In fact, the part of the universe that we can see – stars, planets and nebulae – represents only a small part of all matter in the universe, but according to the best calculations of astronomers, that part is only about four percent.
The rest consists of so-called dark matter and a mysterious force that astronomers have named dark energy. Dark matter is estimated to be 23 percent and dark energy a whopping 73 percent of the combined matter of the universe. The dark energy is believed to drive the ever-accelerating expansion of the universe.
All nebulae are moving away from each other with increasing speed, and this must be due to something acting against the force of gravity. By analyzing the distribution of the microwave radiation in the universe, the amount of dark energy has been estimated at 73 percent. Dark matter shows its existence through its gravitational force, but it is not known what the phenomenon actually is.
Recently, English astronomers at Cardiff University have detected an entire nebula without a single visible star 50 million light-years away. Thanks to the gravitational action of dark matter, it has been possible to prepare a computer simulation that shows its distribution in our part of the universe (see the picture). It seems that the dark matter forms forms that could be called “threads” and “walls”, just like the visible matter.
