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Planetary Fact Sheet – Metric
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|
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|
Mass
(1024kg) |
0.330 |
4.87 |
5.97 |
0.073 |
0.642 |
1899 |
568 |
86.8 |
102 |
0.0125 |
|
Diameter
(km) |
4879 |
12,104 |
12,756 |
3475 |
6794 |
142,984 |
120,536 |
51,118 |
49,528 |
2390 |
|
Density
(kg/m3) |
5427 |
5243 |
5515 |
3340 |
3933 |
1326 |
687 |
1270 |
1638 |
1750 |
|
Gravity
(m/s2) |
3.7 |
8.9 |
9.8 |
1.6 |
3.7 |
23.1 |
9.0 |
8.7 |
11.0 |
0.6 |
|
Escape
Velocity (km/s) |
4.3 |
10.4 |
11.2 |
2.4 |
5.0 |
59.5 |
35.5 |
21.3 |
23.5 |
1.1 |
|
Rotation
Period (hours) |
1407.6 |
-5832.5 |
23.9 |
655.7 |
24.6 |
9.9 |
10.7 |
-17.2 |
16.1 |
-153.3 |
|
Length
of Day (hours) |
4222.6 |
2802.0 |
24.0 |
708.7 |
24.7 |
9.9 |
10.7 |
17.2 |
16.1 |
153.3 |
|
Distance
from Sun (106 km) |
57.9 |
108.2 |
149.6 |
0.384* |
227.9 |
778.6 |
1433.5 |
2872.5 |
4495.1 |
5870.0 |
|
Perihelion
(106 km) |
46.0 |
107.5 |
147.1 |
0.363* |
206.6 |
740.5 |
1352.6 |
2741.3 |
4444.5 |
4435.0 |
|
Aphelion
(106 km) |
69.8 |
108.9 |
152.1 |
0.406* |
249.2 |
816.6 |
1514.5 |
3003.6 |
4545.7 |
7304.3 |
|
Orbital
Period (days) |
88.0 |
224.7 |
365.2 |
27.3 |
687.0 |
4331 |
10,747 |
30,589 |
59,800 |
90,588 |
|
Orbital
Velocity (km/s) |
47.9 |
35.0 |
29.8 |
1.0 |
24.1 |
13.1 |
9.7 |
6.8 |
5.4 |
4.7 |
|
Orbital
Inclination (degrees) |
7.0 |
3.4 |
0.0 |
5.1 |
1.9 |
1.3 |
2.5 |
0.8 |
1.8 |
17.2 |
|
0.205 |
0.007 |
0.017 |
0.055 |
0.094 |
0.049 |
0.057 |
0.046 |
0.011 |
0.244 |
|
|
Axial
Tilt (degrees) |
0.01 |
177.4 |
23.5 |
6.7 |
25.2 |
3.1 |
26.7 |
97.8 |
28.3 |
122.5 |
|
Mean
Temperature (C) |
167 |
464 |
15 |
-20 |
-65 |
-110 |
-140 |
-195 |
-200 |
-225 |
|
Surface
Pressure (bars) |
0 |
92 |
1 |
0 |
0.01 |
Unknown* |
Unknown* |
Unknown* |
Unknown* |
0 |
|
0 |
0 |
1 |
0 |
2 |
63 |
33 |
26 |
13 |
1 |
|
|
No |
No |
No |
No |
No |
Yes |
Yes |
Yes |
Yes |
No |
|
|
Yes |
No |
Yes |
No |
No |
Yes |
Yes |
Yes |
Yes |
Unknown |
|
|
|
* - See the Fact
Sheet Notes.
