By Àlex Santomà
Dark Energy, in the context of physical cosmology, astronomy and celestial mechanics, is a theoretical form of energy that allows us to confirm the expansion of the universe at an accelerating rate, but we do not know if it exists or not, it's only a supposition.
According to the law of the Big Bang, the universe exploded a long time ago, and according to this theory the universe is getting bigger more and more slowly, but when we look at the universe we can prove that it is getting bigger faster and faster, and that's the reason for the invention of Dark Energy.
This type of energy was first named by Michael Turner. Dark Energy should not be confused with Dark Matter, because they are different things. Dark Energy was discovered in 1998 when some physicists were watching the explosion of a distant supernova, and then they confirmed it with the study of microwaves, gravitational lenses and nucleosynthesis. Recently, physicists have discovered that in the universe, 73% of the mass is Black Energy, 23% is Dark Matter and 4% is baryon matter (all the stars, the planets, us, the earth...).
There are two types of models of Dark Energy: the cosmological constant and the quintessence.
