Planets and Stars

How Big Are We?

When we go on a trip in our car, we can drive all day and we think we've gone a long way.  But compared to the size of our planet Earth we have traveled over only a tiny fraction of it's surface.

What seems so big from our view point is so very small compared to the Earth.  It's all relative.

The pictures below do a great job of comparing different things in our universe to show how sizes compare relative to other things.  Our Earth is gigantic to us, especially if we thought about driving all the way around it (though the oceans make that quite difficult).

Let's take a journey in RELATIVE sizes.  Notice that the Earth is big RELATIVE to four of the other planets.


Notice in the picture below how tiny the Earth is RELATIVE to other bigger planets, but bigger RELATIVE to small planets.


Now we begin to compare our big and our small planets RELATIVE to our Sun.  Our Sun is not a very big star, but it's just the right size for us.


Now we're comparing different stars.  The white star is Sirius, also known as the Dog Star.  We see it in our winter sky, and it's the brightest star that we can see, even though it's not the biggest.  Not by a long shot.

Notice how big Arcturus is above, but in the picture below it looks so tiny RELATIVE to Betelgeuse and Antares.  On the other pages we'll be talking about Betelgeuse and Antares, where to find them and some interesting things about them.

And to complete this, the hyper giant star V V Cephei is twice as big as Antares!

To make some sense of this I've made mental image to help visualize something.

If we pictured our Earth as a marble that is one half inch in diameter our Sun would be a ball that is 55 inches in diameter, or just over 4 1/2 feet tall.

In the same scale the blueish star Rigel (above) would be a ball that is 318 feet in diameter – bigger than a U.S. football field is long.

And the hyper giant V V Cephei would be a ball that is 8,600 feet in diameter!  That's just over ONE & a HALF MILES in diameter.

The Earth as big as a marble.  V V Clephei 1.5 miles in diameter.  Relatively speaking.