Hubble Survey Finds Half of the Missing Matter

esocid sends along the news that scientists believe they have found about half the missing matter in the universe. The matter we can see is only about 1/8 of the total baryonic matter believed to exist (and only 1/200 the mass-energy of the visible universe). This missing matter is not to be confused with "dark matter," which is thought to be non-baryonic. The missing stuff has been found in the intergalactic medium that extends essentially throughout all of space, from just outside our galaxy to the most distant regions of space. "'We think we are seeing the strands of a web-like structure that forms the backbone of the universe,' Mike Shull of the University of Colorado explained. 'What we are confirming in detail is that intergalactic space, which intuitively might seem to be empty, is in fact the reservoir for most of the normal, baryonic matter in the universe.'"

Re:Ether

[Anonymous Coward]

Yup, Disproven.

Because Einstein got everything perfect (cosmological constant)
And light (which may or may not have mass) is bent by gravity (bending space time)

Wouldn't it make more sense to go with an aether theory?

You say light travels at the same speed regardless of direction or relative motion? I say bunk requiring some very sophisticated manipulations of time and space (Lorentz contractions) What's wrong with the 'entrained aether' theory? What, you never heard of frame-dragging?

Gravitational lensing? How about gravity increasing the optical density of the aether?

*puts away tin foil hat*

Intersteller Travel Ho!

[Anonymous Coward]

So now Bussard ramjet's are much more feasible because of all the extra fuel. Right?

Re:Oxygen and Hydrogen?

[Anonymous Coward]

It's actually that the atoms are way TOO hot. The oxygens are ionized 5 times. That means that whatever pushed them out there was very violent and hot, and the atoms, even if they were to collide, would never stick.

Re:Ether

[sir fer]

disclaimer: I am a physics graduate. EM waves consist of an oscillating electric field (along with its magnetic counterpart)...what was that electric field doing before it started oscillating? It was probably a static field. Think about this, if I have a magnet and I wiggle it around, the disturbance in the field of the magnet travels outward from the source at the speed of light, but the field was there but merely static initially. Same deal with gravity waves. So whether the local field is static or oscillating, it was always previously existent regardless of its state. While I don't believe in the luminiferous aether either I also don't see how a field disturbance (electric, magnetic or gravitational) can travel through something that isn't there. I hope people can see what I'm talking about because while relativity and the aether don't make sense on their own, there are aspects of both theories that accurately describe reality and as is often the case in modeling reality it is not often a case of either / or, eg wave-particle duality in describing the sub-atomic world.

Re:Ether

[TropicalCoder]

I've got a question for a physics graduate or anybody who can answer it. After reading for the thousandth time about all the ionized gasses in space, I suddenly began to wonder how many electrons were created in the Big Bang? Like - are there enough electrons for every atomic nucleus to fill it's shells - if they weren't ionized? Now, that seems improbable, because an enormous amount of matter was created after the Big Bang - created in stars and super novae. Then this matter that was created - were electrons created at the same time in proportion? ...and in the balance of things - how many electrons are there in the Universe and how many protons are there? ...and how much do all these electrons weigh? ...and all these electrons that were striped from interstellar matter to leave behind ionized gasses - where did they go? Well I would guess they are zinging along some magnetic field lines someplace, quite happy to be alive, but is there some place where they collect in huge clouds? I don't suppose that is too likely, because electrons are antisocial among themselves and stay as far apart as possible, but on the other hand, protons are like that too among their own kind, yet somehow manage to form clouds. So then you think about these huge clouds of hydrogen and helium nuclei, all longing for the company of electrons, but there are none to be found in the region - such huge imbalances must exist. Makes you wonder when matter finally conglomerates into planets and such that somehow there is suddenly just the right number of electrons available so that every single atom can fill is orbital shells. How does this come about?

Re:Dark Matter???

[lgw]

although how the universe's biggest ever black hole could have expanded past its own event horizon is beyond me. But then I'm only a physics grad.

Has it? The "diameter" of the event horizon grows linearly with mass, but an object of fixed density grows with the third root of mass, so as mass increases you'd expect the Schwarzschild diameter to grow faster than the size of the object.

The Schwarzschild "diameter" (circumference over pi) is 4 G M / c^2, or 2.969 * 10^27 m/kg.

The mass of the (observable) universe is about 10^53 kg.

The Schwarzschild diameter of the (observable) universe is therefore about 3*10^10 light years, within an order of magnitude of the probable diameter of the observable universe.

The universe as a whole is probably many orders of magnitude bigger than the observable universe, so it seems quite likely that we're all still inside that event horizon.

Re:Ether

[sir fer]

I assume by "physics graduate" you mean you majored in it in undergrad.

Yes indeed.

First, as a physics graduate, you should know better than to use the phrase "believe in" when talking science.

Well I was using it in the laymans sense (yes I know it sucks that words like "theory" mean different things to different people). But the results of Michelson-Morley seem to discount the idea of the ether and subsequent theory and results also lend credence to the idea that there is no luminiferous (i love that word ;o) ) aether. So i was meaning in the sense that no theory is 100% proven, it's more like a law case where the evidence stacks up to support whatever conclusion it happens to, so I don't believe in the aether because there is not much evidence for it, rather than being biased one way or another.

Second, I suppose you haven't had much field theory (can't fault you for that), so the behavior of electromagnetic fields may seem odd.

What? That a field can oscillate where there was previously no field? Any electric field extends to infinity so perhaps this superposition of fields constitutes a form of aether, but with properties different to what is normally meant from the term. I think it is wrong to throw the baby out with the bathwater, especially when it could simplify things...not saying I'm right or anything, just throwing the idea out there coz it's been brewing in my head for a long time...

Re:Ether

[locofungus]

Why does wavefunction collapse violate SR? SR prohibits information traveling faster than light. The no-communication theorem http://en.wikipedia.org/wiki/No-communication_theorem [wikipedia.org] (I'd always called this the no-signaling theorem) leads to the no-cloning theorem http://en.wikipedia.org/wiki/No_cloning_theorem [wikipedia.org] so if you like, SR "explains" the no-cloning theorem. (The no-cloning theorem still allows a cloning fidelity of 5/6. Last I saw, fidelities of 0.81 had been achieved)

Back to the topic at hand, the interesting thing with special relativity is that while it was created based on the results of the Michelson-Morley experiment, it doesn't actually "explain" that experiment.

Maxwell's equations (see sig) predict that light will propagate with a speed c independent of frame. Einstein had a choice, Newton was wrong or Maxwell was wrong. A non-null result from the MM experiment would invalidate Maxwell's equations.

So, if you like, Maxwell's equations "explain" the null MM result.

Tim.