Transcript Big Bang and Beyond

Big Bang and Beyond
Did someone monkeyed with the laws
of nature ?
Theories of the Origin of the Universe
• Theological “Theories”:
– Greek Mythology (Chaos)
– Hinduism (Cosmic sleep of gods)
– Chinese creation myth (Pangu)
– Biblical account of the creation (God)
• Scientific Theories:
– Continuous creation
– Big Bang Theory – the commonly accepted
theory
Big “Bang”
• Technically, there was no “bang”
• Technically, galaxies are not moving away
from each other
• Reality: space expands
– When there are more space between galaxies,
they “move” away from each other
– Analogy: dots on an expanding balloon
Evidence for the Big Bang
• Theory predicts an expanding universe
– Confirm by Red Shift (Doppler effect) in
spectrum
• Theory predicts cosmic background
radiation
– Background radiation was discovered in
1964 by Arno Penzias and Robert Wilson,
who later won the Nobel Prize for this
discovery
Beyond the Big Bang
• Big Bang Theory explains how the Universe first
started but leaves many unanswered questions
• Time, Space and Matter were created in the Big Bang
– Before the bang, there were no time, no space and no
matter
– Physics has not solved the question “What’s before the Big
Bang”
• If I hear a small bang, I will ask “Who or what
caused it”
– So “Who or what caused the Big Bang” ?
• Other factors determine how the Universe will
develop:
– Amount of matter in the Universe
– Physical properties of the matter
– Strength of the fundamental forces
Fundamental Forces in Physics
• Gravitational force
– Attractive force between objects with mass
– Weakest, long range
• Electromagnetic force
– Attractive and repulsive
– Long range, 1039 times stronger than gravity
• Nuclear Weak force
– Cause neutrons to decade into a protons
– Range <10-17 m, 1028 times stronger than gravity
• Nuclear Strong force
– Hold the nucleus together
– Range <10-15 m, 1041 times stronger than gravity
Gravitational Force
• Law of Gravity:
–
–
–
–
M = mass of one object
m = mass of second object
G = 6.67 x 10-11 Nm2/kg2
r = distance between the objects
Electro-Magnetic Force
• Coulomb Law:
proton
electron
– Strength of EM-force determines how strongly
electrons in an atom are held in orbit
Nuclear Weak-force
• Repelling force that cause beta-decay
neutron
proton
anti-neutrino
electron (beta-particle)
The strength of the
nuclear weak-force
determines how fast
neutrons are converted
into protons and electrons
Nuclear Strong-force
• Hold nucleus together by overcoming the repelling
protons in nucleus:
neutron
proton
proton
neutron
– Strength of the nuclear strong-force determines how fast
nuclear reactions will proceed
Thinkering with the Force...
• Fact:
– The fundamental forces in nature have strength that is
determined by a number of physical constants
– For example: gravitational constant in the Law of Gravity,
Coulumb constant in the Electro-magnetic force
• Question: what would happen to the Universe if the
values of these physical constant were changed ?
• Say, what would happen if the gravitational (or some
other) constant would be off a little bit ?
– We would surely weight a bit more on Earth…BUT...
– Physicists did NOT expect earth-shattering consequences…
Precondition for Life
• Stars of the right type for sustaining life supportable
planets only can occur during a certain range of ages
for the universe.
– stars of the right type only can form for a narrow range of
values of the gravitational constant
• Living cells consists of light and heavy elements
(Hydrogen, Carbon, Oxygen, and metals such as Iron,
Copper, ect)
– To make both light and heavy elements, the strengths of the
fundamental forces must lie within a very narrow range of
values
• Many many other preconditions exists…
Amazing Findings...
• Brandon Carter presented his ideas about the “anthropic
principle” in 1973 in Poland during the 500th birthday of
Copernicus
• The anthropic principle states that
– All the seemingly arbitrary and unrelated constants in physics have
one strange thing in common – these are precisely the value
you need if you want to have a universe capable of sustaining life
• Astronomer Fred Hoyle once said:
– A commonsense interpretation of the facts suggests that a
SUPERINTELLECT has MONKEYED with physics . . . and that there
are no blind forces worth speaking about in nature.
