A large planetary embryo that originated within a protoplanetary disc in early stages of the construction of Solar System and has undergone internal melting to produce a differentiated interior

The act of sending a space probe past a planet or a dwarf planet close enough to record scientific data

The mean plane of Earth’s orbit around the Sun

The astronomical model in which the Earth and planets revolve around the Sun

The average distance between the Earth and the Sun. 1 Astronomical Unit = 149597870700 metres (Approx. 150 million km)

Consists of Dwarf planets, Asteroids, Trojans, Centaurs, Kuiper belt objects, and other trans-Neptunian objects

The accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter

A protostar is a very young star that is still gathering mass from its parent molecular cloud

Also known as Local Arm, Orion Bridge and Orion Spur

A light-year is the distance that light travels in the vacuum in one Julian year (365.25 days). It’s equal to 9.46 trillion kilometres.