Formation of the Universe. What evidence supports current scientific theory?

Transcription

1 Formation of the Universe What evidence supports current scientific theory?

2 Cosmology Cosmology is the study of the Nature, Structure, Origin, And fate of the universe.

3 How did it all begin? Astronomers theorize that the universe came to be in a single moment. According to this theory, all the matter and energy of the universe were at one time concentrated in an incredibly hot dense region, a form of matter called plasma. At a super heated state, it was too hot for atoms to form, or other properties such as gravity or electromagnetic forces to occur And then, Billions of years ago all at once, rapid expansion, and an enormous explosion!!!!!

4 Then what? The universe expanded very quickly -After a few thousand years, some cooling occurred, which allowed for the formation of atoms -first Hydrogen and Helium, but it had to cool still more for the other elements to start to form and be neutral atoms -Anti-matter also formed, composed of antineutrinos, positrons, anti protons. (hhmmm?) - As cooling increased, Gravity pulled atoms together into gas clouds that then evolved into stars and young galaxies

5 The Beginning The Big Bang

6 The Big Bang Theory

7 Center of Universe? There is NO CENTER to the universe Expansion looks the same regardless of where you are in the universe. Every point appears to be the center of the expansion, therefore no point is the center. The universe is infinite.

8 Big Bang evidence 1) Universal expansion and Hubble s Law 2) Cosmic microwave background radiation 3) Abundance of light elements

9 1. Hubble s Law The rate at which a galaxy is moving is directly proportional to its distance from us. In other words, the farther away a galaxy is from us, the faster it travels away from us. Thus the universe is expanding.

10 Age of the universe Since astronomers know how fast the universe is expanding, they can infer how long it has been doing so. - this is based on evidence of the Red Shift Now estimated at BYA How could we determine what is happening? What evidence could be gathered? Spectroscope Lab

11 Light Spectrum background

12 Why Support Big Bang? Explains the red shift we see today in galaxies What s a red shift???

13 The Universe is Expanding By looking at a star s spectrum (lines that indicate what elements are in star) you can determine whether it is moving toward or away from you Edwin Hubble discovered this phenomenon

14 The Expansion of the Universe Cosmological Redshift Space itself is expanding.

15 How the Universe Expands The space between galaxies expands, not the galaxies themselves; objects held together by their own gravity are always contained within a patch of nonexpanding space. Example: raisins in a loaf of bread. As the dough rises, the overall loaf of bread expands; the space between raisins increases but the raisins themselves do not expand.

16 Expanding Cake Analogy Just as all the chocolate chips move apart as the cake rises, all the superclusters of galaxies move away from each other as the space of the Universe expands.

17 Evidence of the Big Bang 2. The cosmic microwave background (CMB) radiation The early universe should have been very hot. The cosmic microwave background radiation is the remnant heat leftover from the Big Bang.

18 WMAP s Baby Picture of the Universe Cosmic Microwave Background Radiation

19 Bell Laboratories Penzias and Wilson (1965) were radio astronomers who worked for Bell Telephone Laboratories. Found a mysterious microwave signal causing background noise in their radio telescope. The signal came from everywhere. Arno Penzias Robert Wilson

20 COBE Cosmic Background Explorer (1989) Probe that looked 15 billion light years into space to detect tiny temperature changes. These temperature changes were evidence of the heat left over from the Big Bang.

21 In Search of The Earliest Photons Wilkinson Microwave Anisotropy Probe (WMAP) satellite, launched in 2001

22 WMAP In June 2001, Wilkinson Microwave Anisotropy Probe (WMAP) captured the glow of the Big Bang by detecting temperature changes just like COBE. WMAP was much more precise.

23 Historical Observations of the CMB & Anisotropy

24 3. Evidence of the Big Bang The abundance of the light elements H, He, Li The Big Bang theory predicts that these light elements should have been fused from protons and neutrons in the first few minutes after the Big Bang. Predicted abundance of elements heavier than hydrogen, as a function of the density of baryons in the universe (expressed in terms of the fraction of critical density in baryons, Omega_B and the Hubble constant)

25 So what About the future? Here are some ideas: Open Universe The universe will continue to expand forever. Big Crunch The universe will slow in it s expansion and gravity will pull all matter back into a single point. Flat Universe The universe will slow its expansion and eventually stop.

26 Fates of the Universe Open Universe little gravity that outward expansion goes on forever Closed Universe gravity will eventually halt the expansion and draw everything. Also known as the Big Crunch

27 Expansion of the Universe is speeding up Very distant Type 1a Supernovae are not as bright as they should be. This means the expansion of the Universe is speeding up instead of slowing down or staying the same. There is something really weird called Dark Energy (not the same as Dark Matter) that is causing this acceleration. Dark Energy acts like anti-gravity, pushing the Universe apart. We do not know what this Dark Energy is, but it makes up 73% of the total energy/matter of the Universe.

28 Composition of the Universe Suppose all the matter and energy in the Universe is $100 in your wallet or purse. $73 would be Dark Energy the mysterious energy that s pushing the Universe apart faster and faster. $23 would be Dark Matter matter that doesn t give off any kind of radiation, so we can t see it but it does have gravity. So out of your Universe of $100, $96 represents Dark Energy and Dark Matter that have yet to be identified. Only $4 would be visible matter the regular stuff we can see, like stars, gas clouds, and dust the same stuff we re made of. Of the visible matter ($4), only one-tenth of it shines as stars. That s 40 cents out of your total $100. The rest of the visible matter is gas clouds and dust.

29 Dark Matter Dark matter is matter that does not give off radiation, but still has gravitational properties. Dark Matter cannot be seen directly, but its presence can be detected by observing its gravitational effects on visible matter. With out it in our universe, it would be hard to tell how fast everything would keep expanding.