antimatter: Molecules made up of atoms made up of antiprotons, antineutrons and positrons.
astronomer: A scientist who works in the field of research that deals with celestial objects, space and the physical universe.
astrophysics: An area of astronomy that deals with understanding the physical nature of stars and other objects in space. People who work in this field are called astrophysicists.
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 put into orbit by a cloud of negatively charged electrons.
black hole: A region of space having such a strong gravitational field that no matter or radiation (including light) can escape.
cosmos: (adj. cosmic) A term that refers to the universe and all that it contains.
disk: A round, flat and generally quite thin object. (in astronomy) A rotating collection of gas, dust, or both from which planets can form. Or the structure of some large rotating bodies in the cosmos, including spiral galaxies such as our Milky Way.
electrical charge: The physical property responsible for electric force; it can be negative or positive.
electron: A negatively charged particle, usually found in orbit around the outer regions of an atom; also, the carrier of electricity in solids.
galaxy: A group of stars – and usually dark matter – all held together by gravity. Giant galaxies, like the Milky Way, often have more than 100 billion stars. The darkest galaxies may have only a few thousand. Some galaxies also have gas and dust from which they make new stars.
gamma rays: High energy radiation often generated by processes in and around exploding stars. Gamma rays are the most energetic form of light.
hypothetical: An adjective describing a hypothesis or an explanation proposed for a phenomenon. In science, a hypothesis is an idea that must be rigorously tested before it is accepted or rejected.
interstellar: Between the stars.
matter: Something that takes up space and has mass. Anything that contains matter on Earth will have a property called “weight”.
Milky Way: The galaxy in which the Earth’s solar system resides.
neutron star: The very dense corpse of what was once a massive star. As the star died in a supernova explosion, its outer layers flew into space. Its nucleus then collapsed under its intense gravity, causing protons and electrons in its atoms to merge into neutrons (hence the star’s name). A single teaspoonful of a neutron star on Earth would weigh over a billion tonnes.
particle: A tiny amount of something.
physical: (adj.) A term for things that exist in the real world, as opposed to memories or the imagination. It can also refer to the properties of materials which are due to their size and non-chemical interactions (such as when one block collides with force into another).
physics: The scientific study of the nature and properties of matter and energy. Classical physics is an explanation of the nature and properties of matter and energy that relies on descriptions such as Newton’s laws of motion. Quantum physics, an area of study that emerged later, is a more precise way of explaining the motions and behavior of matter. A scientist who works in such fields is known as a physicist.
positron: A subatomic particle with the mass of an electron, but a positive electric charge. It is the antimatter counterpart of the electron. So when electrons and positrons collide, they annihilate each other, releasing energy.
scenario: A possible (or probable) sequence of events and how they might unfold.
solar: To do with the sun or the radiation it emits. It comes from ground, Latin for sun.
solar system: The eight major planets and their moons orbit our sun, as well as smaller bodies in the form of dwarf planets, asteroids, meteorites, and comets.
Star: The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they get hot enough, stars emit light and sometimes other forms of electromagnetic radiation. The sun is our closest star.
telescope: Usually a light collecting instrument that makes distant objects appear closer through the use of lenses or a combination of mirrors and curved lenses. Some, however, collect radio emissions (energy from a different part of the electromagnetic spectrum) through an array of antennas.
theoretical physics: A branch of physics that uses mathematical models to understand the nature and properties of matter and energy. A scientist who works in this field is known as a theoretical physicist.
universe: The entire cosmos: All things that exist in space and time. It has developed since its formation during an event known as the Big Bang, around 13.8 billion years ago (a few hundred million years).
wave length: The distance from one peak to the next in a series of waves, or the distance from one trough to the next. It is also one of the “criteria” used to measure radiation. Visible light – which like all electromagnetic radiation travels in waves – includes wavelengths ranging from about 380 nanometers (purple) to about 740 nanometers (red). Radiation with wavelengths shorter than visible light includes gamma rays, x-rays and ultraviolet light. Longer wavelength radiation includes infrared light, microwaves, and radio waves.