A Hot, Hungry Black Hole

That's the big black hole at the center of 1H0707-495, which is an active galaxy far, far out in space. This post is a bit different from the usual fare here, as this blogger is responding to request by a commentor known as "Sun Boy" for Mrs. B to write about this topic. She didn't write this, but did point me to the sources. I know a little bit about the subject, so knew what questions to ask.

For a jocular nickname, let's call 1H0707-495, "Bubba". Why Bubba ? Well, it's very heavy, about 3 to 5 million times the mass of the Sun, and hungry. Imagine a real life Bubba with a big belly at McDonald's eating some double quarter pounders with cheese. Our galactic Bubba "eats" bigtime, too, swallowing matter at the rate of two Earths per hour. That's a lot !

Bubba is heavy, but really quite small. The radius of Bubba itself is about 9 to 15 million kilometers. For a comparison, the radius of the orbit of the planet Mercury around the Sun is much larger - 58 million kilometers. The diameter of the Sun itself is 0.7 million kilometers. [OK: a kilometer is 0.6 miles]. That means Bubba compacts the mass of 3-5 million Sun's into a "ball" with a diameter just about 80 times larger.

Bubba attracts matter with its gravity, which near it's "edge" is so strong the even light can hardly escape. The mass of Bubba curves space so much that light almost curves back onto Bubba. Over it's edge, the light cannot escape.

As gaseous matter is drawn to be swallowed by Bubba, it gets heated by compression. As Bubba is rotating quite rapidly, the gaseous matter forms a disk, sort of like how a dancer's dress will swill around to the horizontal. There is no centrifugal force along the axis of rotation, so the matter compresses into a disk. All that matter is still being drawn into Bubba's pie hole. It gets hotter and hotter, eventually so hot that it emits X-rays. That's how Bubba is seen.

Here's a good source for information on Bubba:
http://www.esa.int/esaCP/SEMTIX0OWUF_index_2.html

That article mentions a theoretical limit on how much matter that Bubba can swallow. Why is there a limit ? As the matter is drawn to the "edge" of Bubba, the matter's gravitational energy is converted to heat and then to radiation. That radiation has a pressure and the compressed gas has a pressure, too. As matter is drawn into Bubba at greater and greater rates, the force of those pressures eventually balance the gravitational attraction. This produces a theoretical limit. However, that might not be the practical limit due to other considerations: streaming, the flat accretion disk, magnetic fields, etc. It's actually a very complex calculation.

Why does streaming matter ? Easy, think of a highway with everyone staying in lane and going fast. Then suppose a bunch of boobs start to change lanes to exit. That can break the streams of cars and cause a jam. Magnetic fields can confine the gas to create streams where more matter can flow.

Well, that's enough for now.

Markets

Another big drop. The Green-Red rule and paying attention to the fundies save me big time. I'll swing the bat again soon.

Krypto has some re-allocations on order: putting cash to work in GLD, SLV and the European ETF, VGK. This cash was waiting for better prices on TIPs, but I'll put it to work now.

Word of the Day

"Revenant" - noun [$10]
Revenant means a person who has returned, esp. from the dead.
Sentence: There is no matter revenant from a black hole, except for quantum processes near the edge that can permit some particles to escape slowly from it.