Dark matter has never been easy to understand, neither has it been a piece of cake to measure. According to recently attained measurements, however, it seems that there is only half the amount of dark matter in the Milky Way than what we previously thought. If you have no idea what dark matter is, don’t feel bad, it’s still a mystery to many of us. So, what is dark matter?
Dark matter is 25% of everything in existence, and it is totally invisible to the naked eye. It is found everywhere alongside humans, animals and objects. The really strange point is that 4% of all things in existence consists of the planets along with everything that inhabits those celestial bodies. Wait! If dark matter is 25% and everything else makes up around 4% then where is the rest? There’s something missing here! What makes up the remaining 71% of existence? The answer is even stranger, even harder to understand –dark energy. So, dark energy makes up the majority of existence, but we aren’t talking about dark energy, not this time.
Back to dark matter
For now, let’s stay focused on dark matter. Dark matter is elusive and odd; it cannot emit, absorb or reflect light. Traditional instruments, used to measure other types of matter, cannot detect dark matter at all. We cannot see it with our human eyes, nor can we sense it in any other way, other than with special instruments used to do so. It doesn’t even interact with electromagnetic force. The only way we know it even exists is by noticing the gravity of the matter as it interacts with visible matter.
How is dark matter measured?
A method was created in the 19th Century by British Astronomer, James Jeans, when dark matter was first measured. The method was originally used to measure the speed that stars traveled throughout the galaxy. Such studies were being done for many years previous to the discovery of dark matter. To reach the dark matter, scientists needed to be able to measure from the mass billions of light years from Earth. Apparently, dark matter is huge, at least 6 billion times larger than the sun, which is half of what scientists once believed. Can you imagine the enormity of this?
According to Dr. Prajwal Kafle, since the measurements were off by half, this means that there are not as many satellite galaxies in the universe. Instead of there being numerous satellite galaxies, there are only three. The large Magellanic cloud, the Small Magellanic Cloud and the Sagittarius Dwarf Galaxy.
Since there isn’t as much dark matter as we once thought, and other things do not seem to be taking up that much space, then maybe it is time to study dark energy a little more. This leaves all other forms of existence within the understanding of this elusive dark energy. This shall be left for later discussion, but for now, we know even more about dark matter and the role it plays within the universe.