The universe is very vast and has so much to offer. Despite that, we don’t know very much about it which is a shame. But what we already know is not only unnerving but absolutely mind-blowing too. So much so that scientists all over the world are confused by it as well.
Almost 95% of the mass of the universe is made up of dark matter. Now, some science fanatics may know what is it while others may have only heard of it in sci-fi movies. Dark matter does not emit light or energy. So how do we know it’s even, well, there?
Hypothesis’ since the 1920s have suggested that there is more matter than what can be observed and ever since then, this hypothesis has been solidifying into a real theory. Pieter van Dokkum who is a researcher at Yale University said that the motions of the stars dictate how much matter there is. It doesn’t matter what type of matter it is. He also happened to lead a team that identified a galaxy called dragonfly 44 which is made up of almost entirely dark matter.
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The mass of large objects can be calculated by studying their motion. But what astronomers expected to see while examining spiral galaxies didn’t add up, it suggested something else was also present. They expected to see the material in the center to move faster than on the outer edges. Instead, they observed the stars in both locations to travel at the same velocity, which indicated that the galaxies contained more mass than what was visible.
This still doesn’t answer what dark matter is. Dark matter is very obviously dark, meaning it’s not in the form of observable stars or planets. Secondly, it is not in the form of dark clouds of normal matter. Normal matter is made of particles called baryons, which absorb passing radiation. Thirdly, dark matter is not antimatter because antimatter produces unique gamma rays when annihilated with the matter. All of this has been said by Nasa. So basically, we know what dark matter isn’t rather than what it is.
Baryonic matter consists of protons, neutrons, and electrons. These are particles that have been confirmed to exist and you probably study about them in physics at high school. Most scientists thank that dark matter is made of non-baryonic matter. WIMPS, also known as weakly interacting massive particles, which have ten to a hundred times the mass of a proton are the lead candidate for what dark matter could be. These particles are difficult to detect as their interactions with normal matter is very weak.
Another candidate for what dark matter could be is the Axion. Physicists originally came up with this particle while fixing a problem with the strong nuclear force. The problem with particles that feel the strong force are that they don’t behave differently when their electric charges are changed or are flipped upside down. This bothered the researched so they came up with an explanation regarding their unusual behaviors. The explanation also suggested that the universe may be full of these hypothetical particles. This explanation also happens to align with the dark matter particle’s theory. These particles have an incredibly low mass but the Big Bang could have produced these Axions in an abundance, explaining the crazily high percentage of dark matter in the universe.
We have no proof that there can only be one type of dark matter particle. After all, the world we know of has so many particles itself. We have photons, neutrinos, Higgs bosons, and even quarks. For now, we’ll let the experts handle this and have faith in them. I mean, they did do something impossible in 2019; capturing an actual image of a black hole.
Until Next time,
Team Doctor ASKY!