Matter expelled from supermassive black hole

[Realitycheck]

Any ideas on what causes/allows the matter to be expelled, in light of all of the gravity that is supposed to keep it there? Why not just keep growing?

 

http://news.yahoo.com/s/ap/20071217/ap_on_sc/death_star

[swansont]

The radiation isn't being expelled from within the event horizon. Matter that's been ionized and accelerated will emit radiation, and matter can be "slingshotted" without having been captured.

[Martin]

The radiation isn't being expelled from within the event horizon...

 

True, and as you indicated, the matter in these jets is not being expelled from within the event horizion either.

 

The earth is constantly being bombarded with matter from these jets---there are a great many and some are aimed approximately in our direction. The matter that arrives here is mostly hydrogen nuclei. We get electromagnetic radiation from them too.

 

Auger observatory in Argentina recently showed conclusively that ultrahigh energy cosmic rays (protons) reaching the earth come from about fifty Active Galactic Nuclei (AGN) which is what we are talking about. These are the fifty nearest ones that are aimed within about 3 degrees of our direction. If the source is too far, the hydrogen nuclei get stopped by interaction with background radiation before they get here. And if the jets aren't aimed within about 3 degrees, they miss

 

the mechanism causing the jets is interesting and I don't fully understand it. It is what Swantsont indicated.

Matter (dust, stars, gas, whatever) spirals in towards these supermassive black holes---or AGNs. As it spirals in tighter it begins colliding with itself and gets hot by millions of degrees. As Swansont says, it ionizes.

 

So the AGN black hole is surrounded by an inspiraling very hot disk of CONDUCTIVE material. conductive because ionized plasma. The conductive plasma CONCENTRATES MAGNETIC FIELD LINES and the rotation twists the lines until the magnetic field around the black hole becomes very intense, especially at the North and South poles. charged particles tend to FOLLOW magnetic field lines.

 

At a certain point the magnetic forces become comparable to graviational and a certain amount of the plasma (instead of continuing to spiral in towards the event horizon of the hole) VEERS OFF AND FOLLOWS THE FIELD LINES out along either the North or the South magnetic poles---by that time it is going very very fast. (near the speed of light). So you get these jets.

 

The matter that doesn't veer off, continues spiraling in towards the event horizon. Once it has crossed the event horizon then it can not any longer escape the black hole----that is just the usual black hole property we are familiar with. The event horizon is the point of no return.

 

The charged particles that DO veer off and follow magnetic field lines outwards along the axis have an interesting feature. They whirl (because of twisted field lines and their own angular momentum) and when charged particles whirl very fast they radiate light. And these particles in the AGN jet can radiate very high frequency, high energy light.

 

So we get all sorts of stuff coming our way from these AGN jets. they are some of the most interesting things being studied in astrophysics now.

 

thanks for flagging this picture. I had never seen a picture of one of these jets hitting a nearby galaxy-----the two galaxies are only 24,000 lightyears apart and in the process of merging one with the other.