Diameter
of hydrogen atom |
1.06 x 10-8 cm |
Diameter
of the Moon |
3.5 x 103 km |
Diameter
of the Earth |
1.3 x 104 km |
Diameter
of the Sun |
1.4 x 106 km |
Diameter
of the Milky Way galaxy |
1.7 x 105 ly |
Distance
to the Moon |
3.8 x 105 km |
Distance
to the Sun |
1.5 x 108 km |
Distance
to the next nearest star |
4
ly |
Distance
to the center of the Milky Way |
2.7 x 104 ly |
Distance
to the nearest galaxy |
1.7 x 105 ly |
Mass
of hydrogen atom |
1.67 x 10-24 gm |
Mass
of the Moon |
7.4 x 1025 gm |
Mass
of the Earth |
6.0 x 1027 gm |
Mass
of the Sun |
2.0 x 1033 gm
(1 MΟ) |
Mass
of the Milky Way galaxy |
5 x 1010 MΟ |
Luminosity
of the Sun |
3.8 x 1033 erg/s
(1 LΟ) |
Luminosity
of the largest stars |
105 LΟ |
Luminosity
of the Milky Way galaxy |
1010 LΟ |
Luminosity
of quasar 3C 273 |
1012 LΟ |
Earth’s
rotation period |
8.64 x 104 s
(1 day) |
Moon’s
revolution period |
28
days |
Earth’s
revolution period |
365.25
days (1 year) |
Sun’s
revolution period within Milky Way |
2.4 x 108 years |
Age
of the solar system |
4.6 x 109 years |
Expected
life span of the Sun |
1.5 x 1010 years |
Age
of the Universe |
1.3 x 1010 years |
Earth’s
equator rotation speed |
0.47
km/s |
Earth’s
revolution speed |
30
km/s |
Sun’s
speed within the Milky Way |
220
km/s |
Milky
Way’s speed within the local Universe |
500
km/s |
Typical
lengths: |
|
Normal
star diameter |
106 km |
Distance
between stars |
a
few ly |
Normal
galaxy diameter |
105 ly |
Distance
between galaxies |
106 ly |
Typical
masses: |
|
Smallest
star |
0.1
MΟ |
Normal
star |
1
MΟ |
Giant
star |
10
MΟ |
Normal
galaxy |
1010 -
1011 MΟ |
Galaxy
cluster |
1014 -
1015 MΟ |
Typical
luminosities: |
|
Normal
star |
1
LΟ |
Giant
star |
103 -
105 LΟ |
Normal
galaxy |
109 -
1010 LΟ |
Quasar |
1012 -
1013 LΟ |
Typical
time spans: |
|
Planetary
revolution |
1
year |
Galaxy
rotation |
107 -
109 years |
Life
of giant stars |
106 -
109 years |
Life
of normal star |
1010 years |
Typical
speeds: |
|
Planetary
orbits |
10
km/s |
Stellar
motion in galaxy |
100
km/s |
Between
nearby galaxies |
100
km/s |
Other
important constants: |
|
1
ly = 9.46 x 1012 km
= 9.46 x 1017 cm |
1
Mly = 106 ly |
1
km = 105 cm |
1
erg = 1 gm cm2/s2 |
1
hour = 3600 seconds |
1
year = 3.16 x 107 seconds |
π =
3.14159265359 |
Hubble’s
constant: H0 = 20 km/(sec Mly) |
Speed of light: c = 2.99792458 x 105 km/s
= 2.99792458 x 1010 cm/s
=1 ly/year |
Newton’s
gravitational constant: G = 6.67 x 10-8 cm3/(gm s2) |
Last updated on Saturday, July 2, 2005 22:22
