Download
1 / 24
250 likes | 642 Vues
"for the discovery of the accelerating expansion of the Universe through observations of distant supernovae" . 2011 Nobel Prize in Physics. Awarded to Saul Permutter Brian Schmidt Adam Riess. As described by the Chem 187S class of 2011/2012. Written in the star s . By the Noble Group
E N D
"for the discovery of the accelerating expansion of the Universe through observations of distant supernovae". 2011 Nobel Prize in Physics Awarded to Saul Permutter Brian Schmidt Adam Riess As described by the Chem 187S class of 2011/2012
Written in the stars By the Noble Group (Timi, Jessica, Bobby,and Ngan)
Cosmos is growing • It was only 100 years ago where the universe was considered to be a calm and peaceful place. No larger than the galaxy: the Milky Way. • Early 20th century, the American astronomer Henrietta Swan Leavitt discovered a way of measuring distances faraway to stars. • She studied thousands of pulsating stars called Cepheids, the brighter ones had longer pulses. • She could then calculate the intrinsic brightness of Cepheids. • If the distance of just one Cepheid stars is known then the distances to other Cepheids can be proven. The dimmer the light, the further away the star.
With the use of the Cepheids, astronomers could conclude that the Milky Way is just one of the many galaxies in the world. • 1920’s: The Mount Wilson telescope in California: they were able to show that almost all of the galaxies are moving away from us. Called the redshift, it occurs when a source of light is receding from us. • Light’s wavelength gets stretched, the longer the wave the redder the color. • Galaxies are rushing away from us and each other, the further away they are the faster they move: Hubble’s Law • The Universe is GROWING.
The coming and going of the cosmological constant • In 1915, Albert Einstein published his General Theory of Relativity, the theory described that either shrink or expand. • Einstein could understand that the universe was not static. In order to stop this unwanted cosmic expansion he added a constant to his equation: the cosmological constant. Later he considered the insertion of the cosmological constant a mistake. • Later in 1997-98: the observations made concluded that the Einstein’s constant put in for the wrong reasons was actually smart.
Discovering the expanding universe was ground breaking just as how the universe was created in the big bang 14 billion years ago. • Ever since then the universe has been expanding, with galaxies moving away from each other due to the cosmological expansion.
Written in the Stars By the Radioactive Group Mat, Dan, Sam, and Lyle
SupernovaeThe new measure of the Universe • The Universe – open, closed, or flat. • The Nobel Laureates • Supernovae- Star explosions
The Universe • Open- The gravitational force of matter is not large enough to prevent the expansion of the universe, so matter is diluted in a larger empty space. • Closed- The big crunch would be created due to the great gravitational force that stops expansion and fall back. • Flat-expansion is believed to decline.
The Nobel Laureates • Expected to measure the cosmic deceleration, or how the expansion of the Universe is slowing. • By locating distant stars and to measure how they come, but cepheids are too far to see with telescopes so a new method needed to found.
Supernovae- Star Explosions • New standard candles. • In the 1990’s, the light sensitive digital imaging sensors were used as better computer telescopes. • The sensors are charged-coupled devices(CCD) were invented by Willard Boyle and George Smith. • Awarded the Nobel prize in 2009.
What is a white dwarf? • White dwarfs are very old stars. • All H and He have been fused- none left. • Not enough energy to fuse larger atoms.
Why do they explode? • Not enough energy to fuse dense elements. • No longer able to fuse- end of life cycle • Terminal step= explosion of light and cosmic radiation.
White Dwarfs, Binary Star Systems and You. • White Dwarf sucks up gaseous younger stars (exponentially greater gravity) • Explodes when it can no longer contain mass (in excess of 1.4 solar masses). • Interior heats until the star tears itself apart. • Initial explosion emits radiation for weeks, decreases over time.
White Dwarfs, Binary Star Systems and You. (cont.) • 6 supernovae occur every minute and only last for a few weeks. • We’re in a constant rush to find them- they tell us how large the universe is and are constantly appearing and disappearing.
An Astounding Conclusion By The Rare Earth Group
Finding A Supernova • Take two pictures of the sky • The first, just after the new moon • The second, three weeks later • The two images would be compared in the hopes of finding a bright dot in the second photograph (a sign of a supernova)
Problems Researchers Encounter • Distinguishing light from supernova and host planet • Dust and debris distorts the light of distant bodies • The supernova had to be far away to prevent local distortion • Supernova fade quickly so researchers needed telescopes asap
Results • Among approximately 50 observed supernova, had weaker light than expected • If the universe was slowing down the brightness should appear brighter • Concluded that the expansion of the universe is not slowing down - as was commonly believe – but speeding up
From Here to Eternity How Dark Energy is Accelerating the Universe
The Accelerating Expansion • The Cosmological Constant – The Static Universe • The Cosm. Constant has a new meaning: Expansion • Expansion began from the Big Bang • Deceleration occurred because of gravity • Dark Energy beat out gravity • Some estimations are too large • The amount of dark energy may not be constant
What is Dark Energy? • Energy that must be present • Caused by the destruction of virtual particles • Even empty space is full of “stuff” • Over 75% of the universe is dark energy • Only 5% is regular matter • The rest is dark matter (Almost 20%) • Yet another mystery • Stars, Galaxies, planets, Nebulae, etc. – 5% • Dark matter pulls, Dark energy pushes
