Author: Emily Jiang
Editors: Sumire Sumi and Hwi-On Lee
Artist: Jenny Luo
The universe has always been something that humans have been curious about, and with the advancement of technology, we continue with our journey to discover the mysteries in space. With new discoveries, new mysteries also follow. Since we do not always have a completely logical explanation for phenomena, we make theories. Nevertheless, how can we assume that something exists when scientists have never directly seen it? Dark matter and dark energy are great examples. We assume dark matter exists because of its effect on its surrounding objects, which explains the obscure behaviors of stars, planets, and galaxies. As for dark energy, we know it exists due to its effect on the expanding universe. However, dark matter and dark energy are phenomena that we cannot observe with our current instrument. Nevertheless, these theories help explain some of the other mysteries in our universe.
Dark matter makes up 27 percent of the universe. It is invisible because it doesn't absorb, emit, nor reflect any light, making it impossible to detect with our current sensors and machines. Scientists have several theories on what dark matter consists of. The most supported theory is WIMPS (weakly interacting massive particles). WIMPS have up to a thousand times the mass of a proton. Since dark matter has mass, it must also contain gravitational force. We know dark matter exists because the whole mystery of the motion of galaxies cannot be explained with just Newton's Law of Gravity and Motion. The galaxies are spinning way too fast, yet for some reason, it has not broken down from the resulting force. Gravity must be keeping the galaxy together, and this magnificent amount of gravity can only be generated from something invisible. This invisible matter is called dark matter, and it contributes to explain the uncertain formation of galaxies.
Dark energy is a theoretical form of energy that counters gravity, making up 68% of the universe. To put it simply, dark energy is like blowing air into a balloon, with the rubber skin representing gravity (which dark energy overcomes). And because dark energy counteracts gravity, it causes the universe to expand at an accelerating rate, driving the universe further apart. Explanations for what dark energy might be is that it is a property of space, a dynamical energy (quintessence) that fills all of space, affecting the universe's expansion rate opposite of matter and energy. We assume dark energy exists because there was a shift from a decelerating universe into an accelerating one.
In general, dark energy and dark matter are placeholders for phenomena we cannot fully explain. Dark energy and dark matter are only theories and can therefore be disproven in the future. But as humans continue to expand our knowledge, we advance with faith that we will solve these mysteries one day.
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