Words To Know

Analogue: a location or object seen to be similar and comparable. read more >>

Asteroid: a rocky object in our Solar System that is smaller than a planet read more >>

Asteroid belt: a region in our Solar System between Mars and Jupiter where the majority of asteroids that orbit the Sun can be found read more >>

Astrobiology: the study of the origin, evolution, and distribution of life in the universe read more >>

Astronaut: someone who has been trained to be a crew member of a spacecraft. read more >>

Atmosphere: the gases that surround a planet

Bacteria: single-celled micro-organisms, thought to be similar to the first life on Earth read more >>

Barred-spiral galaxy: a spiral galaxy with a center that looks stretched out in one direction read more >>

Barren: having little or no life; barren land has little plant life.

By-product: a second product that is made while you are trying to make a main, first product. read more >>

Caldera: a volcanic crater that forms when a volcano collapses after a large eruption read more >>

Capacity: the largest amount that something can hold or make.

Capsule: the part of a spacecraft that has been designed to hold the crew and survive re-entry into the Earth's atmosphere. read more >>

Carbon: one of the most common chemicals in the universe; all life we know of is carbon-based read more >>

Celestial: relating to the sky or space.

Celestial body: a planet, sun, or other object that exists in space. read more >>

Channel: a groove in the land, often formed by the flow of a fluid, such as water or lava.

Classification: a process of grouping things together or naming things based on their similarities or identification. read more >>

Clinker: very irregularly shaped lava crust fragments.

Comet: an small (<20 miles across) object in space made of mostly ice and rock that often has a tail of gas and dust when passing by the sun read more >>

Composition: the different materials that something is made out of.

Compound: made of two or more parts or elements read more >>

Consume: to use up or eat.

Cosmic radiation: high-energy radiation (energy waves or particles) that mostly comes from outside of our galaxy. read more >>

Cosmonaut: another word for astronaut; most commonly, a Russian astronaut.

DNA: deoxyribonucleic acid; the molecule which contains genetic instructions for life read more >>

Drake equation: an equation used to discuss the number of intelligent civilizations currently existing in the Milky Way with which humans could communicate read more >>

Dwarf planet: a planetary body which is large enough to be a planet, but has not become the dominant planetary body in its orbit read more >>

Edge-on: how to describe spiral galaxies that we can see from the side.

Eject: the throw or be thrown out of another object, such as case dust particles shooting out of a dying star.

Electron: a particle smaller than an atom that has a negative charge and is an important part of atoms read more >>

Element: a substance that is made from a single type of atom; elements are the foundation of all materials.

Elliptical: oval shaped, not quite a circle or a sphere read more >>

Elliptical galaxy: a galaxy with little shape; it looks like a cloud of stars read more >>

Embankment: a raised area of land, often on the side of a river or other channel.

Enceladus: a moon of Saturn, and the brightest object in the Solar System due to its surface of ice read more >>

Europa: a moon of Jupiter, and the 6th-largest moon in the Solar System read more >>

Expedition: a journey made for a specific purpose.

Extraterrestrial: relating to things outside of the Earth; relating to space and celestial bodies beyond Earth.

Extrude: to force out or push.

Face-on: how to describe spiral galaxies that we can see from above, showing the spiral arms, for example.

Flyby: an action in which a spacecraft passes close to another object without orbiting it. read more >>

Fossil: a trace (or sign) of an organism living in a past geological period; can be actual remains of a body or an impression of a body or body parts read more >>

Fragment: to break large pieces of material into smaller pieces.

Frictional heat: the heat made by rubbing two things together.

Galaxy: a group of stars that are held together by gravity read more >>

Gamma radiation: a very energetic light that can cause damage to DNA very quickly read more >>

Geologist: a scientist that studies the Earth and other land-based planets, their rocks and other materials, and how they change over time read more >>

Greenhouse gas: a gas that can absorb and give off energy in a certain wavelength; greenhouse gases are the main contributors of current climate change. read more >>

Hydrothermal vent: an area on the seafloor which spews hot water heated from magma read more >>

Ignition: the process of starting the launch of a rocket, in which fuel is used to lift the rocket away from the surface of Earth.

Inclusion: individual pieces of material that are different from the material surrounding them.

Irregular: having an atypical shape.

Irregular galaxy: a galaxy that does not appear to have a typical shape read more >>

Jagged: something that has sharp pieces or sharp points sticking out of it.

