The Big Bang
The Big Bang Theory (not the popular TV show) is a well-known scientific theory. It describes the prevailing cosmological model for the formation of our universe. Scientists and experimentalists proved the likelihood of its occurrence through several means. For instance, physicists detect cosmological waves from space that originated millions of years ago.
The Fate of the Universe
(Source: E. Siegel/Beyond the Galaxy)
In the early 1990s, scientists tried to fathom the current state of the universe and its fate. Consequently, they narrowed down all possibilities to a mere two. The first one indicates that as the universe expands, the energy will decrease until the expansion comes to a halt. The universe will subsequently recollapse, reverting back to its initial state (i.e. initial singularity, followed by The Big Bang).
(Source: E. Siegel/Beyond the Galaxy)
The second one states that the universe will continue expanding. However, said expansion will slow down with the passage of time as gravity will oppose this action. Nevertheless, matter and energy throughout the universe are at such an immense magnitude that they cannot be stopped. Hence, the universe will expand indefinitely at a relatively slower pace.
So far this makes a lot of sense until 1998. The Hubble Space Telescope (HST) revealed that the universe is expanding faster than predicted and is increasing exponentially. This crucial finding has baffled many scientists as it was not at all anticipated. Consequently, this initiated the eagerness of mankind to get to the bottom of this subject matter.
The Surprising Properties of Space
Albert Einstein was first to realise that empty space is not just empty and it actually possesses amazing properties. Up till this very moment, scientists are still discovering many of these properties. Firstly, Einstein determined that it is possible for more space to come into existence. This happens every second as the universe expands!
The second property is that space can possess its own energy, in other words, space is energy itself. This is apparent from the accelerating expansion of the universe. Particularly, space is energy and as more space comes into existence, more energy is manifested thus leading to faster expansion. Einstein truly was a genius!
(Source: Jet Propulsion laboratory, NASA)
This energy, called dark energy, makes up 68 % of the universe according to latest research. So using simple math: 100 % (the universe) – [5 % of normal matter + 68 % of dark energy] = a remainder of 27 %. This begs the question: what constitutes the remaining 27 %?
Dark Matter Matters
Scientists have come up with the theory that this 27% is actually made up of dark matter. So far, scientists are more certain of what dark matter is than what it is not. Dark matter does not interact with visible matter or even light and this proves that the idea of dark matter being anti-matter is wrong. The gravitational effect on normal matter allows the detection of dark matter. This property explains why astronomers perceive certain optical illusions in deep space. The phenomenon, known as gravitational lensing, creates these illusions. To elaborate, invisible clouds of dark matter enable the distortion and magnification of light from distant galaxies. This explicates the formation of peculiar rings and arcs of lights seen in pictures of galaxies.
(Source: ESA/Hubble & NASA)
Although scientists are almost certain of the existence of dark matter, they still do not understand the nature of it. In particular, one of the leading hypothesis states that dark matter are exotic particles that do not interact with normal matter or light but said matter exert a gravitational pull. Several scientific groups, including one at CERN’s (European Organisation of for Nuclear Research) Large Hadron Collider, are currently working to generate dark matter particles for research at their dedicated labs for further investigation.
In 2015, scientists detected gravitational waves originating from two colliding black holes. After conducting research, they inference that black holes are the source of dark matter in the universe. However, after studying over 1050 black holes, a team of astronomers at The University of California refuted this statement in 2018 and have revealed that black holes are in fact are the source of as little as 23 % of the universe’s dark matter.
Space and Humanity
In a nutshell, our present understanding points towards the fact that space is not just empty space as the word suggests. As baffling as it can be, humanity still has a long way to go when it comes to fully comprehending the laws that govern this vast universe. However, this will not stop many of us from getting to the bottom of this. That being said, human beings possess an intrinsic desire to explore and comprehend everything around us. After all, any step closer to figuring out the concepts of space means one step closer towards understanding ourselves better.
Written by Merna Ehab