Our mysterious universe
Our universe is filled with many #mysteries, some that have been solved but many others that are yet to be solved.
Planets, stars and whole galaxies are not steady still in specific positions but they are constantly moving through space. Planets revolve around stars, stars revolve around galactic centers and galaxies are in constant motion toward an unknown destiny.
One of the main mysteries of our universe is the speed in which stars revolve around the center of the galaxy. Given the masses of the stars and planets scientists could predict the exact speed in which galaxies rotate, but the interesting part is that galaxies rotate much faster than expected, which made scientists introduce ''Dark Matter'' in their description of the universe.
Dark matter is the invisible matter that is supposed to increase the speed of the rotation of the galaxy around the galactic nucleus.
Dark matter
Galaxies have this beautiful spiral shape with a bar in the middle and arms branching from the bar. What dark matter is supposed to do (and has been observed) is speed up the rotation of the galaxy, while breaking the speed of the rotation of the bar. The bar still rotates faster than the outer arms of the galaxy because of gravitational reasons. This is the point in which the existence of dark matter is tested, if the bar rotation slows down then it is affected by dark matter, if the bar is not slowed down then nothing affects it.
Saving dark matter
In a study called ''Kinematic Clues to Bar Evolution for Galaxies in the Local Universe: Why the Fastest Rotating Bars are Rotating Most Slowly'' the scientists examined the so called ''corotation circle'' of the galaxy, it is a circle in which all stars inside and outside the bar rotate in equal speed.
It goes like this, if the bar is slowing down then more stars from the galaxy will ''catch up'' with the bar and the circle's radius will increase to more than 1.4 times the length of the bar. If the bar is not slowing down then the circle's radius will be less than 1.4 times the length of the galactic bar. The results were negative and the radii of the corotation circles were smaller than 1.4 times the length of the bar.
But the scientists figured out that the bars are slowing down despite the fact that the corotation radius was less than the 1.4 bar length.
To be continued
That is a good start for science to be sure that dark matter exists, but indeed more Empirical Evidence need to be discovered in order for us to be sure that the mysterious dark matter exists. Because, if it turns out that dark matter doesn't exist then science is in big trouble explaining the consequences associated with it's existence.
