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# astronomysizecomparisons ( ** )

### Astronomy size comparisons

Size comparisons in our solar system and galaxy

• If the Earth was the size of a dime, the Sun would be six feet in diameter.
• If the Sun was the size of a dime, the red giant Antares, a star in the constellation Scorpius, would be a 2-story building (the earth would be a very small period on this scale).
• If the Earth was the size of a dime, Jupiter would be a dinner plate.
• Jupiter contains more mass than all of the other planets in our solar system combined.  The Sun contains 700 time more mass than all of the planets in the solar system combined.
• It would take 1 million Earths to equal the volume of the Sun.
• It would take 43 million Suns to equal the volume of Antares, the previously-mentioned red giant star in the constellation Scorpius.
• If the Sun was a golf ball, where would you place another golf ball to represent the nearest star to our Sun (Alpha Centauri)?  In downtown Seattle or downtown Lincoln, Nebraska (approximately 900 miles away).
• If the Sun was represented by an orange, then Earth would be a grain of sand 30 feet away, Jupiter would be a pea 200 feet away, Saturn would be a cherry pit 400 feet away, Pluto would be a flake of pepper 2000 feet away, and Proxima Centauri would be 1300 miles away.
• If you made a scale drawing of our solar system, with Pluto being 10 inches from the Sun (actual distance 3.6 billion miles), then Proxima Centauri, the nearest star to our Sun, would be over 1 mile away.  Proxima Centauri is 4.3 light-years distant from our Sun, or 25 trillion miles away.
• If our Solar System was the size of a dinner plate, how large would our galaxy be on that scale?  All of North America.
• Why did it take so long to discover the planet Pluto (it was discovered in the 1920’s)?
1. Pluto is very small and very far away.
2. Pluto would fit between the Mississippi River and the East Coast.
3. It takes 8 hours for a photon of light to travel from the Sun to Pluto, traveling at 186,000 miles per second.
4. If the Sun were a golf ball, Pluto would be found 1.5 miles away on that scale, and Pluto would be the size of a small grain of sand.
• Sunlight reaches Earth in 8 minutes, but it takes 4 hours to reach Neptune.
• A space ship traveling from Earth at 25,000 mph would take more than 12 years to reach Pluto.
• If the Earth were compressed to the same degree as the matter in a pulsar or neutron star, it would fit inside the Pentagon.
• One thimble-full of neutron star matter would weight 8 times more than all the cars on our Earth.
• One could put 50 light waves end-to-end across the width of one layer of Saran Wrap.
• If Betelgeuse, the large red giant star in the constellation Orion, were to replace our Sun, it would reach out to the orbit of Jupiter.  A hollow sphere the size of Betelgeuse would hold nearly 43 million objects the size of our Sun.  Mu Cepheus is 3 times bigger than Betelgeuse, and it would reach out to the orbit of Uranus.
• White dwarf stars are about the size of our Earth.
• Sirius, the bright star in the constellation Canis Majoris, is 9 light-years away from Earth.  Thus, when a 9-year old child looks at Sirius, the photons that enter the child’s eye left the star when he or she was born.
• If the words of a standard-sized book represented the volume of our universe, then our solar system would be less than a trillionth of a trillionth of one letter.

Note to myself: If giving a presentation, take the following:

• Dime
• Two golf balls
• Paper plate
• Table
• Telescopes