Chapter 3
Section 1
· patterns of stars in the sky are constellations
· visible light is light you can see with your eyes.
· Light is a form of electromagnetic radiation
· Electromagnetic radiation is energy that can travel directly through space in the form of waves
· Wavelength: distance between the crest of one wave and the crest of the next wave.
· Spectrum: when light spreads out to make a range of different colors with different wave lengths
· Electromagnetic spectrum includes radio waves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma rays.
· Most telescope collect different types of electromagnetic radiation, including visible light
· A building that contains one of more telescopes is called an observatory,
· A spectrograph breaks the light from an object into colors and photographs the resulting spectrum
Astronomers use spectrographs to get info about stars, including their chemical compositions and temperatures.
Section 2
· A giant flat surface containing billions of stars is a galaxy
· The universe is defined as all of space and everything in it
· A Light-year is the distance light travels in one year
· Astronomers often use parallax to measure distances to nearby stars
· Parallax is the apparent change in position of an object when you look at it from different places
· Main characteristics used to classify stars are size, temperature, and brightness
· A star’s apparent magnitude is its brightness seen form earth
· The star’s absolute magnitude is the brightness the star would have if it were at its standard distance from Earth
Section 3
· pulsars are short or pulsating radio sources.
A nebula is a large amount of gas and dust spread out in immense volume
How long a star lives depends on how much mass is has
When a star runs out of fuel, it becomes a white dwarf, a neutron star, or a black hole.
Quasars are bright objects that look almost like stars
Section 4
· Star systems with two stars are called double stars or binary stars
· A system in which one star blocks the light from another is called an eclipsing binary
· Astronomers have classified most galaxies into three main categories: spiral galaxies, elliptical galaxies, and irregular galaxies
· A spiral galaxy has the shape of two twin spirals
· Elliptical galaxies look like flattened spheres
· Irregular galaxies do not have a regular shape
Section 5
· according to the big bang theory, the universe formed in an enormous explosion about 10 – 15 billion years ago
· about 5 billion years ago, a cloud of gas and dust collapsed to form the solar system
KEY TERMS:
CONSTELLATIONS
ELECTROMAGNETIC SPECTRUM
PULSAR
PROTOSTAR
HERTZSPRUNG RUSSELL DIAGRAM
LIFE STAGES OF A STARS
WHEN YOU CAN/CAN'T USE PARALLAX
WHAT 'PARALLAX' IS
WHAT A 'LIGHT YEAR' IS
WAVELENGTH
NEUTRON STAR
WHITE DWARF
BLACK HOLE
ECLIPSING BINARY
RADIO TELESCOPE
REFRACTING TELESCOPE
REFLECTING TELESCOPE
NEBULA
FUSION
QUASAR
BINARY STAR
APPARENT MAGNITUDE
ABSOLUTE MAGNITUDE
THE HOTTEST STARS ARE 'BLUE WHITE' IN COLOR