Planetary Fact Sheet - Ratio to Earth Values
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|
0.0553 |
0.815 |
1 |
0.0123 |
0.107 |
317.8 |
95.2 |
14.5 |
17.1 |
0.0021 |
|
|
0.383 |
0.949 |
1 |
0.2724 |
0.533 |
11.21 |
9.45 |
4.01 |
3.88 |
0.187 |
|
|
0.984 |
0.951 |
1 |
0.605 |
0.713 |
0.240 |
0.125 |
0.230 |
0.297 |
0.317 |
|
|
0.378 |
0.907 |
1 |
0.166 |
0.377 |
2.36 |
0.916 |
0.889 |
1.12 |
0.059 |
|
|
0.384 |
0.926 |
1 |
0.213 |
0.450 |
5.32 |
3.17 |
1.90 |
2.10 |
0.098 |
|
|
58.8 |
-244 |
1 |
27.4 |
1.03 |
0.415 |
0.445 |
-0.720 |
0.673 |
6.41 |
|
|
175.9 |
116.8 |
1 |
29.5 |
1.03 |
0.414 |
0.444 |
0.718 |
0.671 |
6.39 |
|
|
0.387 |
0.723 |
1 |
0.00257* |
1.52 |
5.20 |
9.58 |
19.20 |
30.05 |
39.24 |
|
|
0.313 |
0.731 |
1 |
0.00247* |
1.41 |
5.03 |
9.20 |
18.64 |
30.22 |
30.15 |
|
|
0.459 |
0.716 |
1 |
0.00267* |
1.64 |
5.37 |
9.96 |
19.75 |
29.89 |
48.02 |
|
|
0.241 |
0.615 |
1 |
0.0748 |
1.88 |
11.9 |
29.4 |
83.7 |
163.7 |
248.0 |
|
|
1.61 |
1.18 |
1 |
0.0344 |
0.810 |
0.439 |
0.325 |
0.229 |
0.182 |
0.158 |
|
|
12.3 |
0.401 |
1 |
3.29 |
5.60 |
2.93 |
3.38 |
2.74 |
0.677 |
14.6 |
|
|
0.0004 |
0.113* |
1 |
0.285 |
1.07 |
0.133 |
1.14 |
4.17* |
1.21 |
2.45* |
|
|
0 |
92 |
1 |
0 |
0.01 |
Unknown* |
Unknown* |
Unknown* |
Unknown* |
0 |
|
|
0 |
0 |
1 |
0 |
2 |
63 |
33 |
26 |
13 |
1 |
|
|
No |
No |
No |
No |
No |
Yes |
Yes |
Yes |
Yes |
No |
|
|
Yes |
No |
Yes |
No |
No |
Yes |
Yes |
Yes |
Yes |
Unknown |
|
|
|
* - See the Fact
Sheet Notes.
Planetary Fact Sheet Notes
Mass (1024kg
or 1021tons) - This is the mass of the planet in septillion (1
followed by 24 zeros) kilograms or sextillion (1 followed by 21 zeros) tons.
Strictly speaking tons are measures of weight, not mass, but are used here to
represent the mass of one ton of material under Earth gravity.
Diameter
(km or miles) - The diameter of the planet at the equator, the distance through
the center of the planet from one point on the equator to the opposite side, in
kilometers or miles.
Density
(kg/m3 or lbs/ft3) - The average density (mass divided by
volume) of the whole planet (not including the atmosphere for the terrestrial
planets) in kilograms per cubic meter or pounds per cubic foot.
Gravity
(m/s2 or ft/s2) - The gravitational acceleration on the
surface at the equator in meters per second squared or feet per second squared,
including the effects of rotation. For the gas giant planets the gravity is
given at the 1 bar pressure level in the atmosphere. The gravity on Earth is
designated as 1 "G", so the Earth ratio fact sheets
gives the gravity of the other planets in G's.
Escape Velocity
(km/s) - Initial velocity, in kilometers per second or miles per second, needed
at the surface (at the 1 bar pressure level for the gas giants) to escape the
body's gravitational pull, ignoring atmospheric drag.
Rotation Period
(hours) - This is the time it takes for the planet to complete one rotation
relative to the fixed background stars (not relative to the Sun) in hours.
Negative numbers indicate retrograde (backwards relative to the Earth)
rotation.
