Milky Way Heavier Than Thought, and Spinning Faster

An anonymous reader writes "The Milky Way is spinning much faster and has 50 per cent more mass than previously believed. This means the Milky Way is equivalent in size to our neighbor Andromeda — instead of being the little sister in the local galaxy group, as had been believed. One implication of this new finding is that we may collide with Andromeda sooner than we had thought, in 2 or 3 billion years instead of 5."

Science

[maz2331]

One thing that is great about science is that it does have a way of eventually finding errors and correcting them in the face of new evidence.

As far as galactic collisions are concerned, we are in no immediate danger. 2-3 Gy vs 5 is an academic exercise, as the Sun will most likely increase its output sufficiently by then to boil off the Earth's oceans anyway,

Besides, the density of a galaxy (outside of the core) is so low that the chance of a stellar or planetary collision is negligable anyway.

Or, by then, we would have the technology to detect it and either deflect it or GTFO of the way anyhow.

Still, it is nice to know we're not in the pipsqueak galaxy. Hoorah!?!?

They've already filmed it...

[MillionthMonkey]

Because it's on youtube. http://www.youtube.com/watch?v=dJRc37D2ZZY [youtube.com]

Re:I haven't read the paper, but...

[boot_img]

Actually the orbital velocity is (surprisingly) close to constant, as in most spiral galaxies. In fact, it is these "flat" (i.e. constant as a function of galactocentric radius) rotation curves that were some of the earliest evidence for dark matter.

That having been said, my guess is that the velocities quoted in the press release refer to the Sun's (or more accurately the Local Standard of Rest's) velocity around the Galactic center.

Couldn't find the paper on arxiv.org ...

 

Re:From TFA:

[aXis100]

The visble arms of our galaxy's spiral aren't a fixed buch of stars clustered togther, it's a density wave that travels around the disk. Our solar system will pass in and out of various arms (eventually) as the density wave is travelling at a different speed to the actual rotation.

this is why I'm skeptical

[ILuvRamen]

Remember that the reason dark matter supposedly exist is because scientists calculated the weight of the visible matter in the entire universe and said "well that doesn't match up with the energy/gravity" so they make up some imaginary object to make up the difference. And then a couple years later OMG I guess we were 50% off of the mass of the milky way, oops. If they can't even measure our galaxy properly, then dark matter probably doesn't exist because they're just calculating it wrong. Either that or it's literally regular matter that has almost no light bouncing off it cuz it's too far away from a light source.