A Milky Quasar?

[GeeKay]

With regards to the future merging of the Andromeda Galaxy with our own Milky Way, would this event create a quasar? If so, would this in turn eradicate all existing life in both galaxies? (assuming, of course, that Earth isn't the only repository of life in our part of the universe). Many thanks.

[mathematic]

No. There are many galaxies that are the result of galaxy merges. Quasars are completely different.

 

 

 

http://en.wikipedia.org/wiki/Quasar

[MigL]

Quasars tend to develop in the early stages of galactic formation.

As material and stars 'fall' together to form a galaxy, the central part, being most compressed and including the largest ( hottest burning and shortest lived ) stars invariably forms a black hole which quickly increases in size, eating everything falling into it. As the galaxy matures and stars settle into defined orbits, the infalling material feeding the black holr decreases and the BH becomes dormant like the one at the centre of our galaxy or Andromeda.

The 'quasar' is the polar jets of plasma produced by an active galactic core BH, from the infalling material.

Most quasars are found at great distance, implying long ago, when the universe was young and galaxies were first forming.

 

If the Milky Way/Andromeda 'collision' upset enough orbits such that stars/material started infalling agai into either of the BHs, then sure, one or both could become active again.

Do you know what the typical distance is between stars ? The closing rate is small enough for orbital motions to be established without too much disruption, and probably zero stellar collisions.

And even if a quasar were to be re-activated, the fact that the destructive jets are polar means they would be directed perpendicular to the plane of our galaxy, and we would be safe.

[Airbrush]

The merging of the 2 galaxies will certainly create a double quasar that will oribit itself until they merge into a single larger quasar. That will last millions of years until it goes dormant.

 

As stated above, only those regions of the new supergalaxy "Milkamada" blow torched by the quasars' polar jets will become uninhabitable.

Edited January 8, 2015 by Airbrush

[mathematic]

The merging of the 2 galaxies will certainly create a double quasar that will oribit itself until they merge into a single larger quasar. That will last millions of years until it goes dormant.

 

As stated above, only those regions of the new supergalaxy "Milkamada" blow torched by the quasars' polar jets will become uninhabitable.

Where did you get the idea that galaxy mergers " will certainly create a double quasar"?

[GeeKay]

Yes, I should have done my homework about quasars before popping the question.

 

Three additional thoughts, though: (1) possible disruptive effects caused by the 'merging' of two SMBHs - gravity waves etc? (2) colliding galactic gas and dust clouds? (3) dark matter?

 

I mention these colliding aspects, having ascertained that the closing velocity between the two galaxies is approx 110 km/s (or very roughly equal to the distance between the Earth and the Moon covered in an hour). This doesn't strike me as inordinately fast, at least not by cosmic standards. But it's still fairly brisk - brisk enough, I would imagine, to have all manner of effects at the 'local' level - the interstellar medium, planetary systems etc.

[MigL]

There are examples of other galaxies in the process of colliding, or having already collided.

The two core SMBH will more than likely. fall into orbits about each other, and will keep rotating happily everafter.

 

Or at least, far longer than any of us should care.

[Airbrush]

Where did you get the idea that galaxy mergers " will certainly create a double quasar"?

 

The merger will probably involve the supermassive black holes orbiting each other and spiraling inward over time. Each SBH will be dragging stars, gas, and dust with them, so each SBH will crash through the other's accretion disk. This will stir up everything around both SBHs so both will start feeding on the chaos of stars, gas, and dust.