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Chapter 22: The Birth of the Universe

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1 Chapter 22: The Birth of the Universe
© 2017 Pearson Education, Inc.

2 Particle Accelerators
Large Hadron Collider – CERN (France/Switzerland) fdfa4f47703d196dffb3c361.jpg © 2017 Pearson Education, Inc.

3 Planck Era ends when Gravity
Separates out from Grand Unified Force

4 GUT Era ends when Strong Force
Separates from Electroweak Force. This results in release of enormous amounts of energy causing Inflation. In seconds objects the size of atomic nuclei grow to the size of solar systems!

5 Electroweak Era ends when the Weak Force separates from the Electromagnetic Force.
From this point on the Universe has Four Distinct Fundamental Forces.

6 Theory of Electroweak force predicted the existence of the W and Z Bosons (Weak Bosons) these bosons were discovered in 1983 in high energy accelerator experiments. This is really as far back as theories have fully confirmed the Physics.

7 During Particle Era all sorts of exotic sub-atomic particles are being created in matter-antimatter pairs. Objects such as quarks exist freely. By end of era quarks become locked up in larger particles such as protons, neutrons, etc.

8 Particle Era ends when Universe has cooled to a point where protons and anti-protons can no longer form from vacuum energy. If there were equal numbers of proton and anti-protons, all of them would have annihilated and there would be only photons and no matter. There was 1 extra proton for each 1 Billion proton-anti-proton pairs!

9 During Nucleosynthesis era nuclei are fusing and forming heavier nuclei, but gamma rays are colliding with them and breaking them apart.

10 Nucleosynthesis Era ends when the density universe is too low for fusion to continue. Temperature is still higher than that found in the core of our Sun but nuclei are too far apart. Composition of Universe at this point is 75% Hydrogen 25% Helium and trace amounts of other things. Pretty much what we found today outside of stars.

11 During the Nuclei Era the Universe is a plasma of free moving protons (Hydrogen nuclei), Helium nuclei, and free electrons. Photons are constantly colliding with electrons being temporarily absorbed and re-emitted. Hydrogen and Helium atoms try to form capturing electrons but photons break them apart quickly.

12 Just as in the core of our Sun photons cannot move very far before being absorbed and then re-emitted, they take a very long time to move anywhere and as a result the universe is DARK. The temperature is so high that there is the dense sea of photons bouncing around all these free electrons.

13 Era of Nuclei ends when the Universe cools enough through expansion that nuclei can begin to bind electrons to them and form neutral atoms. Now the photons stop being so dense and the Universe becomes TRANSPARENT! This occurs when the Universe is about 380, 000 years old!

14 Era of Atoms ends when Gravity
Begins to attract matter and forms proto-galactic clouds. These clouds begin to form Stars and Galaxies

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16 Peak of 3000 K Blackbody Radiation is 1000 nm = 1 micrometer (10-6 m)
Since the time of T = 380,000 years Universe has expanded about 1000 x in size. Peak should be shifted to 1000 x 10-6 m or 10-3 m or 1 mm!

17 Neutrons are slightly more massive than Protons
Neutrons are slightly more massive than Protons. Neutrons need slightly more energy to form than Protons. When Universe’s temperature is > 1011 K, particles change into each other equally. When temps fall below 1011 K, Neutrons convert to Protons but the reverse stops. Protons begin to outnumber Neutrons!

18 How do we KNOW Inflation Happened?
Examine temperature variations in Microwave Background Radiation. IF Universe is “Flat” largest variations should occur separated by about 1 degree of angular separation in the sky.

19 Chapter 23: Dark Matter, Dark Energy, and the Fate of the Universe
© 2017 Pearson Education, Inc.

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22 Chapter 24: Life in the Universe
© 2017 Pearson Education, Inc.

23 Astrobiology – Exobiology – Xenobiology
Research in three main areas 1. Origin of Life on Earth 2. Worlds that might have proper conditions for life. 3. Evidence of actual Life elsewhere

24 Why Older Fossils are Rare?
1. Older rocks more rare than younger rocks 2. Old rocks subject to more stresses (heat and pressure) and therefore transformations that destroy fossils occur. 3. Nearly all life prior to a few hundred million years was microscopic, so microscopic fossils are harder to find.

25 How to Date Fossils? Some of the oldest rocks on Earth are found on the Island of Akilia near Greenland. Carbon dating puts them at 3.85 billion years old. These rocks have evidence of fossils which indicate life began on Earth at least 3.85 billion years ago!

26 How Early Life Might Have Begun
Evidence of Oceans 4.3 Billion years ago. However, Bombardment Period going on in Solar System. High Probability comparing to Moon Craters that bombardment would have vaporized oceans and destroyed life. This Bombardment is often referred to as “sterilizing impacts” If life existed before 3.85 Billion years ago, evidence of such life is likely destroyed Bottom Line Life quite likely began Early in Solar System! Perhaps Other Systems also get Life Early?


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