Most of us have ridden on a commercial jet. To fly from coast to coast, it takes about 9 hours right? How long do you think, flying in an airliner, would it take to reach the Moon? Just take a guess… The answer is 18 days. 18 days of airplane food! That’s a long time.
Now, what about the Sun? 20 YEARS! That’s a substantial chunk of a human lifetime. 18 days to the moon, 20 years to the Sun… yet, we’re so proud of our human missions to the Moon, even though it’s just a stones throw away.
Jupiter: 82 years. Pluto… at the very edge of our solar system: it would take about 750 years. That is a very many lifetimes… No one can possibly, truly, grasp these scales. And that’s just the solar system! That’s just our backyard. Stellar scales are much different. If it took 750 years to reach Pluto, how long is it going to take to reach the nearest star, which is about 4.3 light years away?
The answer is that you’re going to have to sit in that plane for about 5 million years. And yet, that is a trip next door. That’s the next star to ours. It would take you as long as it took hominids to evolve after
the split from the chimp lines into modern human beings to reach the nearest star.
We can keep going too. We were just talking about 2 stars; our Sun and our nearest neighbor. Well, how many stars are there in our galactic city, The Milky Way galaxy? There are around 100 billion stars in our galaxy – most of them separated by at least a plane ride of 5 million years.
Well, how many galaxies are there in the known universe? Again, probably about 100 billion. That means that there are as many stars in the universe as there are grains of sand in all the beaches and all the deserts on Earth! Think of holding a handful of sand, each a star. Imagine digging down as far as you could in the middle of the Gobi desert and look up at all the sand around you…