Evidence for Universe Expansion Found

Yahoo (AP) ^ | 3/16/2006 | MATT CRENSON

[The_Victor]

I think the experiment you refer to is a demonstration of black surfaces and heat reflection not photon energy/mass but I could be wrong..was once.......

You know the experiment, but it is not about heat, but rather a demonstration that light has momentum (and therefor mass). One side of the vanes is black to absorb photons, and the other is silver to reflect them. Shine a light on it and the device spins. I can't find one online though. I remember seeing them in the ads in the back of "Boy's Life."

[PatrickHenry]

SciencePing

An elite subset of the Evolution list. See the list's explanation at my freeper homepage. Then FReepmail to be added or dropped.

[hosepipe]

[ Turtles. It's turtles all the way down. ]

Why turtles?.. Why NOT Moonbats..?

[Netheron]

The photons have a momentum, not a mass.

Anyway, the windmill/lightbulb doesn't really have much to do with photon momentum, it has more to do with differences in temperature on the vanes and the gas molecules inside the bulb.

[King Prout]

I suppose it is theorized that C did not get established as a property of radiant energy until after this "expansion" business.

[VadeRetro]

But if the space-time grid's real...

Is this the first you've heard of the expansion of the universe? It does not conflict with relativity. Relativity at first predicted it, although Einstein was unnerved enough to find a way to revise that feature out. The universe has some finite volume (although incredibly huge, far far bigger than the part we can see) but no edge or surface. Within it, everything is still relative to the observer's frame of reference. Outside of it... who knows?

[Zeppo]

When I questioned the meaning, I was questioning the writer's choice of words, which appear at best to be confused mumbo-jumbo, and at worst are completely devoid of meaning. I was not questioning the intrinsic meaning of the variations.

"Stretching across the entire sky" is not properly descriptive of a "hugeness" of variations - indeed, a constant microwave background could also "stretch across the entire sky". So, I'm still wondering what, exactly, the author was trying to convey with that strange wording...

[The_Victor]

So you're claiming light has weight?

Yes,....

well, sort of.

Light has momentum. The photons have no rest mass, but since they move at the speed of light and from all relative observers, always move at that speed, the photos have a measurable mass associated with it's high velocity. Do a Google search on "light, momentum, photon, mass" and you'll turn up a ton of good explanations.

[taxcontrol]

One problem remains with the inflation theory. In order for the universe to expand that rapidly, the matter that existed in the first instance of the universe would have to travel MUCH faster than the speed of light.

[xroadie]

I question the introduction of the term "sky" in the whole thing. I'll have to read this later, after several sips of a good single malt..

[VadeRetro]

In order for the universe to expand that rapidly, the matter that existed in the first instance of the universe would have to travel MUCH faster than the speed of light.

No. The space is expanding. The mass is just staying put within the space.

[The_Victor]

The photons have a momentum, not a mass.

But in order to have momentum, mass is required. Photons have no rest mass, but since they are never at rest, they have a measurable mass, even if that mass is purely associated with it's velocity.

[MineralMan]

"Why turtles?.. Why NOT Moonbats..?
"

It's a Hindu thing. You wouldn't understand.

[The_Victor]

differences in temperature on the vanes and the gas molecules inside the bulb.

The bulb is supposed to be pumped down to a vacuum.

[beezdotcom]

"The expansion of the universe isn't like that. The universe is not an object; it doesn't "take up space". It is space. As it grows, it doesn't mean that there is less space for objects; it means there is more space for objects. Nothing needs to be displaced to admit its expansion." --Physicist

True enough...although I *would* like to hear some more about in how many dimensions (4, 10, 11, 26) spacetime could (or could not) be expanding, based on observations like these. Some of us need a little extra help in connecting the dots to know if observations support, preclude, or leave open those possibilities.

[MineralMan]

"No. The space is expanding. The mass is just staying put within the space."

I don't think this is going to get across. The concepts are just a little too difficult for most folks to grasp, I'm afraid.

The concept of space isn't something that most people understand, and it's hard to explain, since it requires stepping away from observable reality.

[The Sons of Liberty]

growing from the size of a marble to a volume larger than all of observable space in less than a trillion-trillionth of a second.

Doesn't that violate the law that nothing can travel faster than the speed of light?

[ahayes]

Nope, things aren't allowed to move through spacetime faster than the speed of light, but spacetime can stretch and carry stuff with it that fast.

[The_Victor]

I don't think this is going to get across. The concepts are just a little too difficult for most folks to grasp, I'm afraid.

The balloon analogy was what worked for me.

[Vicomte13]

Nope, it's not the first I've heard of the expansion of the universe.

I remember the epicycles and geometrics of a past age too.

It's pretty clear to me that we're in one of those "epicycle phases" of our knowledge, where what we're seeing is odd and doesn't work very well with something else we think, but all we've got is the model so we have to soldier on until someone has a brilliant insight that makes the thing simpler and rational.