Sun and Planet Summary The following table lists statistical information for the Sun and planets:
Distance (AU) Radius (Earth's) Mass (Earth's) Rotation (Earth's)
# Moons Mean Temp.
0 C
Atm. Composition
Obliquity Density (g/cm3)
Sun 0 109 332,800 25-36* 9 +6000 --- --- 1.410
Mercury 0.39 0.38 0.05 58.8 0 -180
+430 None 0.1° 5.43
Venus 0.72 0.95 0.89 244 0 +465 Co2 177.4° 5.25
Earth 1.0 1.00 1.00 1.00 1 -89
+58 N2+O2 23.45° 5.52
Mars 1.5 0.53 0.11 1.029 2 -82
+0 Co2 25.19° 3.95
Jupiter 5.2 11 318 0.411 16 -150 H2+He 3.12° 1.33
Saturn 9.5 9 95 0.428 18 -170 H2+He 26.73° 0.69
Uranus 19.2 4 17 0.748 15 -200 H2+He 97.86° 1.29
Neptune 30.1 4 17 0.802 8 -210 H2+He 29.56° 1.64
Pluto 39.5 0.18 0.002 0.267 1 119.6° 2.03
1 AU = Astronomical Unit = 149 598 000 kilometers = 150 x 106 km Speed of Light = 299 792 458 m / s = 3 x 108m/s.
Our solar system consists of an average star we call the Sun, the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. It includes: the satellites of the planets; numerous comets, asteroids, and meteoroids; and the interplanetary medium. The Sun is the richest source of electromagnetic energy (mostly in the form of heat and light) in the solar system. The Sun's nearest known stellar neighbor is a red dwarf star called Proxima Centauri, at a distance of 4.3 light years away.
The whole solar system, together with the local stars visible on a clear night, orbits the center of our home galaxy, a spiral disk of 200 billion stars we call the Milky Way. The Milky Way has two small galaxies orbiting it nearby, which are visible from the southern hemisphere. They are called the Large Magellanic Cloud and the Small Magellanic Cloud. The nearest large galaxy is the Andromeda
Galaxy. It is a spiral galaxy like the Milky Way but is 4 times as massive and is 2 million light years away. Our galaxy, one of billions of galaxies known, is traveling through intergalactic space.
Sun than is Neptune. The axis of rotation for most of the planets is nearly perpendicular to the ecliptic. The exceptions are Uranus and Pluto, which are tipped on their sides.
Composition Of The Solar System
The Sun contains 99.85% of all the matter in the Solar System. The planets, which condensed out of the same disk of material that formed the Sun, contain only 0.135% of the mass of the solar system. Jupiter contains more than twice the matter of all the other planets combined. Satellites of the
planets, comets, asteroids, meteoroids, and the interplanetary medium constitute the remaining 0.015%. The following table is a list of the mass distribution within our Solar System.
• Sun: 99.85% • Planets: 0.135% • Comets: 0.01% ? • Satellites: 0.00005%
• Minor Planets: 0.0000002% ? • Meteoroids: 0.0000001% ?
• Interplanetary Medium: 0.0000001% ?
The visible solar atmosphere consists of three regions: the photosphere, the chromosphere, and the solar corona. Most of the visible (white) light comes from the photosphere, this is the part of the Sun we actually see. The chromosphere and corona also emit white light, and can be seen when the light from the photosphere is blocked out, as occurs in a solar eclipse. The sun emits electromagnetic radiation at many other wavelengths as well. Different types of radiation (such as radio, ultraviolet, X-rays, and gamma rays) originate from different parts of the sun. Scientists use special instruments to detect this radiation and study different parts of the solar atmosphere.
The solar atmosphere is so hot that the gas is primarily in a plasma state: electrons are no longer bound to atomic nuclei, and the gas is made up of charged particles (mostly protons and electrons). In this charged state, the solar atmosphere is greatly influenced by the strong solar magnetic fields that thread through it. These magnetic fields, and the outer solar atmosphere (the corona) extend out into interplanetary space as part of the solar wind
The Sun is not a quiet place, but one that exhibits sudden releases of energy. One of the most frequently observed events are solar flares: sudden, localized, transient increases in brightness that occur in active regions near sunspots. They are usually most easily seen in H-alpha and X-rays, but may have effects in the entire elecromagnetic spectrum. The X-ray brightness from a large flare often exceeds the X-ray output from the rest of the Sun. Another type of event, the coronal mass ejection, typically disrupt helmet streamers in the solar corona. As much as 1e13 (10,000,000,000,000)
All of these forms of solar activity are believed to be driven by energy release from the solar magnetic field. How this energy release occurs, and the relationship between different types of solar activity, is one of the many puzzles facing solar physicists today. The amount of solar activity on the Sun is not constant, and is closely related to the typical number of sunspots that are visible. The number of sunspots and the levels of solar activity vary with an 11 year
The Earth has a magnetic field with north and south poles. The Earth's magnetic field reaches 36,000 miles into space.
The magnetic field of the Earth is surrounded in a region called the magnetosphere. The
magnetosphere prevents most of the particles from the sun, carried in solar wind, from hitting the Earth.
Some particles from the solar wind can enters the magnetosphere. The particles that enter from the magnetotail travel toward the Earth and create the auroral oval light shows.
The Sun and other planets have magnetospheres, but the Earth has the strongest one of all the rocky planets. The Earth's north and south magnetic poles reverse at irregular intervals of hundreds of thousands of years.
Interplanetary Space
Nearly all the solar system by volume appears to be an empty void. Far from being nothingness, this vacuum of "space" comprises the interplanetary medium. It includes various forms of energy and at least two material components: interplanetary dust and interplanetary gas. Interplanetary dust consists of microscopic solid particles. Interplanetary gas is a tenuous flow of gas and charged
particles, mostly protons and electrons -- plasma -- which stream from the Sun, called the solar wind.
The solar wind can be measured by spacecraft, and it has a large effect on comet tails. It also has a measurable effect on the motion of spacecraft. The speed of the solar wind is about 400 kilometers (250 miles) per second in the vicinity of Earth's orbit. The point at which the solar wind meets the interstellar medium, which is the "solar" wind from other stars, is called the heliopause. It is a
The solar magnetic field extends outward into interplanetary space; it can be measured on Earth and by spacecraft. The solar magnetic field is the dominating magnetic field throughout the interplanetary regions of the solar system, except in the immediate environment of planets which have their own magnetic fields.
The Terrestrial Planets
The Jovian Planets
