I found this in sci.physics and thought it would be of *enormous*
interest, especially to those who are contemplating maps...
Richard
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Subject: Relative distances and sizes in the Universe.
Several weeks ago I posted a request for slide sets comparing the
relative distances in the solar system and the other stars: It would
seem that slide sets of this scale system are rather hard to come by.
I sent out a request to several other computer networks, along with
calling a number of planetariums, museum stores, and searched through
various scientific catalogues, all without significant result.
I was able to use my resources and gather some information
from several friends on various types of relative celestial scales,
and have come up with some relevant information.
The first selection depicts the solar system on a major league
baseball field from E. C. Slipher's "Planet" section of THE WORLD BOOK
ENCYCLOPEDIA P, VOLUME 15, Field Enterprises Educational Corporation,
Chicago, Illinois, 1964. If the Sun were the size of a United States
half-dollar (fifty cents) on home plate, the planet Mercury would be
120 centimeters (four feet) away, Venus would be 225 centimeters
(7.5 feet) away, Earth would be 315 centimeters (10.5 feet) distant,
Mars would be 480 centimeters (sixteen feet) away, Jupiter would be
1,650 centimeters (55 feet) from the Sun (at the pitcher's mound),
Saturn would be 3,030 centimeters (101 feet) away (near second base,
and the last planet in the infield), Uranus would be 6,075 centimeters
(202.5 feet) away, Neptune would be 9,540 centimeters (318 feet) away,
and Pluto would be 12,615 centimeters (420.5 feet) distant from the
Sun, deep in the outfield.
To compare planetary diameters, if the Sun were the size of an
average beachball, then Jupiter would be a golf ball, Saturn a Ping-
Pong ball, Uranus and Neptune marbles, Mercury and Pluto pinheads,
and Venus, Earth, and Mars would be about half the size of tackheads.
The next comparison scale comes from the "Life on Other Worlds"
section of Carl Sagan's PLANETS, LIFE Science Library, 1966. This
one depicts the solar system on a map of Europe and Africa, with the
average distance between the Sun and Earth, 150 million kilometers
(93 million miles) - also known as one Astronomical Unit (A.U.) -
now equaling 240 kilometers (150 miles). If the Sun were situated
in Norway, Saturn would orbit just south of Italy, and Pluto would
be 10,400 kilometers (6,500 miles) away along the Cape of Good Hope
in South Africa.
The next source on various celestial scales comes from THE
STARFLIGHT HANDBOOK: A PIONEER'S GUIDE TO INTERSTELLAR TRAVEL, by
Eugene F. Mallove and Gregory L. Matloff (John Wiley & Sons, Inc., New
York, 1989, ISBN 0-471-61912-4, hardcover), which gives the following
description on page 5: If the Sun were the size of a one-centimeter
(0.4-inch) marble, then Earth would be 0.1 millimeters (0.004 inches)
in diameter and one meter (39.37 inches) from the Sun. The planet
Pluto would orbit 42 meters (139 feet) from the Sun, and Proxima
Centauri - the Sun's nearest stellar neighbor - would be 292
kilometers (175 miles) away.
The next two books listed are both authored by Neil McAleer.
The first is THE COSMIC MIND-BOGGLING BOOK (Warner Books, Inc.,
New York, 1982, ISBN 0-446-37932-8, paperback). On the front cover
of the book, the following comparison is made (one of my favorites,
from an aesthetic point of view): If the solar system out to the
orbit of Pluto could fit in a coffee cup, the Milky Way Galaxy
would be the size of the North American continent.
On page xiii - If you had a specially-designed automobile
which could handle the rigors of spaceflight, it would take you
201 billion years to "drive" from the Sun to the center of the
Milky Way Galaxy at 161 kilometers per hour (100 miles per hour).
Also, if the solar system were 2.54 centimeters (one inch) across,
the Milky Way Galaxy would be 161,000 kilometers (100,000 miles) wide.