– And Fred Hoyle was an..Atheist
The strength of the Gravitational force
• If gravitational force was made a bit stronger, stars will be more
massive and burn more violently and unstable:
– More harmful radiation to life – deadly to life…
• If gravitational force was made a bit weaker, stars are too light
and do not become super-novae:
– Element heavier than iron are only formed when stars
explode as a super-novae; no life possible without them…
The strength of the EM-force
• If the electro-magnetic force is slightly weaker:
– Too weak to hold electrons in orbits about nuclei
– Universe will consists of loose protons and electrons, no
atoms, and thus no life will be possible
proton
electron
• If the electro-magnetic force is slightly stronger:
– atom could not "share" an electron orbit with other atoms
– No chemical reactions possible and no life
Strength of the Nuclear Weak-force
• If Nuclear Weak-force is made a bit stronger:
– neutrons would decay more readily, and there would be little
to no neutrons left
– Neutrons are necessary to form heavier elements used in
living cells – no neutrons, no heavy elements, no life.
• If Nuclear Weak-force is made a bit weaker:
– Plenty of neutrons will be available
– Stars can use neutrons to burn most or all of the hydrogen
into helium (and subsequently to heavy elements)
– But little or no hydrogen will be left… no hydrogen, no
water, and no life…
Strength of the Nuclear Strong-force
• If Nuclear Strong-force is made a bit stronger:
– Nuclear reactions will be very efficient (fast)
– Most or all hydrogen will be converted to Helium and then
on into Iron
– No hydrogen, no water, and thus, no life possible…
• If Nuclear Strong-force is made a bit weaker:
– Force is too weak to overcome electro-magnetic repulsion of
protons in nuclei
– multi-proton nuclei would not hold together
– No carbon or oxygen, no proteins, no water, and thus no life
possible…
That’s just the beginning...
• Many more amazing “coincidences” that make life
possible have been discovered
– The composition of our sun is just right, the distance of the
Earth to the sun is just right, the size of the Earth is just
right, the orbit of the Earth is just right, the size of our
moon is just right and even the giant planets (Jupiter) are
just right for life on Earth…
• Other amazing “coincidences” makes it possible for
the stars and galaxies to form
A coincidence at nuclear scale
• The following is an account of a series of
amazing “coincidences” in nature that dazed
an atheist astronomer and many others
• I have to take you into nuclear Physics
• Brace for the ride – please ask questions if
you don’t understand something
Nuclear Reaction
• Electrons can only occupy a number of specific orbits around
the nucleus – each orbit represents a certain energy level
• So also, nucleus of atoms can occupy a number of specific
energy levels
• In a nuclear reaction, the Law of Conservation of Energy must
hold:
Kinetic + nuclear energy before =Kinetic + nuclear energy after
Nuclear Reaction 2
• When nuclei collide, they form a new nucleus:
• If the energy level of the new nucleus is very different from one of
its natural energy state, the new nucleus is unstable and will
decompose (radio-activity):
Nuclear Resonance
• If sum total of kinetic and nuclear energy before and after are
very close to each other, the nuclear reaction will proceed very
rapidly
– In such case, we say there is “Nuclear Resonance”
• Resonance between atomic nuclei depends on:
– Structure of the nuclei involved
– Temperature under which the nuclear reaction takes place
• Resonance between atomic nuclei are extremely rare in nature.
Nuclear Reaction in Stars
• Matter are converted into energy in stars through a
number of nuclear reactions
• The three primary nuclear reactions (after these, the
star is almost burned up) are:
– Proton-proton cycle
– Helium fusion
– Carbon cycle
Proton-proton cycle
• The proton-proton cycle will burn Hydrogen into Helium (first
phase of star development)
• When all Hydrogen are burned, phase 2 kicks in…
Helium Fusion
• After all the Hydrogen is converted to Helium, the
star converts Helium to…. What ?
• Here we have a major problem...
• When two Helium nuclei are fused into Beryllium-8,
the resulting Beryllium-8 isotope is highly unstable
– Beryllium-8 has a half life of 10-16 seconds !!!
Helium
Beryllium-8
Helium
< 0.0000000000000001 sec
According to the physics of Beryllium-8,
stars cannot burn Helium
A Stellar Mystery
• Dilemma:
– According to the physical properties of Beryllium-8, stars
cannot burn beyond Helium
– Yet, Helium is being converted in Carbon in stars all the time
• First proposed solution: Triple collision
Helium
Carbon-12
Helium
Helium
Triple collisions are extremely rare and the rarity cannot
explain the abundance of carbon
Ed Salpeter’s solution...
