asteroid: A rocky object in orbit around the sun. Most asteroids orbit in a region that falls between the orbits of Mars and Jupiter. Astronomers refer to this region as the asteroid belt.
astrophysicist: A scientist who works in an area of astronomy that deals with understanding the physical nature of stars and other objects in space.
atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
black hole: A region of space having a gravitational field so intense that no matter or radiation (including light) can escape.
celestial: (in astronomy) Of or relating to the sky, or outer space.
colleague: Someone who works with another; a co-worker or team member.
cosmologist: A scientist who studies the origin and development of the cosmos, or universe.
cosmos: (adj. cosmic) A term that refers to the universe and everything within it.
dark matter: Physical objects or particles that emit no detectable radiation of their own. They are believed to exist because of unexplained gravitational forces that they appear to exert on other, visible astronomical objects.
fluctuation: (v. fluctuate) Some type of change in a pattern or signal that varies at irregular intervals and often by amounts that are hard to predict.
gravity: The force that attracts anything with mass, or bulk, toward any other thing with mass. The more mass that something has, the greater its gravity.
hydrogen: The lightest element in the universe. As a gas, it is colorless, odorless and highly flammable. It’s an integral part of many fuels, fats and chemicals that make up living tissues. It’s made of a single proton (which serves as its nucleus) orbited by a single electron.
Mars: The fourth planet from the sun, just one planet out from Earth. Like Earth, it has seasons and moisture. But its diameter is only about half as big as Earth’s.
mass: A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.
matter: Something that occupies space and has mass. Anything on Earth with matter will have a property described as “weight.”
model: A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others.
orbit: The curved path of a celestial object or spacecraft around a galaxy, star, planet or moon. One complete circuit around a celestial body.
particle: A minute amount of something.
physical: (adj.) A term for things that exist in the real world, as opposed to in memories or the imagination. It can also refer to properties of materials that are due to their size and non-chemical interactions (such as when one block slams with force into another). (in biology and medicine) The term can refer to the body, as in a physical exam or physical activity.
physicist: A scientist who studies the nature and properties of matter and energy.
planet: A large celestial object that orbits a star but unlike a star does not generate any visible light.
primordial: An adjective that refers to something that goes back to the beginning of time or to the earliest existence of something.
quantum: (pl. quanta) A term that refers to the smallest amount of anything, especially of energy or subatomic mass.
real time: A term that connotes immediacy; something is being studied, recorded and/or reported at the very time it is happening.
satellite: A moon orbiting a planet or a vehicle or other manufactured object that orbits some celestial body in space.
solar system: The eight major planets and their moons in orbit around our sun, together with smaller bodies in the form of dwarf planets, asteroids, meteoroids and comets.
solar wind: A flow of charged particles (including atomic nuclei) that have been ejected from the surface of the star, such as our sun. It can permeate the solar system. When emitted by a star other than the sun, this radiation is known as a stellar wind.
star: The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they become hot enough, stars will emit light and sometimes other forms of electromagnetic radiation. The sun is our closest star.
subatomic: Anything smaller than an atom, which is the smallest bit of matter that has all the properties of whatever chemical element it is (like hydrogen, iron or calcium).
sun: The star at the center of Earth’s solar system. It is about 27,000 light-years from the center of the Milky Way galaxy. Also a term for any sunlike star.
system: A network of parts that together work to achieve some function. For instance, the blood, vessels and heart are primary components of the human body’s circulatory system. Similarly, trains, platforms, tracks, roadway signals and overpasses are among the potential components of a nation’s railway system. System can even be applied to the processes or ideas that are part of some method or ordered set of procedures for getting a task done.
technology: The application of scientific knowledge for practical purposes, especially in industry — or the devices, processes and systems that result from those efforts.
universe: The entire cosmos: All things that exist throughout space and time. It has been expanding since its formation during an event known as the Big Bang, some 13.8 billion years ago (give or take a few hundred million years).
