Module 2: Exploring the Universe Flashcards
A region of space having a gravitational field so intense that no matter or even light can escape.
Black Hole
The shape of a planet’s orbit, which is a stretched-out circle
Ellipse
A galaxy that does not have an internal structure. They look like round or flattened balls and have little dust and gas between the stars.
Elliptical Galaxies
huge collections of stars, gas, and dust held together by gravity
Galaxies
Earth-centered
Geocentric
an invisible attractive force between all objects that have mass
Gravity
sun-centered
Heliocentric
A galaxy that does not have a regular shape. Many form from the gravitational pull of neighboring galaxies.
Irregular Galaxies
The force of gravity between two objects depends on their masses and the distance between them
Law of universal gravitation
a group of about 30 galaxies closest to the Milky Way
Local Group
the amount of matter in something
Mass
A spiral galaxy that contains our solar system
Milky Way
The process where atoms combine and release large amounts of energy
Nuclear fusion
To move around another object in a curved path
Orbit
A cloud of dust and gas from which a solar system forms
Planetary nebula
A condensed leftover material from a planetary nebula that eventually becomes a planet
Protoplanet
A contracting region within a nebula that will eventually become a star
Protostar
The Sun and eight planets that revolve around it
Solar system
A type of galaxy where stars, gas, and dust exist in arms that spiral out from a central disk.
Spiral Galaxies
An object in space made of gases in which nuclear fusion reactions occur that emit energy
Star
A cloud of gas and dust where stars form
Stellar Nebula
The largest object in our solar system that exerts the strongest pull of gravity
Sun
the cluster of galaxy clusters in which the Milky Way is located. The Local Group is one of its members.
Virgo Supercluster
the gravitational pull on a mass
Weight
Inner Planets
Mercury, Venus, Earth, and Mars – made of solid, rocky materials
Outer Planets
Jupiter, Saturn, Uranus, Neptune – made of ice and gases
A scientist who studies stars, planets, and other objects in space
astronomer
a device shaped like a long tube that helps you see things that are far
away
telescope
to identify the presence of something
detect
Relating to light or the way we see things
optical
A person who travels and works in space
astronaut
The United States government agency responsible for most space missions and space-flight technology
National Aeronautics and Space
Administration (NASA)
International Space Station (ISS)
A large, artificial satellite that orbits Earth. It serves as an orbiting research laboratory.
