Theory on the Formation Theory on the Formation of the of the

UniverseUniverse

Popular TheoriesPopular TheoriesSteady State TheorySteady State Theory - theory suggesting that the - theory suggesting that the universe & everything within it is unchanging.universe & everything within it is unchanging.

Elastic TheoryElastic Theory - the universe acts like a rubber band, - the universe acts like a rubber band, expanding & contracting over time (currently it is expanding & contracting over time (currently it is expanding)expanding)

Big Bang TheoryBig Bang Theory - most widely accepted theory by - most widely accepted theory by scientists todayscientists today

What is a Theory?What is a Theory? Theories are an Theories are an explanationexplanation of a natural phenomenon of a natural phenomenon

that is supported by a large body of scientific evidence that is supported by a large body of scientific evidence obtained from many observations, experiments and obtained from many observations, experiments and laws.laws.

Theories are:Theories are: Based on evidenceBased on evidence TestedTested Effective in problem solvingEffective in problem solving The explanation of The explanation of HOWHOW

Origin Origin of the of the

UniverseUniverse

Big Bang Theory Big Bang Theory • occurred approx. 14 billion years agooccurred approx. 14 billion years ago• model for the beginning of the universemodel for the beginning of the universe

http://rainbow.ldeo.columbia.edu/courses/v1001/7.html

Infinitely dense point Infinitely dense point not governed by our not governed by our physical laws or timephysical laws or time

All matter and energy All matter and energy contained in one contained in one point the size of a point the size of a pinhead.pinhead.

The temperature was The temperature was so great that atoms so great that atoms could not existcould not exist

Building a UniverseBuilding a Universe

http://rainbow.ldeo.columbia.edu/courses/v1001/7.html

Universe came into existence at one moment in time and then expanded rapidlyInstantaneous filling of space with all matter.

Building a UniverseBuilding a Universe

Not an explosion, but rather an expansion of space itself, with all its matter and energy

After the BangAfter the Bang Ever since the big bang, the Ever since the big bang, the universe has been universe has been

expanding and coolingexpanding and cooling..

1010-43 -43 seconds after the Big Bang…seconds after the Big Bang…(that’s 0.00000000000000000000000000000000000000000001 seconds)(that’s 0.00000000000000000000000000000000000000000001 seconds)

The four fundamental forces were created:The four fundamental forces were created: Gravity, Gravity, Electromagnetic, Electromagnetic, Weak Nuclear, Weak Nuclear, Strong NuclearStrong Nuclear

After the BangAfter the Bang 3-20 minutes after the 3-20 minutes after the

Big Bang…Big Bang… NucleosynthesisNucleosynthesis = creating = creating

new nuclei from existing new nuclei from existing nuclei (two H’s make one nuclei (two H’s make one He)He)

It took billions of years It took billions of years for the universe to cool for the universe to cool down enough to allow down enough to allow stars and planets to stars and planets to form.form.

TodayToday All the matter and energy in the universe is still All the matter and energy in the universe is still

expanding.expanding. And has been expanding for the last 10-15 billion And has been expanding for the last 10-15 billion

years.years.

Summarizing, “A cosmological theory theory that the Summarizing, “A cosmological theory theory that the universe originated approximately 13.7 billion years universe originated approximately 13.7 billion years ago from the violent explosion of a very small point of ago from the violent explosion of a very small point of matter of extremely high density and temperature.”matter of extremely high density and temperature.”

The Size of the UniverseThe Size of the Universe

Edwin Hubble found…Edwin Hubble found… Universe is continuously expanding

Galaxy’s velocity is proportional to its distance (galaxies that are twice as far from us move twice as fast)

Taken every galaxy the same amount of time to move from a common starting position to its current position

Edwin P. Hubble (1889-1953)

Hubble's Law

Hubble’s Evidence of an Expanding Universe Doppler shift - wavelength emitted by something moving away from us

is shifted to a lower frequency Sound of a fire truck siren - pitch of the siren is higher as the fire truck moves towards you, and lower as it moves away from you

Wave compression or stretching due to velocity

Works with sound or light (electromagnetic waves), but…velocity changes have to be comparable to their speed to some degree.

Sound-340.29 m/sSound-340.29 m/s Light-300000 m/sLight-300000 m/s

Visible LightVisible Light

Visible wavelengths emitted by objects moving away from Visible wavelengths emitted by objects moving away from us are shifted towards the red part of the visible spectrumus are shifted towards the red part of the visible spectrum

The faster they move away from us, the more they are red-The faster they move away from us, the more they are red-shifted. Thus, red-shift is a reasonable way to measure shifted. Thus, red-shift is a reasonable way to measure the speed of an object the speed of an object

When we observe the red-shift of When we observe the red-shift of galaxies. galaxies.

The galaxy appears to be moving away The galaxy appears to be moving away from us – from us –

universe is expanding. universe is expanding.

Expanding Demo

Red Shift - moving away since the wavelength is getting longer and the frequency shorter

Blue Shift - moving closer since the wavelength is getting shorter and the frequency higher

Evidence for Big BangEvidence for Big Bang Red shiftRed shift - as light from distant galaxies approach - as light from distant galaxies approach

earth there is an increase of space between earth earth there is an increase of space between earth and the galaxy, which leads to wavelengths being and the galaxy, which leads to wavelengths being stretchedstretched

Cosmic Microwave Background radiationCosmic Microwave Background radiation (CMB) left over from the Big Bang shows that as left over from the Big Bang shows that as the universe expands the wavelength of its energy the universe expands the wavelength of its energy wave expand, stretch and cool wave expand, stretch and cool

AnAn abundance of hydrogen and helium in the abundance of hydrogen and helium in the far reaches of the universefar reaches of the universe - consistent with - consistent with the Big Bang theory that a mixture of hydrogen and the Big Bang theory that a mixture of hydrogen and helium was created at the beginning of the universehelium was created at the beginning of the universe

Working timeline since the Big BangWorking timeline since the Big Bang