Electromagnetic Propagation

[labelwench]

I'm not certain if this is the best thread to post the following on, but as there is mention of dark matter in some of the posts, I'll park it here for you to make of it what you will.

Regards,

Labelwench

Something big is going on at the center of the galaxy, and astronomers are happy to say they don’t know what it is.

A group of scientists working with data from NASA’s Fermi Gamma-Ray Space Telescope said Tuesday that they had discovered two bubbles of energy erupting from the center of the Milky Way galaxy. The bubbles, they said at a news conference and in a paper to be published Wednesday in The Astrophysical Journal, extend 25,000 light years up and down from each side of the galaxy and contain the energy equivalent to 100,000 supernova explosions.

“They’re big,” said Doug Finkbeiner of the Harvard-Smithsonian Center for Astrophysics, leader of the team that discovered them.

The source of the bubbles is a mystery. One possibility is that they are fueled by a wave of star births and deaths at the center of the galaxy. Another option is a gigantic belch from the black hole known to reside, like Jabba the Hutt, at the center of the Milky Way. What it is apparently not is dark matter, the mysterious something that astronomers say makes up a quarter of the universe and holds galaxies together.

http://www.nytimes.com/2010/11/10/sc...=1&ref=science

[Meem]

I just thought of something. We already did that dark matter wind experiment. It is the same set of experiments that disproved an aether wind.

Light changes its velocity depending on the medium its traveling through. The Michelson-Morley experiment (and others) based their conclusions on this premise. They showed there was no appreciable change in light speed, in space, because there was no medium (aether wind) to change its velocity.

Based on these findings, wouldn't this also mean that light's speed wasn't affected by dark matter ("a ghostly sea of subatomic particles thought to permeate the cosmos"). So, if you believe aether doesn't exist based on these experiments then wouldn't it conclude that dark matter couldn't exist either....

Just a thought

Dark matter perhaps, but as for the aether. If it is always there everywhere, the idea that one might be able to measure a change in light speed because of it seems a bit bonk to me. Where would aether not be, for C to change its speed? I was always under the impression the very idea behind aether was that it is "The Field."

[ShawnD]

Hi, Meem. Thanks for the insight. Seems a bit bonk to me too.

These experiments, I believe, were based on the aether being stationary and similar to normal matter. It would have a sort of wake if an object moved through it (like a boat moving through water).

Like SteveA was saying; if the aether was moving with us then we might not be able to measure it like this. There would be no aether drag. The drag caused by the Earth moving through the aether is what these experiments are based on. Aether may just move with us.

But it seems that if we were moving through dark matter, and it permeates the cosmos as believed, then wouldn't it also be effected by drag? Wouldn't this drag also change the speed of light? Wouldn't these experiments have already shown that? I wonder if the scientists will look back at these experiments and say dark matter can't exist because theres no change in the speed of light? I doubt it. They would try different experiments to prove it (which they are). So hopefully I can find different types of experiments done to disprove (or prove) aether.

The way I look at it is that dark matter moves with with us, like aether if it exists. Its possible that dark matter may not be concentrated enough to change the speed of light. Or, dark matter may not affect the speed of light locally, and neither may aether. I hope I'm not ranting.