A celestial body that orbits the sun, is round due to its own gravity, and has cleared its orbital path

A rotating cloud of gas and dust from which the sun and planets formed

Any nebula from which stars and exoplanets may form

A small body from which a planet originated in the early stages of development of the solar system

Planetesimals joined through collisions and force of gravity to form larger bodies

Denser materials sink forcing less dense materials to outer layers

Large amounts of gases released from volcanic eruptions

Aristotle's model of the universe where everything revolved around Earth

When planets sometimes appear to move backward in the sky relative to the stars

Planets moving in small circles as they revolve in larger circles

Copernicus' model where planets revolve around the sun at different speeds and distances

A closed curve whose shape is determined by two points within the shape

The degree of elongation of an elliptical orbit

The time required for a body to complete a single orbit

The tendency of an object to resist a change in motion unless an outside force acts on it

The force that must cause the curve in an orbit

One of the highly dense planets nearest to the sun

Mercury, Venus, Mars, and Earth are

Bowl-shaped depression caused by collisions with other space objects

The planet closest to the sun is

Mercury is named after which god?

The second planet from the sun is

The planet that is almost the same size, mass, and density as Earth is

The third planet from the sun is

The fourth planet from the sun is

The planet that once had liquid water, but now only has frozen water is

A planet that has a deep, massive atmosphere

Jupiter, Saturn, Uranus, and Neptune are

What separates the inner and outer planets?

The fifth planet from the sun is

What is the largest planet in our solar system?

The giant storm that has been raging for several hundred years on Jupiter is

The sixth planet from the sun is

The least dense planet in our solar system is

The seventh planet from the sun is

The planet that rotates parallel to the plane of its orbit is

The eighth planet from the sun is

Neptune is named for the

A region starting just beyond the orbit of Neptune containing dwarf planets and other small bodies of ice

Objects beyond Neptune's orbit are known as

Any object that orbits the sun, is round due its own gravity, has not cleared its orbit, and is not a satellite

Pluto, Eris, Makemake, and Haumea are TNOs or

Planetlike objects that orbit stars other than Earth's sun

A large celestial body that is composed of gas and that emits light

The combination of light atomic nuclei to form heavier atomic nuclei

Devices that separate light into different colors or wavelengths

A display of colors and lines characteristic of each element

Bands of color crossed by dark lines where the color is diminished

Motion as it appears from Earth

Stars always visible in the night sky are known as

An observed change in the frequency of a wave when the source or observer is moving

The distance that light travels in one year

An apparent shift in the position of an object when viewed from different locations

The brightness of a star as seen from Earth

The brightness that a star would have at a distance of 32.6 light-years from Earth

The total amount of energy a star gives off each second

The location on the H-R diagram where most stars lie

The diagonal pattern on the H-R diagram going from lower right to upper left

A large cloud of gas and dust in interstellar space

A region in space where stars are born

A flattened disk that has a central concentration of matter

A state where nuclei and free electrons move independently

A very large and bright star whose hot core has used most of its hydrogen

Highly luminous stars that are more massive than the sun are known as

A cloud of gas that forms around a sunlike star that is dying

A small, hot, dim star that is the leftover center of an old sunlike star

A star that suddenly becomes brighter

A star that has such a tremendous explosion that it blows itself apart

A star that has collapsed to the point that the electrons and protons have been smashed together

A rapidly spinning neutron star that emits pulses of radio and optical energy

An object so massive and dense that even light cannot escape its gravity

One of 88 regions into which the sky has been divided in order to describe the locations of celestial objects

Pairs of stars that revolve around each other and are held together by gravity

Another name for the center of mass

A group of stars formed by a collapsed nebula with a spherical shape

A group of stars formed by a collapsed nebula with a loose shape

A collection of stars, dust, and gas bound together by gravity

Giant stars that brighten and fade in a regular pattern

A large galaxy with a nucleus of bright stars and flattened arms that spiral around the nucleus

A large galaxy with a nucleus of bright stars and flattened arms that spiral around the nucleus with a bar through the center

Galaxies that vary in shape from nearly spherical to very elongated are known as

Galaxies with no particular shape and low total masses are known as

The cloudlike band that can be seen across the sky when we look through the plane of our galaxy

The name for our galaxy and its closest neighbors

The shortened name for quasi-stellar radio source

A very luminous object that produces energy at a high rate

The study of the origin, properties, processes, and evolution of the universe

Theory that all matter and energy in the universe was compressed and exploded to expand in all directions

The sudden event that precipitated the expansion of the universe

Radiation uniformly detected from every direction in space

The name of the temperature equal to -273°C

The type of matter that does not give off light, but can be detected by its gravity

The type of energy believed to act as a force that opposes gravity