5) What could this unseen matter be?Small cold objects like planets, asteroids, brown dwarfs. Tiny particles like dust or gas. Black holes. Neutrinos. All of these possibilities were tested and couldn’t account for more than a tiny fraction. 6) The unseen matter is called “dark matter” and is invisible because itA)only emits high-energy radiation such as X-rays and gamma rays.B)only emits low-energy radiation such as microwaves and radio waves.C)absorbs and reflects light but does not emit other radiation like stars do.D)does not absorb, emit or reflect any type of radiation or light.Astronomers checked all wavelengths and found that 80% of the mass is invisible. Absorption and reflection would make the matter visible.
7) If you can’t see the dark matter how do you know it is there?There is not enough dark matter in the solar system to affect the motions of the planets. Orbital motion and