galaxy
(astronomy) a collection of star systems
wavelength
The distance between crests of waves, such as those of the electromagnetic spectrum.
Leo
a zodiacal constellation in northern hemisphere between Cancer and Virgo
milky way
The name of our galaxy, a spiral galaxy that contains about 400 billion stars
solar system
system of nine planets, including Earth, and other objects that revolve around the Sun
gamma ray
the high-energy photon emitted by a nucleus during fission and radioactive decay
black hole
remnant of a star that is so dense that nothing, not even light, can escape its gravity field
x ray
electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target
radio telescope
an instrument that collects and records radio waves traveling through space and can be used day or night under most weather conditions; provides information to map the universe and look for life on other planets
optical telescope
a telescope that uses lenses or mirrors to collect and focus visible light
compass
drafting instrument used for drawing circles
big bang
the initial explosion that resulted in the formation and expansion of the universe
refracting telescope
an optical magnifying instrument in which light from an object passes through a double convex lens and is bent to form an image at the focal point
reflecting telescope
a telescope that uses a curved mirror to collect and focus light
standard time zones
areas roughly defined by twenty-four 15� sections of longitude, each centered on a time meridian that establishes the hour of the day
spectra
Astronomers study the composition of stars by observing this.
electromagnetic radiation
a form of energy that exhibits wavelike behavior as it travels through space
Ptolemy
Alexandrian astronomer who proposed a geocentric system of astronomy that was undisputed until Copernicus (2nd century AD)
heliocentric
Theory that sun is center of the universe
kelpers
Who's laws of planetary motion are: zero-mass object orbiting the Sun
1.The orbit of every planet is an ellipse with the Sun at one of the two foci.
2.A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.
3.The square
messier
Many of the most famous Deep Sky Objects were observed and catalogued by a famous astronomer named Charles _______
Galileo
This man's invention of the telescope confirmed the heliocentric theory of the universe. He was put on trial by the Pope for his beliefs.
gravity
(physics) the force of attraction between all masses in the universe
inertia
a disposition to remain inactive or inert
Halley
English astronomer who used Newton's laws of motion to predict the period of a comet (1656-1742)
Hubble
United States astronomer who discovered that (as the universe expands) the speed with which nebulae recede increases with their distance (1889-1953)
transparency
picture consisting of a positive photograph or drawing on a transparent base
Polaris
the brightest star in Ursa Minor