One light year (distance that light travels, at approximately 186,000 miles per second, in a year) = 5,880,000,000,000 miles

Our average or somewhat larger than average size galaxy, the Milky Way Galaxy (so named from the bright band of stars at the edge of the galaxy), of about 100 billion stars, is disk-shaped and 100,000 light years in diameter and 2,000 to 10,000 light years thick in most places, about 30,000 light years thick at the center. Our solar system, in one of its spiral arms (about 30,000 light years from the center), circles the center of the galaxy about once each 230 million years. Our group of galaxies has about 25 other galaxies. About a billion other galaxies have been discovered, and it has been estimated that there are 100 billion galaxies. The most distant objects observed are about ten to the tenth power light years away from us.

It was realized by Pythogoras and Aristotle to be spherical. About 8,000 mi. in diameter, first approximately determined (to within 10 or 15%) in 3rd cent. BCE (Before Common Era, equivalent to BC) by Eratosthenes of Cyrene, by comparing the angles of the sun's shadow at Alexandria and Aswan.

PLANET, DIAMETER, MI. FROM SUN, ORBITS SUN, ROTATES ON AXIS

Mercury 3,100 mi. 36 million 88 days 59 days

Venus 7,700 mi. 67 million 225 days 244 days

Earth 7,920 mi. 93 million 365 days 24 hours

Mars 4,200 mi. 141 million 687 days 24 hours 24 minutes

Jupiter 88,640 mi. 483 million 11.9 yrs. 9 hours 50 minutes

Saturn 74,500 mi. 886 million 29.5 yrs. 10 hours 39 minutes

rings 165,000 mi.

Uranus 32,000 mi. 1,782 million 84 years 23 hours

Neptune 31,000 mi. 2,793 million 165 days 15 hours 48 minutes

Pluto 1,500 mi. 3,670 million 248 years hours

The sun is about 93 million miles from earth, has a diameter of 864,500 miles, ritates on its axis in about 25 days. 99.86% of the mass of the solar system resides in the sun.

Centered in or near Peoria, Illinois, is the Lakeview Museum Community Solar System. It has a scale of 43 feet equaling 1 million miles.

Sun 36 ft. diameter

Mercury 1.5" .25 mi. away from sun

Venus 3.8" .5 mi.

Earth 4" .75 mi.

Mars 2.2" 1.2 mi.

Jupiter 45" 4 mi. rings 76"

Saturn 38" 8mi. rings 90"

Uranus 16" 15 mi. rings 32"

Neptune 15" 23 mi. rings 30"

Plato 1" 40 mi.

The whole model extends roughly 60 miles wide across the state, with comets represented on 6 continents.

In general:

If earth is one inch in diameter, the Sun. is almost 3 yards in diameter, the distance from Sun to earth is almost 1,000 feet, Sun to Pluto well over 7 miles.

Another way to help visualize the relative sizes in the solar system is to imagine a model in which it is reduced in size by a factor of a billion.

Then the Earth is about 1.3 cm in diameter (the size of a grape).

The Moon orbits about a foot away.

The Sun is 1.5 meters in diameter (about the height of a man) and

150 meters (about a city block) from the Earth.

Jupiter is 15 cm in diameter (the size of a large grapefruit) and 5 blocks away from the Sun.

Saturn (the size of an orange) is 10 blocks away;

Uranus and Neptune (lemons) are 20 and 30 blocks away.

A human on this scale is the size of an atom; the nearest star would be over 9000 km away.

Excerpts from Carl Sagan's "The Cosmic Calendar" in The Dragons of Eden (Random House, 1977):

Jan. 1 Big Bang

May 1 origin of Milky Way Galaxy

Sept. 9 origin of solar system

Sept. 14 formation of Earth

Dec. 19 first fish

Dec. 20 first land plants

Dec. 21 first land animals

Dec. 31: 10:30 p.m. first human beings

11:59:35 first civilizations

11:59:56 birth of Jesus

11:59:59 Renaissance (so the last half millennium on this scale has taken about half a second to pass)

From John Van Duyn Southworth's The Story of the World (Pocket Books, 1954): Depths of excavation required to reach certain parts of the past (the first 26 feet actually excavated in a cave in Iraq, the remainder theoretical extensions based on accumulation of about a foot of material each 2,700 years)

8 inches birth of Jesus

2-4 feet Neolithic (New Stone Age) period

4-111 feet Paleolithic (Old Stone Age) period

370 feet Eolithic (Dawn Stone Age) period start, first true human beings a

million years ago (more recently extended to about two million years)

370 ft.-7 mi. early mammals

7-14 miles dinosaurs

32 miles first plant life on land

43 miles first simple sea life

70 miles first single living cells

Billion in U.S. usage is 1 followed by 9 zeros, in British usage 1 followed by 12 zeros (the U.S. system was modeled on the French, but the French later changed to agree with the British and German systems).

From U. of Kansas Dept of Geology lecture on Web:

Earth is 4.55 billion years old:

How long to count 4.5 billion at rate of one per second? 145 years.

How tall is a stack of 4.5 billion one-dollar bills? 359 miles.

If a roll of toilet paper with 280 sheets represents the age of Earth, the entire history of multicellular life on earth (from the time of the trilobites) is 4 meters long, compared to the 31 meter length of the whole roll. 20 years is less than one percent of the thickness of a hair.

Philosophical and Other Resources

Created Feb. 14, 2000, by Alan Anderson, aanderso@curry.edu or caa@gis.net

URL of this site: http://websyte.com/alan/bigold.htm

Visits since Feb. 14, 2000
FastCounter by bCentral