Why Study Nature?

Power (Control over it)

“When will the Nile flood?” (time/astronomy)

“What will make my sick baby better?” (medicine)

“How can I make my spear fly faster and farther?” (physics)

Celebrity StatusA-List partiesRed carpet treatmentMTV interviews

Because we must.

Mankind has always been driven to understand the world.

The world is inherently simple and beautiful. It can be understood.

And always: Babes…never forget the babes…

As a single, unified thing thereexists in us both life and death,waking and sleeping, youth andold age, because the former things having changed are nowthe latter, and when those latter

things change, they become the former.

- Heraclitus (quoted in

pseudo-Plutarch, Consolation to

Apollo )

Being is ungenerated and indestructible, whole, of one kind and unwavering, and complete. Nor was it, nor will it be, since now it is, all together, one, continuous...That it came from what is not I shall not allow you to say or think — for it is not

sayable or thinkable

that it is not...How might what is then perish? How might it come into being? For if it came into being it is not, nor is it if it is ever going to be. Thus generation is

quenched and perishing unheard of.

- Parmenides circa 480 BC

Science Is About Simplification

PHILOSOPHIÆ NATURALIS PRINCIPIA MATHEMATICA AUCTORE ISAACO NEWTONO

Editio tertia MDCCXXVI Axiomata sive Leges Motus

Lex I Corpus omne perseverare in statu suo quiscendi vel movendi uniformiter in directum,

nisi quatenus a viribus impressis cogitur statum illum mutare. Lex II

Mutationem motus proportionalem esse vi motrici impress", et fieri secundum lineam rectam qua vis illa imprimitur.

Lex III Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones

in se mutuo semper esse æquales et in partes contrarias dirigi.

PHILOSOPHIÆ NATURALIS PRINCIPIA MATHEMATICA Author Isaac Newton Third edition (1726) Three Laws of MotionLaw I Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. Law II The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Law III For every action there is an equal and opposite reaction.

221

r

mmGF

Everything pertaining from astronomical motion to falling here on Earth can befully described by Newton’sLaw of Gravity plus his laws of motion.

Science Is About Simplification

oc

J

Electricity

Magnetism

ElectroMagnetism

Light

ThreeBecome

one

t

t

DJH

BE

0B

D

James Clerk Maxwell (~1864)

Modern Nomenclature

Then may we not fairly plead in reply that our true lover of knowledge naturally strives for truth, and is not content with common opinion, but soars with undimmed and unwearied passion till he grasps the essential nature of things ?

- Plato Republic

• Science addresses many things:– What is the ultimate nature of reality?– What is the simplest expression of nature?– Amongst all of the undeniable change, is there

anything that is permanent and enduring?

– How did the universe come into existence and what is its ultimate fate?

– What is the ultimate answer to the ultimate question?

42What is the root of it all?From where comes meaning?ا لله

Moslems

PUNS

Mensans

DOG

DyslexicChristians

GOD

Christians

Beauty in the Universe

Innermost SpaceHigh Energy Particle Physics is a study of the smallest pieces of matter.

It investigates the deepest and most fundamental aspects of nature.

It investigates (among other things) the nature of the universe immediately after the Big Bang.

It also explores physics at temperatures not common for the past 15 billion years (or so).

Periodic Table

u

du u

d d

Proton NeutronElectron

Gluons hold quarks togetherPhotons hold atoms together

Helium Neon

All atoms are madeof protons, neutronsand electrons

tb

cs

ud

While quarks have similar electric charge, they have vastly different masses (but zero size!)

=e2/ħc

Fermi National Accelerator Laboratory(a.k.a. Fermilab)

• Begun in 1968

• First beam 1972 (200, then 400 GeV)

• Upgrade 1983 (900 GeV)

• Upgrade 2001 (980 GeV)

Jargon alert: 1 Giga Electron Volt (GeV) is 100,000 times more energy than the particle beam in your TV.

