1) Name the following: a) The smallest and largest planets of the
... 3) Why does the planet Mars look red? Name its two satellites. 4) What is the difference between a meteor and meteorite? 5) What is a Light year? Express the value of one Light year in kilometres. 6) Stars twinkle while planets do not. Give reason. 7) Why is mercury known as the morning star or eve ...
... 3) Why does the planet Mars look red? Name its two satellites. 4) What is the difference between a meteor and meteorite? 5) What is a Light year? Express the value of one Light year in kilometres. 6) Stars twinkle while planets do not. Give reason. 7) Why is mercury known as the morning star or eve ...
Planetary system
A planetary system is a set of gravitationally bound non-stellar objects in orbit around a star or star system. Generally speaking, systems with one or more planets constitute a planetary system, although such systems may also consist of bodies such as dwarf planets, asteroids, natural satellites, meteoroids, comets, planetesimals and circumstellar disks. The Sun together with its planetary system, which includes Earth, is known as the Solar System. The term exoplanetary system is sometimes used in reference to other planetary systems.A total of 1968 exoplanets (in 1248 planetary systems, including 490 multiple planetary systems) have been identified as of 1 October 2015.Of particular interest to astrobiology is the habitable zone of planetary systems where planets could have surface liquid water.