Perspective

In our busy day to day lives, it's difficult to truly imagine the scale of things in the universe.  From our perspective, the earth is a flat, stationary center of the universe, and all of the celestial bodies seem to revolve around us.  In fact, this was what humanity believed for many centuries.  Upon observing the sky, however, we gained a completely new view of the cosmos.  The Earth is actually round and revolves around the sun in an elliptical orbit, just like the 7 other planets (sorry, Pluto).  In addition, Earth is rather small compared to its siblings, which themselves are tiny compared to the Sun.

The distances between the planets, however, are even more immense.  Jupiter, the largest planet, appears as a dot in the night sky, and the Sun, capable of holding over a million Earths within its volume, can be covered by your thumb held at arm's length.  Once we leave the solar system, though, distances become even larger.  Our nearest star, Proxima Centauri, is over 4 ly away.   The nearest galaxy is thousands of light-years away.  It is clear that our solar system, our galaxy, and the universe mainly consist of emptiness.

Many find these distances frightening or saddening, but astronomers find them fascinating and enlightening.  The Earth is perhaps no more than a negligible speck, floating in the middle of nothingness amongst billions of other planets, revolving around billions of stars, in billions of galaxies.  But despite the insignificance of humanity in time and space, we've managed to discover so much about this enormous universe within a few hundred years.  And there's even more to be discovered.

I'll finish this blog post with a video that I put together about a year ago during winter vacation.

Narrated and written by Carl Sagan.