--------- #1285 - How the Universe was Born?
- This review discusses the beginning of the Universe and how it evolves. New technology is teaches us more details. It is a simple process that grows in complexity. The evolution of life starts with this complexity and takes us to where we are today.
- Attachment - Big Bang
- As astronomers look at ever more distant objects they look backwards in time toward the birth of the Universe. The images they see are billions of years younger then they actually are today. It took billions of years for the light to reach us even though it was traveling at 670,633,500 miles per hour. Light had a lot of distance to cover in order to reach us.
- What we see in astronomy is always old information.
- How will astronomers know when they see the first objects that ever existed?
- The light itself did not escape the Big Bang for 380,000 years. The Universe was a fireball of hot plasma, charged fundamental particles, that did not let the light escape. The Universe expanded and cooled for 380,000 years until it was cool enough for neutral atoms to freeze out of the charged plasma. Protons and electrons slowed down enough to form neutral atoms. This is when the Cosmic Microwave Background first released its transparency. Up until that moment the plasma was opaque.
- We call it microwave but when light was first released it was high energy Gamma Rays. The high frequency, short wavelengths traveled through the expanding Universe and lost energy as wavelengths were stretched out longer and longer. The expanding space stretched the wavelengths out to the microwave wavelengths we see today. The temperature fell from 3,000 Kelvin to 3 Kelvin over that distance.
- By studying the slight temperature variations in the Cosmic Microwave Background astronomers can deduce that the first stars turned on 200,000,000 after the Big Bang.
- When the first galaxies formed they were extremely chaotic and closer together. They were irregular galaxies that experienced frequent collisions and mergers. The first galaxies were far different than the orderly spiral galaxies we have today.
- Before 380,000 years, before light was released, the Universe had an eerie, defused, blue-violet glow but no discrete sources of light. The make up of the Universe was mostly hydrogen nuclei, protons, When the Universe expanded and cooled to 3,000 Kelvin the protons captured the free electron and created the neutral hydrogen atom. Some helium existed as well as traces of deuterium (heavy hydrogen, or hydrogen atom with a neutron), lithium ( 3 protons), and beryllium ( 4 protons ).
- Dark Matter started to coalesce under gravity into small filaments that grew larger and larger. This became the skeletal scaffolding upon which the galaxies would form. Where Dark Matter filaments intersected a gravity sink hole formed. these sink holes compressed the gas and formed molecular hydrogen gas.
- Hydrogen molecules radiate energy more efficiently and cooled quickly. Dark clouds formed and cooled to 300 Kelvin. This cooling had the effect of separating the normal matter ( baryonic matter ) from Dark Matter. Dark Matter does not radiate electromagnetic energy. Each cold dark molecular cloud held 1,000,000 times Solar Mass in the size 1/1,000th the diameter of our galaxy.
- The relentless gravity squeezed the hydrogen into a denser and denser cloud that eventually formed helium nuclei. This was the birth of nuclear fusion and the first stars were born fusing hydrogen into helium.
- The stars were big and lived short lives. They died as supernovae forming every heavier elements up the Periodic Table of 100 different elements. The complexity of the Universe began.
- Most stars were giant stars greater than 100 Solar Mass. They lived only a few million years before exploding into supernovae. The core temperatures of these giant stars reached 10,000,000,000 Kelvin.
- Many of the supernovae explosions left Blackholes of 10 Solar Mass. Shock waves from the supernovae collided with surrounding gas clouds triggering additional star formation.
- Once the heavier elements filled the gas clouds in the interstellar space cooling became even more efficient and smaller stars the size of our Sun could form. They were ultra-blue stars with surface temperatures of 50,000 to 80,000 Kelvin.
- We say the early stars were ultra-blue but the wavelengths we see today are so stretched that they are in the infrared. In fact, so far into the infrared that the Hubble Space telescope does not have the instrumentation needed to see them We need the replacement , the Webb Space telescope, to see the stars in the 200,000,000 to 300,000,000 year era after the Big Bang.
- In 1990 ground based telescopes could see to 6,000,000,000 years old
- In 1995 Hubble Space Telescope could see to 1,500,000,000 years old.
- In 2004 the Hubble Ultra Deep Field could see to 800,000,000 years old.
- In 2010 the Hubble ultra Deep field Infrared could see to 480,000,000 years old.
- In ???? the Webb Space Telescope will see to 200,000,000 years old.
- A star like our Sun lives for billions of years. As it approaches death it begins to pulsate. The result is an expanding bubble called a Planetary Nebula that forms. Planetary Nebulae only live for 10,000 years before the gas dissipates and the core is reduced to a White Dwarf star.
- White Dwarfs are 0.5 to 1.4 Solar Mass and remain a carbon-oxygen ash slowly cooling in space for billions of years. White Dwarf diameters are about the size of the Earth. Astronomers have found and recorded about 1,500 of these White Dwarf stars in our galaxy.
- A higher mass star, >1.4 Solar Mass, has greater gravitational force compressing their core even hotter. These super hot cores fuse elements heavier and heavier up the element iron. Iron is the heaviest element nuclear fusion can create because heavier than iron and nickel the elements have to absorb energy to fuse rather than emit energy. It is the energy radiation in stars that fight gravity and keep them from collapsing.
- When larger mass stars try to fuse elements above iron the core collapses the electrons into protons creating neutrons. This collapse happens in stars in less than one second. The sudden collapse to the core results in a rebound sending a shockwave that tears through the in falling material. The resulting explosion is extremely bright, emitting 100 times more energy than our Sun will emit over its entire lifetime.
- If the inner core survives with a Solar Mass of 1.4 to 3.0 the remnant is a Neutron Star that collapses to a size 12 miles in diameter. The Neutron Star spins rapidly as it collapses and generates a strong magnetic field. Like an ice skater pulling in her arms in a spin the diameter of the star shrinks from 60,000,000 miles to 12 miles spinning faster and faster. Example: The Crab Nebula Neutron Star completes 30 rotations per second.
- If the inner core survives with a Solar Mass greater than 3.0 than its gravity overcomes even neutron degeneracy pressure and the neutrons collapse into a Blackhole. At the Blackholes event horizon the gravity is so immense that even light can not escape.
- So here is a summary of the Universe evolution to date:
------------- 0 years ------------------------ Big Bang ------------------------ Redshift 1000
------------ 17,000,000 years -------------- Universe is cold and dark ----- 90
------------ 100,000,000 years --------------1st stars are forming ------------- 30
------------200,000,000 years ------------- 2nd generation of stars begin forming the interstellar medium of supernovae debris. --------------------------------------- 20
----------- 500,000,000 years ------- 1st galaxies form with 2nd generation stars --10
------------9,000,000,000 years ---------- the solar system forms.--------------- 4
------------13,750,000,000 years ---------- you are reading this review -------- 0
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707-536-3272, Tuesday, August 2, 2011
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