Table of Contents
What kind of matter in the universe that has gravity but does not emit light?
dark matter
Unlike normal matter, dark matter does not interact with the electromagnetic force. This means it does not absorb, reflect or emit light, making it extremely hard to spot. In fact, researchers have been able to infer the existence of dark matter only from the gravitational effect it seems to have on visible matter.
How much dark matter is there?
Dark matter makes up about 27\%. The rest – everything on Earth, everything ever observed with all of our instruments, all normal matter – adds up to less than 5\% of the universe.
Is there dark matter in our solar system?
The answer is, very very little. Dark Matter has recently been identified as ordinary matter, all sorts of planets and other smaller bodies, essentially lying outside solar systems. It’s called Dark because it’s too cold to give out its own light, and too distant from any star to be visible by reflected light.
Do we have dark matter in our bodies?
Even though, at any given instant, there’s only around 10-22 kilograms of dark matter inside you, much larger amounts are constantly passing through you. Every second, you’ll experience about 2.5 × 10-16 kilograms of dark matter passing through your body.
Is dark matter invisible?
Scientists have not yet observed dark matter directly. It doesn’t interact with baryonic matter and it’s completely invisible to light and other forms of electromagnetic radiation, making dark matter impossible to detect with current instruments.
How does dark matter form galaxies?
In the formation of galaxies, it is the overdensities of dark matter that gravitationally attracts into higher density clumps first, which then provides the gravitational force for ordinary matter to clump up within it. However, in order for ordinary matter to collapse enough to form stars, it must lose a great deal of energy and angular momentum.
How does dark matter lose energy and angular momentum?
Ordinary matter can lose energy and angular momentum through radiation and collisions between the particles, but dark matter particles don’t do this because of their weak electromagnetic interactions. As a result, it is extremely unlikley there are very dense objects like stars made out of entirely (or even mostly) dark matter.
How did dark energy come about?
According to current theories dark energy has always been around and has always exerted the same force. However, in the early universe, matter was closer together and the effects of gravity caused the expansion of the universe to slow down.