Answer:
b. flat rotation curves in spiral galaxies
Explanation:
Dark matter accounts for majority of the matter in the universe (about 85%). It is considered to be composed of subatomic particles which are yet to be discovered. Dark matter cannot be observed because it does not emit light that can be detected. Only its gravitational effect is visible.
Astronomers when calculated the mass of the visible matter and tried to account for the observed speed of stars in the galaxy, there was a mismatch. To understand what caused this mismatch, astronomers gave name to the invisible matter as the Dark Matter.
The expected velocity of stars should decrease away from the near the center of the galaxy but a constant velocity of stars was observed that is a relatively flat rotation curve was obtained.
Thus, flat rotation curves in spiral galaxies in an evidence of Dark Matter.
A person who has been forced to leave their country in order to escape war, persecution, or natural disaster. Hope that helps!
Answer:
Actually the radiation belts are a negative side effect of the earths magnetic field as well as the Suns magnetic field. As cosmic particles collide with particles in the atmosphere they decay into energetic protons while the outer belt is mostly electrons made in geomagnetic storms.
if it didn't exist we could launch more satellites or have larger space stations without the worry of perpetual radiation exposure as for earth there would be no negative consequences to the loss of the energy.
Answer:
As the moon orbits Earth, it cycles through eight distinct phases. The four primary phases occur about a week apart.
Explanation:
look back at the phases.
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