The solar system Cardiff Astronomical Society

Sun Statistics Mass (kg) 332,830 Equatorial radius (km) 695,000 Equatorial radius (Earth = 1) Mean density (gm/cm^3) 1.41 Rotational period (days) 25-36* Escape velocity (km/sec) Luminosity (ergs/sec) 3.83E+33 Magnitude (Vo) Mean surface temperature 6,000°C Age (billion years) 4.5 Principal chemistry Hydrogen 92.10% Helium 7.80% Oxygen 0.06% Carbon 0.03% Nitrogen 0.01% Neon 0.01% Iron 0.00% Silicon 0.00% Magnesium 0.00% Sulphur 0.00% All others 0.00%

Mercury Statistics Mass (kg)3.30E+23 Mass (Earth = 1)5.53E-02 Equatorial radius (km)2, Equatorial radius (Earth = 1)3.83E-01 Mean density (gm/cm^3)5.42 Mean distance from the Sun (km)57,910,000 Mean distance from the Sun (Earth = 1) Rotational period (days) Orbital period (days) Mean orbital velocity (km/sec)47.88 Orbital eccentricity Tilt of axis (degrees)0 Orbital inclination (degrees)7.004 Equatorial surface gravity (m/sec^2)2.78 Equatorial escape velocity (km/sec)4.25 Visual geometric albedo0.1 Magnitude (Vo)-1.9 Mean surface temperature 179°C Maximum surface temperature427°C Minimum surface temperature-173°C Atmospheric composition Helium42% Sodium42% Oxygen15% Other1%

Venus Statistics Mass (kg)4.87E+24 Mass (Earth = 1) Equatorial radius (km)6, Equatorial radius (Earth = 1) Mean density (gm/cm^3)5.25 Mean distance from the Sun (km)108,200,000 Mean distance from the Sun (Earth = 1) Rotational period (days) Orbital period (days) Mean orbital velocity (km/sec)35.02 Orbital eccentricity Tilt of axis (degrees) Orbital inclination (degrees)3.394 Equatorial surface gravity (m/sec^2)8.87 Equatorial escape velocity (km/sec)10.36 Visual geometric albedo0.65 Magnitude (Vo)-4.4 Mean surface temperature482°C Atmospheric pressure (bars)92 Atmospheric composition Carbon dioxide 96% Nitrogen Trace amounts of: Sulphur dioxide, water vapour, carbon monoxide, argon, helium, neon, hydrogen chloride, and hydrogen fluoride.

Earth Statistics Mass (kg) 5.98E+24 Mass (Earth = 1) 1.00E+00 Equatorial radius (km) 6, Equatorial radius (Earth = 1) 1.00E+00 Mean density (gm/cm^3) Mean distance from the Sun (km) 149,600,000 Mean distance from the Sun (Earth = 1) 1 Rotational period (days) Rotational period (hours) Orbital period (days) Mean orbital velocity (km/sec) Orbital eccentricity Tilt of axis (degrees) Orbital inclination (degrees) 0 Equatorial escape velocity (km/sec) Equatorial surface gravity (m/sec^2) 9.78 Visual geometric albedo 0.37 Mean surface temperature 15°C Atmospheric pressure (bars) Atmospheric composition Nitrogen 77% Oxygen 21% Other 2%

Mars Statistics Mass (kg) 6.42E+23 Mass (Earth = 1) 1.07E-01 Equatorial radius (km) 3, Equatorial radius (Earth = 1) 5.33E-01 Mean density (gm/cm^3) 3.94 Mean distance from the Sun (km) 227,940,000 Mean distance from the Sun (Earth = 1) Rotational period (hours) Rotational period (days) Orbital period (days) Mean orbital velocity (km/sec) Orbital inclination (degrees) 1.85 Equatorial surface gravity (m/sec^2) 3.72 Equatorial escape velocity (km/sec) 5.02 Magnitude (Vo) Minimum surface temperature -140°C Mean surface temperature -63°C Maximum surface temperature 20°C Atmospheric pressure (bars) Atmospheric composition Carbon Dioxide (C02) 95.32% Nitrogen (N2) 2.70% Argon (Ar) 1.60% Oxygen (O2) 0.13% Carbon Monoxide (CO) 0.07% Water (H2O) 0.03% Neon (Ne) 0.00% Krypton (Kr) 0.00% Xenon (Xe) 0.00% Ozone (O3) 0.00%

