astronaut noun A person who is trained to travel and work in a spacecraft. The astronaut spent six months conducting experiments aboard the space station. + asteroid noun A small, rocky body that orbits the sun, smaller than a planet. Scientists tracked an asteroid passing safely between Earth and the moon last week. + atmosphere noun The mixture of gases surrounding a planet, or the overall mood or feeling of a place. Earth's atmosphere protects us from harmful radiation from the sun. + comet noun A celestial body of ice and dust that orbits the sun and develops a glowing tail when near it. Astronomers tracked the comet for months before it became visible to the naked eye. + constellation noun A group of stars that forms a recognizable pattern and is traditionally named after a figure or object. On a clear night, you can easily spot the constellation known as the Big Dipper. + cosmos noun The universe considered as an ordered, harmonious system. Ancient philosophers marveled at the vastness and order of the cosmos. + crater noun A large bowl-shaped depression in the ground, often caused by a volcanic eruption, explosion, or impact. The meteorite left a massive crater in the desert thousands of years ago. + eclipse noun An event in which one celestial body blocks the light from another, as seen from a certain viewpoint. Crowds gathered in the park to watch the total solar eclipse through protective glasses. + galaxy noun A huge system of stars, gas, and dust held together by gravity. Our solar system is located within the vast Milky Way galaxy. + gravity noun The attraction between objects that have mass. Gravity pulls the falling apple toward Earth. + launch verb To start or introduce something new, such as a product, project, or organization. The company will launch its latest smartphone at a press event next month. + lunar adjective Relating to the moon or measured by its cycles. The lunar calendar determines the date of several traditional holidays. + meteor noun A piece of rock or debris that burns brightly as it enters Earth's atmosphere. They stayed up late watching meteors streak across the night sky. + meteorite noun A piece of rock or metal from space that survives its fall through the atmosphere and lands on Earth. Scientists carefully examined the meteorite that had struck the field last spring. + mission noun An important task or purpose that a person or organization is sent to accomplish. The charity's mission is to provide clean water to remote villages. + moon noun The natural satellite that orbits the Earth and is visible mainly at night. A full moon lit up the entire campsite last night. + nebula noun A huge cloud of gas and dust in outer space, often visible as a hazy, glowing patch among the stars. The telescope captured stunning images of a nebula thousands of light-years away. + orbit noun The curved path that an object in space follows around a star, planet, or other larger body. The satellite completes one orbit of Earth roughly every ninety minutes. + planet noun A large celestial body that orbits a star and does not produce its own light. Earth is the third planet from the sun in our solar system. + rocket noun A vehicle or device propelled by burning fuel that shoots out at high speed, used to launch spacecraft or weapons. The rocket lifted off the launch pad in a cloud of smoke and flame. + rover noun A vehicle designed to travel over rough or unfamiliar terrain, especially one used to explore another planet. The Mars rover sent back detailed images of the planet's rocky surface. + satellite noun An object, natural or artificial, that orbits a planet or other larger body in space. The satellite transmits weather data back to stations on Earth. + shuttle noun A vehicle that travels regularly back and forth over a short route between two places. We took the shuttle from the hotel to the airport early this morning. + solar system noun The sun together with the planets, moons, and other bodies that orbit it. Students built a model of the solar system for their science project. + space station noun A large spacecraft that orbits Earth and allows astronauts to live and work there for extended periods. Astronauts conducted experiments aboard the space station for six months. + spacecraft noun A vehicle designed to travel and operate beyond Earth's atmosphere. The spacecraft entered orbit around Mars after a seven-month journey. + spacesuit noun A protective, pressurized suit worn by astronauts to survive outside a spacecraft. The astronaut checked her spacesuit for leaks before the spacewalk. + star noun A large, glowing ball of gas in space that produces its own light and heat through nuclear reactions. On a clear night, thousands of stars are visible far from city lights. + telescope noun An optical instrument that uses lenses or mirrors to make distant objects, especially in space, appear closer and larger. Through the telescope, we could clearly see the rings of Saturn. + universe noun All of space and everything that exists within it, including planets, stars, and galaxies. Astronomers now estimate that the universe contains billions of separate galaxies. + void noun A completely empty space; a sense of emptiness where something is felt to be missing. After her grandmother passed away, a void remained that nothing seemed to fill. + zero-gravity adjective Relating to a condition in which objects appear to have no weight because gravitational pull is not felt. Astronauts train for zero-gravity conditions by flying in an aircraft that dives sharply through the air. + cosmonaut noun An astronaut trained by the Russian or former Soviet space program. The cosmonaut spent six months aboard the space station conducting experiments. + interstellar adjective Occurring or existing between stars, especially referring to the space between star systems. The spacecraft was designed for an ambitious interstellar journey to a neighboring star system. + light-year noun A unit of astronomical distance equal to the distance light travels in one year, about 9.46 trillion kilometers. The nearest star system to our sun is a little over four light-years away. + module noun A separate, self-contained unit that can be combined with other units to form a larger system. Students must complete four modules before starting the final year of the degree. +