Formation of the Universe In the very beginning

Formation of the Universe

“In the very beginning, there was a void, a curious form of vacuum, nothingness containing no space, no time, no matter, no light, no sound. Yet the laws of nature were in place and this curious vacuum held potential. A story logically begins at the beginning, but this story is about the universe and unfortunately there are no data for the beginnings—none, zero. We don’t know anything about the universe until reaches the mature age of a billion of a trillionth of a second. That is, some very short time after creation in the big bang. When you read or hear anything about the birth of the universe, someone is making it up— we are in the realm of philosophy. Only God knows what happened at the very beginning. ” --Taken from The God Particle by Leon Lederman, a Nobel Prize winner

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

Universe in a Nutshell

Big Bang Theory l The Big Bang Theory was first proposed in the late 1920’s. l It states that there was an infinitely small, infinitely dense point that contained everything that is the universe. l This singularity was incredibly dense and hot.

Big Bang Theory l The Big Bang is believed to have occurred between 10 and 15 billion years ago. (Most scientists agree that the universe is 13. 7 billion years old. ) l Two elements, hydrogen and helium were created in the primordial fireball, along with small amounts of lithium and beryllium.

Georges Henri Lemaitre l Late 1920’s l Belgian Astronomer and Jesuit Priest l Known as the “Father of the Big Bang” l First suggested that the universe formed from a singularity but had no evidence.

Edwin Hubble l 1929 l Studied light given off by galaxies. l Noticed that light from most galaxies was shifted to the red end of the electromagnetic spectrum. l Proposed Hubble’s Law after studying these galaxies.

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

Electromagnetic Spectrum

Hubble’s Law l l All Galaxies exhibit redshifts of spectral lines. More Distant Galaxies Recede Faster

Cosmic Microwave Background Radiation l Long-wavelength radiation that fills all space. l Can be detected using special antenna. (1% of this can be detected in the static on your TV set. ) l George Gamow (1940’s) predicted there should be “echoes” of the Big Bang “explosion. ”

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

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

WMAP l Wilkinson Microwave Anisotropy Probe (WMAP) captured the “glow” of the Big Bang by detecting temperature changes just like COBE. l WMAP was much more precise.

Historical Observations of the CMB and Anisotropy

What’s the Universe Made Of? l 4 % Atoms l 22% Cold Dark Matter l 74% Dark Energy

What is Dark Matter? l Dark matter: this generally refers to "exotic" matter that interacts only weakly with ordinary matter. While no such matter has ever been directly observed in the laboratory, its existence has long been suspected.

What is Dark Energy? l Dark energy: this is a truly bizarre form of matter, or perhaps a property of the vacuum itself, that is characterized by a large, negative pressure (repelling force). This is the only form of matter that can cause the expansion of the universe to accelerate, or speed up.

Steady State Theory l Opposes the Big Bang Theory l Steady State Theory states that the universe has always been essentially the same as it is today and that it will continue that way forever.

Steady State Theory l As matter moves apart, new matter is created to fill the gaps. l Cosmic Background Radiation in the universe ruled out the Steady State Theory.

Evidence of the Big Bang 1. The expansion of the universe Edwin Hubble's 1929 observation that galaxies were generally receding from us provided the first clue that the Big Bang theory might be right.

Evidence of the Big Bang 2. 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. l 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)

Evidence of the Big Bang 3. 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.

Limitations of the Big Bang 1. Structure in the universe The Big Bang theory makes no attempt to explain how structures like stars and galaxies came to exist in the universe.

Limitations of the Big Bang 2. Fluctuations in the cosmic microwave background (CMB) radiation The temperature of the CMB is observed to vary slightly across the sky. What produced these fluctuations and how do they relate to stars and galaxies?

Limitations of the Big Bang 3. The inflationary universe A very short, but especially rapid burst of growth in the very early universe (“inflation”) provides an elegant, yet untested, explanation of the previous puzzles.

Big Picture Timeline

Fates of the Universe l Open Universe l Closed Universe l Flat Universe l Accelerating Universe

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

Fates of the Universe l Flat Universe – slowing down but never halting. l Accelerating Universe - expansion of the universe will speed up. (Most accepted theory because of dark energy. )

Light l A light year is defined as the distance that light travels in one earth year. l Light travels at 300, 000 km/s or l 186, 000 mi/s l

Into the Past Time and Space are Inseparable… l Light travels at a finite speed (3 x 108 m/s) l When you look into the night sky, you look into the past… l The farther out you look, the farther back in time you see… l The sequence of events in the evolution of the universe are “written” in space like an eternal movie… l

Into the Past Time Required for Light to Travel to the Earth Moon 1. 25 seconds Sun 8. 5 minutes Centrari 4. 5 years Betelgeuse 1200 years Milky Way 100, 000 years Andromeda 2. 2 million years Virgo Cluster 60 million years Hydra Super Cluster 3 billion years Quasars 13 billion years Cosmic Microwave Background Radiation (CMB) 13. 5 billion years