It is thought by many astronomers that quasars are the most distant objects yet detected in the Universe. With the massive amounts of energy a quasar emits, it can be a trillion times brighter than our own sun. Because of this, they often drown out the light from all other stars in the same galaxy. Yet, despite this, they are not visible to the naked eye.
Quasars were first detected in the 1960s as sources of radio waves. In addition to radio waves and visible light, quasars also emit ultraviolet rays, infrared waves, X-rays, and gamma-rays. Most quasars are larger than our solar system. A quasar is approximately 1 kiloparsec in width. Because of their distance, when we view quasars, we are seeing light from very early in the life of our universe, giving scientists information about the early stages of the Universe.