Stars, Galaxies and Universe

Absolute magnitude

The brightness of a star as seen from a distance of 10 parsecs. Absolute magnitude. Absolute magnitude is a measure of how bright a star would appear if it were 10 parsecs away from Earth.

Apparent magnitude

The brightness of a star as seen from Earth apparent magnitude. Apparent magnitude is a measure of how bright a star appears to us in the sky from Earth.

Big bang theory

States that the universe began with a huge explosion 13.8 billion years ago. Big Bang Theory. The Big Bang Theory explains how the universe started from an extremely hot and dense point and has been expanding ever since.

Binary star

A star system with two stars. Binary star. A binary star is a system where two stars orbit around a common center of mass.

Black hole

A region in space with gravity so strong that no matter or light can escape it. A black hole is an area in space where gravity pulls so much that even light cannot get out.

Chromosphere

The middle layer of the Sun's atmosphere. Chromosphere. The chromosphere is a thin layer of the Sun's atmosphere just above the surface, known for its reddish color visible during solar eclipses.

Constellation

A pattern or shape formed by a group of stars. Constellation. A constellation is a group of stars that forms an imaginary outline or meaningful pattern on the night sky, often representing animals, mythological people, or objects.

Corona

The outermost layer of the Suns atmosphere. Corona. The corona is a glowing halo of hot, ionized gases surrounding the Sun, visible during a solar eclipse.

Cosmic background radiation

The electromagnetic radiation left over from the big bang. Cosmic background radiation. It is the faint glow of light that fills the universe, a remnant from its very early stages after the big bang.

Electromagnetic spectrum

All the wavelengths or frequencies of electromagnetic radiation. Electromagnetic spectrum. The electromagnetic spectrum is the range of all types of light, from radio waves to gamma rays, that travel through space.

Galaxy

A massive system of stars, gases, and dust held together by gravity. A galaxy is a giant cosmic collection of stars, planets, and other matter bound by gravity.

Globular cluster

A large group of old stars densely packed into a roughly spherical shape. Globular cluster. A globular cluster is a tight, spherical collection of ancient stars bound together by gravity.

Hertzsprung Russell diagram

A graph that plots the surface temperature of stars against their absolute brightness. Hertzsprung Russell diagram. It is a chart used by astronomers to classify stars and understand their evolution.

Hubbles law

Sure! "States that the farther away a galaxy is, the faster it is moving away as the universe expands. Hubble's law. In simple terms, Hubble's law means that the universe is expanding, with distant galaxies moving away faster than those nearby."

Light year

The distance light travels in a year 9.5 trillion km. light year. A light year is the distance light travels in one year in space.

Main sequence

The distinct diagonal band on an H-R diagram that includes 90 of all stars main sequence. Main sequence stars are those that are in the stable phase of their lifecycle, fusing hydrogen into helium in their cores.

Nebula

A huge cloud of gas and dust in space, where new stars form. Nebula. A nebula is a massive space cloud where stars are born.

Neutron star

A dense core composed mainly of neutrons, left behind after a supernova explosion. Neutron star. A neutron star is a super compact object formed when a massive star's core collapses under gravity after a supernova, squeezing its mass into a small, incredibly dense ball mostly made of neutrons.

Nuclear fusion in the sun

The process by which hydrogen atoms join together to form helium, inside the sun. Nuclear fusion in the sun is when hydrogen atoms combine to create helium, releasing energy that powers the sun.

Open cluster

A group of no more than a few thousand stars, all of which are about the same age. Open cluster. An open cluster is a collection of stars that formed together in the same region of space and are loosely bound by gravity.

Parallax

The apparent change in position of an object when viewed from different places. Parallax. Parallax is the way an object's position seems to shift when you look at it from different angles or locations.

Photosphere

The surface layer of the Sun that gives off light. Photosphere. The photosphere is the outer layer of the Sun that emits the light we see.

Protostar

A very young star, before nuclear reactions begin at its core. Protostar. A protostar is a cloud of gas and dust in space that is gradually forming into a new star.

Pulsar

A rapidly spinning neutron star that emits radio waves. Pulsar. A pulsar is a highly magnetized, rotating neutron star that sends out beams of radiation, which can be detected on Earth as regular pulses.

Quasar

The very bright center of a distant galaxy. Quasar. A quasar is an extremely bright and energetic object powered by a supermassive black hole at the center of a galaxy.

Solar wind

A stream of electrically charged particles released by the Suns corona. Solar wind. Solar wind is the flow of charged particles from the Sun that can affect space weather around Earth.

Supernova

The bright explosion of a dying supergiant star. Supernova. A supernova is the massive explosion of a star that releases a huge amount of light and energy when it reaches the end of its life.

Universe

Everything that exists, including the stars, planets, and energy. Universe. The universe is all of space and everything within it, from the smallest particles to the largest galaxies.

White dwarf

The hot dense core of a star left behind when its outer layers have escaped into space. White dwarf. A white dwarf is the remains of a small or medium-sized star after it has exhausted its nuclear fuel and shed its outer layers.