A variable that is changed or manipulated by the experimenter.
What is a dependent variable?
A variable that is measured by the experimenter.
What are control variables?
Variables that could affect the outcome of the experiment. they are purposefully controlled so that they don't influence the result.
What is a hypothesis?
An educated guess on the outcome of an experiment based on prior knowledge.
What is a celestial object?
Any object that exists in space such as a planet, star or moon.
What is an astronomer?
A scientist who studies astronomy.
What is revolution?
The time it takes for an object to orbit around another object; Earth;s revolution around the sun is 365.24 days.
What is rotation?
The turning of an object around an imaginary axis running through it; the Earth's rotation around it's axis is 24 hours.
What is a constellation?
A group of stars that seem to form a distinctive constellation in the sky.
What us a light-year?
The distance that light travels in one year.
What is apparent magnitude?
The brightness of a star as seen from the Earth.
What is latitude?
The location above below the equator.
What are tides?
The rising and falling of ocean waters caused by the Moon's and Earth's gravity.
What is an ellipse?
A curve that is generally referred to as being oval or the shape of an egg.
What are the phases of the Moon?
The monthly progression of changes in the appearance of the Moon that result from different portions of the Moon's sunlit side being visible from Earth.
What is an eclipse?
The phenomenon in which one celestial object moves in front of another, as viewed from Earth.
What is a lunar eclipse?
The phenomenon in which the full Moon passes into the Earth's shadow.
What is a solar eclipse?
The phenomenon in which the shadow of the Moon falls onto Earth's surface.
What is a planet?
An object that orbits one or more stars (and is not a star itself), is spherical, and does not share its orbit with another object.
What is a solar system?
A group of planets that circle one or more stars.
What is retrograde rotation?
The movement of an object in the sky, usually a planet, from west to east; this effect is generally produced when Earth is passing the planet in its orbit.
What is an astronomical unit (AU)?
The average distance between Earth and the Sun (150 000 000 km).
What is orbital radius?
The average distance between the Sun and an object that is orbiting the Sun.
What is a comet?
An object composed of rocky material, ice, and gas; comes from the Kuiper Belt or Oort Cloud.
What is an asteroid?
An object in space that ranges in size from a tiny speck, like a grain of sand, to 500 km wide; most asteroids originate in the asteroid belt between Mars and Jupiter.
What is a meteor?
A meteoroid that hits Earth's atmosphere and burns up.
What is a meteorite?
A meteoroid that is large enough to pass through Earth's atmosphere and reach the ground, without being totally burned up.
What is a meteoroid?
A piece of rock moving through space.
What is electromagnetic radiation?
Radiation consisting of electromagnetic waves that travel at the speed of light (such as visible light, radio waves and X-rays).
What is a refracting telescope?
A telescope that uses a lens to collect the light from an object.
What is a refracting telescope?
A telescope that uses a mirror to collect light from an object.
What is a satellite?
An artificial object or vehicle that orbits Earth, the Moon, or other celestial bodies; also a celestial body that orbits another body of larger size (for example the Moon is the Earth's natural satellite).
What is the Solar Nebula Theory?
The theory that describes how stars and planets form from contracting, spinning disks of dust and gas.
What is a star?
A celestial body made of hot gases, mainly hydrogen and some helium.
What is a nebula?
A cloud of interstellar gas and dust.
What is a protostar?
A hot, condensed object at the center of a nebula.
What is nuclear fusion?
The process of energy production in which hydrogen nuclei combine to form helium nuclei.
What is the photosphere?
The surface layer of the sun.
What is a sun spot?
An area of strong magnetic fields on the photosphere.
What is a solar wind?
Streams of fast-moving charged particles ejected by the sun into the solar system.
What is luminosity?
A star's total energy output per second; its power in Joules per second (J/s).
What is absolute magnitude?
The magnitude of a star that we would observe if the star were 32.6 light-years from Earth.
What is a spectroscope?
An optical instrument that produces a spectrum from a narrow beam of light, and usually projects the spectrum onto a photographic plate or a digital detector.
What is an H-R Diagram?
The Hertzsprung-Russel Diagram is a graph that compares the properties of the stars.
What is the Milky Way?
The galaxy that includes the solar system; appears as a hazy white band in the night sky.
What is a galaxy?
A huge collection pf stars, planets, gas and dust that is held together by gravity.
What is a star cluster?
A collection of stars held together by gravity.
What is an open cluster?
A collection of 50 to 1000 stars; open clusters appear along the main band of the Milky Way.
What is a globular cluster?
A collection of a 100 000 to a million stars that is arranged in a distinctive spherical shape; globular clusters are around the center of the Milky Way.
What is the Local Group?
The small group of about 47 galaxies that includes the Milky Way.
What is a supercluster?
A gigantic cluster of 4 to 25 clusters of galaxies that is hundreds of millions of light-years in size.
What is cosmology?
The study of the universe.
What is the Doppler effect?
The change in pitch of a sound due to the motion of the source relative to an observer; also, the change in frequency of a light source to its motion relative to an observer.
What is the redshift?
The effect in which objects moving away from an observer have their wavelengths lengthened, toward the red end of the visible spectrum.
What is the blueshift?
The effect in which objects moving away from an observer have their wavelengths shortened, toward the blue end of the visible spectrum.
What is the big bang?
The event that may have triggered the expansion of the universe 14 billion years ago.
What is Cosmic Microwave Background (CMB) radiation?
The radiation left over from the big bang, which fills the universe.