Mercury retrograde is, more or less, an optical illusion. Yet it holds great weight in astrology. Here's how it might affect your sign.

Its radius, the distance from the core's centre to the surface, is 2,440 kilometres. Mercury is about 2.6 times smaller than Earth. How hot is Mercury? Mercury's sun-facing side is scorched by ...

having short orbital periods of between two and seven Earth days (for comparison, our sun's closest planet, Mercury, orbits in 88 days). It is likely they all have masses less than Earth's.

Narrator: As the solar system grew, four rocky planets: Mercury, Venus, Earth and Mars ... They are much smaller than the gas planets and rotate more slowly.

This is the only known star with a multi-planet system entirely comprised of planets smaller than Earth. The innermost planet has ... To put their mass in perspective, Mars has about 11% the mass of ...

The Sun and its planets – Mercury, Venus, Earth, Mars, Jupiter ... be strong enough to ‘clear the neighbourhood’, pulling smaller nearby objects into its orbit.