Scientists Say Our Universe is 80% Dark Matter--But, Where Is It All?

Dark matter is everywhere -- at least, that's what physicists think.

And even though we can't see it, scientists can still detect it and understand more or less how much of it exists in our universe. By measuring the cosmic microwave background, researchers have determined that 80 percent of the Universe's mass is comprised of dark matter. That's a lot.

Unfortunately, this same method of measuring the CMB doesn't tell us anything about where all of this dark matter is distributed. 

According to ArsTechnica, black matter can't be detected using the light it absorbs or emits. Rather, scientists must locate dark matter based solely on its gravitational signature. Certain very dense parts of galaxies can actually mimic the presence of dark matter, like near stars or black holes. 

In the face of dark matter's seemingly elusive nature, astronomers are beginning to make some notable progress in their search for it. One method that is yielding promising results is to measure whole swaths of galaxies, instead of one at a time. Also, by paying attention to the motion of stars and gases, scientists can make more sense of individual, chaotic galactic cores and hopefully locate any dark matter present there. 

Another avenue potentially presenting itself is detectable dark matter particles.  Scientists are analyzing signals from the center of our galaxy that could be caused by dark matter particles annihilating themselves. 

Scientists are looking to many new methods of observing the cosmos in order to tell us exactly where all of the dark matter in the Universe is located. One such method is being employed by the Gaia mission, which is producing a 3D map of a "billion stars and their motions" in order to provide scientists with data related to the very structure of our Milky Way galaxy, as well as its satellite galaxies, reports Ars. 

This new information will permit astronomers to work backward, and determine the gravitational field controlling the motion of the stars observed. Once that is done, scientists ought to have an accurate map of the dark matter residing in several areas that have so far proved difficult to observe. 

So even though dark matter isn't visible to the naked eye, scientists say one day soon we'll be able to point out exactly where much of it is distributed in our galaxy.