|Speaker:||Raymond L. Orbach, Department of Energy|
|Topic:||“Genesis: Science and the Beginning of Time”|
The 2159th meeting of the Philosophical Society of Washington was called to order at 8:19 PM in the Powell Auditorium of the Cosmos Club. President Haapala was in the chair. President Haapala introduced the speaker for the evening, Raymond L. Orbach who is the Director of the Office of Science at the Department of Energy. The speaker received his bachelor of science in physics from California Institute of Technology. He received his Ph.D. in physics from the University of California, Berkeley. He served on the faculty of UCLA and became provost of the College of Letters and Science. Before his appointment at DOE, he was Chancellor of the University of California, Riverside from 1992 through 2002, and he is now Chancellor Emeritus. Mr. Orbach addressed the society on Genesis: Science and the Beginning of Time.
The history of the universe since the Big Bang (Genesis) can be divided into eight epochs where observation and theory describe events critical to the evolution and future of our world. These epochs represent “The BIG questions” which we are now able to place in theoretical perspective, and in many cases, measure directly.
In the beginning, there was the Superstring Era. Everything started with a tiny dot containing all the energy of the universe. Then an expansion of the space-time continuum took place took place in 10 billionths of a trillionth of a trillionth of a trillionth of a second after the Big Bang. In this first epoch the temperature was 10 trillion trillion times the temperature of the interior of our sun. In this Superstring Era, the matter particles, such as various quarks were indistinguishable from each other and could swap identitities.
The second epoch is called the Grand Unification Theory (GUT) Era. In the GUT Era, things cooled down enough so that gravity became distinguishable, but the strong force, the weak force, and electromagnetism were still all together, because the temperature was still so high – everything was at one billion times the temperature of the sun. This all took place in 10 trillonths of a trillionth of a trillionths of a second.
The third epoch is called the Inflation Era. The cooling of the Inflation Era caused the strong force to become distinguishable, but the weak force and electromagnetism remained together, constituting the electroweak force. This era was characterized by a repulsive gravitational force that made everything inflate very rapidly in a period of 10 billionths of a trillionth of a trillionth of a second.
The fourth epoch is called the Electroweak Era. In the Electroweak Era, the temperature cooled down to 100 million times the temperature at the center of our sun during a “long” period of a tenth of a billionth of a second. The weak force separated from electromagnetism. In this era, matter predominated over antimatter. The Higgs field first appeared. The current research to find the Higgs boson seeks to verify that the mass of elementary particles was derived from this field.
The fifth epoch is called the Particle Era. It took place over a 300-second period with temperatures cooled down to 1,000 times the temperature at the center of the sun. Protons and neutrons fused together to form light nuclei like deuterium, helium, and lithium.
The sixth epoch is called the Recombination Era. It took place over a 300,000-year period. During this period the temperature of the universe cooled down to 3,000° Celsius, which is one ten-thousandth the temperature at the center of the sun. Neutral atoms formed from the combination of nuclei and electrons. Light, which was previously trapped, escaped and propagated throughout the universe. The Cosmic Background Radiation was formed in this period. It has been analyzed using the Cosmic Background Explorer satellite.
The seventh epoch was the era of Galaxy and Star Formation. In the next 200 million years since the Big Bang, the average temperature of the universe cooled down to 15 Kelvin (-258° Celsius) and the stars formed.
The eighth epoch is the Present Era. Experiments indicate that the universe is now 13.7 billion years old. The average temperature is now 2.7 Kelvin (-270.4° Celsius). Experiments have shown that the stars we see only constitute less than 0.5% of the mass and energy in the universe. Free hydrogen and helium constitute another 3% of the mass and energy. Neutrinos constitute 0.3% and heavy elements constitue 0.03%.
We have found from the rotation of the galaxies that 23% of the mass and energy of the universe is dark matter, which affects the motion of the galaxies but emits no radiation. Dark matter may be weakly interacting massive elementary particles, such as neutrinos.
We have found from the acceleration and expansion of the universe that dark energy comprises 73% of the mass and energy of the universe. The dark energy (discovered in 1997) appears to give an outward push that overcomes the pull of gravity and makes the expansion of the universe accelerate.
We hope to learn more about the origin of the universe from various experiments. These include the SNAP (SuperNova/Acceleration Probe), a space telescope with a camera capable of capturing a billion pixels. The DOE Office of Science sponsors the Tevatron proton/anti-proton collider at Fermilab ouside Chicago, which is looking for the lightest supersymmetric particle. The DOE Office of Science also sponsors the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The Rare Isotope Accelerator (RIA) is a proposed project to probe unstable isotopes with an overabundance of protons or neutrons, which would be useful in studying the formation of heavy elements in supernovae. There is also a search for the Weakly Interacting Massive Particle (WIMP) in a mine near Ely, Minnesota. The pace of discovery is quickening and a great deal has been learned within the past few years.
The President thanked the speaker for the Society. Mr. Orbach kindly agreed to answer questions from the floor. The questions included:
Q- Would the Superconducting Supercollider have helped study the history of the universe?
A- Yes. We lost a window of opportunity when it was not funded. The Large Hadron Collider can only handle 1/3 of the energy. The SSC would have been useful for looking back to the time of more massive particles.
Q- Could dark matter be anti-matter?
A- No. If it were, we would all be annihilated by now. Cosmic rays are a sample of the galaxy. In cosmic rays, protons outnumber antiprotons 10,000 to one.
Q- Would a telescope on the dark side of the moon help these studies?
A- No. The moon is not the problem. It is the earth's atmosphere. The best way to get a better view is a telescope in space like SNAP.
Q- Traditionally, physics is first taught toward the end of a high school education, after biology. Would earlier be better?
A- Yes. Physics would be good background for other subjects. It seems to be put off because people consider it to be hard.
President Haapala adjourned the meeting for the social hour at 10:13 PM . He made the usual parking announcements and reminded everyone not to carry alcoholic beverages outside the auditorium.
|David F. Bleil|
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