On pages 3-4 - If the Sun were the size of a sixty-centimeter
(two-foot) beachball, Earth would be the size of a pea and 6,450
centimeters (215 feet) away. The planet Jupiter would be a large
orange 31,680 centimeters (1,056 feet) distant from the Sun.
On pages 12-13 - If the Sun were a 14-centimeter (5-inch) orange,
Earth would be a sesame seed fifteen meters (49 feet) away. Pluto
would be the size of a grain of millet six hundred meters (3,400
feet) away, and the star Alpha Centauri would be four thousand
kilometers (2,500 miles) from the Sun.
On page 83 - If you could fly a specially modified Boeing 747
jetliner through space at 965 kilometers per hour (six hundred miles
per hour), it would take you 1,903 years to fly from the orbit of
the planet Uranus out to the orbit of Neptune.
On page 128 - If the Sun were a basketball in New York City,
then Alpha Centauri would be another basketball eight thousand
kilometers (five thousand miles) away in Honolulu, Hawaii.
On page 129 - If you traveled at the speed which the APOLLO
spacecraft used in an average six-day round-trip journey to Earth's
Moon (approximately 40,000 kilometers per hour/25,000 miles per hour),
it would take you 850,000 years to reach Alpha Centauri. By contrast,
the faster PIONEER 10 and 11 and VOYAGER 1 and 2 Jovian probes will
reach that distance (4.3 light years) in only eighty thousand years.
On page 161 - If you used a starship traveling at one-tenth the
speed of light (300,000 kilometers per second/186,000 miles per second)
to reach the farthest star in the Milky Way Galaxy, the ship would
take 800,000 years to reach it from the Sun. If one Astronomical
Unit (A.U.) - the distance between the Sun and Earth, which is
roughly 150 million kilometers/93 million miles - were reduced to
2.54 centimeters (one inch), then that farthest star would be
127,000 kilometers (79,000 miles) away.
The next selection is from the other Neil McAleer book, THE
MIND-BOGGLING UNIVERSE (Doubleday & Co. Inc., Garden City, New
York, 1987, ISBN 0-385-23039-7, paperback):
On pages 10-11 - If the solar system out to Pluto were 2.54
centimeters (one inch) in diameter, then the center of the Milky
Way Galaxy would be 609 kilometers (379 miles) away. Also, to
walk one A.U. at five kilometers per hour (three miles per hour)
would take 3,500 years. To drive one light year at 88 kilometers
per hour (55 miles per hour) would take 12.2 million years.
On page 15 - The Milky Way Galaxy's longest spiral arm of gas,
dust, and stars is 125,000 light years long. It would take an
automobile driving at 88 kilometers per hour (55 miles per hour)
1.5 trillion years to cover that distance.
On page 35 - An automobile driving at 88 kph (55 mph) would
take 52 million years to reach Proxima Centauri from the Sun.
The next selection comes from THE UNIVERSE...AND BEYOND by
Terence Dickinson (Camden House Publishing, Ltd., Camden East,
Ontario, Canada, 1986, ISBN 0-920656-48-X, paperback):
On pages 16-19 - If the actual distance between the Milky Way
Galaxy and the Andromeda Galaxy (two million light years) were shrunk
to a typical book-reading distance, then the most remote galaxies
known would be 1.6 kilometers (one mile) away.
If the Sun were shrunk to the size of a 2.54-centimeter (one
inch) Ping-Pong ball, Earth would become a dust speck 240 centimeters
(eight feet) away, with the Moon being an even smaller speck just
6.25 millimeters (0.25-inch) from Earth. Jupiter would be a pea
1,200 centimeters (forty feet) from the Sun, and Pluto is a dust
speck nine thousand centimeters (three hundred feet) away. The
Oort Cloud of comets surrounding our solar system would be the
size of atomic particles and reside several kilometers distant,
with the comets themselves averaging several meters apart from
each other. The Alpha Centauri trinary star system would consist
of two walnuts (Alpha and Beta) and a pea (Proxima) 640 kilometers
(four hundred miles) from our solar system.
