science astronomy

Solar system

A system of celestial bodies (planets, moons, etc.) that orbit around a central star

Planet

A celestial body that orbits a star and rotates on its own axis

Star

A hot ball of electrically charged gas

Moon

A natural satellite that orbits a planet

Satellite

An object in space, either man-made or natural

Dwarf planets

Celestial bodies that lack the mass to clear their orbit around the sun

Galaxies

Extremely large areas of space containing billions of stars, planets, and dust held together by gravity

Universe

The entirety of matter and energy that exists

Inner planets

Terrestrial planets made of rocks with compositions similar to Earth

Outer planets

Gas giants composed mainly of gas and are large in size

Asteroids

Small rocky objects orbiting the sun

Comets

Objects with fixed orbits around the sun, mostly made of ice and dust, with visible tails

Meteoroids

Small rocky objects floating in space

Meteor

A meteoroid that has entered Earth's atmosphere

Meteorite

A meteor that has landed and impacted Earth's surface

Equinox

When Earth's axis is not tilted towards or away from the sun, occurring in autumn and spring

Summer Solstice

The day when the Sun's direct rays hit the furthest North on the Globe, marking the longest day of the year (June 21)

Winter Solstice

The day when the Sun's direct rays hit the furthest South, marking the longest night of the year (December 21)

Luminosity

The amount of energy a star produces per second, with the Sun as the reference point

Star cluster

A group of stars that are close together