SPACE

Day

The amount of time it takes the Earth to spin once on its axis (24 hours).

Month

Based on the length of time it takes the moon to orbit the Earth once (about 29.5 days).

Leap Year

An extra day added every four years to make up for the lost quarter-days in a year (365.25 days).

Jewish Leap Year

Adds an extra month 7 times in 19 years to synchronize the lunar and solar calendars.

Gravity

One of the four fundamental forces, it is a force of attraction between large bodies.

Evidence of Earth's Roundness

1. Ships disappear bottom-first over the horizon. 2. Changing star patterns when traveling from the northern to southern hemisphere. 3. Earth’s curved shadow on the moon.

Light Year

The distance that light travels in one year, approximately 9.5 trillion kilometers.

Astronomical Unit (AU)

The average distance between the Earth and the sun, equal to 150,000,000 kilometers.

Constellation

A pattern of stars in the night sky; there are 88 total constellations.

North Star

Officially named Polaris, it is directly aligned with the north pole, appearing motionless in the night sky.

Earth’s Seasons

Caused by Earth’s 23.5° tilt; affects heat and sunlight received in the Northern and Southern Hemispheres.

Tides

Caused by the moon’s gravity on Earth’s bodies of water, also influenced by the sun’s gravity.

Lunar Eclipse

Occurs when Earth gets between the sun and moon, blocking sunlight from the moon.

Solar Eclipse

Occurs when the moon gets between the Earth and sun, blocking sunlight from reaching the Earth.

Inner Planets

Mercury, Venus, Earth, and Mars, known as terrestrial planets.

Outer Planets

Jupiter, Saturn, Uranus, and Neptune, known as gaseous planets.

Dwarf Planet

A smaller planet that has not 'cleared its orbit'; Pluto is an example.

Kuiper Belt

Region of the Solar System beyond Neptune containing dwarf planets, comets, and dust.

Oort Cloud

Outer limit of the Solar System believed to be composed mostly of icy comets.

Comets

Chunks of dust, ice, and rock from the outer Solar System, with a tail and eccentric orbit around the sun.

Asteroids

Rocky pieces of space debris orbiting the sun that do not have tails, many found in the Asteroid Belt.

Meteoroid

A relatively small space rock that broke off from a celestial object.

Meteor

A meteoroid that burns up in Earth’s atmosphere.

Meteorite

A meteoroid large enough to survive its trip through the atmosphere and land on Earth.

Sun Composition

Primarily composed of hydrogen gas, functioning through nuclear fusion of hydrogen into helium.

Aurora Borealis

The Northern Lights happen when charged particles from the Sun hit Earth’s atmosphere and create colorful lights in the sky. Northern Lights.

Star Life Cycle Outcomes

Supernova, white dwarf, or black hole at the end of a star's life.

First Satellite

Sputnik, which was launched in 1957.

First Person in Space

Yuri Gagarin.

First Person on the Moon

Neil Armstrong.

Canada's Contribution to ISS

The Canadarm, a crane-like mechanical arm.

Terraforming

The process of making a planet habitable over decades or centuries.

Observable Universe Width

Approximately 93 billion light years.

Visible Matter in the Universe

Only 4% of the universe; the rest is dark matter and dark energy.