Originally Posted By: Marchimedes
But what I was looking for is has the so-called scientists accounted for the normal interstellar matter I referred to as normal mass of galaxies?

Regarding interstellar - as opposed to intergalactic - distribution of Dark Matter, I don't know what the current data is purported to suggest. A few years ago, I asked an astronomer if dark matter might affect the orbits of planets in our Solar System. His answer was no, because the Dark Matter seems to occupy the space around the Milky Way, and if there is some local interstellar Dark Matter, it's an insufficient amount to have a measurable effect. So, in other words, all (as far as anyone can tell) of the stuff within the visible galaxy is reckoned to be normal matter, with Dark Matter surrounding it and affecting the characteristics of its rotation. Since no one yet knows what DM is, it's not a good time in history to be making bold assertions about it. The research is ongoing.

http://www.solstation.com/x-objects/darkhalo.htm

Originally Posted By: Marchimedes
And another question...

I'm looking for information of how long it would take to get to light speed from a dead stop at various accelerations. For instance, at 2 G's how long would it take to get to c?

Thanks to RickB, who did the work for us...

At 1g:

99%............6.8 years
99.9%..........21.66 years
99.99%.........68.5 years
99.999%........216.76 years

You can cut those times in half by going at "2g" instead of "1g"...but you still have the same problem of the times stretching out to infinity.


http://answers.yahoo.com/question/index?qid=20090425080114AAIsYZx

I find it difficult to grasp, Marchi, since it's all about frames of reference (with more than a bit of maths to understand). For example:

"So in theory you can travel across the galaxy in just 12 years of your own time"

So the times above are as witnessed by the guys at mission control, not to anyone aboard the spacecraft.

http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html


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"Time is what prevents everything from happening at once" - John Wheeler