Milky Way is Much Bigger Than Previously Thought

It is well known that the Universe is vast; so vast, in fact, that there is still a lot that we don't know. But we at least thought that we knew a decent amount about our own galaxy. It turns out that that's not the case. The Milky Way is reportedly much bigger than we previously thought - 50 percent larger, to be exact, according to new research.

So how is it that scientists never realized this?

"In essence, what we found is that the disk of the Milky Way isn't just a disk of stars in a flat plane - it's corrugated," lead author Heidi Newberg, from the Rensselaer Polytechnic Institute, said in a statement. "As it radiates outward from the Sun, we see at least four ripples in the disk of the Milky Way. While we can only look at part of the galaxy with this data, we assume that this pattern is going to be found throughout the disk."

The findings show that the features previously identified as rings are actually part of the galactic disk, extending the known width of the Milky Way from 100,000 light-years across to 150,000 light-years.

"Going into the research, astronomers had observed that the number of Milky Way stars diminishes rapidly about 50,000 light years from the center of the galaxy, and then a ring of stars appears at about 60,000 light years from the center," explained researcher Yan Xu. "What we see now is that this apparent ring is actually a ripple in the disk."

This discovery was made by revisiting astronomical data from the Sloan Digital Sky Survey (SDSS) which, in 2002, established the presence of a bulging ring of stars beyond the known plane of the Milky Way. However, these newly found ripples are not to be confused with the galaxy's iconic spiral arms.

Previous research has suggested that a dwarf galaxy or dark matter lump passing through the Milky Way would produce a similar rippling effect. If this is the case, then the ripples could potentially help scientists measure the lumpiness of dark matter in our galaxy.

The findings were published in The Astrophysical Journal.

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