What is Dark Energy

Dark energy is an unknown form of energy which is hypothesised to permeate (spread throughout) all of space, tending to accelerate the expansion of the universe.


What is Dark matter??

The velocity of rotation for spiral galaxies depends on the amount of mass contained in them.

But the outer arms of the Milky Way are rotating much too fast to be consistent with the amount of matter that we know exists in them.

Such fast rotation is possible only when there is more mass, and that extra mass is believed to come from the dark matter.

Dark matter is a hypothetical form of matter that is thought to account for approximately 85% of the matter in the universe.

Dark energy plus dark matter constitutes 95.1% of the total content of the universe (the rest in the normal matter). In short, we are unsure about what’s there in 95% of the universe!

The majority of dark matter is thought to be composed of some as-yet-undiscovered subatomic particles.

The name dark matter refers to the fact that it does not appear to interact with observable electromagnetic radiation, such as light.

It is thus invisible (or ‘dark’) to the entire electromagnetic spectrum, making it extremely difficult to detect.

Dark matter interacts with the rest of the universe only through its gravity (that’s how we know it exists).