astronomer: Scientists engaged in research fields that deal with celestial bodies, space, and the physical universe.
black hole: A region of space with a gravitational field so strong that no matter or radiation (including light) can escape.
cloud: A plume of molecules or particles, such as water droplets, that moves under the action of external forces such as wind, radiation, or water currents. (in atmospheric science) An airborne mass of water droplets and ice crystals that moves as a plume, usually high in the Earth's atmosphere. Its movement is driven by the wind.
core: Something in the center of an object (usually a round shape).
element: A component of a larger structure. The smallest unit of each of the more than 100 substances (in chemistry) is one atom. Examples include hydrogen, oxygen, carbon, lithium, and uranium.
fuel: A substance that releases energy during a controlled chemical or nuclear reaction. Fossil fuels (coal, natural gas, oil) are common types that release energy through chemical reactions that occur when heated (usually to the point of combustion).
gravity: A force that attracts something with mass or volume to another thing with mass. The greater the mass of something, the greater its gravitational force.
mass: A number that indicates how much an object resists acceleration and deceleration. Basically, it is a measure of how much material an object is made of.
nebula: Clouds of cosmic gas and dust that exist between major adult stars. Telescopes can detect these clouds by the light they emit or reflect. Some nebulae appear to act as nurseries where stars are born.
neutron star: A very dense corpse of what was once a huge star. When the star died in a supernova, its outer layer was scattered into space. Then its center collapsed under the strong gravitational force, and the protons and electrons in the atoms fused into neutrons (hence the star's name). A teaspoon of a neutron star would weigh more than a billion tons on Earth.
planet: A large celestial body that orbits a star, but unlike a star, it does not produce visible light.
pulsar: Name of a rotating ultra-dense neutron star. A teaspoon weighs 1 billion tons on Earth. This represents the end of a star's life that began with four to eight times the mass of the Sun. When this star died in a supernova explosion, its outer layer was scattered into space. Its center then collapsed under its strong gravity, and the protons and electrons in the atoms that made it up fused into neutrons (hence the star's name). As these stars rotate, they emit short, regular pulses of radio waves or X-rays (sometimes both occurring at alternating intervals).
star: The basic building blocks that make up galaxies. Stars develop when clouds of gas are compressed by gravity. When a star gets hot enough, it emits light and sometimes other forms of electromagnetic radiation. The sun is the closest star to us.
solar: The star at the center of Earth's solar system. It is located approximately 27,000 light years from the center of the Milky Way galaxy. It is also a word that refers to a star like the sun.
supernova: (plural: supernovae or supernovas) A star whose brightness suddenly increases significantly due to a catastrophic explosion in which most (or all) of its mass is ejected.
universe: The entire universe: Everything that exists beyond time and space. It has been expanding ever since it formed during an event known as the Big Bang about 13.8 billion years ago (which may take hundreds of millions of years or more).
white dwarf: A small, extremely dense remnant of a star that is now the size of a planet. It's what's left when a star with about the same mass as our Sun runs out of hydrogen in its nuclear fuel and sheds its outer layer.
Source: www.snexplores.org
