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The universe is a peculiar thing. It seems like every other day astronomers find something new and incredible about it that can either simply amaze us or contradict everything we knew about it. Astronomer Evan Kirby and his team found out, while they were tracking the Triangulum II galaxy with the Keck Observatory, that this particular galaxy has a massive density of dark matter. In other words, if you’re a Star Wars fan, you can even say the galaxy has joined the dark side.
Now, the universe contains matter which is either dark or luminous. Scientists say that about 85 percent of the universe is made up of dark matter. These particles of dark matter do not usually interact with normal matter, unless there is a gravitational force that attracts them. The Triangulum II has approximately 1,000 stars and the astronomers have traced 6 of them, measuring how fast they move around the center of the galaxy.
Since this galaxy only has 1,000 stars it is supposed to be, by cosmic standards, a welterweight. However, at a closer look, astronomers discovered that it was filled with dark matter, because the total mass they measured was a lot greater than the mass of the stars. Researchers claim that this galaxy has the highest ratio of dark matter to luminous matter of all. How did they find this out? After they measured the stars’ speeds, they realized that their very high speed meant there had to be more mass that would explain the rapid movement of the stars.
To explain this uncommon characteristic of a galaxy, astronomers came up with some theories. One of them is that Triangulum II is home to a cloud of WIMPs. Now, don’t get judgmental, in the cosmic world, WIMPs are Weakly Interacting Massive particles which means they carry mass but they are almost like ghosts, not interacting with normal matter. They, however, exert a gravitational force, but do not interact via electromagnetic force. Nonetheless, if two of them collide they will, most probably, annihilate each other. If this theory stands, scientists say the galaxy should be emitting an excess of gamma-ray radiation.
On the other hand, another group of astronomers claims that the stars which are outside Triangulum II are faster than the ones which were recently tracked with the Keck Observatory and this would go in contradiction with what the Kirby’s team estimated. This would also mean that the gravitational field of our galaxy is destroying Triangulum II. However, if this is not the case, then the small galaxy could be in what scientists call a dynamic equilibrium.
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