Space is full of galaxies that have cannibalised each other to survive, but one of these – Tucana II – has a much more intriguing story than previously envisaged. Experts announced that the ring of dark matter circling the dwarf galaxy, or its “halo,” is as much as five times larger than estimated. It has also been tipped to re-write the story of the infant years of the universe since it suggests that the first galaxies were spread out much further than thought.
Dark matter is a form of unknown matter that is said to account for a huge amount of unknown matter in the universe and its presence is implied in a variety of astrophysical observations, including unexplainable gravitational effects.
For this reason, most experts believe dark matter is abundant in the universe and that it has had a strong influence on its structure and evolution, but, they also believe it could play a role in its demise.
Cosmologist Renee Hlozek explained why during a TedTalk.
She said: “The end of the universe is intimately linked to what the universe contains.
“We can predict how the universe will change with time if we measure the amounts or energy densities of the various components in the universe today.
“So, what is the universe made of? The universe contains all the things that we can see, like stars, gas, and planets.
“We call these things ordinary or baryonic matter. Even though we see them all around us, the total energy density of these components is actually very small, around five percent of the total energy of the universe.
“Just under 27 percent of the rest of the energy density of the universe is made up of what we call dark matter.”
The researcher went on to detail where the rest of the energy comes from.
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And the expert detailed the role dark energy could play in the universe’s doomsday.
She continued: “The leading idea for dark energy is that it is a cosmological constant. That means it has the strange property that it expands as the volume of space increases to keep its energy density constant.
“So, as the universe expands as it is doing right now, there will be more and more dark energy. Dark matter and baryonic matter, on the other hand, doesn’t expand with the universe and becomes more diluted.
“Because of this property of the cosmological constant, the future universe will be more and more dominated by dark energy, becoming colder and colder and expanding faster and faster.
“Eventually, the universe will run out of gas to form stars, and the stars themselves will run out of fuel and burn out, leaving the universe with only black holes in it.
“Given enough time, even these black holes will evaporate, leaving a universe that is completely cold and empty. That is what we call the heat death of the universe.”