Spacemen Biff
Give way, to the left or to the right?
RED ALERT! High-speed alien fugitives are invading our Milky Way
Rare hypervelocity stars tearing through the Milky Way galaxy are runaway suns that have escaped neighbouring galaxies, according to research presented at this year’s National Astronomy Meeting in Hull, England. Hypervelocity stars are travelling between 300 and 700 kilometers (186 and 435 miles) per second faster than our …
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Thursday 6th July 2017 14:05 GMT Farnet
Re: Spacemen Biff
interesting sunwise and widdershins are all down to your viewing perspective, but if we has an opportunity you view the universe from the theoretical overhead vantage point would all the rotations (planets around a sol, galaxies around a black hole, and the universe in general), be evenly mixed or would there be a logical rotation (eg 70% sunwise, or clockwise)?
just something i've never really thought about, and would assume there would some logic behind it all.
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Thursday 6th July 2017 18:22 GMT stephanh
Re: Spacemen Biff
@ Farnet
The question if the universe as a whole is rotating is actually a serious topic in cosmology. I recall it being discussed in "Gravitation" by Misner, Thorne & Wheeler. If it were the case, you would expect to see some deviation in the background radiation in the direction of the axis of rotation. No such deviation has been observed, but that just puts an upper bound on the rotation (i.e. the universe is not rotating very fast).
Interestingly, in a rotating universe you could establish the axis of rotation, but the question of the center of rotation would by meaningless; every observer would appear to be at the center.
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Thursday 6th July 2017 12:24 GMT Named coward
Re: Hypervelocity...
momentum relative to the speed ?
They are travelling at some speed greater than the escape velocity of the Milky Way at their location, relative to the milky way rest frame. The speed relative to the Sun (or earth) can be greater or lesser than this speed, depending on their location and direction. So you can say they are traveling very fast. You can also say they are slow (compared to, say, the speed of light)
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Thursday 6th July 2017 12:45 GMT Cuddles
Re: Hypervelocity...
"Are they really moving that quickly, or is it only an apparent velocity based on their momentum relative to the speed and direction of travel of the Milky Way itself?"
What do you mean "really"? All velocities are measured relative to something else. Obviously since the question is why and how these stars are travelling faster than the escape velocity of the Milky Way, the frame of reference here is the Milky Way. Their velocities relative to other things will be entirely different. None of the velocities measured relative to anything are more or less real than any of the others, although the vast majority of them will be irrelevant in trying to figure out what's happening.
What you're asking is essentially equivalent to asking whether a car moving at 30 mph is really moving that fast or is it just relative to the Earth's surface. Yes, that is the velocity relative to the Earth's surface. You could measure its velocity relative to the centre of mass of the Andromeda galaxy and that would be just as real, but not particularly useful.
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Friday 7th July 2017 04:38 GMT JCitizen
Even at those speeds..
which seem fantastic - it will probably take them forever to even get close enough to a star system to perturb it. In fact they may pass right though our entire galaxy and NEVER hit anything at all. That saddens me as I love collisions, but by that time the Earth will probably be destroyed by something completely unexpected. I certainly will not be around any more! I hope these massive computer simulations show data that can be made into a video - maybe even a 3D video to show them prancing through our universe without a care in the - uh - world. Heh, Heh!
Biting the hand that feeds IT
