Dark energy and dark matter
In recent decades evidence has grown for the presence of two mysterious entities in the universe
Made of matter
As its name suggests, dark matter is commonly thought to consist of a series of invisible particles. Dark energy, on the other hand, is not
thought to consist of particles.
Outwards vs inwards
The presence of dark matter adds
extra gravity that helps glue galaxies and clusters of galaxies together. In contrast dark energy has an anti-gravitational effect, pushing galaxies apart.
How much?
Dark energy dominates the total energy/mass budget of the universe. It is thought to make up 68 per cent, with dark matter contributing 27 per cent. The remaining five per cent is
normal matter.
Getting experimental
There are lots of experiments all around the world trying to snare a dark matter particle as it arrives at the Earth. There are no dark energy detectors.
Extra strength
Dark energy is currently dominating dark matter because the rate at which the universe is expanding appears to be accelerating. That's despite dark matter's natural inclination to clump together.
Old vs new
The first hints of dark matter date back to the 1930s. Dark energy, on the other hand, only became apparent in 1998 when astronomers accurately measured the expansion rate of space.