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."
Milky Way ties with neighbor in galactic arms race
-- submitted from IRC
(Score: 1, Interesting) by Anonymous Coward on Friday February 16 2018, @06:50AM (1 child)
Well, this is good. If it had been an unequal collusion, God knows what would have happened! Usually, when galaxies collide, there is not all that much disruption, since galaxies, like most things, are mostly open space. So we could pass through the Andromeda Galaxy, and never know it, except for the swarm of Ort Cloud objects that would suddenly be headed for near-Sol orbit, and suddenly put on a course that endangers Earth. Fricking Republican Galaxies!
(Score: 2) by bob_super on Friday February 16 2018, @07:22PM
> galaxies, like most things, are mostly open space
That darn gravity thing, which gives them their cute shapes, may have some things to say about that.
You don't need direct collision for a bigger star to rip out the outer solar system from half a light-year away, or for a supermassive black hole to do that from a few hundred light-years away.
Pretty good details in the most appropriate place : https://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_collision [wikipedia.org]
(Score: 3, Interesting) by All Your Lawn Are Belong To Us on Friday February 16 2018, @02:46PM (2 children)
(And nice story and catch, BTW. +1 Awesome, regardless of what I say below...)
I wonder if the original, though, is actually 800 billion times weight/heavier, or 800 billion times solar mass? Fail 1 if I'm right that we're actually talking mass.
And since Google readily tells me that the Andromeda galaxy is 110,000 l.y. radius (Wikipedia says 220K l.y. diameter), and the Milky Way is 100,000 l.y. diameter per both Google and a NASA Goddard page..... No, the Andromeda galaxy isn't the same "size" as the Milky Way. Mass, maybe. But "size" is a volumetric or distance measurement. And if they're the same mass and different sizes, you don't get a claim on equal density, either.
This sig for rent.
(Score: 1, Interesting) by Anonymous Coward on Friday February 16 2018, @03:40PM
I'm not sure how well we can actually measure the milky-way. It seems odd, since it is so close, but the problem is that it gets in the way when we try to measure it, because we are measuring from the inside.
Other galaxies are easier, we can just look at them and see, but we don't have a mirror to look at ourselves with, galactically speaking.
(Score: 2) by tangomargarine on Friday February 16 2018, @04:01PM
Weight? Weight in relation to what? Usually you measure the weight of something as compared to the surface of whatever you're standing on, planet/sun/asteroid/whatever, but for an entire galaxy?
So in relation to the supermassive black hole at the middle, I guess? Does every galaxy have one of those?
Augh! Why are we suddenly switching to mass?!
Or is it somehow easier to figure out the mass first and then work from there to math out the weight?
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 3, Funny) by snufu on Saturday February 17 2018, @04:42AM
it's how you fuse them.