Mick Groszko asks ‘How big is space anyway?’



With all the excitement last July of pictures from NASA’s New Horizon satellite flyby of Pluto, we heard a lot about how far away it is, how long it takes to get there, etc., etc., etc.

Do you ever get lost when you hear numbers like a million miles, a billion miles, a trillion miles or even lightyears? Do these all seem like just big numbers?

Astronomers use these huge numbers all the time but I find it is really hard to get a realistic picture of this that I can visualize. I’ll try to paint a picture of our sun and it’s planets to scale, and see if this helps.

Start with our home planet, Earth.

It is huge, 8000 miles in diameter and 25,000 miles around at the equator.

Think of all the 7 billion people, hundreds of countries, mountains, oceans, cultures and a few billion years of history that make up our little rock’s existence in the universe. Now shrink our mother earth down to a small pebble about the thickness of a nickel.

This is just a little smaller than a BB.

On this scale, our sun would be about nine and half inches in diameter.

This is about the size of a basketball.

Try and imagine how many earths (BBs) would fit in our sun (the basketball).

Now realize on this scale, our earth is over 28 yards from the basketball. Picture our earth, the BB, rotating around the basketball almost a 1/3 of a football field away. Space is pretty empty.

Let’s now look at some of the other planets. Mercury is about one third the size of the earth (a small grain a sand) and rotates approximately 11 yards from the sun.

Venus is slightly smaller than the earth and is 20 yards from the sun. Mars is one half of earth and 43 yards from the sun.

Now the big gas giant planets.

Jupiter is one inch in diameter (a ping pong ball), rotating 147 yards from the sun.

Saturn is three quarters of an inch and 270 yards from the sun. Uranus and Neptune are both about one third of an inch big and are at 542 yards and 850 yards respectively.

That’s almost a half a mile.

On to Pluto.

It is half of mercury, so a very small grain a sand. It is almost two thirds of a mile from our sun.

So the solar system we live in is made up of five grains of sand, two ping pong balls and a couple of marbles going around a basketball in a circle about a mile and a third across.

This should help explain why we did not know much about Pluto until we got there.

Even the Hubble Space Telescope could not see much.

And now the real stunner.

The closest star to our sun is Alpha Centauri which is 4.3 light years away.

On our new cosmic scale it would be another basketball 1015 miles away.

So we have a basketball in Petoskey, Michigan and the closest star to us is another basketball just south of Atlanta, Ga. with nothing in between.

Now imagine the 100 billion basketballs, all thousands of miles apart that make up our Milky Way Galaxy.

Next time you are out enjoying the beautiful night sky, I hope you marvel at the magnificent universe we are a part of.

Mick Groszko is an amateur astronomer and astrophotographer in the Petoskey area and can be contacted at mgroszko1@aol.com

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