Terms

Astronomy

Scientific study of what is beyond the earth.

Celestial object

Any object that exists in space.

Universe

Everything that exists, including all energy, matter and space.

Star

Massive collection of gasses held by its own gravity that emits huge amounts of energy.

Luminous

Producing or giving off light; shining.

Sun

Our star, an average star.

Scientific notation

Putting numbers into manageable form, with the first number between 1 and 9 and the exponent indicating the number of decimal places.

Planet

A large round celestial object that travels around a star.

Solar system

The sun and everything that travels around it.

Satellite

A celestial object that travels around a planet or dwarf planet.

Orbit

The closed path of a celestial object or satellite as it travels around another celestial object.

Moon

A natural satellite

Galaxy

A huge, rotating collection of gas, dust, and billions of stars, planets, and other celestial objects.

Milky Way

The galaxy that the Earth is in.

Corona

The outer part of the sun’s atmosphere.

Sunspots

Dark spots on the earth’s surface that are cooler than the surrounding area.

Galileo Galilei

Astronomer who lived approximately 400 years ago; the first to observe and study sunspots in detail.

Aurora Borealis

Display of shifting colours in the northern sky caused by solar particles colliding with matter in the Earth’s upper atmosphere.

Aurora Australis

Simultaneous display of Aurora Borealis in the southern pole.

Astronomical unit

Approximately 150 million km; average distance from the sun to Earth.

Dwarf planet

A celestial object that orbits the sun, has a spherical shape but does not dominate its orbit.

Asteroid

Space rocks with metal found in a band called the 'asteroid belt' between Mars and Jupiter.

Meteoroid

Pieces of rocky debris smaller than asteroids.

Meteor shower

When a number of meteors radiate from one point in the sky visibly on a certain date.

Comet

Chunk of ice, dust, and rock that breaks down when it approaches the sun, causing the ice to melt.

Coma

A gaseous cloud formed when a comet sublimates from the sun’s heat.

Light pollution

Pollution from manmade lights, often found near cities.

Artificial satellites

Help forecast the weather, monitor agriculture, assist military activities, and explore the universe.

Manmade

Sputnik 1

The first artificial satellite sent by the Soviet Union.

Alouette 1

Used to observe the Earth’s ionosphere; first satellite by Canada, placing it third in the space race.

RADARSAT

Allows satellites to view all parts of the Earth in polar orbits.

GPS

A group of satellites that work together to determine the positions of given objects on the surface of the Earth.

Kuiper Belt

Space past Neptune that holds space junk.

Eris

A dwarf planet located beyond Neptune.

Oort Cloud

The most distant region of our solar system filled with icy objects and space debris.

Light years

A unit of distance, not time - the distance that light travels in a year.

Solar Mass

A unit of mass used in astronomy to describe the mass of stars.

Andromeda

The furthest galaxy we can see without technology, currently on a collision course with the Milky Way.

Edwin Hubble

The first to see other galaxies but did not make the Hubble telescope.

Dark matter

Isn’t visible but must be there because of how other objects interact and move; makes up the majority of the universe.

Dark energy

Isn’t visible but is responsible for the expansion of the universe; stronger than gravity.

Big Bang Theory

The leading explanation about how the universe began.