Bellringer Tatooine is a fictional planet that has a sunset which contains 2 suns. This would be what kind of star system?

The Expanding Universe Notes

How the Universe Formed By looking at the most distant objects in the universe, scientists can estimate the age of the universe. Light from the Andromeda Galaxy took 3 million years to get to Earth, and that’s the closest galaxy to us, out of an estimated 100 billion galaxies.

Nearly every visible object in this image is a distant galaxy.

How the Universe Formed Astronomers estimate the age of the universe at billion years old billion years ago, the part of the universe we see now was no larger than the period at the end of this sentence. This tiny universe was incredibly hot and dense. This universe then exploded in what scientists call the big bang.

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How the Universe Formed The Big Bang Theory states that the universe formed in an instant, billions of years ago, in an enormous explosion. As the universe expanded, it began to cool. After a few hundred thousand years, the first atoms formed. After about 200 million years after the big bang, the first stars and galaxies formed.

How the Universe Formed The original Big Bang Theory came from a Catholic Priest by the name of George Lemaître. After viewing the red shift that occurs as galaxies (and any other object) move away from us, he concluded that the universe had to have originated from a infinitely small singularity. In 1927, he originally called his theory the “hypothesis of the primeval atom.”

How the Universe Formed 2 years after George Lemaître published his findings, Edwin Hubble confirmed his data my viewing many more spectrums from various galaxies, all of them showing a red doppler shift. Hubble confirmed that with the exception of our local cluster, all galaxies are moving away from us and from each other. Hubble’s Law states that the farther away a galaxy is, the faster it is moving away from us.

How the Universe Formed To understand how the the galaxies are moving, think of raisin bread dough that is rising. If you could shrink yourself to sit on a raisin, you would see all of the other raisins moving away from you. res/lambda/RaisinBread.swf res/lambda/RaisinBread.swf

How the Universe Formed In 1965, another piece of evidence to support the Big Bang Theory was discovered. Two American Physicists noticed that no matter where they pointed there radio telescope, there was always some faint radiation detected. At first they thought it was bird droppings on the telescope, but after cleaning it, they discovered that the universe itself was emitting this radiation from all directions.

How the Universe was Formed This radiation is now known as Universal Cosmic Background Radiation. The universe is microscopically warmer than absolute zero because this radiation energy has spread throughout the universe from the original big bang explosion.

Wilkinson Microwave Anisotropy Probe (WMAP) image of the entire sky, showing very little variation in the cosmic background radiation.

How the Universe was Formed To imagine this concept, pretend that you heat up a closed oven to 700 degrees Fahrenheit. If you suddenly opened the door, the heat would escape from the oven and spread out (diffuse) evenly across whatever room it was opened into.

How the Universe was Formed The Big Bang Theory has two pieces of evidence as proof of its legitimacy and accuracy: Universal Expansion Universal Cosmic Background Radiation Using these pieces of evidence, scientist have concluded that the universe began as an infinitesimally small singularity about billion years ago.

Formation of the Solar System As stated in “Lives of Stars,” before our sun and solar system ever formed, a supernova occurred right here. The supernova left behind a planetary nebula - a gas cloud of hydrogen and helium, as well as every element needed to make the 8 planets and everything else in this solar system, including you.

Hubble image of a nebula in Orion in the process of forming a sun and planets.

Formation of the Solar System Something eventually disturbed the nebula (probably another nearby supernova), causing a collapse of the gasses towards the center. Because hydrogen and helium are the lightest elements, they fly towards the center first, eventually forming a protostar (smaller than the original) that will become our sun, Sol. The leftover, heavier elements begin to rotate around the protostar, colliding with each other, getting bigger and bigger, forming planetesimals.

As the particles rotate around the protostar, they flatten out (like pizza dough) into a disc shape that is called an accretion disc.

Formation of the Solar System Planetesimals eventually collided with other planetesimals to form planets. The protostar eventually begins nuclear fusion, becoming a full-fledged star. When fusion begins, the star blows out the most of the leftover particles. These particles are now the Oort Cloud.

The Future of the Universe There used to be two opposing views as to how the universe would die: Expanding forever, eventually turning dark and cold. The Big Crunch, where the universe begins to shrink back into its original Big Bang state.

The Future of the Universe Two recent discoveries have eliminated that down to one. Dark matter is matter that does not give off EM radiation, therefore cannot be seen. But studying the gravity of galaxies, it is estimated that about 23% of the entire universe is made of dark matter.

The Future of the Universe Dark Energy is a force that opposes the gravitational attraction of matter. In other words, it pushes outward. It is estimated that dark energy accounts for 73% of the known universe.

The Future of the Universe Okay, so we’ve got two forces in opposition: All matter and dark matter tend to reverse universal expansion, and form a Big Crunch. The original Big Bang expansion energy and dark energy tend towards continued expansion. So which one is greater?

The Future of the Universe The most recent discoveries have concluded that not only is the universe still expanding, but it is actually accelerating - expanding faster. Therefore, the only logical end to the universe is to continue to expand, stars will explode, and there won’t be enough gravity to collapse them back together. The universe will eventually grow cold, grow dark, and die.