· 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.
· 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
· 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
· 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
· 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
HERTZSPRUNG RUSSELL DIAGRAM
LIFE STAGES OF A STARS
WHEN YOU CAN/CAN'T USE PARALLAX
WHAT 'PARALLAX' IS
WHAT A 'LIGHT YEAR' IS
THE HOTTEST STARS ARE 'BLUE WHITE' IN COLOR