The “Big Bang” Theory The beginning of everything we know

What is the Big Bang? The theory says that all matter in the universe came together due to gravity. It became so dense that the pressure caused it to “explode”. This happened approximately 15 billion years ago. All of the matter moved outward and the universe is still expanding.

What proof do we have? Background Radiation –Scientists detect a background radiation when they study the universe. The radio signature is consistent wherever they look. Doppler Red Shift (The Doppler Effect) –The light from stars is analyzed and the spectrum is shifted toward the longer wavelengths of light – toward the red

What is the Doppler Effect? When energy waves are given off by a moving object the waves are… –Stretched when it is moving away –Compressed when it is moving closer The Doppler Effect is used when analyzing star light, determining the speed of a ball or motor vehicle, and for weather radar.

A stationary train sends the same sound wave in every direction and the whistle has the same sound or pitch no matter where you are standing.

A moving train will have a higher pitch whistle when it is moving toward you and a lower pitch after it passes you.

TrainAmbulanceTruck Car Horn Doppler Song Hear the Doppler Effect!

So what happened after the “Big Bang”? Matter started to “clump” back together This was due to gravity The galaxies, stars and planets formed from these clumps of dust and gas There are billions of galaxies in the universe and each galaxy consists of billions of stars

So What about Earth? Our solar system, including the Earth, formed about 4.6 billion years ago. That is about 10 billion years after the “Big Bang”. Hominids (early ancestors of man) have only been around for about 3.6 million years and Homo sapiens for only about 200,000 years.

So what’s the deal with Stars? Stars are giant balls of mostly gas (usually hydrogen and helium) that give off huge amounts of energy through nuclear fusion. Nuclear fusion is a process that joins two nuclei together and gives off a lot of energy in the process. The Sun is our closest star. All stars go through a similar evolution or life cycle which includes… –Hydrogen (H) to Helium (He) and then Helium (He) to Carbon (C)

Star Life CycleNebula (Stellar Cloud)Protostar (Cloud Compresses)Star Is created when fusion begins Stars like the sun take about 10 billion years to convert all Hydrogen to Helium Star will expand then cool Red Giant Red Giant is formed (Luminosity increase while temps. decrease) Helium in core now reacts (fusion) to form Carbon Star contracts. Temps. too cool for Carbon fusion. White Dwarf Stars energy production stops. White Dwarf is created. Novas Some White Dwarfs do not just cool and die. Some may have large explosions called Novas. Explosion may cause star to become a million times as bright – for a short period of time. Super-Nova A Super-Nova is a large explosion(s) that destroys a star. Neutron Star After explosion of a Super- Nova, a dense ball of neutrons may be formed = Neutron Star Black Hole When leftovers are too dense – a Black Hole may be produced. – So dense, light cannot escape. The END!! or is it?              

So what about the origins of life? There is evidence that the organic material (amino acids) necessary for life arrived on Earth in meteorites. Organic material is carbon based compounds and is part of all life as we know it. It may have been lightning that made these compounds become “alive”. Water was necessary for life to evolve and this may have come from comets Oxygen in the atmosphere was given off by early organisms that were very abundant

When did life arrive on Earth? Evidence suggests that life arrived on Earth about 3.6 billion years ago. These life forms were the simplest form of life – simple bacteria. There is evidence of multi-cellular life as far back as 1 billion years. As organisms with shells and eventually bones arrive the fossil record becomes more detailed because these are more easily preserved.