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Wed Feb 14, 2018, 08:17 PM

Milky Way ties with neighbor in galactic arms race

Astronomers have discovered that our nearest large neighbour, the Andromeda galaxy, is roughly the same size as the Milky Way. It had been thought that Andromeda was two to three times the size of the Milky Way, and that our own galaxy would ultimately be engulfed by our supposedly bigger neighbour. But the latest research, published today, evens the score between the two galaxies.

The study found the weight of the Andromeda is 800 billion times heavier than the sun, on par with the Milky Way. Astrophysicist Dr Prajwal Kafle, from the University of Western Australia node of the International Centre for Radio Astronomy Research, said the study used a new technique to measure the speed required to escape a galaxy. "When a rocket is launched into space, it is thrown out with a speed of 11 km/s to overcome the Earth's gravitational pull," he said. "Our home galaxy, the Milky Way, is over a trillion times heavier than our tiny planet Earth so to escape its gravitational pull we have to launch with a speed of 550 km/s. We used this technique to tie down the mass of Andromeda."

Dr Kafle said the research suggests scientists previously overestimated the amount of dark matter in the Andromeda galaxy. "By examining the orbits of high speed stars, we discovered that this galaxy has far less dark matter than previously thought, and only a third of that uncovered in previous observations," he said. The Milky Way and Andromeda are two giant spiral galaxies in our local Universe, and light takes a cosmologically tiny two million years to get between them.

Read more at: https://phys.org/news/2018-02-milky-ties-neighbor-galactic-arms.html#jCp

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Reply Milky Way ties with neighbor in galactic arms race (Original post)
Calista241 Feb 14 OP
PJMcK Feb 14 #1
SCantiGOP Feb 14 #2
SWBTATTReg Feb 15 #3
SCantiGOP Feb 15 #4
SWBTATTReg Friday #5

Response to Calista241 (Original post)

Wed Feb 14, 2018, 08:30 PM

1. Interesting article but poorly written

Thanks for posting the link, Calista241.

Earlier today, I was watching a video that detailed what the collision of the Milky Way and Andromeda will look like. Here's the link to the YouTube clip:

Obviously, it will take many millions of years but two things struck me a amazing.

First, because of the (literally) astronomical distances involved, there probably won't be many, if any, collisions of stars; the space between them is just so vast.

Second, the two galaxies will likely intersect and then bounce back and forth until the super-massive black holes at the center of each galaxy merge. Then the resultant new galaxy, (Milkydromeda? AndroWay?), will eventually resolve itself into a new massive spiral galaxy.

Of course, all of this will take a bit more than a human lifetime!

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Response to Calista241 (Original post)

Wed Feb 14, 2018, 08:49 PM

2. The collision of individual stars

Iíve been watching a series on The Science Channel called How the Universe Wotks.
One episode dealt with this merging of the two galaxies. To illustrate how vast the distances are between the estimated 2 billion stars they said this is how likely it would be for two to collide: take an area twice the size of the Pacific Ocean. Randomly drop a particle the size of a pollen grain somewhere over that area while releasing a like sized particle to float up from somewhere on the ocean floor. The probability of those two colliding is equal to the chances of two of the stars colliding.

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Response to SCantiGOP (Reply #2)

Thu Feb 15, 2018, 07:43 AM

3. Just curious, two billion stars in both galaxies seems understated...

I thought each galaxy had roughly 100-200 billions stars each? Just a curious ?. Thanks.

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Response to SWBTATTReg (Reply #3)

Thu Feb 15, 2018, 10:36 AM

4. I think youre right

Did a quick google. Numbers this big are about impossible to process anyway.

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Response to SCantiGOP (Reply #4)

Fri Feb 16, 2018, 11:21 AM

5. Yes, numbers this big are amazing...

I heard 200 billion galaxies and 200 billion stars in each. Can you imagine? Amazing. Thanks and Have a good day!

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