The light from distant galaxies shows redshift because the universe is expanding. As the galaxies move away from us, the light they emit gets stretched, causing its wavelength to increase and shift towards the red end of the spectrum. This redshift can help scientists determine the velocity at which galaxies are moving away from us and provide insights into the expansion of the universe.
We can't be sure. The only thing we know for sure is that it could be explained asthe speed with which that galaxy is receding from us. If that's actually the causeof the red shift, then from all the red shifts that we observe, we have to concludethat all of the distant galaxies are receding from us, and the farther away one isalready, the faster it's receding. If all of that is true, then the whole universe isexpanding. This is the research that made Hubble famous.Well said, but there is another reason. Maybe the light is coming from a large star (gravity hole, red shift due to gravity).
The red shift spectra of galaxies show that most galaxies are moving away from us, indicating that the universe is expanding. This observation supports the Big Bang theory, which suggests that the universe began in a state of high density and temperature and has been expanding ever since. The amount of red shift in a galaxy's spectrum can also provide information about its distance from us and its velocity.
The star is moving away from us. Therefore, the Doppler effect must be considered. The Doppler effect is waves (in this case light) will be compressed in front of a moving object and stretched behind the object. This stretching creates a long wavelength. Red light has a long wavelength (the longest of visible light), so we call this stretching red shift.
In simplest terms, the shift of galactic spectral lines towards the red end of the spectrum would indicate simply that the galaxy in question is receding from the observer. This is an example of the Doppler effect, where the frequency is lowered (wavelengths become longer, and in this case energy of the photons is decreased) by the relative motion of the observer. The redshifting of galaxies in all directions became the primary evidence of an expanding universe (cosmological redshift). Because the expansion of the universe is fairly uniform in all directions, those galaxies that are most distant are receding the fastest and thus evidence the greatest amount of redshift. By contrast, if a characteristic spectral line of a galaxy or other object shifted towards the blue end of the spectrum (shorter wavelengths), it would be traveling towards the observer.
If the distance between us and a object emitting a wave (sound or light) is increasing, then the wavelength of the wave it emits will be red-shifted. If the distance is decreasing, it will be blue-shifted. This is true for a car driving towards us with its horn blaring, or a distant galaxy emitting hydrogen lines.
The red end of the spectrum.
The red shifts show the galaxies are under centripetal force and the red shift indicates the centrifugal force. This indicates that the universe is in continuity, the centripetal and centrifugal forces are in balance.
They actually are. Galaxies that are only millions of light years won't show much difference - that's too short compared to the age of galaxies. But there is definitely a trend in galaxies at distances of billions of light-years. Their metallicity is lower (i.e. they have had fewer supernovas to pollute the interstellar gas), and there is a greater percentage of disc galaxies (elliptical galaxies are thought to form by the collision of disc galaxies).
No. You can figure out exactly what elements are in stars and galaxies by examining the color spectrum of the light detected; the frequencies of the bright and dark lines in the spectrum tell you what's what. But there's a problem. For distant galaxies, the light spectrum is wrong. The frequency lines of the spectrum are all too low. One possible explanation of the incorrect spectrum is that those stars and galaxies are MOVING AWAY from us, and that the spectrum is shifted toward the red end of the color spectrum because of the Doppler effect. So scientists believe that the "red-shift" on the color spectrum of stars and galaxies indicate that they are moving away. Not all galaxies show a red-shift; the Andromeda Galaxy, M31, shows a pronounced BLUE-shift, indicating that it is heading TOWARD us. In fact, scientists believe that the Milky Way and Andromeda will probably collide in about 3 billion years.
We can't be sure. The only thing we know for sure is that it could be explained asthe speed with which that galaxy is receding from us. If that's actually the causeof the red shift, then from all the red shifts that we observe, we have to concludethat all of the distant galaxies are receding from us, and the farther away one isalready, the faster it's receding. If all of that is true, then the whole universe isexpanding. This is the research that made Hubble famous.Well said, but there is another reason. Maybe the light is coming from a large star (gravity hole, red shift due to gravity).
Some nearby galaxies move towards us (blueshift), some move away from us (redshift). Galaxies that are farther away all move away from us (redshift); this means that the Universe is expanding.
The red shift spectra of galaxies show that most galaxies are moving away from us, indicating that the universe is expanding. This observation supports the Big Bang theory, which suggests that the universe began in a state of high density and temperature and has been expanding ever since. The amount of red shift in a galaxy's spectrum can also provide information about its distance from us and its velocity.
Many objects observed in the universe show a red shift. It is believed that this red shift is caused by a Doppler effect - that is, that the objects are moving away from us at a significant fraction of the speed of light. If this is true, then it is evidence for an expanding universe.
to take photographs of very distant galaxies, and show data of them to NASA. It is used, because there is too much light pollution in a lot of places on Earth, making it hard to use a telescope, but in space there is no light pollution (therefore, it can see the galaxies that we can't see on Earth).
Earth has a thick atmosphere, making it difficult to see details in objects being looked at in a telescope. While you could send lots of telescopes into space, the process takes time and money. Light rays like Infra Red can be used to cut through the atmosphere and allow you to see stars and planets on Earth's surface. Also, certain light rays can be used to see what objects in space are made of.
The observations made from distant galaxies suggest that Dark energy exists. This is because of the fact that the galaxies are moving away from each other. This is given by Hubbles law.Instead of being attracted by the force of gravitation,galaxies tends to move away suggesting the presence of a gravity opposing force called dark energy.
Irregular galaxies show no distinct feature or symmetry.