Very large Doppler shifts <red and blue shifted> of stars near galactive centers is evidence of:?
368264
i'm guessing supermassive blackholes, as it appears most if not all galaxies have one at the center.
1046890
Through the study of other stars 'wobble' within our own galaxy, we have detected planets larger than Jupiter, we believe.  Though, this is through a calculation with the doppler effect.  So to play it safe, as far as we know now it is Jupiter.  But to say that this will always be true would be bold and naive.
924822
This is something related to what is called the Doppler effect. You can experience it first hand when a police car is approaching and then going away: the sound of the siren is higher pitched when it is getting closer, and lower pitched when it goes away.\nThe same effect occurs with light.  A light emitter -- a star of a whole galaxy -- will seem to be bluer (higher frequency) if it is getting closer, or redder if it is moving away.  How much bluer or redder is called blue (or red) shift. If one knows what should be the neutral color of the light (and we do, thanks to the spectroscopic lines of emission) then the speed of the object can be derived by said amount of blue or red shift.  This is what allowed Edwin Hubble to deduct that the universe was in expansion, as most galaxies have a redshift that is greater the further they are.
84059
The boundary of the solar system is probably very loose indeed. You could perhaps mean where the Suns gravitational influence is canceled by other stars or where the solar wind no longer reaches. Dust and space is most likely what you'll find. Space is pretty boring, trying to understand it is not :)
1090971
Physics. Tasty, tasty physics.\n\nIt occours for the same reason a car rushing by you seems to change sound. To a stationary observer, the frequency (pitch) of the soundwaves made by the car as it drives away will decrease, so the pitch in your ear gets lower and lower as the car gets further and further from your location.\n\nSounds waves and light waves work much the same way - I used the car example to help with visualization. :3 It's all the Doppler Effect in action.\n\nSo, to answer your questions...\n\nIf space itself were not expanding, but galazies were moving away from each other, yes, redshift would still occour, since it's the light sources that matter, not the size of what they're contained in. If the stars are moving away, you will experience redshift looking at them.\n\nLight does indeed travel at a constant speed, but you've got the second part wrong. Yes, the energy, wavelength, and frequency changes. But all waves in a single medium (IE space) will have the same speed.\n\nTake a look at the equation v = lamba (f), which in words is velocity of the wave equals the wavelength times the frequency. If the wavelength doubles, frequency will halve, and velocity remains the same.
86731
The splitting and shift of a spectral line into several components in the presence of an electric field.
241465
No. Wave dispersion separates frequencies. The Doppler effect is caused by motion towards or away from a source, altering the perceived frequency.
70579
Interesting. I vaguely remember a "great attractor" from chaos theory, but what I find when I look it up now is that it refers to a cluster of galaxies, "in the direction of Centaurus and Hydra" where nobody is sure why they're grouped like that.\n\nHere's a direct quote from another source though which I think directly addresses what you're asking about: The galaxy rotational problem refers to the phenomenon of the descrepency between the observed rotational motion of the matter of the galactic disc from the predictions of Newtonian dynamics. (See links below and search for "12.25.I".)\n\nI think in layman's terms what they're boggling about is the "bar" shape that occurs in most galaxies, our own apparently included. A recent issue of Scientific American had a very good theory on how that occurs and why.\n\nIf I'm getting the gist of it right, they're not sure why clusters of stars occur in a semi-pinwheel pattern, since based on observed mass there simply isn't enough to cause such a structure to form or remain stable.  The theory in SciAm had something to do with a coincidence of travelling wave patterns rather than any deep dark mysteries of physics, filiments, or anything else.\n\nSee http://www.sciam.com/, October 2005 issue, p. 43, "Ripples in a Galactic Pond." Very nice article and they explained it more clearly than anything I could put together.
658414
The brighter it is, the cooler the star is.\nThe darker it is, the hotter the star is
1135249
The proof is red-shift.\n\nAs things recede from each other at a high fraction of c (speed of light), the waves stretch out; visible light takes on a higher red content.  The SPEED of light remains the same, but the frequency changes.\n\nConversely, when things approach each other, they blue-shift; the light becomes more blue.
66324
If the sun were part of a binary system, it would revolve around the barycenter of the binary system. We would be able to dected this movment by comparing the Sun's position to other nearby stars and to more distant stars. Since we don't dectect any such movement around the barycenter, that means that any such compainion star must be very very small, making the barycenter close to the sun's positon, or very far away, making the motion of the sun about the barycenter very slow. \n\nNeither of these conditions are true of any other binary star system we see, so no.
502188
Red shift or blue shift is not caused by a change in the speed of light.  It's caused the the light waves being compressed or stretched.  It's just like the same phenomenon with car sound changing as the car goes by: the speed of sound does not change just because the car is moving.
