Unit 11: Astronomy

H-R Diagram

Hertzsprung-Russell diagram, a graph that shows the relationship between a star's surface temperature and absolute magnitude

Hubble Tuning

Hubble classified giant galaxies by appearance. Galaxy properties (color, mass, gas content, star formation rate)

Crescent

Moon phase in which less than half of the Moon appears to be illuminated.

New moon

Moon phase that occurs when the Moon is between Earth and the Sun, at which point the Moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth.

Black dwarf

The final stage of a white dwarf

Quarter

The phase of the Moon when half of the Moon's near side is lit

Season

A period of the year characterized by particular conditions of weather, and temperature; Due to the tilt of the earths axis

Gaseous planet

massive planets (such as our solar system's 4 outer planets Jupiter, Saturn, Uranus, and Neptune) that are composed mainly of hydrogen and helium

Terrestrial planet

one of the highly dense planets nearest to the sun; Mercury, Venus, Mars, and Earth

Astronomical unit

the average distance between the Earth and the sun; approximately 150 million kilometers

Lunar

the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon

Solar Nebula

the cloud of gas and dust that formed our solar system

Light year

the distance that light travels in one year; about 9.46 trillion kilometers

Main-sequence

the location on the H-R diagram where most stars lie; it has a diagonal pattern from the lower right (low temperature and luminosity) to the upper left (high temperature and luminosity)

Waning

the moon's period during which the visible surface of the moon decreases

Waxing

the moon's period during which the visible surface of the moon increases

Revolution

the motion of a body that travels around another body in space; one complete trip along an orbit

Rotation

the spin of a body on its axis

Big Bang Theory

the theory that states that the universe began with a tremendous explosion about 13.7 billion years ago

Convection

the transfer of thermal energy by the circulation or movement of a liquid or gas

Protostar

A contracting cloud of gas and dust; the earliest stage of a star's life

Meteor

a bright streak of light that results when a meteoroid burns up in the Earth's atmosphere

Supernova

a gigantic explosion in which a massive star collapses and throws its outer layers into space

Nebula

a large cloud of gas and dust in interstellar space; a region in space where stars are born or where stars explode at the end of their lives

Red giant

a large, reddish star late in its life cycle

Meteorite

a meteoroid that reaches the Earth's surface without burning up completely

Meteoroid

a relatively small, rocky body that travels through space

Comet

a small body of ice, rock, and cosmic dust that follows an elliptical orbit around the sun and that gives off gas and dust in the form of a tail as it passes close to the sun

White dwarf

a small, hot, dim star that is the leftover center of an old star

Asteroid

a small, rocky object that orbits the sun, usually in a band between the orbits of Mars and Jupiter

Neutron star

a star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons

Spring tide

a tide of increased range that occurs two times a month, at the new and full moons

Neap tide

a tide of minimum range that occurs during the first and third quarters of the moon

Black hole

an object so massive and dense that even light cannot escape its gravity

Redshift

as an object moves away from the observer at high speed, the light from the object appears redder