Quasars (short for "quasi-stellar objects") are extremely bright and energetic astronomical objects found at the centers of some galaxies. They are powered by supermassive black holes, which are millions to billions of times the mass of the Sun.Quasars are regions around supermassive black holes that emit large amounts of radiation, particularly in the form of electromagnetic waves (radio waves, X-rays, and visible light). These objects are so luminous that they can outshine the entire galaxy they reside in. Quasars were first discovered in the 1960s and were originally observed as faint star-like points of light. The energy emitted by a quasar comes from the accretion disk of material that falls into the supermassive black hole. As this material spirals in, it gets heated to extreme temperatures, emitting vast amounts of radiation. This radiation is what makes quasars visible across enormous distances, sometimes billions of light-years away. Quasars are often observed at great distances, meaning they are seen as they were in the early universe. Many quasars are located billions of light-years from Earth, which means we are seeing them as they were billions of years ago. This makes them important tools for studying the early universe.

This image you see right here is 3C 273, one of the most famous and well-studied quasars. It was the first quasar to be identified, and it remains one of the brightest quasars visible in the night sky. It is located about 2.4 billion light-years away from Earth, making it one of the closest and brightest quasars to our planet. Despite its great distance, it can be observed with a small telescope due to its high luminosity. 3C 273 was first identified as a quasar in 1963 by astronomer Maarten Schmidt. At the time, it was initially observed as a star-like object that emitted unusual spectral lines. Schmidt discovered that the object was not a star but a very distant galaxy with an active nucleus, and he realized that its unusual spectrum was due to a large redshift, indicating it was moving away from us at a very high speed. The name 3C 273 comes from the fact that it is the 273rd object cataloged in the Third Cambridge Catalog of Radio Sources (hence the name 3C). It is classified as a radio-loud quasar, meaning it emits strong radio waves. This is a common feature of many quasars. 3C 273 is one of the brightest quasars in the sky, with an apparent magnitude of 12.9 in visible light. While this is not visible to the naked eye, it is easily visible through a telescope. It is approximately 100 times more luminous than the entire Milky Way galaxy. 3C 273 has a supermassive black hole at its center, which is estimated to have a mass of around 886 million solar masses. This black hole is responsible for the intense energy output of the quasar.