THE BIG BANG,
by Roger Fritz, 1-3-06
It's amazing how much we can figure out about the universe from the clues we see around us. These clues show us that humans have been around for about 8 million years, that 65 million years ago an asteroid hit the earth and killed most of the dinosaurs, that before that dinosaurs ruled the earth for 180 million years, that life is about 4 billion years old, and that Earth is about 5 billion years old. And they show that the universe began in an explosion from a point, 13.2 billion years ago.
Science doesn't know what existed before the big bang. All that's known is that it wasn't time or space. The first moment before the big bang, there was nothing.
At the first moment of the big bang, all the matter and energy that are in the universe today, existed at a single point, impossibly dense, inconceivably hot, and quite dark. Time began, and space began to expand at a speed faster than the speed of light. In fact, the expansion of space is the only thing that can move faster than the speed of light. (Glanz, 00)
In The January 2006 issue of Discovery Magazine there's an article on page 54 about the Big Bang being re-enacted in the laboratory. Scientists at Brookhaven National Laboratory have recreated the searing-hot mix of exotic particles that filled the universe in the first microseconds after the Big Bang. The fireball they produced is 150,000 times as hot as the center of the sun. Their experiment found out that the universe started out not as a hot, dense cloud of gas, as has been thought. But as a strangely sublime, friction-free liquid.
They have a colossal atom smasher at Brookhaven, and it took them hundreds of scientists 3 years to collect the data. At the temperatures they achieved, ordinary matter melts down into a soup of quarks and gluons. Scientists expected the particles would fly freely in all directions, but they flow together in coordinated streams like a perfect liquid. At this point, the scientists at the laboratory are puzzled and surprized.
In order to talk about this whole thing, I have to remind you that a microsecond is a millionth of a second, or 10 to the minus 6 seconds.
10 to the minus 43 seconds (a trillionth of a trillionth of a trillionth of a ten millionth of a second) after the big bang: the universe had cooled to 100 million trillion trillion degrees. Gravity separated from the unified force. So far there had been only a single force.
10 to the minus 34 seconds (a trillionth of a trillionth of a ten billionth of a second): the temperature had dropped to a billion billion billion degrees. The strong and weak forces split off from the unified force. This enabled quarks and their anti-matter counterparts to coalesce.
10 to the minus 27 seconds (a billionth of a billionth of a billionth of a second): the universe was the size of the earth. (Folger, p. 48)
10 to the minus 10 seconds (a ten billionth of a second): the electromagnetic force separated from the unified force. This enabled electrons to form.
10 to the minus 5 seconds (a hundred thousandth of a second): the universe had cooled to a trillion degrees. Quarks began forming into protons, neutrons, anti-protons and anti-neutrons. For every 10 billion particles of anti-matter, there were 10 billion and 1 bits of ordinary matter. Matter and anti-matter annihilated each other, rendering most of space empty and releasing photons, flashes of light in the darkness. The universe sparkled, but for less than a second.
1 second after the big bang: electrons and positrons (anti-matter electrons) finished annihilating each other, leaving a remnant of electrons.
1 minute after the big bang: neutrons and protons formed the nuclei of helium, lithium and heavy forms of hydrogen. Heavier elements wouldn't be formed until billions of years later, by stars. The temperature was down to a billion degrees.
300,000 years after the big bang: the temperature was down to 3000 degrees. The radiation had been so intense that no particles could stay joined as atoms. But now nuclei began capturing electrons as they whizzed past, and matter as we know it began to form, as neutral hydrogen. The universe became transparent to low frequency infrared radiation, but not to light. This radiation has had its wavelength stretched by the exansion of the universe, so that we now see it as radio frequency waves. This is what we see now as the cosmic background radiation.
For its first 300,000 years, the universe was a hot cauldron of charged particles, a plasma. Light couldn't travel far in this boiling subatomic stew before bouncing off something, so it looked like a thick fogbank, glowing but nearly opaque. Sound, however, could travel freely. The subatomic particles emerging from the vacuum caused one sound, and phase changes caused another. The entire universe rang each time there was a phase change. Since the sound was all different frequencies mixed together, it sounded more like a cymbal than a bell.
The universe was almost completely smooth and featureless, but not quite. Sound echoing through the universe had created standing waves. If you put sand on a plate and touch the plate with a tuning fork, the sand will dance into a pattern. Different tones make different patterns. Something like this happened.
The formation of hydrogen and the release of the infrared radiation stopped the sounds, silencing the universe but leaving a slight lumpiness in place. This clumping of matter left faint but distinct imprints in the primordial glow. We can still see the early lumpiness in the cosmic background radiation. (Svitil, August 2000, p. 16)
Gravity first formed a web of filaments connecting the lumps, and then contracted that into a web. This web is the largest scale structure that exists. Voids between the strands emptied out as matter fell into the strands. Strands of the structure became thinner, as rivers of ordinary matter and dark matter flowed along the strands toward intersections. Matter pooled at the intersections. Roundish lumps tended to collapse into pancake shapes. Intersecting pancakes formed more filaments, and intersecting filaments formed more lumps.
100 million years after the big bang: gravity in the web's intersections coalesced hydrogen gas into the first stars. Space was (and still is) filled with a fog of hydrogen atoms. When the stars ignited, they were hot, and much more massive than the sun, and their light was mostly ultraviolet. The light ionized the hydrogen atoms, turning space transparent. The fog burned off, so to speak. Bubbles of clarity expanded from each new star. (Folger p. 48)
One of the mysteries in astronomy is that quasars formed at the same time as the first stars. Quasars shine as brightly as billions of suns, and the light is thought to be from matter and energy circling around and pouring into the supermassive black holes at the center of each galaxy. When the black holes first formed, they sucked in neighboring matter. The matter spiralling around the black hole rubbed against each other and got so hot that energy was emitted. The energy caused a wave of star formation, and it also pushed back the interstellar matter until the black hole stopped feeding and became quiet. The result is that the black hole at the center of a galaxy is about one half of one percent of the mass of the galaxy.
900 million years after the big bang: The expanding bubbles of clear space met up, and light could now travel freely through the universe.
6 billion years: Galaxies began to group together into clusters.
7 billion years: Our solar system formed.
9 billion years: Clusters gathered into superclusters.
10 billion years: Life on Earth began.
Oregonian, 2-10-00, article by James Glanz, NY Times News Service
Discover, October 1992, page 74, The Fingerprint of Creation, by
Discover, May 2000, page 48, The Magnificent Mission, by Tim
Discover, August 2000, page 16, Let There Be Microwaves, by Kathy
Oregonian, 4-7-01, article by James Glanz, NY Times News Service:
Scientists see dim beginning of cosmos
New York Times on the web, 8-4-01. Exploring Cosmis Darkness, Scientists See Signs of Dawn, by James Glanz.
Oregonian, 8-17-01, p. A22. A trip through time: Tracing the cosmic web, by James Glanz.
Discover Magazine, January 2006, page 54: The Big Bang is re-enacted in the laboratory.
Here's a version of The Big Bang you can download: