When we look up into the night sky, the thing that dominates our view is mostly stars and planets, which seem to make up everything in space, but is that how it really is? The objects that dominate most parts of space are also those that seem to be invisible. The lowest of what we make up space is what we can observe with the naked eye. The majority of space, however, is, practically, invisible.
The visible aspect of outer space makes up only 5% of the vast cosmos, while the other two aspects, known as dark matter and dark energy are what dominate the celestial heavens above. Dark energy is thought to make up for 68% and the other 27% is thought out to be dark matter. These two are the current problems that have left physicists yearning for an explanation. Dark matter is active ongoing research in the field of astronomy as of now.
Initially known as, “invisible matter” by astronomers because of its unusual trait of being invisible and not being able to be observed by observing the universe, dark matter is of great importance in astronomy. While scientists are still trying to figure out what it actually is, the one thing for sure is that we know more about what it is not than we do about what it actually is.
What is it?
For starters, dark matter is, quite obviously, dark. Not being in the form of stars and planets that we are so used to seeing, to be observed is quite a difficult task to accomplish. Another thing that makes it impossible for the matter to be visible, is that there is far too little visible matter to make up for the 27% of the dark matter, that study suggests there be.
Secondly, contrary to what most people may think it to be, dark matter is not in the form of dark clouds of normal matter. Dark matter is made up of completely different particles, known as baryons. Scientists know this because they’re able to detect baryonic clouds by their absorptions of the matter passing through them. At the same time, dark matter does not produce the unique gamma rays, produced when antimatter and matter annihilate with each other, making it impossible for it to be antimatter.
The main properties of dark matter are that it is dark, again pretty obvious, meaning that it emits no light, making it hard to observe. It is not visible at all, so no x-ray and is not infrared. Research also rules out the possibility of hydrogen gas, since we can usually detect such clouds in x-ray, radio, or infrared and simply because large clouds of hydrogen don’t have enough gravitational force as dark matter. For us to detect the presence of dark matter, it is vital that it interact with visible matter gravitationally as that is the only piece of information we have of the particles. Dark matter must be massive enough to cause gravitational effects that we often see in galaxies and clusters of them.
As of now, scientists study dark matter by observing the effects it has on objects we can actually view. According to some scientists, dark matter may be the thing responsible for the unexplained motions of stars within galaxies. To study dark matter, computers play a significant role. They help create models, that predict galaxy behaviour, to help scientists study off of. Along with computers, satellites are also being used to study dark matter. With the help of the Hubble Telescope, an interesting discovery was made, back in 1997. The image Hubble took revealed light from a distant galaxy cluster, being bent by another cluster of something that was not visible. The light was bent in a way that helped scientists estimate that whatever was bending the light, must be 250 times greater than the mass of the visible matter in the cluster. These led researchers to believe that dark matter accounts for the force bending the light.
At this point in our research, we have laid out a few dark matter possibilities that are practical. As mentioned before, it may be possible that dark matter is made up of baryonic particles. They make up the dark matter and it’s tied up in brown dwarfs or in small dense chunks of a heavy element (one of the possibilities may be a black hole). The possibilities are endless and the search continues, as active as ever. Maybe dark matter is not made up of baryonic particles at all, but of other more exotic particles, created in the early days of the universe, like axions, neutrinos, or weak interacting massive particles (WIMPS). It may also be made up of normal objects like cold gasses, dark galaxies, or massive compact objects halos (MACHOS). Who knows? Research has led us this far and the road further down is looking even brighter. Maybe not in our lifetime, but in the next 100+ (maybe earlier?) we’ll know exactly what this strange trait of the universe is.
About the Author!
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