Milky Way galaxy is 50% bigger, more arms, about to eat Andromeda?

The manner in which the Milky Way galaxy is depicted on television, in works of art, and in print makes most individuals think astronomers knew pretty much what the galaxy looks like. However, we're now finding out it wasn't so. Recently, it has been discovered that the size of the galaxy has actually been highly underestimated, and that its overall shape is notably different.

It has always been assumed that the Milky Way is much smaller than the Andromeda Galaxy, which is our nearest neighboring galaxy. A team of Harvard astrophysicists have now concluded that it's actually 50% larger than it was believed in the past, and more than likely has four arms – not two. This startling revelation came following advanced measurements of how fast our galaxy rotates.

It’s currently impossible to determine exactly what the galaxy looks like, as we live well within it and gaining a proper perspective is all but impossible. The easiest way to measure it is to measure the quickness that the galaxy rotates, and then compare those readings to how much mass would have to exist in effort to generate that much velocity. Sounds simple, right?

The Harvard team discovered that the Milk Way is currently rotating at a speed of 600,000 miles per hour, which is 100,000 miles per hour faster than estimates from the past. This math equates to a 50% mass increase over what was initially reported.

A drawback to this finding is that there is a greater potential for collision with the Andromeda Galaxy, which has been known for some time to be “stuck with us” rather than moving further and further away as other galaxies are. It appears also that the increase in mass may cause a collision sooner rather than later. ...

via TG Daily - Our Milky Way galaxy is 50% bigger than previously thought.

My personal favorite Milky Way Galaxy story was the one that described why the Milky Way seems tilted to us on Earth. As I recall, this is because the Earth, in fact, belongs to another unnamed galaxy which the Milk Way is in the process of eating. Our own galaxy is on the same plane as our solar system and the Earth's rotation. I won't be surprised if the Milky Way goes after Andromeda too.

Hmm. Could the Milky Way's galaxy eating habit explain differences in axial tilt and rotation of planets within our solar system? Could our own solar system contain planets from more than one galaxy? ( Mars eyes Jupiter suspiciously...)