547799
The main reason is because of the general expansion of the universe.  \n\nThe best analogy is to imagine a polka-dot balloon.  As you blow up the balloon, all the dots are moving away from each other.  From the point of view of any one of the dots, all the other dots seem to be moving away from it, and the further away a dot is, the faster the dot seems to be moving.\n\nThus with the galaxies in the Universe; as we look at them with our telescopes, it appears that the farther away a galaxy is from us, the faster it is moving away from us.  But actually, all the galaxies including ours are moving away from each other as the Universe expands.\n\nThe red-shifting is part of what's known as the Doppler effect.  You'll easily notice this effect with regard to sound.  As, say, a car with a stuck horn passes by you, you'll hear a higher pitch to the horn as it approaches you and then it lowers as it moves past and away from you.  This is because the car is moving, relative to you, at a significant fraction of the speed of sound; so as the car approaches, the sound waves start to "catch up" with each other, shortening the wavelength and producing a higher tone.  Then as the car moves away from you, the sound waves get "left behind," the wavelength is stretched out and the tone sounds lower.\n\nThe same thing happens with light, though the relative speed has to be much greater in comparison with the speed of light.  The further away a galaxy is from us, the faster it is moving away relative to us, and the light from the stars in that galaxy is red-shifted as the wavelengths are stretched out.  If the stars were moving towards us with the same speed, the wavelengths would be shortened and the light would be blue-shifted.
325262
Yes, there are. The overall magnetic field around galaxies is an actively researched subject. The magnetic fiels of compact stars tend to be very large and contribute to the way pulsars act, for example.
135567
well there are two answers.  The pole is actually shifting as we speak albeit to such a minor degree that we would never notice during our lifetimes.  The present 'north star' polaris was not always the 'north star' and in the future a new 'north star' will take it's place.  There have been drastic pole shifts possibly resulting from the passage of an enormous comet or asteroid within or close to the orbit of the moon.  When this occurs, drastic changes take place in a short span of time.  It is theorized that the break-up of pangaea into the continents was caused by a sudden pole shift.  From Straight Dope :Geologist Jean Andrews of Columbia University has found evidence to suggest that 180 million years ago the poles were displaced about 22 degrees from their present alignment, with the North Pole located on the northern coast of what is now the Soviet Union.
845717
An international team of astronomers from France, Italy, the UK and Australia has found a previously unknown galaxy colliding with our own Milky Way. This newly-discovered galaxy takes the record for the nearest galaxy to the centre of the Milky Way. Called the Canis Major dwarf galaxy after the constellation in which it lies, it is about 25000 light years away from thesolar system and 42000 light years from the centre of the Milky Way. This i closer than the Sagittarius dwarf galaxy, discovered in 1994, which is also colliding with the Milky Way. The discovery shows that the Milky Way is building up its own disk by absorbing small satellite galaxies. The research is to be published in the Monthly Notices of the Royal Astronomical Society within the next few weeks.\n\nThe discovery of the Canis Major dwarf was made possible by a recent survey of the sky in infrared light (the Two-Micron All Sky Survey or "2MASS"), which has allowed astronomers to look beyond the clouds of dust in the disk of the Milky Way. Until now, the dwarf galaxy lay undetected behind the dense disk. "It's like putting on infrared night-vision goggles," says team-member Dr Rodrigo Ibata of Strasbourg Observatory. "We are now able to study a part of the Milky Way that has been previously out of sight".\n\nThe new dwarf galaxy was detected by its M-giant stars =AD cool, red stars that shine especially brightly in infrared light. "We have used these rare M-giant stars as beacons to trace out the shape and location of the new galaxy because its numerous other stars are too faint for us to see," explains Nicolas Martin, also of Strasbourg Observatory. "They are particularly useful stars as we can measure their distances, and so map out the three-dimensional structure of distant regions of the Milky Way disk." In this way, the astronomers found the main dismembered corpse of the dwarf galaxy in Canis Major and long trails of stars leading back to it. It seems that streams of stars pulled out of the cannibalised Canis Major galaxy not only contribute to the outer reaches of the Milky Way's disk, but may also pass close to the Sun.\n\nAstronomers currently believe that large galaxies like the Milky Way grew to their present majestic proportions by consuming their smaller galactic neighbours. They have found that cannibalised galaxies add stars to the vast haloes around large galaxies. However, until now, they did not appreciate that even the disks of galaxies can grow in this fashion. Computer simulations show that the Milky Way has been taking stars from the Canis Major dwarf and adding them to its own disk - and will continue to do so.\n\n"On galactic scales, the Canis Major dwarf galaxy is a lightweight of about only one billion Suns," said Dr. Michele Bellazzini of Bologna Observatory. "This small galaxy is unlikely to hold together much longer. It is being pushed and pulled by the colossal gravity of our Milky Way, which has been progressively stealing its stars and pulling it apart." Some remnants of the Canis Major dwarf form a ring around the disk of the Milky Way.\n\n"The Canis Major dwarf galaxy may have added up to 1% more mass to our Galaxy," said Dr Geraint Lewis of the University of Sydney. "This is also an important discovery because it highlights that the Milky Way is not in its middle age - it is still forming." "Past interactions of the sort we are seeing here could be responsible for some of the exquisite detail we see today in the structure of the Galaxy," says Dr Michael Irwin of the University of Cambridge.
789785
The stars themselves don't.  It is just an illusion.  The miles of air in our atmosphere between our eyes and the star changes in temperature and humidity which makes the star look like it is flickering when it really glows at a constant rate.