Top 10 planets facts

Jupiter moons. Jupiter's moons, especially Io (spot on the left), are powerful sources of auroras on Jupiter. These arise from electric currents along field lines, generated by a dynamo mechanism due to the relative motion between the rotating planet and the moving moon.

Iapetus. The ridge is 13 km high, 20 km wide and 1300 km long. Its origin is not known, but considering the amount of craters, it's safe to assume that it is a very old geological feature.

Venus is much brighter than other planets. It is due to its proximity to the Sun (source of light), and bright clouds of sulfuric acid in its atmosphere.

Uranus is the seventh planet from the Sun. It has the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224 °C; −371 °F).

Uranus and Neptune. The diameters of Uranus and Neptune are respectively 25 362 km and 24 622 km - the difference is only 2.92%.

Eight. These are Mercury, the Venus, the Earth, Mars, the Jupiter, the Saturn, the Uranus and the Neptune. The Pluto is excluded from the list since 2006, and it is classified as one of dwarf planets (not even the largest of them).

Cosmic rays. The only efficient protection against high energetic cosmic radiation, one we are granted with, is Earth's magnetic field. Both during a long flight to Mars and through the stay on the planet, that did not form electromagnetic field, astronauts would be exposed to ionization.

Uranus. Sometimes the Earth is close to the extension of its axis of rotation. Then it is possible to observe Uranus' moons revolve around the planet.

Uranus. Upper parts of Uranus' atmosphere are composed of condensed hydrocarbons, mainly methane crystal particles. Contrary to the rest of gas giant planets, it's hard to observe clouds and storm bounds.

A terminator or twilight zone is a moving line that divides the daylit side and the dark night side of a planetary body. A terminator is defined as the locus of points on a planet or moon where the line through its parent star is tangent. An observer on the terminator of such an orbiting body with an atmosphere would experience twilight due to light scattering by particles in the gaseous layer.