Length of Day
(hours) - The average time in hours for the Sun to move from the
Distance from
Sun (106 km or 106 miles) - This is the average
distance from the planet to the Sun in millions of kilometers or millions of
miles, also known as the semi-major axis. All planets have orbits which are
elliptical, not perfectly circular, so there is a point in the orbit at which
the planet is closest to the Sun, the perihelion, and a point furthest from the
Sun, the aphelion. The average distance from the Sun is midway between these
two values. The average distance from the Earth to the Sun is defined as 1
Astronomical Unit (AU), so the ratio table gives this distance in AU.
* For the Moon, the average distance from the Earth is given.
Perihelion,
Aphelion (106 km or 106 miles) - The closest and
furthest points in a planet's orbit about the Sun, see "Distance from
Sun" above.
* For the Moon, the closest and furthest points to Earth are given, known as
the "Perigee" and "Apogee" respectively.
Orbital Period
(days) - This is the time in Earth days for a planet to orbit the Sun from one
vernal equinox to the next. Also known as the tropical orbit period, this is
equal to a year on Earth.
* For the Moon, the sidereal orbit period, the time to orbit once relative to
the fixed background stars, is given. The time from full Moon to full Moon, or synodic period, is 29.53 days.
Orbital
Velocity (km/s or miles/s) - The average velocity or speed of the planet as
it orbits the Sun, in kilometers per second or miles per second.
Orbital
Inclination (degrees) - The angle in degrees at which a planets orbit
around the Sun is tilted relative to the ecliptic plane. The ecliptic plane is
defined as the plane containing the Earth's orbit, so the Earth's inclination
is 0.
Orbital
Eccentricity - This is a measure of how far a planet's orbit about the Sun
(or the Moon's orbit about the Earth) is from being circular. The larger the
eccentricity, the more elongated is the orbit, an eccentricity of 0 means the
orbit is a perfect circle. There are no units for eccentricity.
Axial Tilt
(degrees) - The angle in degrees the axis of a planet (the imaginary line
running through the center of the planet from the north to south poles) is
tilted relative to a line perpendicular to the planet's orbit around the Sun.
*Venus rotates in a retrograde direction, opposite the other planets, so the
tilt is almost 180 degrees, it is considered to be spinning with its
"top", or north pole pointing "downward" (southward).
Uranus rotates almost on its side relative to the orbit, Pluto is pointing
slightly "down". The ratios with Earth refer to the axis without
reference to north or south.
Mean
Temperature (C or F) - This is the average temperature over the whole
planet's surface (or for the gas giants at the one bar level) in degrees C
(Celsius or Centigrade) or degrees F (Fahrenheit). For Mercury and the Moon,
for example, this is an average over the sunlit (very hot) and dark (very cold)
hemispheres and so is not representative of any given region on the planet, and
most of the surface is quite different from this average value. As with the
Earth, there will tend to be variations in temperature from the equator to the
poles, from the day to night sides, and seasonal changes on most of the
planets.
Surface
Pressure (bars or atmospheres) - This is the atmospheric pressure (the
weight of the atmosphere per unit area) at the surface of the planet in bars or
atmospheres.
*The surfaces of Jupiter, Saturn, Uranus, and Neptune are deep in the
atmosphere and the location and pressures are not known.
Number of Moons
- This gives the number of IAU officially confirmed moons orbiting the planet.
New moons are still being discovered.
Ring System?
- This tells whether a planet has a set of rings around it, Saturn being the
most obvious example.
Global
Magnetic Field? - This tells whether the planet has a measurable
large-scale magnetic field. Mars and the Moon have localized regional magnetic
fields but no global field.
The term "terrestrial
planets" refers to Mercury, Venus, Earth, Moon, Mars, and Pluto.
![[NASA Logo]](Planetary_Fact_Sheet_2pages_files/image003.gif)
The term "gas
giants" refers to Jupiter, Saturn, Uranus, and Neptune.
Author/Curator: Dr. David R. Williams, dwilliam@nssdc.gsfc.nasa.gov
NSSDC, Mail Code 633,
+1-301-286-1258
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