Earth and Space Vocab (Universe)

Elliptical Galaxy

galaxies look like spheres or ovals and do not have spiral arms

Irregular galaxy

blobs

Spiral galaxy

shaped like a pinw

Milky Way

we are located in this galaxy which is a spiral galaxy

Planet

a celestial body that must orbit a star, have enough gravity to be a sphere, and must be able to clear its’ path of debris

Inner Planets

the four planets closest to the sun; Mercury, venus, earth, mars; They are also known as terrestrial planets

Terrestrial planets

made up of mostly rock and metal

Outer planets

the outer planets are the other four; Jupiter, saturn, uranus, and neptune. They are also called Jovian planets or gas planets.

Dwarf Planet

a celestial body that orbits the sun, has enough mass to assume a nearly round shape, and canNOT clear its path of debris

Exoplanet

a planet outside our solar system. it orbits a different start than our sun

Planetesimal

small rock-like objects held together by gravity. As they gather more and more dust, ice and other planetesimals they become planets. 

Moon (aka natural satellite)

an object that orbits a planet or something else that is not a star.

Asteroid

large, rocky bodies that orbit the sun

Asteroid Belt

The majority of known asteroids orbit within the asteroid belt between Mars and Jupiter

Meteoroid

Objects in space that range in size from dust grains to small asteroids. “small space rocks”

Meteor

when meteoroids enter earth’s atmosphere (or that of another planet *Mars*) at high speed and burn up, making fireballs. We call them shooting stars.

Meteorite

when a meteoroid survives a trip through the atmosphere and hits the ground

comet

ball of ice and dust. When it nears the sun it warms up, creating a tail of ice and gas.

Kuiper Belt

a doughnut-shaped region of ice objects beyond the orbit of neptune.

Oort cloud

giant spherical shell surrounding our solar system, it is like a big, thick-walled bubble made of icy pieces of space debris. Most of our comets probably come from this area.

NEO’s (Near Earth Objects)

smaller objects like asteroids and meteoroids that are within 3.0 astronomical units of earth

Star

a brilliantly glowing sphere of hot gas held together by its’ own gravity

Nebula

an enormous cloud of dust and gas; where stars are formed

Black Hole

an area of such immense gravity that nothing, not even light, can escape from it. It’s created when a massive star dies.

Quasar

when gas and dust fall into a supermassive black hole at the center of a galaxy, electromagnetic radiation is emitted. This creates a rare and extremely bright object in the center of the black hole. 

Dark Matter

it does not absorb, reflect, or emit light. Completely invisible. We only assume it exists because without it, the behavior of starts, planets, and galaxies wouldn’t make sense. We mostly know it is there because of its gravitational pull on visible matter in space.

Dark Energy

Our universe is expanding and something is making it expand faster and faster. We don’t know what this energy is or where it comes from, but it is there. 

Void

a large, mostly empty, area that contains very few or no galaxies. Voids are also known as dark space. Think of it like holes in Swiss cheese or the gaps in a spider web.

Gravitational Wave

An invisible (fast) ripple in space. It carries energy and is moving through a gravitational field, produced when a massive body is accelerated or otherwise disturbed (like when a star explodes).