The never ending expanse of the universe around us has recently been re-imagined to be an expanding bubble contained in yet another dimension. The whole universe has been modeled to be accommodated on the surface of the bubble and researchers say this could pave the way for us to solve the mysteries about dark matter and dark energy. So what are they and how much do we know about them?
Only Five Percent Of The Universe Is Visible
All the celestial bodies that we have observed till date like the stars, planets and galaxies are all composed of protons, neutrons, and electrons bundled together into atoms. Together they make up only about five percent of the mass of our universe.
The rest 95 percent isn’t exactly empty as studies suggest, contrary to what we have known till date. The dark void of space appears to be made of a mysterious, invisible substance called dark matter (25 percent) and a force that repels gravity known as dark energy (70 percent).
What Is Dark Matter?
Scientists have not been able to observe dark matter directly yet, but have been able to gather many evidences of their existence. Some of the reasons why they’re so difficult to observe are:
- It’s completely invisible to light and other forms of electromagnetic radiation. In fact, light bends around regions of space with high concentrations of dark matter.
- Dark matter does not interact with ordinary matter. They are not antimatter either, as antimatter emits gamma rays when it reacts with normal matter.
- Not to be confused with black holes. Though dark matter can exert gravitational force, they are not even nearly as destructive or concentrated as black holes.
Dark matter is everywhere and it probably contains exotic particles that don’t interact with normal matter or light but still exert a gravitational pull. It is currently not possible to visually study with our technology.
Dark Matter Makes It Possible For Galaxies To Exist
We all grew up knowing that space is a large vacuum composed of stars and planets contained in galaxies. But studies have suggested, taking into consideration the enormity of the galaxies and the sheer number of stars in them, that their gravity is not strong enough to form such complex structures.
This has strengthened the belief in scientists that there exists something among these galaxies which are responsible for their formation. This “something” is matter and it doesn’t reflect or emit light. In other words, its dark matter.
What Is Dark Energy?
Dark energy is even more mysterious and scientists haven’t been able to get much insight about them either. Right now, just like in with dark matter, it’s just theory with no evidence to prove its existence. One theory suggests that dark energy is an intrinsic property of our Universe, which was previously thought to be more or less empty.
Way back in 1929, Edwin Hubble noticed how light from distant galaxies shifts towards the red end of the electromagnetic spectrum as it travels through space. He determined that our Universe was expanding, as the wavelengths of light are stretched, shifting them towards the color red.
Last year in February, Space.com published an article stating, “Recent Hubble Space Telescope findings suggest that the universe is expanding much faster than expected — and astronomers say the rules of physics may need to be rewritten in order to understand why.”
Scientists now think that the accelerated expansion of the universe is driven by a kind of repulsive force which seems to be growing stronger as the universe expands. For lack of a better name, scientists call this mysterious force dark energy.