The Black Hole That Kills Galaxies - Quasars

TL;DR

Quasars can effectively kill galaxies by heating their gas, pushing it outward, and stopping new stars from forming. These active galactic cores are powered by feeding supermassive black holes and can shine with the power of a trillion stars. A typical quasar consumes one to a hundred Earth masses of gas per minute, so read on to discover how such a compact object transforms an entire galaxy.

Transcript

The universe looks like a vast empty ocean  sprinkled with the rare islands of galaxies..   But this is an illusion. Just a small  fraction of all atoms are found in galaxies,   while the rest is thought to be drifting  in between, in the intergalactic medium.   Like the roots of some massive tree,  gas spreads out from each galaxy,   gravity funne... Read More

Key Insights

• 🤩 The intergalactic medium contains the raw materials, such as hydrogen and helium, necessary for galaxy and star formation.
• 🈷️ Quasars are among the most powerful objects in the universe, emitting vast amounts of energy and reshaping their surrounding cosmos.
• 🖤 Quasars are formed by the feeding of supermassive black holes in the centers of galaxies, with their energy coming from the space surrounding the black holes.
• 🤩 Quasars can heat up their galaxies and prevent star formation, pushing out gas and ultimately changing the structure of the galaxy.
• 🖤 The Milky Way's history regarding quasars is uncertain, while the future merger with Andromeda could potentially turn our supermassive black hole into a quasar.
• ❓ Understanding distant quasars can provide insights into the history and evolution of galaxies.
• 🤩 Quasars have the potential to create new stars through compression of gas or shockwave interactions.

Questions & Answers

Q: How can a quasar kill a galaxy?

A quasar heats its galaxy until the hot gas can no longer collapse to form stars. It can also push gas out of the galaxy, depriving it of the raw material needed for future star formation. The galaxy remains after the quasar turns off, but it is permanently changed.

Q: What is a quasar?

A quasar is the active core of a galaxy, powered by a feeding supermassive black hole. Its light comes from a massive orbiting disk of gas called an accretion disk, not from inside the black hole.

Q: Why are quasars so powerful?

Matter spiraling toward a black hole accelerates to almost the speed of light, and collisions and friction heat the accretion disk to hundreds of thousands of degrees. The energy released by falling matter can be 60 times greater than the energy released by nuclear fusion in a star’s core.

Q: How bright can a quasar be?

A quasar can shine with the power of a trillion stars and appear thousands of times brighter than the entire Milky Way. From a region not much bigger than the solar system, a galactic core can release many times more energy than all of its stars combined.

Q: How much matter does a typical quasar consume?

Typical quasars consume one to a hundred Earth masses of gas per minute. This intense feeding produces enormous amounts of light and radiation, but it may last only a few million years.

Q: What are quasar jets, and how large can they become?

The brightest quasars tangle magnetic fields around nearby matter into narrow cones and launch enormous beams like particle accelerators. These jets plow through the circumgalactic medium and form plumes hundreds of thousands of light-years in size.

Q: When were quasars most common?

Quasars peaked in number 10 billion years ago, when the universe and its galaxies were still young. At that time, the universe was about a third of its current size, so denser filaments of gas could feed quasars more readily.

Q: Can quasars create stars as well as stop them?

Quasars primarily inhibit star formation by heating gas and pushing it out of galaxies. However, their interactions with gas can briefly compress it, and shockwaves may trigger the creation of new stars.

Summary & Key Takeaways

• The intergalactic medium is filled with raw materials like hydrogen and helium, which flow into galaxies and create stars.

• Quasars, the most powerful objects in existence, reside in the centers of galaxies and emit enormous amounts of energy, reshaping the cosmos around them.

• Quasars are formed by the feeding of supermassive black holes in galaxies, and their energy comes from the space surrounding them, not from inside the black holes themselves.