If Earth's solar orbit were reduced to the size of a United
States dime, the average distance between stars is now a little
over one kilometer (1.6 miles). The Milky Way Galaxy would be
the actual size of Earth. The distance to the Andromeda Galaxy
would be over half the actual distance between Earth and the Moon.
If you could hold the Milky Way Galaxy in your hand, the stars
in it would be sub-atomic in size, and the Andromeda Galaxy would
be 210 centimeters (seven feet) away.
My final textbook selection comes from CYCLES OF FIRE, by
William K. Hartmann and Ron Miller (Workman Publishing, New York,
1987, ISBN 0-89480-502-9, paperback):
On pages 14-15 - If Earth were the diameter of a microparticle
of soot, then the Sun would be one hundred times larger, the size
of a mote of dust, or one hundredth of a millimeter across. The
solar system would be the size of a saucer, and the Oort Cloud of
comets would exist several house lots away. Alpha Centauri would
be another dust mote one to two city blocks from the Sun, and the
Milky Way Galaxy would be the size of North America. Some of the
other nearby galaxies would be the varying sizes and distances of
Earth's continents. The known limits of the Universe would stretch
halfway across the solar system.
My friend and co-worker Drew LePage came up with some various
calculations on the celestial distance scale:
If the orbit of Pluto were the size of a U.S. dime, this would be
the size of various distances in the Universe:
Earth's orbit would have a diameter of about 0.5 millimeter (about
half the thickness of a dime).
One light year would be about 15.2 meters (49.9 feet).
One parsec (3.26 light years) would be about 49.7 meters (163 feet).
The closest star would be 65.4 meters (214 feet) away.
The closest one hundred known stars would be inside a sphere about
640 meters (2,100 feet) across.
The Sun would be 456 kilometers (283 miles) from the center of the
Milky Way Galaxy.
The Milky Way Galaxy would be 1,520 kilometers (945 miles) across.
To put intergalatic distances into perspective, if the Milky Way
Galaxy were the size of a dime:
The orbit of Pluto would be about the size of a hydrogen atom.
The Andromeda Galaxy would be 41.8 centimeters (16.5 inches) away.
One megaparsec would equal 61.9 centimeters (2.03 feet).
The recently discovered "Wall" of Galaxies would be about 40 meters
(125 feet) to 60 meters (190 feet) away, about 3 meters (10 feet) thick,
and extend for at least 100 meters (300 feet).
The most distant quasar known would be about 2.6 kilometers
(1.7 miles) away.
The size of the observable Universe would be about 5.7 kilometers
(3.5 miles) across.
If nothing else, these figures should give some idea as to just
how incredibly vast the known Universe is.
Larry Klaes [email removed]
or - ...!decwrl!wrksys.dec.com!klaes
or - [email removed]
or - [email removed]
or - [email removed]
N = R*fgfpneflfifaL
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Subject: Re: Relative distances and sizes in the Universe.
In article [email removed] [email removed]
(CUP/ASG, MLO5-2/G1 6A, 223-3283 12-Dec-1989 1233) writes:
> If the solar system out to the
> orbit of Pluto could fit in a coffee cup, the Milky Way Galaxy
> would be the size of the North American continent.
>
> Also, if the solar system were 2.54 centimeters (one inch) across,
> the Milky Way Galaxy would be 161,000 kilometers (100,000 miles) wide.
These two don't jibe. One inch is smaller than a coffee cup, but 161,000
km is definitely larger than North America. The proper ratios (using 4.2
light hours and 100,000 light years) is one to about 200 million, and 208
million inches is 3156 miles, so the coffe cup vs North America analogy is
the "correct" one. The ratio of 1 inch to 100,000 miles is about the ratio
of the *Earth's* orbit to the Galaxy.
Other than that, the article was fascinating. I've often tried
to convey to friends the vastness of the solar system alone, and then
the galaxy... and the Universe... Some of the analogies wowed me yet again.
Gosh, this is a BIG place.
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