Space that appears empty actually contains dark energy and dark matter.Dark matter does not emit electromagnetic radiation.Scientists theorize that dark energy is causing the expansion of the universe to accelerate.
Explanation:
The question is incomplete, the correct form is:
Which statements explain current theories about dark energy and dark matter? Check all that apply.
- Space that appears empty actually contains dark energy and dark matter.
- Dark matter does not emit electromagnetic radiation.
- Scientists believe dark energy will cause the universe to collapse inward to a single point.
- Scientists theorize that dark energy is causing the expansion of the universe to accelerate.
- Dark matter includes all of the dust, ice, and debris that scientists observe in black holes.
Dark energy rises as an explanation of the accelerated expansion of the Universe, since it was expected that this slows down since the big bang, as a consequence of the gravitational attraction between the different objects (galaxies, planets, etc) but instead the observations show how it is accelerated.
In the other hand, Dark matter was born to explain why stars that were farther from the supermassive black hole in the center of the Milky Way galaxy didn't decrease its rotational velocity as it was expected.
Where v is the rotational velocity, G is the gravitational constant, M is the mass of the supermassive black hole, and r is the orbital radius.
If the distance increases the orbital speed decreases (inversely proportional).
So, the theory said that it must be matter that contributes to the increase of the orbital velocity in the outer regions of the disk of the Milky Way.
And since astronomers use electromagnetic radiation to study any different object in the universe, it is believed that dark matter do not emit electromagnetic radiation, since it can not be detected directly.
