Black Holes-How Do the Jets Expel Anything? (stars, light, solar)

[sky1949]

Sorry if this has been asked and answered already, but I missed it. Since black holes have such strong gravity that even light can't be emitted, how is it that there are the two jets spewing something out on the two opposing poles?

[SolarDub]

This isn't material being spewed from inside the black hole.
Material that falls into stellar objects such as young stars or black holes form disks, called 'accretion disks'. Indeed, these disk like structures can extend at vast distances from the young stars - our planets are considered to have formed from material that condensed within such disks.

Anyway, such disks can exhibit strong magnetic field lines that, near the central star, are aligned perpendicularly to the disk. Material that falls into the star can be captured by the magnetic fields and blasted away from the disk along these field lines. These produce phenomena such as 'bi-polar outflows'.

Not only does this mechanism occur for 'small-scale' young, 'pre-main sequence' or 'T-Tauri' stars, but also for young, energetic galaxies, 'quasars'. The mechanism also arises for in-falling material forming accretion disks around black-holes. Magnetic fields capture the material before it enters the black-hole and is blasted away from the black-hole region as two bi-polar outflow jets.

Also, check out the associated Harbig-Haro objects that are often produced when bi-polar outflow jets strike the surrounding interstellar material that causes shock-waves that emit radiation that can be observed.

[sky1949]

SolarDub: Thank you. I'll read up on this.