Question

21. Recent measurements of the expansion rate of the Universe show that it is accelerating as opposed to being constant. Cosmologists think this is due to

a. the missing mass in the Universe.

b. “dark energy” that, like dark matter, has yet to be detected directly.

c. neutrinos.

d. supernovae.

22. (T/F) One reason “dark matter” is dark is because it does not emit light, nor does it interact

      with normal matter through the electromagnetic force.

23. (T/F) “Dark energy” is called dark because it also doesn’t emit light, and we don’t know what it is, but it is apparently causing the expansion of the Universe to accelerate.

Answer 1

21. Recent measurements of the expansion rate of the Universe show that it is accelerating as opposed to being constant. Cosmologists think this is due to - cosmologists can tell, the mysterious force behind the accelerated expansion of the universe, a force that we call dark energy, remains constant.

Option (b)

22. True, Dark matter is called dark because it does not appear to interact with observable electromagnetic radiation, such as light, and so it is undetectable by existing astronomical instruments. 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.

23.) True, dark energy is at a fundamental level, we know some of its properties by inference. We know that it is something that uniformly fills the otherwise ‘empty’ space and causes the expansion of the universe to accelerate.