Oh great question! I love star gazing! Stars are giant balls of glowing gas and these giant balls shine because the gas inside them is so hot that a process called “nuclear fusion” takes place (this is where 2 atoms come together or “fuse”) to form a different kind of atom… this process gives off a lot of energy that we can see as light. Great questions Bronagh!
And when this light reaches the earth it has to pass through our atmosphere before it reaches our eyes. Because our atmosphere is full of a mixture of gases all at different temperatures and movements, this causes the stars we see to “twinkle” or shine, like I think you mean.
Also Bronagh, many stars you can see in the night sky seem like a single, distant glimmer of light. However most stars you see are actually two star systems, or binary star systems. They are so far away however that they just appear as one speck of light.
Technically speaking, our nearest and most visible star is actually the Sun, although there are actually some stars almost 100 times MORE massive than the sun.