arXiv A website that posts research papers — often before they are formally published — in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance and statistics. Anyone can read a posted paper at no charge.
colleague Someone who works with another; a co-worker or team member.
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.
glass A hard, brittle substance made from silica, a mineral found in sand. Glass usually is transparent and fairly inert (chemically nonreactive). Aquatic organisms called diatoms build their shells of it.
graduate student Someone working toward an advanced degree by taking classes and performing research. This work is done after the student has already graduated from college (usually with a four-year degree).
granite A type of hard igneous rock, which contains coarse-grained inclusions (essentially mini rocks within a rock) of various minerals, chiefly quartz, feldspar and mica.
hypersonic Moving at more than five times the speed of sound.
macro (antonym: micro) An adjective that means on a big or broad scale.
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.”
metal Something that conducts electricity well, tends to be shiny (reflective) and malleable (meaning it can be reshaped with heat and not too much force or pressure).
micrometer (sometimes called a micron) One thousandth of a millimeter, or one millionth of a meter. It’s also equivalent to a few one-hundred-thousandths of an inch.
obsidian A hard, dark, glasslike volcanic rock.
particle A minute amount of something.
physicist A scientist who studies the nature and properties of matter and energy.
plasma (in chemistry and physics) A gaseous state of matter in which electrons separate from the atom. A plasma includes both positively and negatively charged particles. (in medicine) The colorless fluid part of blood.
quarks A family of subatomic particles that each carries a fractional electric charge. Quarks are building blocks of particles called hadrons. Quarks come in types, or “flavors,” known as: up, down, strange, charm, top and bottom.
square (in geometry) A rectangle with four sides of equal length. (In mathematics) A number multiplied by itself, or the verb meaning to multiply a number by itself. The square of 2 is 4; the square of 10 is 100.
star The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they become dense enough to sustain nuclear-fusion reactions, 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).
theoretical An adjective for an analysis or assessment of something that based on pre-existing knowledge of how things behave. It is not based on experimental trials. Theoretical research tends to use math — usually performed by computers — to predict how or what will occur for some specified series of conditions. Experimental testing or observations of natural systems will then be needed to confirm what had been predicted.
tissue Made of cells, it is any of the distinct types of materials that make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues.
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).
vaporize To convert from a liquid to a gas (or vapor) through the application of heat.
wake An area of disturbed air or water left behind an object (such as a boat or animal) moving through it.
Originally posted by: Lillian