Quasars, which are highly luminous active galactic nuclei powered by supermassive black holes, can last for billions of years. Their lifespan is influenced by factors such as the availability of gas and dust for accretion onto the black hole. While individual quasars may shine brightly for a significant portion of the universe's history, they eventually may fade as their fuel diminishes. Overall, the active phase of a quasar can last anywhere from tens of millions to several billion years.
Not the existence of quasars, but the fact that all quasars are distant from us. The best explanation for what we observe when we see quasars is that they are super-massive black holes in early galaxies, burning up solar "fuel" so rapidly that they eventually run out. We do not observe any quasars near to us, so the conditions that allowed quasars to form must have existed only several billion years ago. If our Universe has not changed its basic structure and density over the last 15 billion years or so, then the conditions that would allow quasars would allow them to exist at any time over that span. This would mean that there should be just as many quasars close to us as there are far from us. But we just don't see that. As is the case with many of the things we see, this is easy to explain via Big Bang Cosmology but almost impossible to explain with any alternative.
Quasars are the unusual type of active galaxy in the universe.
Quasars are not gone; they are still observed in the universe. Quasars are powered by accretion of material onto supermassive black holes at the centers of galaxies, which can make them appear as some of the brightest and most powerful objects in the universe. However, the number of observed quasars may be influenced by factors such as the current stage of galaxy evolution or observational limitations.
Typically, a galaxy may contain one or a few quasars. Quasars are incredibly luminous objects powered by supermassive black holes at the centers of galaxies. They are rare and only occur under specific conditions, so it is not common for a galaxy to have multiple quasars.
Quasars are thought to be the centers of distant galaxies where supermassive black holes are actively accreting matter. The intense energy emitted by this process makes quasars some of the brightest objects in the universe. Studying quasars can provide valuable insights into galaxy formation and evolution.
12.8 billion light years away.
The fact that most quasars are very distant means they were like that when the Universe was quite a bit younger than it is today.
quasars
Quasars are thought to be distant super-massive black holes.
The first quasars were discovered in the 1950's
Yes. Quasars are the size of the solar system.
Quasars do not have galaxies in them, quasars are at the hearts of galaxies. All quasars are located in galaxies, as a quasar involves massive amounts of material falling into a supermassiv black hole. Neither of these can be found outside of a galaxy.
Not the existence of quasars, but the fact that all quasars are distant from us. The best explanation for what we observe when we see quasars is that they are super-massive black holes in early galaxies, burning up solar "fuel" so rapidly that they eventually run out. We do not observe any quasars near to us, so the conditions that allowed quasars to form must have existed only several billion years ago. If our Universe has not changed its basic structure and density over the last 15 billion years or so, then the conditions that would allow quasars would allow them to exist at any time over that span. This would mean that there should be just as many quasars close to us as there are far from us. But we just don't see that. As is the case with many of the things we see, this is easy to explain via Big Bang Cosmology but almost impossible to explain with any alternative.
pulsar and quasars
Not entirely - although it is believed that quasars are caused by a gigantic black hole.
Quasars are the unusual type of active galaxy in the universe.
Quasars are not gone; they are still observed in the universe. Quasars are powered by accretion of material onto supermassive black holes at the centers of galaxies, which can make them appear as some of the brightest and most powerful objects in the universe. However, the number of observed quasars may be influenced by factors such as the current stage of galaxy evolution or observational limitations.