is that it seems to be expanding faster than the speed of light and accelerating. There are galaxies moving away from us faster than the speed of light so there may well be galaxies that we will never see.

The Boddy theory of the universe is that it is all receding from us at a great rate of knots due to having seen how humans behave.
 

Incubus

Champion Elect
Traditionally scientists and physicians are loath to consider the possibility of anything moving away from us faster than the speed of light because they tend to consider that anything that cannot be proved (and this one thing that obviously can't be "seen" or detected in any waway) shouldn't be called science. Which is limiting when you think about it.

I mean in the case of far-away galaxies it's not the galaxies themselves that are moving quicker, it's the space between us and them which is expanding. That paved the way of all sorts of fascinating theories, the multiverse and so, that "classical" scientists refuse to contemplate because they cannot be physically proven.
 
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sushifiesta

Champion Elect
Contributor
I think you're completely wrong to be honest Incubus . Any theory that solves a problem will eagerly be considered by scientists but it will not and should not be accepted as the correct theory until predictions from it are proven experimentally. That's what science is.

Galaxies moving away from each other faster than the speed of light is well known and not controversial, no one refutes it. It's possible because of the details of general relativity, which I will not pretend to understand.
 

Incubus

Champion Elect
I didn't say that everything hypothetical should be accepted as fact, but there is a school of thought that says that everything that is conceivable does exist in one form or other.
Which I'm personally a firm believer in. That doesn't make it science of course, but I think our own imagination is a small replica of phenomena that are displayed on a much broader scale.
 

Bill Boddy

Professional layabout
Contributor
What I feel odd about galaxies moving away from us at above the speed of light is that we are being told that it's not the galaxies that are moving, it is space that is stretching. If space is a physical entity what is it made of, or if it is not a physical entity how can it be said to be stretching.

It's like two knots which are a foot apart. If they are both on the same piece of elastic which you pull then they will move further apart but if they are not attached to each other in any way or form how can stretching a piece of nothing make any difference to their distance apart.
 

Incubus

Champion Elect
That's the age-old question isn't it? What we keep being told by scientists is that even nothing... is something. And even empty space has properties, and even explosive properties - hence the big bang.
The theory of relativity explains everything that's very huge and and quantum mechanics tells us about the infinitely small.
The former has physical laws that apply to everything with mass and the latter tells about random stuff where particles can be in two places at once and something pops in and out of existence. So the two don't quite tally up.

Clearly though, nature has only one way of operating.
How can something as vast as the universe come out... absolutely nothing?

Clearly, nature is a lot smarter than us.
 

Mephistopheles

Banned
Contributor
As far as I can tell the only way for Galaxy's to be moving away from each other faster than the speed of light is not because they are actually moving faster than the speed light or even moving at the speed of light it's simply because they are moving in opposite directions the same way that if two cars are travelling in opposite directions and they are each doing 100 mph then they are moving away from each other at 200 mph.

Simples.....
 

sushifiesta

Champion Elect
Contributor
It's not that simple actually Mephistopheles . Say I give you some equipment to measure the speed of light and stand 1 km away from you with a torch. I shine the torch, you measure the light when it reaches you and find the speed of it: 3 x 10^8 metres per second if we're doing all of this in a vacuum.

Now I get in a car, set off and shine the torch at you whilst travelling 100 mph. If you measure the speed of the light when it gets to you again, you will measure 3 x 10*8 metres per second again - not 3 x 10^8 metres per second plus 100 mph

If I travel away from you at 100 mph and we do the same: 3 x 10^8 metres per second, not 3 x 10^8 metres per second minus 100 mph.

If we're both in cars travelling at 100 mph, or any other speed, towards or away from each other - 3 x 10^8 metres per second.

The speed of light is always 3 x 10^8 metres per second no matter how fast the various observers are travelling, provided their speed is constant (each person/object can be travelling at different speeds but not accelerating/decelerating). This still confuses me and I am yet to hear a completely convincing explanation/analogy, but nevertheless this is how the universe works.

When you introduce acceleration you move to the realm of general relativity, as opposed to special relativity. I really know nothing about general relativity but somehow it changes things so that the laws of physics are consistent with galaxies moving away from each other faster than the speed of light, and other phenomena.
 

Mephistopheles

Banned
Contributor
Well that's pissed on my chips sushifiesta :(

But I wasn't saying that the speed of light had changed I was simply saying that the speed of the galaxy's moving away from each is increased by their individual speeds relatively speaking as they both have mass and they both have momentum as do the cars I was talking about.

But you are probably right and I am probably as dense as a an iron ingot....:)
 
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Mephistopheles

Banned
Contributor
I found the answer to both our questions here sushifiesta

http://www.physicsforums.com/showthread.php?t=67852

This is the one I was trying my weakest to explain and it seems to be fine as long as you are talking about it in the third person...

To make this explicit here, we're dealing with two different kinds of velocities. The equations of relativity always deal with the velocity of an object as measured by a specific observer, or more precisely, in a specific inertial reference frame.

The velocity in the first part of SpaceTiger's example is a different kind of velocity. We didn't measure that velocity "directly"; we inferred it from the difference in the velocities of the two objects, as measured by us. People often call this a "separation velocity" or "closing velocity" depending on whether which direction the objects are moving.

Classically, the separation or closing velocity of two objects as measured by a third observer equals the velocity of either object as measured by the other one (ignoring signs). In relativity this is not true. To get the velocity of either object as measured by the other one, from the velocities of the two objects as measured by the third observer, you have to use the relativistic velocity-addition formula.

There's nothing fundamentally wrong with the separation velocity. Sometimes it's a perfectly sensible quantity to use. It's just not the kind of velocity that the relativistic transformation equations apply to.
 
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Mephistopheles

Banned
Contributor
I have a problem with theories and that is Scientist seem to take some known quantities that they think they understand and create a theory to explain those quantities whilst at the same time completely ignoring the things they know nothing about but they believe must exist even if the unknown quantities go against what they think they know.

I believe I will have to come up with a universal theory about everything and present it to the egg heads for their approval, I'll get straight on that later today after I've had a bit of a lay down....
 
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