Jupiter Statistics Mass (kg)1.90E+27 Mass (Earth = 1)3.18E+02 Equatorial radius (km)71,492 Equatorial radius (Earth = 1)1.12E+01 Mean density (gm/cm^3)1.33 Mean distance from the Sun (km)778,330,000 Mean distance from the Sun (Earth = 1) Equatorial escape velocity (km/sec)59.56 Magnitude (Vo)-2.7 Mean cloud temperature-121°C Atmospheric pressure (bars)0.7 Atmospheric composition Hydrogen90% Helium10% Mean orbital velocity (km/sec)13.07 Rotational period (days) Orbital period (days) Orbital inclination (degrees) Equatorial surface gravity (m/sec^2)22.88

Saturn Statistics Mass (kg) 5.69E+26 Mass (Earth = 1) 9.52E+01 Equatorial radius (km) 60,268 Equatorial radius (Earth = 1) 9.45E+00 Mean density (gm/cm^3) 0.69 Mean distance from the Sun (km) 1,429,400,000 Mean distance from the Sun (Earth = 1) Orbital eccentricity Tilt of axis (degrees) Orbital inclination (degrees) Equatorial surface gravity (m/sec^2) 9.05 Equatorial escape velocity (km/sec) Visual geometric albedo 0.47 Magnitude (Vo) 0.67 Atmospheric composition Hydrogen 97% Helium 3% Mean cloud temperature -125°C Atmospheric pressure (bars) 1.4 Rotational period (hours) Orbital period (years) Mean orbital velocity (km/sec) 9.67

Uranus Statistics Discovered by William Herschel Date of discovery1781 Mass (kg)8.69E+25 Mass (Earth = 1)1.45E+01 Equatorial radius (km)25,559 Equatorial radius (Earth = 1) Mean density (gm/cm^3)1.29 Mean distance from the Sun (km) 2,870,990,000 Mean distance from the Sun (Earth = 1) Rotational period (hours)-17.9 Orbital period (years)84.01 Mean orbital velocity (km/sec)6.81 Orbital eccentricity Tilt of axis (degrees)97.86 Orbital inclination (degrees)0.774 Equatorial surface gravity (m/sec^2)7.77 Equatorial escape velocity (km/sec)21.3 Visual geometric albedo0.51 Magnitude (Vo)5.52 Mean cloud temperature-193°C Atmospheric pressure (bars)1.2 Atmospheric composition Hydrogen83% Helium15% Methane2%

Neptune Statistics Discovered by Johann Gotfried Galle Date of discovery September 23, 1846 Mass (kg) 1.02E+26 Mass (Earth = 1) 1.71E+01 Equatorial radius (km) 24,746 Equatorial radius (Earth = 1) 3.88E+00 Mean density (gm/cm^3) 1.64 Mean distance from the Sun (km) 4,504,300,000 Mean distance from the Sun (Earth = 1) Rotational period (hours) Orbital period (years) Mean orbital velocity (km/sec) 5.45 Orbital eccentricity Tilt of axis (degrees) Orbital inclination (degrees) Equatorial surface gravity (m/sec^2) 11 Equatorial escape velocity (km/sec) 23.5 Visual geometric albedo 0.41 Magnitude (Vo) 7.84 Mean cloud temperature -193 to -153°C Atmospheric pressure (bars) 1-3 Atmospheric composition Hydrogen 85% Helium 13% Methane 2%

Pluto Statistics Discovered byClyde W. Tombaugh Date of discoveryFebruary 18, 1930 Mass (kg) 1.27e+22 Mass (Earth = 1) 2.125e-03 Equatorial radius (km) 1,137 Equatorial radius (Earth = 1) Mean density (gm/cm^3) 2.05 Equatorial surface gravity (m/sec^2) 0.4 Equatorial escape velocity (km/sec) 1.22 Visual geometric albedo 0.3 Magnitude (Vo) Mean distance from the Sun (km) 5,913,520,000 Mean distance from the Sun (Earth = 1)) Rotational period (days) Orbital period (years) Mean orbital velocity (km/sec) 4.74 Orbital eccentricity Tilt of axis (degrees) Orbital inclination (degrees) Atmospheric composition 0.3 Methane Nitrogen

Asteroids are material left over from the formation of the solar system. One theory suggests that they are the remains of a planet that was destroyed in a massive collision long ago. More likely, asteroids are material that never coalesced into a planet. In fact, if the estimated total mass of all asteroids was gathered into a single object, the object would be less than 1,500 kilometers (932 miles) across -- less than half the diameter of our Moon.

The Comets Comet Hale-BoppComet Neat 17P/Holmes

That’s all folks And thank you for the invite You are all welcome to join us at one or more of our lectures at the Cardiff university or attend one of the public observing sessions. Please make yourself known on arrival for a warm welcome