Universe The sum of all matter and energy that exists, that has ever existed, and that will ever exist. We will focus on the belief that there is only one universe
Universe Occupants Star-a huge ball of hot gas that emits light Galaxy- a collection of millions or billions of star bound together by gravity.
Measuring Distances Distances in the universe are beyond comprehension. We use a unit called a light year. (9.5 x 1015 m) It measures on how far light travels in one year. Pg 526-527 compare distances
Distances Light travels at 3.0 x 108 m/s or 186,000 mi/sec By car, it would take you 10 million yrs to travel one light year.
Distance When you look at objects in space, you are looking back in time. The greater the distance, the further back in time you are looking.
Distance Our sun is only 1.5 x1011 m away, which less than one light year. The next closest star is Alpha Centauri is 4.3 light years away.
Galaxies It is estimated that there are 100 billion galaxies. Our galaxy is the Milky Way. But the nearest galaxy is 2 million Lt.Yrs away. It is named Andromeda
Milky Way Facts Chocolate covered caramel and nougat. Only 120 calories Made by Mars candy
Milky Way Facts It is made up of stars, clouds and dust known as interstellar matter. Every star you see in our sky is part of the milky way Spiral shape
Galaxy Types There are three types: Spiral Elliptical Irregular
Spiral Have spiral arms that branch out from a cluster of stars near the center. Milky way and Andromeda Younger galaxies Bluish color
Elliptical Oval or egg shaped Older galaxies Reddish in color
Irregular These galaxies have no defined shape. Some contain very little clouds or dust (older)
Galaxy Clusters Clusters are groups of galaxies held together by gravity. Some clusters contain thousands of galaxies and are referred to as superclusters. .
Universe is Expanding In 1929 Edwin Hubble concluded that the universe was expanding. He studied the spectral lines of stars in distant galaxies.
Universe is Expanding He found that distant galaxies shifted to the Red end of the spectrum. This indicated that waves were stretching out and thus moving away from us. (wavelengths were getting bigger)
Daily Journal • If Hubble had observed that the spectral lines in light from every galaxy were shifted toward the blue end of the spectrum, what might he have concluded about the universe? • Unscramble: • BAGNBIG • OENLTLTISNCOA
Universe is Expanding He concluded that galaxies are moving away from each other. This means that the universe is expanding.
How the Universe was Created? Big Bang Theory It is generally believed that the universe is 15 billion yrs old. This theory begins with the premise that nothing but an “atom” existed before the Big Bang.
Big Bang Theory From this “super atom” came a large explosion that produced everything we see today. (mass, space, time, and energy)
Evidence of Big Bang Scientist working NJ detected cosmic background radiation in the form of microwaves. This radiation was predicted by the theory. The radiation has shown a cooling trend which has allowed scientist to measure the overall temperature of the universe. (2.7 K) Also the amount hydrogen (most common element)
Future of the Universe Three options exist: It will expand forever It will expand then stabilize at a given size It will stop expanding and fall back on itself.
Future of the Universe The amount of matter in the universe will determine which option will be followed.
Stars and the Sun 16.2