Astronomy - JV

Apogee

the point on the orbit of a heavenly body, especially the moon, or of a man-made satellite, at which it is farthest from the Earth

Andromeda Galaxy

a spiral galaxy appearing to the naked eye as a fuzzy oval patch in the constellation Andromeda. Andromeda is the chained lady, between Pisces and Cassiopeia

Asteroid Belt

Region of space between the orbits of Mars and Jupiter on which most asteroids are located

Asteroid

any of the thousands of small bodies (480 miles to less than 1 mile in diameter) that revolve about the Sun

Atmosphere

gaseous envelope surrounding a heavenly body

Astrophysics

deals with physical properties of celestial bodies and with interaction between matter and radiation on the interior of celestial bodies and in interstellar space

Big Bang Theory

Theory of how the universe was formed

Big Dipper

Group of bright stars in Ursa Major resembling a dipper

Constellation

any of various groups of stars to which a name has been given

Black Hole

Theoretical massive object formed at the beginning of the universe or by gravitational collapse of a star exploding as a supernova; gravitational field so strong that no radiation can escape

Comet

Celestial body moving about the Sun surrounded by an envelope of dust and gas

Cosmic Rays

Mainly protons produced by the Sun and other stars, strike the atmosphere of the Earth, some absorbed, some form the Van Allen belt, some reach Earth's surface

Cosmology

Deals with the general structure and evolution of the universe

Cosmic Microwave Radiation

Electromagnetic radiation filling the universe

Eclipse

Light of the Moon obscured by the Earth getting between the Moon and Sun (lunar eclipse); light of the Sun obscured by the Moon getting between the Sun and a point on the Earth (solar eclipse)

Fixed Star

Any of the stars that apparently always remain in the same position in respect to one another

Galaxy (Milky Way)

Large system of stars held together by mutual gravitation; galaxy of our solar system

Jupiter

5th in order from the Sun, 4 moons = Io, Europa, Ganymede, Callisto, 90% hydrogen, 10% helium

Light Year

distance traveled by light in one solar year, 5.88 trillion miles

Mars

4th in order from the Sun, red because rusty - iron oxidized, tallest volcano in solar system, CO2 atmosphere, valleys and canyons on surface, Martians live here

Mercury

Nearest to the Sun, 3/5 of Earth's diameter, 88 days to orbit the Sun, virtually no atmosphere

Meteor

shooting star, meteoroid that has entered the Earth's atmosphere

Moon

Any planetary satellite

Mount Palomar

Northeast of San Diego, observatory, one of the world's largest reflecting telescopes

Neptune

Farthest planet from the Sun (since Pluto was demoted), stormiest planet, thin dark rings, blue methane gas in atmosphere

Neutron Star

Dense compact star, composed mostly of neutrons, collapsed core of a supernova

Nebula

cloud of interstellar gas and dust

North Star

Polaris, in constellation Ursa Minor, outermost star on handle of Little Dipper

Orbit

Curved path around a celestial body, elliptical

Perigee

the point on the orbit when nearest to the Earth

Pluto

No longer a planet. Core is reddish-brown, discovered in 1930 by Clyde Tombaugh

Planet

a celestial body orbiting a star, rounded by its own gravity

Planetarium

a center of learning about space

Polaris

North Star

Ptolemaic Universe

geocentric theory

Pulsar

a rotating star

Red Shift

occurs when electromagnetic radiation emitted/reflected is shifted towards the red end of the spectrum due to the Doppler effect

Saturn

6th planet, 2nd largest, gas giant

Satellite

any object in orbit around a planet

Solar System

refers to a Sun and the planets that orbit it

Space Telescope

any instrument in outer space used for observation of space/its features

Solstice

the two days a year when the day and night are the longest, usually around June 20 and December 21

Star

celestial body that produces its own light and consists of a mass of gas held together by its own gravity

Sun

star that is orbited by all the planets and other bodies of our solar system, supplies heat

Supernova

massive star that undergoes a sudden increase in brightness and size

Sunspots

any of the relatively cool dark spots that appear in groups on the surface of the Sun

Telescope

arrangement of lenses, mirrors, or both that collects visible light allowing observation of distant objects

Universe

all matter and energy, galaxies, and contents of the space between galaxies, regarded as a whole

Uranus

7th planet from the Sun, 3rd largest

Ursa Major

constellation in polar region of the Northern Hemisphere

Ursa Minor

near north celestial pole, ladle-shaped

Venus

2nd planet from the Sun, 4th smallest

White Dwarf

whitish star that is dense and small, about the size of Earth

Zodiac

band of the celestial sphere that extends about 8 degrees north and south of the ecliptic

Binary Star (Double Star)

system of two stars that orbit a common center of mass

Altitude

height of a thing above reference level

Corona

irregular envelope of gas outside the chromosphere of the Sun

Celestial Sphere

imaginary sphere with Earth at its center

Ecliptic

great circle on the celestial sphere that is made by the plane containing Earth's orbit around the Sun

Nadir

point on the celestial sphere that is below the observer

Plasma

protoplasm or cytoplasm

Occultation

passage of a celestial object between an observer and another celestial object, blocking the object from view