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We can measure fairly accurately the radial speed of a star or galaxy by measuring the Doppler shift of the emitted light from the star. Stars emit specific frequencies of light, and we can measure the frequencies to determine what elements are contained within the star. But since we know exactly what the frequencies are, we can measure the precise frequencies that we measure from the star. A star moving toward us will have its light "blue-shifted", or compressed a tiny bit in frequency. The amount of the compression tells us the radial velocity. A star whose light is red-shifted is moving away from us.
Radial velocity is the part of the velocity that is directly toward or away from us; Doppler shifts don't tell us anything about a star's side-to-side motion.
One of the astonishing discoveries of Edwin Hubble is that most galaxies are moving away from us, and the farther away they are, the faster they seem to be receding. Some nearby galaxies are moving closer, but the more distant the galaxy, the faster it is moving moving away. He determined this by the "red shift" of the light from distant galaxies.
What else can I help you with?
What is an increase in the wavelength of light as a galaxy moves away from earth?
Red Shift
What is the galaxy next to the Milky Way called?
The nearest "big" galaxy after the Milky Way is called the Andromeda galaxy, because with our line of sight from earth, it appears to be in the the constellation Andromeda. It is 2.5 million light years away.
What does the increase in wavelength of light from a galaxy mean?
This is usually expressed, equivalently, as a reduction in frequency. It means that the galaxy moves away from us. For more information, you may want to read about redshift.
How do you determine how quickly a distant galaxy is moving away from the earth?
Like sound, light waves moving away from the observer are stretched making the wavelength longer and when light comes toward us it appears to become compressed. Since the bottom end of the spectrum is red and the top blue, an object which radiates light appears to be red shifted when it moves away from us as the light wave is stretched. It has been observed that all stars are red shifted, therefore the conclusion is that all stars are moving away from us in space. This effect is called Doppler shift and is the reason a car engines note sounds higher as the car approaches and lower as it moves away from the listener.
Is the Hubble galaxy the closest major galaxy to our own?
No, the Hubble Galaxy (Messier 31, or the Andromeda Galaxy) is not the closest major galaxy to our own. The Andromeda Galaxy is located about 2.537 million light-years from the Milky Way. The closest major galaxy to us is the Triangulum Galaxy (Messier 33), which is approximately 3 million light-years away.
When a star or galaxy moves quickly away from an observerthe light it emits?
Red. It's called Redshift When it moves quickly away it's called Blueshift
What is the pattern between how far away galaxies are and how quickly they are moving?
The farther a galaxy, the faster it moves away from us.
What is the relationship between galaxy's distance from earth and the speed?
The farther away the galaxy is from ours the faster it moves from our galaxy.
What is an increase in the wavelength of light as a galaxy moves away from earth?
Red Shift
How did Hubble tell the universe was expandining?
By the redshift of the galaxies. In general, the farther away a galaxy is from us, the faster it moves away from us.
How can you measure how fast the universe is expanding?
By using some method other than the Doppler effect to calculate the distance of a distant galaxy, and using the Doppler effect to see how fast it moves away from us. A galaxy's distance and how fast it moves away from us are roughly proportional.
What is the galaxy next to the Milky Way called?
The nearest "big" galaxy after the Milky Way is called the Andromeda galaxy, because with our line of sight from earth, it appears to be in the the constellation Andromeda. It is 2.5 million light years away.
What does the increase in wavelength of light from a galaxy mean?
This is usually expressed, equivalently, as a reduction in frequency. It means that the galaxy moves away from us. For more information, you may want to read about redshift.
How do you stop your dog from eating horse manure?
You could use PET CORRECTER but be sure to praise him/her if she/he moves away when you have quickly sprayed this (away from its face ).
What sentence can you make with the word decadent?
When industry moves away, a flourishing town may quickly become decadent.
What is the name of the vessel the moves blood away from the heart called?
artery
What is an effect called in which a star or galaxy appears to move away from an observer?
red shift
