Quasars are dusty stellar debris left over from the collapse of very massive stars.
A quasar is a bright, luminous, active galactic nucleus where a massive black hole with a mass up to a million times that of the Sun lies surrounded by a luminous gaseous jet stream. These jets are constantly spinning at very high speeds and they can reach speeds of several million miles per hour. The jet streams are made from very hot, low density dust particles, which are spiraled around the black hole.
The outer edges of these jets have a strong effect on the surrounding space as well. Radio telescopes have been used to study how the distribution of matter in and near these compact elliptical structures changes as a result of this jet stream. In fact astronomers have even discovered quasars within galaxies that contain relatively few black holes.
Quasars, like many other compact stars, are born from a process called a hypervelocity collapse.
This is a change in a star’s atmosphere from the rapidly spinning environment of a very near solar system to that of a much farther away universe. In most instances, this collapse occurs in a cloud of gas which is very cold. In the case of quasars this cloud was extremely hot, which can be compared to our own Galaxy. When the cloud was warmed enough it would collapse back into a black hole.
When astronomers study quasars using tools such as the Very Large Telescope (VLTV), they are able to measure how far away these objects are.
They can also detect the relative amount of emission or the amount of energy emitted by the system as a whole. These measurements allow astronomers to map out the distribution of distant objects in the nearby Universe. Scientists use these maps to study the properties of matter which makes up the bulk of the visible Universe, and can even help us understand more about our own galaxy.
Astronomers study quasars using specialized telescopes such as those at Keck, Hawaii, that focus light on specific wavelengths to produce a spectrum. The wavelengths of a spectrum depend upon their geometric location and direction. By measuring how strong the emission lines are, and how spread out they are, astronomers can map out the distribution of distant celestial bodies in the sky. Since the emission lines of ordinary objects are quite uniform, this method of mapping out quasars can give us a clear idea of their sizes, and where they lie in the sky.
Another method astronomers use to study quasars is by looking for accretion disks.
These disks have accreted material that has formed around a black hole over time. Similar to clouds, they are made up of gas, dust, and ice, and spin very quickly. While these disks may seem very small to the eye, they are actually many times larger than the nucleus of an average star. In fact, astronomers estimate that they account for around 70% of the total brightness in the universe.
Since astronomers can detect these emission lines, they can also study these disks to find out more about the properties of matter that makes up them. Scientists have been able to measure the temperature and composition of these objects by using telescopes in space, or through studies of ground-based telescopes. By using telescopes, scientists have found that quasars, much like the distribution of ordinary stars, are made up of neutral gas. They also know that they are very hot, emitting x-rays, gamma rays, and high energy radiation. Based on these results, astronomers have theories about how quasars, and by extension other exploding stars, came into existence.
Another great example of how we use telescopes to study the movement of quasars is with the help of supernovae.
Supernovae are explosions that eject large amounts of matter into space, creating huge clouds of gas and dust that astronomers use to study the distribution of matter in the universe. With the help of these bright explosions, astronomers have found that the expansion rate of the universe is accelerating, and that it is due to a black hole at the center of a galaxy or a cluster of galaxies.
If there is a large enough cloud of gas on the interior of this cloud, it can completely fill the black hole, which causes it to expand, and take on a different color. The colors of these clouds have shown to be consistent with what we expect to see in a Milky Way galaxy or a Virgo Supercluster, which is located in the southern hemisphere.