they simply absorb every other color of light. What we see is the color that is reflected by the object.
for instance, a shirt is not blue, but it absorbs every color of light except for blue, which bounces off the fabric and into our eyes.
so technically, the shirt "is not" blue, but reflects blue light
You can see back in time!
When you are looking at the stars, remember that stars are 'Lightyears" away. This means that the distance is how far a light particle can travel in a year (5,878,625,370,000 miles!)
So, if we look at a star, like Rigel which is 864 lightyears away, we are actually seeing the light that Rigel produced 864 years ago
Further away stars might already be dead
Rho Cassiopaeiae is 3,400 lightyears away and is 300,000 times brighter than our sun. The light we see today was emitted around the time of Ancient Egypt, and it was from a dying star. It may be dead today, but we won't know for another 3,500 years!
it takes 8 minutes for us to see the light from our sun!
The furthest galaxies we can see are about 13.5 billion lightyears away
this tells us the age of the observable universe
All of the planets in our solar system can fit in the space between the earth and the moon!