Chapter 21 power point

• Stars,galaxies, and the universe.

constellation• A pattern of

stars in the sky.

Visible light• Electromagneti

c radiation that can be seen with the unaided eye.

Electromagnetic radiation

• Energy that travels through space in the form of waves.

Wavelength

• The horizontal distance between two wave crests.

Spectrum

• The range of wavelength of electromagnetic waves.

Refracting telescope

• A telescope that uses one or more mirrors to gather and focus light.

Convex lens

• A piece of transparent glass curved so that the middle is thicker than the edge

Reflecting telescope

• A telescope that uses one or more mirrors to gather light.

Radio telescope

• A device used to detect radio waves from objects in space.

Observatory

• A building that contains one or more telescopes.

Spectrographs

• An instrument that separates light into colors and photographs the resulting spectrum.

Galaxy

• A giant structure that contains hundreds of billions of stars.

Universe

• All of space and everything in it.

Light-year

• The distance that light travels in a year.

Parallax

• The apparent change in position of an object when seen from different places.

Giant star

• A very large star much larger than the sun.

Apparent magnitude

• The brightness of a star as seen from earth.

Absolute magnitude

• The brightness of a star as if it were a standard distance from earth.

Hertzsprung-Russell diagram

• A graph relating the temperature and brightness of a star.

Main sequence

• An area on the H-R diagram that runs from the upper left to the lower right and includes more than 90% of all stars.

Pulsar

• A neutron star that produces radio waves

Nebula

• A large amount of gas and dust in space spreaded out in an immense volume

Protostar

• A contracting cloud of gas and dust the earliest stage of a stars life.

White Dwarf

• The remaining hot core of a star after its outer layers have expanded and drifted out into space.

Supernova

• The explosion of a dying giant or supergiant star.

Neutron Star

A tiny star that remains after a supernova explosion.

Black Hole

• The remains of an extremely massive star pulled into a small volume by the force of gravity.

• A distant galaxy with a black hole at its center.

Quasar

Binary Star

• A star system that contains two stars.

Eclipsing Binary

• A star system in which one star periodically blocks light from another.

Spiral Galaxy

• A galaxy whose arms curve outward in a pinwheel pattern

Elliptical Galaxy

• A galaxy shaped like a flattened ball containing only old stars.

Irregular Galaxy

• A galaxy that does not have a regular shape.

Big Bang

• The initial explosion that resulted in the formation and expansion of the universe.

Bibliography

• The science book

• And ->

This power point is by Shanan Nathan Doug