A Look at Space: Part 2: Galaxies

Wrong, it depends also velocity, objects closer to source of gravity must have greater velocity than those in larger orbit.
If speed is too small then gravity wins and object descents to smaller orbit until it has gained enough speed to resist gravity.
If speed is too high object starts rising to larger orbit until balance has been achieved. (object have to rise from gravity hole which requires energy and that "consumes" speeds)

And when mass (star or whatever) collapses to black hole it's gravity doesn't increase, companion star (/planets) woul still remain in same orbit without knowing that it's orbiting black hole.
Cygnus X-1 is good example of binary system in which other is black hole.


Will we get sucked into the black hole at the center of the Milky Way?





[edit on 18-9-2004 by E_T]

Thanks for the information E_T.
I meant to say : No, but if we were a lot closer to the black hole, we would.

"Black holes, even the one at the center of our galaxy, are very small. Only if you get very close to a black hole's event horizon does it start pulling everything in."



Wouldn't the gravity increase strongly since the mass collapses creating a point of infinite density?

i dont know but cygnus X-1 is my favorite Rush song

external image
I think this is a Black hole in action!

Hi PanzerDiv,

I understand why you thought that the black hole in the center of M82 is the source of all that ionized hydrogen filaments, but it is not the case according to some evidence here:
www.journals.uchicago.edu...

According to the scientists, the cause of this galactic "superwind" is a collision between its neighbor galaxy M81*.

"Recent evidence indicates that this gas is being driven out by the combined emerging particle winds of many stars, together creating a galactic 'superwind.' The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light, and can be seen in visible light with a small telescope towards the constellation of Ursa Major." Source: antwrp.gsfc.nasa.gov...

Other pictures of M82:
external image
Source: antwrp.gsfc.nasa.gov...
external image
Source: antwrp.gsfc.nasa.gov...

Click here for an image featuring both galaxies.
"These two mammoth galaxies have been locked in gravitational combat for the past billion years. The gravity from each galaxy dramatically affects the other during each hundred million-year pass. Last go-round, M82's gravity likely raised circulating density waves rippling around M81 resulting in the richness of M81's spiral arms. M81, though, left M82 a messy pulp of exploded stars and colliding gas so violent it emits bright X-rays. In both galaxies, colliding gas has created a recent abundance of bright new stars. In a few billion years only one galaxy will remain."

Btw, the picture of M82 was posted on page 2 of this thread.

*Here is a picture of M81 (the neighbor of M82 that possibly caused the superwind):
external image
Source: antwrp.gsfc.nasa.gov...