Space - Grade 9

Science - Space

Star

A massive, glowing ball of hot gas (mostly hydrogen and helium) that produces light and heat through nuclear fusion. Example: The Sun.

Star Compistion

Mostly hydrogen (~70%) and helium (~28%), plus small amounts of heavier elements like carbon and oxygen.

Gas Giant

A large planet made mostly of gases like hydrogen and helium, with a small rocky core. Examples: Jupiter, Saturn.

Terrestrial Planet?

A rocky planet with a solid surface, like Earth or Mars.

Moon

A natural satellite that orbits a planet. Example: Earth's Moon.

Moon Composition

Rock, ice, or a mix of both—varies by moon.

Asteroid

A small, rocky object that orbits the Sun—mostly found in the asteroid belt.

Asteroid Composition

Rock, metal (like iron and nickel), and sometimes carbon-rich materials.

Meteoroid

A small rock or piece of metal traveling through space. Becomes a meteor when it enters Earth’s atmosphere.

Meteoroid Composition

Rock, iron, and nickel.

Comet

An icy body that releases gas and dust when near the Sun, forming a glowing tail.

Comets composition

Ice (like water and CO₂), dust, and rocky particles.

Black hole

A region in space with such strong gravity that nothing, not even light, can escape. Formed from collapsed stars.

Galaxy

A massive system of stars, gas, dust, and dark matter held together by gravity. Example: The Milky Way.

Galaxy composition

Stars (hydrogen and helium), gas clouds, dust, and dark matter.

Nebula

A huge cloud of gas and dust in space, often a star nursery. Example: The Orion Nebula.

Nebula composition

Mostly hydrogen and helium, with traces of heavier elements.

Parallax

The apparent shift in the position of an object when you view it from two different places.

Measuring parallax distance

• Measure a star’s position 6 months apart.

• Calculate the shift (parallax angle).

• Use the formula

Altitude (in astronomy)

The angle between an object in the sky and the horizon (0° = horizon, 90° = directly overhead).

Azimuth

he direction of a celestial object measured in degrees along the horizon, starting from North (0°) and going clockwise (East = 90°, South = 180°, etc.).

Electromagnetic radiation

Energy that travels in waves through space, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Radio waves use

Used for communication

Microwaves use

Cook food + satellite data

Infra-red waves use

Detects heat

Visible light

What we can see

Ultraviolet light

Caused sunburns, sterilizes stuff

X-ray use

See inside bodies

Gamma ray use

Treat cancer, released in space explosions

Spectroscopy

The study of how light (or any EM radiation) is emitted, absorbed, or scattered by materials—used to find out what stars and planets are made of.

Emission spectrum

Bright lines on a dark background showing which wavelengths of light a substance gives off (emits). Each element has a unique pattern—like a fingerprint.

Absorption spectrum?

A continuous rainbow of light with dark lines where certain wavelengths are absorbed by a gas or material—used to identify what’s in stars.

Doppler Effect

The change in the frequency of a wave as the source moves closer or farther from the observer. (Like how a siren sounds different when it passes you.)

Redshift

When light from an object in space is stretched to longer (redder) wavelengths because it’s moving away from us—evidence the universe is expanding.

Blueshift

When light from an object is squished to shorter (bluer) wavelengths because it’s moving toward us.

Main types of telescopes

• Refracting telescopes

• Reflecting telescopes

• Radio telescopes

Refracting telescope

A telescope that uses lenses to bend (refract) light and form an image.

Reflecting telescope

A telescope that uses mirrors to gather and focus light.

Radio telescope

A telescope that detects radio waves from space instead of visible light.

Pros of refracting telescope

Clear images, simple design

Cons of refracting telescope

Expensive lenses, can distort color

Famous example of a refracting telescope

Galileo's telescope

Pros of a reflecting telescope

Cheaper to build large, no color distortion

Cons of a reflecting telescope

Needs perfect mirror alignment

Famous example of a reflecting telescope

Hubble Space Telescope (it has mirrors!)

Pros of a radio telescope

Can observe through clouds, dust, or even in daytime

Cons of a radio telescope

Lower image resolution, can be affected by moisture

Famous example of a radio telescope

Arecibo Observatory

Artificial Satellite

Human made objects (typically spacecrafts) that are launched into arbit around a celestial body (often earth).

Artificial Satellite use

Communication, remote sensing, weather monitoring, scientific research, and navigation

Space Probes

An unpiloted, unmanned device sent to explore space and gather scientific info

Rockets

A vehicle that uses jet propulsion to accelerate without using the surrounding air.

Rovers

A planetary surface exploration device designed to move over the rough surface of a planet or other planetary mass celestial bodies

Space stations

Are capable of supporting a human crew in outer space for an extended period of time and is therefore a type of habitat

Space shuttles

Are designed to go into orbit around Earth

Use of space shuttles

To transport people and cargo to and from orbiting spacecraft.

Geostationary Orbit

A special orbit where a satellite moves around Earth at the same speed the Earth rotates. Rotates on the equator. Appears to be stationary.

Use of geostationary orbit

TV and Radio broadcasting, weather satellites, communication satellites

Low earth orbit

The area of space that close to Earth’s surface, where satellites move around the planet very fast.

Use of low earth orbit

Earth observation, space stations, and internet. Satellites like ISS.

Polar Orbit

A satellite path that goes over Earth’s poles, allowing it to cover the entire globe as the planet rotates.

Use of polar orbit

Mapping, weather, and Earth observation.

Heliocentric orbit

An orbit around the Sun, not Earth. “Helio” means Sun. Planets, comets, asteroids, and some satellites follow heliocentric paths.

Heliocentric orbit use

Studying planets and the solar system, tracking asteroids and comets. Observing the Sun without Earth’s interference. Spacecraft like Voyager, Parker Solar Probe, and Mars missions use it.

Sun synchronous

A special type of polar orbit where a satellite passes over the same part of Earth at the same local solar time every day. Like a daily routine

Use of sun synchronous

Earth observation, climate & weather monitoring, imaging (e.g. before/after photos of disasters or glacier melt). Used by satellites like Landsat, Sentinel, and Earth-monitoring missions

Lagrange Point

A point in space where the gravitational pull of two big objects (like the Earth and Sun) perfectly balances with a satellite’s orbital motion.

Use of Lagrange point

• Holding satellites in stable spots

• Space telescopes (like James Webb at L2!)

• Solar weather observation (like SOHO at L1)

• Deep space missions needing low fuel