Extremely large or related to astronomy. Often used to describe something vast or related to space science.

Related to the sky or outer space. Includes stars, planets, and other heavenly bodies.

The study of the interaction between matter and electromagnetic radiation. Analyzes light spectrum Identifies elements in stars.

The change in light waves to longer wavelengths as objects in space move away from the observer. Evidence for expanding universe. Related to Doppler effect.

A point in space where density and gravity become infinite, such as the center of a black hole.

A model of the universe where the sun is at the center.

A model of the universe where Earth is at the center.

The path one object takes as it revolves around another object in space. Circular or elliptical path, involves gravitational forces.

The study of the origin, evolution, and eventual fate of the universe. Includes Big Bang theory - Examines universe's structure.

The observation that the farther away a galaxy is, the faster it is moving away.

The theory that the universe originated in a huge explosion that released all matter and energy.

a mysterious force that appears to be causing the expansion of the universe to accelerate

the theory that the universe experienced a sudden and brief burst in size immediately after the Big Bang

Faint, uniform microwave radiation, the cooled afterglow of the Big Bang.

the increase in the wavelength of light due to an object moving away from the observer.

the increase in the wavelength of light due to an object moving towards from the observer.

a particle of light

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

A galaxy with no clear shape; often smaller, full of gas/dust, with lots of star formation.

A collapsed star with gravity so strong that not even light can escape.

The longest stage of a star's life where it fuses hydrogen into helium.

The massive explosion of a large star at the end of its life.

The extremely dense core left after a supernova (made mostly of neutrons).

A spiral galaxy with a central bar-shaped structure of stars.

The early stage of a star forming as gravity pulls gas and dust together.

The cooled, "dead" remnant of a white dwarf (theoretical—none exist yet).

Oval or football-shaped galaxy with older stars, little gas/dust, and less new star formation.

A giant cloud of gas and dust; the "stellar nursery" where stars are born.

The hot, dense leftover core of a small/medium star.

A galaxy that is shaped like a pinwheel with arms of stars, gas, and dust spiraling out from the center.

The outer layers of a dying medium star puff off into space, creating colorful gas clouds.

A later stage when the star expands as it runs out of hydrogen fuel.

A hybrid between elliptical and spiral galaxy; disk-like but without spiral arms.

A graph that plots stars by their absolute magnitude and temperature, showing different stages in star evolution.

A measure of the brightness of a celestial object as seen from Earth.

The intrinsic brightness of a celestial object, such as a star.

The distance light travels in one year, approximately 5.88 trillion miles.

A large, bright, gaseous feature appearing above the surface of the Sun and extending into the corona.

A region on the Sun's surface that is marked by intense magnetic activity, which inhibits convection and causes reduced surface temperature.

The outermost layer of the Sun's atmosphere, characterized by high temperature and low density.

A massive system consisting of billions of stars, star systems, star clusters, dust, and gas bound together by gravity.

The lighter part of a shadow where only some light is blocked. Occurs during eclipses. Found on the edges of the shadow. People in the penumbra during a solar eclipse experience a partial eclipse.

The action of moving around something in a path that takes a full circle. Involves a complete orbit. Takes place in a regular cycle.

When the moon moves between the Earth and the sun, blocking sunlight and casting a shadow on Earth. Occurs during the new moon phase. Only visible from specific areas on Earth.

When day and night are equal in length due to the sun being directly over the equator. Happens twice a year (spring and fall). Marks a change in seasons.

When the sun reaches its highest or lowest point in the sky, creating the longest or shortest day of the year.

When the Earth moves between the sun and the moon, casting a shadow on the moon. Occurs during the full moon phase. Visible from anywhere on Earth where it's night.

Relating to an axis, or an imaginary line through the center of a rotating object. Earth's axial tilt is 23.5°. Causes seasons and day/night.

A type of tide that occurs when the gravitational forces of the moon and sun align, creating the greatest difference between high and low tides. Happens during the new moon and full moon phases.

The type of tide that occurs when the gravitational forces of the moon and sun are at right angles, causing the least difference between high and low tides. Happens during the first and last quarter moon phases. Gravitational forces from the moon and sun partially cancel each other out.

Related to spring or occurring during spring. Refers to events or characteristics of spring. Often associated with growth, renewal, and warmth.

The darkest part of a shadow where all light from a source is blocked. Occurs during eclipses. Found in the center of the shadow. People in the umbra during a solar eclipse experience a total eclipse.

A series of events that repeat in the same order. Predictable and continuous. Includes events like moon phases, seasons, and tides.

Related to autumn or occurring during autumn. Refers to events or characteristics of fall. Often associated with cooler temperatures, shorter days, and falling leaves.