Starship Asterisk*

mjimih wrote:The reason I'm flabbergasted is bc my whole life I was worried about them, they're being mean with insatiable appetites and far flung influence. Now it sounds like they're not nearly as scary as I thought. dang movies

mjimih wrote:bellicosity wrote: so, if it's such a picky eater, how'd it get so large to begin with???

Did our black hole grow early on with a higher ratio of/more heavier material around? And now in a more mature galaxy, it consumes more light objects?

Joe New wrote:"...only about 1% or less of the gas within the black hole's gravitational influence ever reaches the event horizon, losing enough heat and angular momentum to fall into the black hole..." Heat??? How can/does heat affect matter's reaction to gravity? Thanks!

adam1234 wrote:I hardly think that heat may affect matter's reaction to gravity.

New Scientist wrote:Scalding soup

Some scientists noted, though, that the brightness estimate assumed the gas coming from the stars was relatively cool, and that it could easily slip down the black hole's gullet, says Daniel Wang of the University of Massachusetts in Amherst. To find out what's really going on, Wang and his colleagues used NASA's Chandra X-ray Observatory to measure the temperature and brightness of gas at different distances from the black hole.

They found that the gas gets hotter and less abundant the closer it is to the black hole. The researchers estimate that less than 1 per cent of the surrounding gas ultimately comes near enough to be eaten. Wang thinks the food is just too hot.

Quasars are champion eaters because they slurp up relatively cool gas, below 1 million °C. Such gas is dense and flows in an orderly fashion into a quasar's maw, like water swirling into a drain. But the gas around Sagittarius A* is much hotter – collisions between stellar winds in the starry disc heat the gas to 10 million °C before it even starts to fall towards the black hole. This hot gas is tenuous and its particles zip around randomly, making it hard to corral.

"It's very hard to get steam into the sink," says Wang. That means the black hole should not get the blame for apparently turning up its nose at hot gas on its plate. "The black hole wants to suck it in, but it cannot," says Wang. Bizarrely, the tiny fraction of gas our black hole does imbibe may get in because it has transferred some of its jitteriness to gas particles that are thrown outwards, possibly by the black hole's own magnetic field lines.

BDanielMayfield wrote:

Ah, our friendly Super Massive Black Hole is hidden inside there. It is the anchor of the Milky Way and perhaps it's a giant recycler too.

It's a trivial mass concentration compared with the mass of the galaxy. At most, a few million suns, a ten thousandth of a percent of the total galactic mass. It could go away, and the dynamics of the galaxy would be substantially unchanged. And virtually none of the mass of the galaxy will ever have a close encounter with it.

Not much of an anchor. Not much of a recycler.

Ferrarese and Merritt established a correlation between the mass of a black hole and the speed at which the stars in its galaxy are moving ("A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies," The Astrophysical Journal, 539, L9-L12 (2000)). This "M-sigma" relation is the most fundamental connection yet discovered between SBHs and their host galaxies and it has been hailed as one of the most important discoveries to come out of the Hubble Space Telescope.

ErnieM wrote:If the Sagittarius A* went away, would our Sun move faster or slower? What is the over all impact on our Solar system?

Yes, the central galactic coffee is just too hot!

Ann

BDanielMayfield wrote:

New Scientist wrote:Scalding soup

Some scientists noted, though, that the brightness estimate assumed the gas coming from the stars was relatively cool, and that it could easily slip down the black hole's gullet, says Daniel Wang of the University of Massachusetts in Amherst. To find out what's really going on, Wang and his colleagues used NASA's Chandra X-ray Observatory to measure the temperature and brightness of gas at different distances from the black hole.

They found that the gas gets hotter and less abundant the closer it is to the black hole. The researchers estimate that less than 1 per cent of the surrounding gas ultimately comes near enough to be eaten. Wang thinks the food is just too hot.