Lander: a spacecraft capable of safely landing on a planetary surface. read more >>

Landform: a feature or formation on the surface of a planet. read more >>

Launch pad: the structure and location from which rockets lift off. read more >>

Lava: melted rock that erupts or comes out of the ground of a planetary body read more >>

Lunar eclipse: when the Sun, Earth, and Moon are aligned and the Moon passes behind Earth, into its shadow read more >>

Magma: the hot molten fluid that forms when rocks melt inside the Earth; once magma erupts and cools, it forms new volcanic rocks read more >>

Magnetic: when a material produces a magnetic field (that attracts certain metals) read more >>

Mantle: the layer of a planet that is found between the core and the crust read more >>

Meteor: a rock from space that travels through part of Earth's atmosphere.

Meteorite: a rock from space that lands on Earth read more >>

Meteoroid: a rock in space that is somewhere between a pebble to a meter-wide boulder in size read more >>

Mineral: solid, inorganic (do not come from plants or animals) substances that occur naturally. Minerals make up sand, soil and rocks.

Mission: a specific travel assignment or trip into space.

Molten: something that is liquified due to heat.

Multicellular: an organism made of more than one cell read more >>

Ode: a poem or other writing, usually written to honor a certain person or subject. read more >>

Orbit: to follow the path of an orbit; an oval or circular path that an object follows around a larger object tdue to the attraction of the large object’s gravity; an object that orbits can be called an orbiter or a satellite.

Orbiter: a space platform with analytical instruments and cameras orbiting a planetary body such as a planet or a moon. read more >>

Organic carbon: organic carbon is a compound where carbon atoms are directly bonded to other carbon atoms; organic carbon is the primary building block for all forms of life on Earth.

Organic compounds: small molecules which contain carbon and are important for life read more >>

Organism: a living thing

Panspermia: Greek for “seeds”, a theory for the origin of life which says life did not begin on Earth, but began somewhere else and was transported to Earth read more >>

Photosynthesis: a set of reactions that change light energy into chemical energy. Photosynthesis also produces energy-rich carbohydrates like starch. Photosynthesis occurs in the chloroplast of a plant cell read more >>

Planet: the large, ball-shaped objects in orbit around stars, particularly the eight planets in our own solar system.

Planetary body: a planet or moon present in our solar system. read more >>

Radar: radio waves that are used to measure characteristics of an object read more >>

Radioactive decay: when an element is unstable, it emits energy in the form of radiation and forms a more stable element.

Reconnaissance: observation or research on a location that is done before visiting, to learn information about the location.

Reliability: the amount something can be depended on to perform a function.

Remote sensing: studying an object from far away, without physically touching it. read more >>

Robot: any machine that completes a complex task, usually under human direction. read more >>

Rock: a solid mineral-based material that forms part of the ground on a planetary body read more >>

Rocket: a vehicle that travels by controlling exploded fuel. read more >>

Rover: a space exploration vehicle that can move around on the surfaces of planets, moons, or other objects in the Solar System. read more >>

Rubbled: material that has been ground up into smaller pieces.

Rubbly: a rubbled texture on the surface of a lava flow.

Satellite: any object that orbits another object in space. read more >>

Sediment: small bits of materials that have been broken down, often from rocks read more >>

Spacecraft: a vehicle used for traveling in space, can either be entirely robotic or can be built to carry people.

Spectrometer: a tool that measures wavelengths of light read more >>

Spiral: a shape created by curving a line around its starting point; for example, when you roll up a matt, if you look at the edge you will see a spiral. read more >>

Spiral galaxy: a galaxy where the stars, gas and dust are grouped into arms that twist around the center read more >>

Star: a ball of hot, dense material held together by its own gravity read more >>

Surface roughness: the texture of a surface.

Target: a desired destination or object.

Technique: a way of completing a task or job.

Terrestrial planet: a planet made mostly of rocks and metals. In our Solar System, the terrestrial planets are Mercury, Venus, Earth, and Mars read more >>

Texture: the feel of an object (e.g., hard, soft, smooth, slimy, rough are all textures).

Thruster: a small engine on a spacecraft that is used to make small adjustments to direction of travel. read more >>

Universe: all existing material and space that we can observe considered as a whole. read more >>

UV radiation: highly energetic light that can cause damage to DNA over time read more >>

Vast: very large.

Velocity: the rate of change in an object's position. read more >>

Viscosity: the measure of a fluid's resistance to flow. read more >>

Volcanic vent: an opening of a volcano or a rift beneath a magma chamber. read more >>

Volcano: an opening in the Earth's crust through which rock, lava, or smoke exits or has exited; often surrounded by a mountain, hill, or landform of some type read more >>

How Do We Know the Earth Is Round?
Answer »

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