The universe is organised in structures:
- Visible ordinary matter, which makes up our planets, galaxies and ourselves. It represents only 5% of the universe’s energy.
- Invisible dark matter, that can only be identified through its effects on gravity, and which supports cosmic structures (such as galaxies). It represents about 27% of the universe’s energy.
- Dark energy, a sort of fluid that puts a strain on the geometrical tissue that brings galaxies to dilute. It represents about 68% of the universe’s energy.
To this day, the shape of the universe remains unknown.
Recent work suggests the universe could be more complex than just a sphere, or a two-dimensional surface.
The latest result of astro-physicist Jean-Pierre Luminet suggests that the universe could look like a polyhedron with 12 faces.
A black hole is an area in the cosmos where the gravitational attraction is strong enough to suck up any of the light that tries to get out of it.
It grows out of the explosion of a massive star. Such an explosion is called a supernova, and releases a very big amount of energy.