Scale of
the Universe
Units of measuring astronomical distance:
Astronomical
Unit (A.U.) º The average
distance of the Earth from the sun. (1
A.U. = 92.9 million miles = 149.6 million km.)
Light
Year (ly) º The distance that light travels in one year. (1 ly = 5.9 million million miles = 9.5
million million km)
Scientific notation:
104 = 10,000 10-4
= .0001
103 = 1,000 10-3 = .001
102 = 100 10-2 = .01
101 = 10 10-1 = .1
100 = 1
e.g.’s, 3.54 x 106
= 3,540,000 = 3.54 million
3.54 x 10-6 = .00000354
1 ly = 5.9 x 1012 mi =
5,900,000,000,000 mi
1 AU = 9.29 x 107 mi =
92,900,000 mi
1 mi = 1.08 x 10-8 AU =
.0000000108 AU
Outline of
Universe from Earth
The current model of the universe is based on a succession
of orbital systems progressing to larger and larger dimensions.
Earth-Moon
system – The Moon orbits the Earth every 27.3 days and has an orbital radius of 3.8 x 105 km.
Solar
system – 9 planets, their moons, asteroids and comets orbit the
Sun at different rates. The most
distant planet (Neptune) has an orbital radius of 4.5 x 109 km and completes a revolution every 164.8 years.
Galaxy –
hundreds of billions of stars (solar
systems) orbit the galactic center (black hole(?)). Our sun has an orbital radius of 2.8 x 1017 km (30,000 ly) and an orbital period estimated at
250 million years (2.5 x 108
yrs.)
There are millions of galaxies outside our “Milky Way”
galaxy, although they do not (with some exceptions) orbit one another to form a
larger system of galaxies.
|
System |
Size (km) |
Time
(years) |
|
Earth |
12,750 |
.00274
(1 day) |
|
Earth-Moon |
380,000 |
.0767 (1
month) |
|
Earth-Sun |
149,600,000 |
1 |
|
Solar
System |
4,497,000,000 |
164.8 |
|
Nearest
star |
9,500,000,000,000 |
-- |
|
Galaxy |
280,000,000,000,000,000 |
250,000,000 |
|
Universe |
100,000,000,000,000,000,000 |
15,000,000,000 |
Our Scale model
On
our scale model the length of the room (Moore 107) is the distance from the
Earth to the Sun (1 A.U.)
The
radius of the Sun on this scale is just 5.2 cm.
(The
actual radius of the sun is 6.95 x 108 m)
The
radius of the Moon’s orbit around the Earth is just 2.9 cm. (actual: 3.84 x 108 m)
The
radius of the Earth is just half of one millimeter. (6.4 x 106 m)
|
Object |
Actual distance from Sun (AU) |
Scale distance |
|
Mercury |
.387 |
4.32 m |
|
Venus |
.723 |
8.08 m |
|
Earth |
1 |
11.2 m |
|
Mars |
1.52 |
17 m |
|
Jupiter |
5.20 |
58.1 m (63.5 yds) |
|
Saturn |
9.58 |
107 m (117 yds) |
|
Uranus |
19.2 |
214 m (234 yds) |
|
Neptune |
30.1 |
336 m (.20 mi) |
|
Pluto |
39.2 |
438 m (.27 mi) |
|
Proxima Centauri (the closest star to our Sun) |
265083 |
2978 km (1850 mi) This is the approximate distance from Richmond,KY
to L.A., CA !! |
|
Galaxy |
1.87 x 109 |
2.1 x 1010 m |