Our Galaxy

fskmh

Expert Member
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Feb 23, 2007
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1,184
#21
Water wirlpools clockwise in the southern hemisphere and anticlockwise in the northern hemisphere.
On the equater water moves straight down the whole with no spinning.
There is actually a tourist attraction on the equator in one of the countries crossing it, where you can watch water move straight down ;p

although there are people saying its a myth, ive seen it first hand, it actually did spin in different directions in different hemispheres.
http://www.snopes.com/science/coriolis.asp

I have been watching a large amount of the series 'Cosmos' by Carl Sagan and was wondering. What it the large glowing center to our galaxy? And why is it that the galaxy is spiraled?
It's the dust being bombarded by light at frequencies above that of optical light. The dust heats up and scatters this light at lower frequencies from IR to optical red. This obscures everything in the visible part of the EM spectrum. The galaxy also has a halo of old stars that give it a spherical glow.

The structure of the galaxy is due to gravitational forces. In spiral galaxies you can discern galactic arms consisting of gas, dust, stars etc. and then interarm regions that are more sparsely populated. All of this is "circling the drain" that is the supermassive black hole at the centre of the galaxy.
Gravitational perturbations also occur as galaxies tend to congregate into local groups. One example is the interaction of our galaxy with the Small Magellanic Cloud, which is a nearby dwarf galaxy.

More details and pictures here:
http://casswww.ucsd.edu/public/tutorial/MW.html
http://www.sciam.com/space/article/id/what-process-creates-and
 
Joined
Jan 17, 2008
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1,953
#22
All of this is "circling the drain" that is the supermassive black hole at the centre of the galaxy.
Are you suggesting that the spiral effect is due to the black hole. Comparable to water going down a drain, in this case the drain = the black hole ?

If true then can I assume that galaxies only exist because black holes exist, as it is most certainly the glue that keeps everything together?
 

fskmh

Expert Member
Joined
Feb 23, 2007
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1,184
#24
Are you suggesting that the spiral effect is due to the black hole. Comparable to water going down a drain, in this case the drain = the black hole ?

If true then can I assume that galaxies only exist because black holes exist, as it is most certainly the glue that keeps everything together?
No, the inward rotation is due to the initial angular momentum from when the galaxy formed. The black hole isn't what causes the galaxy to exist, it's the other way around. Observations with the Hubble telescope have shown this: http://hubblesite.org/newscenter/archive/releases/2000/22
 

Highflyer_GP

Honorary Master
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Jul 2, 2005
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10,125
#26
Roberta M. Humphreys (2006) estimates the radius of VY CMa at 1800 to 2100 solar radii. To illustrate, if our Sun was replaced with VY Canis Majoris, its surface would extend to the orbit of Saturn. Assuming the upper size limit of 2100 solar radii, light would take more than 8 hours to travel around the star's circumference.
Woah that is huge :eek:

I always thought that this comparison puts things into perspective: http://www.rense.com/general72/size.htm

And keep in mind that Antares is 700 times bigger than the Sun. VY Canis Majoris is 2100 times bigger.
 

Claymore

Executive Member
Joined
Jan 20, 2004
Messages
7,444
#32
Water wirlpools clockwise in the southern hemisphere and anticlockwise in the northern hemisphere.
On the equater water moves straight down the whole with no spinning.
There is actually a tourist attraction on the equator in one of the countries crossing it, where you can watch water move straight down ;p

although there are people saying its a myth, ive seen it first hand, it actually did spin in different directions in different hemispheres.
Coriolis forces (basically, things close to the equator moving faster (due to earth's rotation) than things further away); but the effect over small areas is negligible, and you'll experience bigger effects from basin shape, drain shape, imperfections, water movement,etc.
 
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