Final answer:
Quasars are highly luminous objects powered by supermassive black holes, emitting energy in intense bursts as matter falls into them. Their variability on short timescales indicates a small energy-emitting region. Quasars are crucial for understanding galactic evolution and the effects of supermassive black holes in the universe.
Step-by-step explanation:
The celestial objects that send energy out into space in pulses, and not steadily like young stars, are commonly known as quasars. Quasars are extremely luminous and can emit vast amounts of energy that can be observed across cosmic distances. The source of a quasar's immense power is a supermassive black hole at the core of a galaxy. As matter from surrounding regions of the galaxy spirals into the black hole, it forms an accretion disk and releases energy in the form of light and other electromagnetic radiation, including intense bursts, making quasars incredibly bright and variable on rapid timescales. Quasars tend to be much more luminous than active galaxies, partly because of the enormous gravitational forces at play near the supermassive black hole, causing more material to accelerate and release energy.
This energy is often in the form of light, but can also include other types of electromagnetic radiation, such as gamma rays. The discovery of quasars helped us understand that supermassive black holes play a central role in the evolution of galaxies and can shape their surroundings profoundly.
Generally, quasars are found in the early stages of galactic evolution and can be used to probe evolution in the universe. Supermassive black holes are believed to exist at the cores of many galaxies, including our own Milky Way, and are a key factor in the process of galactic development. Therefore, understanding quasars provides insights into both the early universe and the dynamic processes occurring in galactic cores driven by black hole activity.