In short, those arms are made of "stars, dust and gas". They are visible as spiral arms because they have a higher density of those objects than the space between them.
The arms are an area where the density of stars (and planets and other objects) is unusually high and where the start are young - recently formed- and this also gives those starts their visibility as young starts are also very bright.
Answer:
Repulsion
Explanation, due to this repulsion with the proton and the electron, each electron experiences a nuclear charge that is somewhat less than the actual nuclear charge.
Answer:
More energy
Explanation:
The amount of energy carried by a wave is related to the amplitude of the wave itself. In particular, the amount of energy carried by the wave is proportional to the square of the amplitude of the wave:
where
E is the energy
A is the amplitude
This means, for instance, that if the amplitude of a wave is doubled, the energy it carries increases by a factor 4.
