Question: What is the difference between dark matter and dark energy??

Loan Nguyen answered on 17 Nov 2015:

Dear Matt,
I have not yet spoken to Stephen Hawkins but instead referred to my loyal friend; the web. Now I ask myself the question why did i not study Physics; it is so fascinating!

I didn’t know that our universe has 100 billion galaxies (I have no idea how many zeros this number would have!), each galaxy with billions of stars and each star is a sun to a collection of planets and moons. Below is the definition of the three different form of matter which you asked me (the percentage varies depending on which website you read).

1. The universe, with all its galaxies suns, planets and moons, down to the smallest life-form, atom and electron of what we can see is made of normal matter. Normal matter only accounts for 5% of what is in the universe!

2. 21% of the universe is made up of dark matter. dark matter is the gravity force which hold the universe together. We cannot see dark matter and dark matter does not give out any energy.

3. 74% of the universe is made of dark energy. Dark energy has the opposite effect to dark matter. dark energy has an outward pushing force, causing the universe to grow and expand.

The force of dark matter is more noticeable on a ‘small scale’ such as galaxies. The effect of the dark energy is more on a ‘large scale’, affecting the growth of the entire universe.

You have made me work hard for this answer Matt, I hope you will find it helpful. I have enjoyed finding out the answer for you.

Best of luck with school.

Loan