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The Rest of the Universe. Stars and Galaxies. Stars. constellations- an imaginary picture made by groups of stars; example: The Big Dipper The color of the star indicates the temperature. Blue is the hottest, red is the coolest.
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The Rest of the Universe Stars and Galaxies
Stars • constellations- an imaginary picture made by groups of stars; example: The Big Dipper • The color of the star indicates the temperature. Blue is the hottest, red is the coolest. • apparent magnitude- how bright a star looks from Earth. Things far away appear to look dim.
A Star’s Life 1. Birth- created from cloud of gas and dust 2. Adulthood- uses hydrogen and helium for nuclear fusion fuel 3. Old age- enlarges into a red giant or supergiant 4. or 4. Explodes in a supernova! 4. Uses up its fuel and becomes a dwarf star (white, then brown then black when doesn’t give off any more light) 5. Neutron star (2-3 times mass of our sun) 5. Black hole (>7 times mass of our sun) or
Galaxies • galaxy- a group of stars, gas and dust held by gravity • Three types: spiral (our Milky Way), elliptical and irregular • Stars revolve around the center of their galaxy. • Most galaxies have a black hole in the center! • Light-year= the distance light travels in one year • Nothing can go faster than the speed of light.
What’s Next • The universe is expanding, constantly getting bigger, so things are getting further apart. • It could a) keep expanding forever b) slow down and stay the same size c) slow and start shrinking • No one knows what will happen!