• Faced with the dilemma that stars convert Helium into Carbon
at great rate, and no plausible explanation for this process, the
astrophysicist Ed Salpeter proposed the following solution in
1952:
Helium
Helium
Beryllium-8
Helium
BUT Beryllium
is extremely unstable
Carbon-12
Fred Hoyle’s insight
• Fred Hoyle realized that the only way that Salpeter’s
solution can produce Carbon at the rate that is
happening in stars is:
Helium
Helium
Beryllium-8
Helium
Nuclear resonance !!!
(Very fast reaction)
Problem: there is no known energy level
of the Carbon-12 nucleus that is near
the sum total energy values of He and Be
Carbon-12
Fred Hoyle’s wild guess
• So Fred Hoyle hypothesized (guessed) that there must be such
a natural energy level of the Carbon-12 nucleus
• Hoyle calculated the temperature inside a large star to be about
100 million degrees
• and worked out how much kinetic energy this would give to the
particles rushing around in the star's atmosphere.
• Knowing the masses of both beryllium-8 and Helium, his
hypothesis predicted that there must be an excited state at an
energy of 7.6 million electron volts in the nucleus Carbon-12…
• I did tell you that nuclei resonance was rare… everyone was
skeptical about Hoyle’s prediction...
• A team at Cal. Tech. led by Willy Fowler (later a Nobel Prize
winner) began the search for the mysterious resonant state in
carbon-12, and discovered it - just 4 percent above Hoyle's
prediction !!!
Yet another amazing coincidence...
• We are not out of the wood yet... Heavier elements
must be formed – specifically:
Carbon-12
Oxygen-16
Helium
– You want to form Oxygen (necessary for life !)
– But you want to keep some Carbon (also necessary for life)
A missed resonance
• In order to have this nuclear reaction going:
Carbon-12
Oxygen-16
Helium
– You need a natural energy level of Oxygen-16 close to the
sum total of the energy levels of Carbon-12 and Helium
– But not too close - if the level is too close, most or all
Carbon-12 will be converted, so you want this energy level
to be off a bit
Another “coincidence”
• Well…they did find that resonance level of Oxygen-16
and it did miss the resonance level to slow the
production of Oxygen-16
• These two coincidences caused atheist atronomer
Fred Hoyle to comment:
– If you wanted to produce carbon and oxygen in roughly
equal quantities by stellar nucleosynthesis, these are the two
basic levels you would have to fix, and your fixing would
have to be just about where these levels are actually found
to be....
– A commonsense interpretation of the facts suggests that a
SUPERINTELLECT has MONKEYED with physics . . . and that
there are no blind forces worth speaking about in nature
Flatness-oldness problem
• The following incredibly precise tweaking of the
Universe is known as the Flatness-oldness problem
• The amount of matter created in the Big Bang has a
profound impact on how the Universe will develop
– Matter attract and will pull the Universe back together
towards one point
– There is a critical amount where the attraction will halt the
expansion and the Universe will slow down and stop
expanding
– If the total mass in the Universe is less than critical, the
Universe will keep expanding
– If the total mass in the Universe is more than critical, the
Universe will stop expanding and contract (Big Crunch)
Place your bet...
• Suppose X represents the critical mass of the
Universe, what do you think that the total of mass of
the Universe is ?
0
X
• There are so many possible values to pick from for
the total mass of the Universe
– An does it matter how much mass there is in the Universe ??
(You will be amazed by the results)
Some results from Theoretic Physics
Interpretations of the results
• IF the density of the matter after 1 nsec from the Big Bang is
equal to 447,225,917,218,507,401,284,017 mg/cc, the
Universe would have collapsed by now.
• IF the density of the matter after 1 nsec from the Big Bang is
equal to 447,225,917,218,507,401,284,015 mg/cc, the
Universe expands so rapidly that galaxies and stars cannot
form.
• To get the (flat) Universe in which we (probably) live in, the
density of the matter after 1 nsec from the Big Bang must be
equal to 447,225,917,218,507,401,284,016 mg/cc – not
one gm more nor one gm less
• No wonder than many scientists believe that, the
Universe was designed
And there is much more...
• There are many more examples of coincidences in
nature without which life could not have developed
• Science has coined a term to describe these strange
“coincidences”: Anthropic Principle (The Universe is
“destined” to support (human) life)
• For more examples:
– http://cheungpc.mathcs.emory.edu
(Not) The End
(just out of time…)