Supernovaes

Dark energy makes up most of our universe. Every object out in space is bound to interact with it at one point or another because it is claimed to be the cause of the expansion of the universe. The dark energy pushes objects further apart in space and making astronomers want to learn more and more about this mysterious dark energy. Astrophysicists first discovered cosmic acceleration by examining the apparent brightness of tens of distant Type Ia supernovae, exploding stars that briefly become as bright as an entire galaxy of billions of stars. There is a Dark Energy Survey that will continue to examine this further by finding and making detailed measurements of several thousand supernovae. To determine the distances to these stars, cosmologists use the fact that Type Ia supernovae are nearly "standard candles": exploding stars of this type all have nearly the same absolute brightness or luminosity when they reach their brightest phase. By comparing the apparent brightness of two supernovae, we can then determine their relative distances. What is causing this distance is the dark energy pushing them further and further apart.   
                                                
                                               http://www.darkenergysurvey.org/images/sn94d-1.jpg

                                                

 http://i1-news.softpedia-static.com/images/news2/Understanding-the-Origin-of-Type-Ia-Supernovae-2.jpg

References:

1.       "What is Dark Energy?", Nola Taylor Redd, http://www.space.com/20929-dark-energy.html

2.       “Big Bang: How Did the Universe Begin?”, Yuki D. Takahashi, Spring 2000, http://www.ugcs.caltech.edu/~yukimoon/BigBang/BigBang.htm

3.         “Dark Energy, Dark Matter”, NASA Official: Ruth Netting, April 30, 2013, science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/ 

Cosmological Constant

The discovery of dark energy was quite surprising to people when they first found out. Although people were surprised by the discovery, it is not an entirely new concept. Albert Einstein along with other astronomers did not know that the universe was expanding. When he found that the equations that he came up with did not work for a static universe, a cosmological model in which the universe is both spatially infinite and temporally infinite, and space is neither expanding nor contracting. He threw in a hypothetical repulsive force that would fix the problem by balancing things out, an extra part that he called the "cosmological constant." When Einstein discovered that the universe was expanding, he threw out the concept of the cosmological constant. Today astronomers refer to the theory as dark energy. Even though Einstein thought it was a mistake in the equations he came up with, little did he know, he had discovered dark energy.

                                       

                                            http://wfirst.gsfc.nasa.gov/about/darkenergy.jpg

                                           

http://www.scholarpedia.org/w/images/thumb/b/b8/CosmologicalConstant2.jpeg/350px-CosmologicalConstant2.jpeg

References:

1.   “Dark Energy, Dark Matter”, NASA Official: Ruth Netting, April 30, 2013,science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

2    2.  “Dark Energy Explore More: Fate of the Universe”, Hubble Discoveries,http://hubblesite.org/hubble_discoveries/dark_energy/de-fate_of_the_universe.php

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The Universe's Composition

Everything in the universe is made up of protons, neutrons and electrons.  Material composed of protons, neutrons and electrons is what astronomers call baryonic matter (ordinary atoms). [2] Until recent discoveries, astronomers thought almost the entire composition of the universe was baryonic matter until evidence suggested there is something more that we cannot see. [3] According to NASA, our universe is roughly made up of 68% dark energy, 27% dark matter, and about 5% normal matter. What exactly are these? [4] Dark energy is a form of energy that permeates all of space, producing a repulsive force that accelerates the expansion of the universe. Dark matter is matter that does not emit or absorb electromagnetic radiation. It is thought to constitute most of the mass in the universe. Normal matter is matter in galaxies-including stars, gas, and dust-that emits electromagnetic radiation. Dark energy was discovered when two separate teams of astronomers studied a Type Ia supernovae in 1998. They both independently found that the distances to the galaxies which had the supernovae they were observing were farther than when they had been found using other methods. There is so much that is a mystery about dark energy, forming more questions everyday about the universe.

                                                      

                                                               Composition Pie Chart

                  http://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/DMPie_2013.svg/250px-DMPie_2013.svg.png

References:

1.       “The Composition of the Universe”, Hubble News, https://www.spacetelescope.org/science/composition_of_universe/

2.       Webmaster: Britt Griswold, NASA Official: Dr. David T. Chuss, Friday, 01-24-2014, wmap.gsfc.nasa.gov/universe/uni_matter.html

3.       “Dark Energy, Dark Matter”, NASA Official: Ruth Netting, April 30, 2013, science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

4.       “21^st Century Astronomy: Stars and Galaxies fourth edition, Norton & Company, Inc., 500 Fifth Avenue, New York, N.Y. 10110

From the Beginning

According to the big bang theory, the universe began by expanding from an infinitesimal volume with extremely high density and temperature. Space itself began expanding from that moment on. The big bang is not like an explosion of matter in otherwise empty space; rather, space itself began with the big bang and carried matter with it as it expanded [3].  [1] When the word first got out that the expansion of the universe was accelerating, many astronomers questioned the results. They felt that the observations had to have been wrong, or there was some sort of mistake in interpreting the results. The whole concept was so difficult to believe because it requires significant changes in our understanding of the way the universe works. Before scientists had discovered dark energy, there were two theories on how expansion would work. [2] One theory was in a “Big Crunch” where there would be enough matter in the universe to slow down expansion until it reached the point where it would come to a stop and start to retract. [3] The other theory and what was thought to be the most likely, the “Big Chill”, said there would be too little matter to stop the expansion and everything would just drift on forever, slowing down yet never stopping. It would continue to expand until everything was faded and died out, ending in a vast, dark, and cold state. According to this theory, the universe should be expanding more slowly now than it did in the past due to gravity. Astronomers were stunned to read the results stating there is some force appearing to be pushing the universe apart which they called dark energy. [3] With the discovery of dark energy came a new and more violent theory for the future of the universe called the “Big Rip”. This theory stated that as the universe expands ever faster, all of gravity's work will be undone. Clusters of galaxies will disband and separate. Then galaxies themselves will be torn apart. The solar system, stars, planets, and even molecules and atoms could be shredded by the ever-faster expansion. The universe that was born in a violent expansion could end with an even more violent expansion.

                                      

                                      Image of the possible outcomes of the universe

                   http://sumire.ipmu.jp/wp-content/uploads/2010/10/Future-View-of-the-Universe.jpg

References:

1.       1. "What is Dark Energy?", Nola Taylor Redd, http://www.space.com/20929-dark-energy.html

2.       2.“Dark Energy Explore More: Fate of the Universe”, Hubble Discoveries, http://hubblesite.org/hubble_discoveries/dark_energy/de-fate_of_the_universe.php

3.       3.“Big Bang: How Did the Universe Begin?”, Yuki D. Takahashi, Spring 2000, http://www.ugcs.caltech.edu/~yukimoon/BigBang/BigBang.htm