Take a moment to take your eyes off this page and look around. What did you see? Are you sitting indoors and hence were you able to take in everything that is around you? Or are you outside and therefore you stared up at the vast open skies?
Irrespective of what you saw, you know well that it is a miniscule part of everything that you can see. For there is so much out there to see, from ants, elephants, and mountains to oceans, moons, and even galaxies.
We see just 5%
Suppose, if I were to tell you that everything that our eyes can see accounts for only a fraction of the universe, would you believe it? Believe it or not, that is the truth about our universe.
Everything that our eyes can see constitutes less than one in 20 parts of the universe. If what we can see makes up less than 5% of the universe, what is the rest of the universe made of?
The answer to that question is dark energy and dark matter. The invisible force that holds galaxies and the cosmic web together is the dark matter and it makes up about 27% of the universe. The major portion – the remaining 68% – is dark energy and it is responsible for the universe expanding at an accelerated rate.
The dark in these names corresponds to a sense of unknown, rather than literal darkness. This is because there is a sense of mystery and more is unknown than known at the moment about these two unrelated phenomena.
Has dark energy been detected?
Even though both these components are invisible, a little bit more has been gleaned, about dark matter than dark energy. This is simply because of the fact that the existence of dark matter was suggested in the 1920s, but dark energy was discovered only in 1998.
We might soon get to learn more about dark energy as a new study led by researchers at the University of Cambridge and reported in September 2021 in the journal Physical Review D suggest that certain unexplained results from their XENON1T experiment may have been caused by dark energy.
The experiment, designed to detect dark matter, threw up an unexpected or excess signal over the expected background about a year ago. Further investigation by the researchers allowed them to conclude that this signal could be attributed to dark energy.
This means that it could be possible to directly detect dark energy within the next decade. While we are far from understanding what dark energy is, such detections could pave the way for exciting times ahead.
Picture Credit : Google