58 terms

Grade 9 Space

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Terms in this set (...)

asterism
a star pattern that is not a constellation; may consist of a small group of stars within a constellation or individual stars from different constellations
asteroid
one of many small rocky bodies in our solar system, most of which orbit the Sun between Mars and Jupiter
astrolabe
an ancient instrument used to locate and predict the positions of the Sun,
astronomical unit (AU)
a measurement equal to the average distance between the Sun and Earth, about 150 million km
aurora borealis/australis
spectacular displays of light visible in the sky near the North and South Poles, respectively; caused by high energy particles in the solar wind entering Earth's atmosphere at the poles
axis
an imaginary line through Earth, extending from the North Pole to the South Pole; Earth spins on its axis at a speed of 1670 km/h, or 0.5 km/s
Big Bang theory
the theory that proposes that the universe formed approximately 13.7 billion years ago when an unimaginably tiny volume of space suddenly and rapidly expanded to immense size
black hole
a large sphere of incredibly tightly packed material with an extraordinary amount of gravitational pull created when a star collapses into itself; called "black" because nothing, not even light, can escape the powerful gravitational field
celestial body
a natural object in space, such as the Sun, the Moon, a planet, or a star
thermonuclear reaction
the fusion of two or more atoms to create a different, larger atom, and a great deal of energy
telescope
an instrument that gathers and focusses light or other types of electromagnetic radiation to magnify distant objects
sunspots
dark patches on the sun's surface that are slightly cooler than the surrounding areas
spiral galaxy
one of three basic galaxy shapes; a galaxy with many long "arms" spiralling out from a centre core made up of stars that formed long ago
solar wind
streams of high-energy particles ejected by the Sun; when some of these particles enter Earth's atmosphere they cause the auroras,
solar prominences
large loops of super-hot gas that extend out from the Sun's surface
solar radiation
energy emitted from the Sun in the form of electromagnetic radiation
satellite
an electronic device put in orbit around Earth to relay information
revolution
the motion of Earth as it orbits the Sun at 30 km/s; one full revolution takes almost a year
rotation
the motion of Earth as it spins on its axis from west to east at 1670 km/h; one full rotation takes almost a day
retrograde motion
an apparent switch in the motion of a celestial body from eastward to westward motion, or vice versa, as viewed from Earth
rover
a small, sophisticated, robotic probe designed to land on a planet, explore and test the surface, and send information back to Earth
red shift
a shifting of light from an object toward the red (longer wavelength) end of the spectrum as the object moves away from Earth
radio telescope
a large receiver that collects radio waves (which have longer wavelengths than visible light) and therefore can detect objects that are invisible to optical telescopes
quasar
a region of extremely high energy that develops as the supermassive black hole in the centre of a galaxy attracts more matter into itself
probe
a space vehicle carrying scientific instruments and sent to fly past, orbit, or land on a celestial body to collect data
planet
a celestial body that orbits one or more stars, is large enough that its gravity holds a spherical shape, and is the only body occupying the orbital path
Oscillating theory
states that the universe is closed and will go through a series of expansions and contractions, or Big Bangs and Big Crunches, in an ongoing cycle
optical telescope
reflecting or refracting telescope used to focus light from distant objects
orbit
the regular path of an object, such as a celestial body or an artificial satellite, around another body such as a planet or star
nebula
a cloud of gas and dust in space
moon
a celestial body that orbits a planet
light-year
the distance that light, which moves at 300 000 km/s, travels in a year; equals about 9.5 trillion km
irregular galaxy
one of three basic galaxy shapes; a galaxy that has neither spiral arms nor an obvious central core, made up of a mix of newly forming stars and old stars.
Hubble Space Telescope
an optical telescope that was launched into Earth orbit in 1990; provides images of distant galaxies and stars; light reaching its mirrors has not been distorted by the atmosphere
high mass star
star that has 12 or more times the mass of the Sun; consumes fuel quickly to rapidly reach a large size, but also burns out quickly
heliocentric
representing the Sun as the centre of the universe
geosynchronous orbit
the orbit of a satellite that is moving at the same speed and direction as Earth's rotation, with the result that the satellite stays stationary above a fixed point on Earth
geocentric
representing Earth as the centre of the universe
gamma rays
high-frequency electromagnetic radiation released from exploding stars, neutron stars, and galaxies; cannot be detected by telescopes on Earth's surface because the rays are absorbed by Earth's atmosphere
asterism
a star pattern that is not a constellation; may consist of a small group of stars within a constellation or individual stars from different constellations
asteroid
one of many small rocky bodies in our solar system, most of which orbit the Sun between Mars and Jupiter
astrolabe
an ancient instrument used to locate and predict the positions of the Sun, Moon, planets, and stars
astronomical unit (AU)
a measurement equal to the average distance between the Sun and Earth, about 150 million km
aurora borealis/australis
displays of light in the North and South poles caused by the interaction of solar wind and the gases of the Earth's atmosphere
axis
An imaginary line through the Earth extending through the North and South pole
Big Bang theory
the theory that proposes that the universe formed approximately 13.7 billion years ago when an unimaginably tiny volume of space suddenly and rapidly expanded to immense size
black hole
a large sphere of incredibly tightly packed material with an extraordinary amount of gravitational pull created when a star collapses into itself; called "black" because nothing, not even light, can escape the powerful gravitational
field
...
celestial body
a natural object in space, such as the Sun, the Moon, a planet, or a star
fusion the process in which the nuclei of atoms fuse together to form larger single atoms, creating an enormous amount of energy
...
elliptical galaxy
one of three basic galaxy shapes; a galaxy that ranges in shape from a perfect sphere to an elongated but flattened ellipse and contains some of the oldest stars in the universe
ellipse
an oval shape for which the distance from one focal point to a point on the edge of the ellipse and then to the other focal point is the same no matter which point on the edge of the ellipse you choose
ecliptic
the path followed by the Sun through the sky, as seen from the Earth
dwarf planet
a celestial body orbiting the Sun that has enough mass to have a nearly round shape due to its own gravity, has not cleared the neighbourhood around its orbit, and does not orbit any object other than the Sun; generally smaller than a planet
cosmological red shift
wavelengths of radiated light that are being constantly stretched (lengthened) as the light crosses the expanding universe
constellation
a distinctive pattern in the night sky formed by a group of stars; the pattern often looks like a familiar object, such as an animal
comet
a small body made up of rocky material and ice that occurs in the Kuiper Belt and the Oort Cloud; when a comet is bumped into the inner solar system, the Sun's light may make the comet's tail visible from Earth
circumpolar constellation
a constellation that never appears to "set", or dip below the horizon; this classification depends on the position of the viewer