Question

Define with example: Planet, Satellite, Shooting star, Planetoid.

Answer 1

Planet: By the declaration of the International Astronomical Union, General Assembly 2006, a planet is the one :
1. Orbits around the Sun,
2. Has sufficient gravity to overcome rigid forces and create a hydrostatic equilibrium i.e. it forms a nearly round shape.
3. Has cleared the neighbourhood space around its orbit.
This is mainly in the context of our solar system. For extrasolar planets, definitions are highly debatable.
Satellite: A satellite can be of two types, though both have the overlapping parameter of revolving around a planet in a specific orbit. The two types are:
1. Artificial Satellite: An artificial satellite is an artificial object intentionally placed in a specific orbit to revolve around the planet.
2. Natural Satellite: A natural satellite is a celestial body that revolves around a planet or a celestial body of greater mass, in a specific orbit in which it is naturally placed after a cosmological event.

Shooting Star: A shooting star is a meteoroid passing through the earth's atmosphere and leaving a strong white tail behind, as it burns due to friction while passing through the atmosphere. A hypervelocity star, capable of moving at high velocities in the universe is also referred to as a shooting star.

Planetoid: A planetoid is an asteroid revolving around the Sun, and mostly found in the asteroid belt between Mars and Jupiter in our solar system. Although the term asteroid is ambiguously defined the widely accepted definition is that an asteroid is a celestial object with a diameter ranging from few hundred to few thousands of kilometres.