If you made a beam the hard way,it would take 1,000,000,000 batteries

Increasing ‘Violence’ of Collision

ExpectedNumber

ofEvents

Run II

Run I

Increased reach for discovery physicsat highest masses

Huge statistics for precision physicsat low mass scales

Formerly rare processesbecome high statisticsprocesses

1

10

100

1000

The Main Injector upgrade was completed in 1999.

The new accelerator increases the number of possible collisions per second by 10-20.

DØ and CDF have undertaken massive upgrades to utilize the increased collision rate.

Run II began March 2001

How Do You Detect Collisions?

• Use one of two large multi-purpose particle detectors at Fermilab (DØ and CDF).

• They’re designed to record collisions of protons colliding with antiprotons at nearly the speed of light.

• They’re basically cameras.

• They let us look back in time.

Typical Detector (Now)

30’

30’

50’

• Weighs 5,000 tons• Can inspect

10,000,000 collisions/second

• Will record 50 collisions/second

• Records approximately 10,000,000 bytes/second

• Will record 1015 (1,000,000,000,000,000) bytes in the next run (1 PetaByte).

Spooky?

Remarkable Photos

This collision is the most violentever recorded (and fully understood). It required thatparticles hit within 10-19 m or 1/10,000 the size of a proton

In this collision, a top and anti-top quark were created,helping establish their existence

Modern Cosmology• Approximately 15 billion

years ago, all of the matter in the universe was concentrated at a single point

• A cataclysmic explosion (of biblical proportions perhaps?) called the Big Bang caused the matter to fly apart.

• In the intervening years, the universe has been expanding, cooling as it goes.

Big Bang Theory

White Sox Version

Black Body Radiator

Universe

• A black body radiator is one which absorbs all light which is incident on it.

• Such a body can also emit light, if sufficiently hot.

• Since the universe is the remnant of a hot explosion, it should thus have a temperature and an ‘afterglow’.

?

?

??

Afterglow From the Big Bang

Afterglow From the Big Bang

• In 1964, while working at Bell Labs, Penzias and Wilson discovered a radio hiss that they couldn’t make go away.

• They had (by accident!) discovered the remnant ‘echo’ of the Big Bang

• The universe was shown to have a temperature of 2.726K (-450 °F)

How Does the Afterglow Work?

+

+

++

+

+

+

+

+

+

Proton

Electron

Photon

+

+

Proton

Electron

PhotonH+ =

Proton Electron Hydrogen

HH

HH

HH

H

HH

H

H H

H

H

How Does the Afterglow Work?

Mysteries of the Afterglow

The temperature of the universe is uniform everywhere to parts per million.

Why?

The temperature of the universe has slight non-uniformities, at the parts per million.

Why?

Answers to both of these questions exist but are beyond the scope of this talk. Get Peter to bring in a cosmologist soon.

History of the Universe (Readers Digest Version)

the universe was all concentrated at a single spot

You are here

Then God (or whoever, I’m not getting into that tonight) said “Let there be light,”

and instead there was a vast explosion that created the universe and spread all of the matter that has ever been

observed (and more) throughout the Cosmos.

Hmmmmmmmmmm…..Large explosions hot temperatures very high energies Ice melts water evaporates steam ionizes atomic nuclei break apart quarks escape the nuclei….

Now (13.7 billion years)

Stars form(1 billion years)

Atoms form (380,000 years)

Nuclei form (180 seconds)

??? (Before that)

4x10-12 seconds

Nucleons form (10-10 seconds)

Quarks differentiate (10-34 seconds?)

The Universe’s Recipe

Mysteries

How do we know about the universe before 10-12 seconds?  

Just what is the simplest and most fundamental thing in the universe?

Does the unification/simplification stuff discussed earlier continue to hold?

The Early Universe• The forces have been unified. What about the particles?

Possibly the true nature of particles is that they are actually minute vibrating 11-dimensional strings.

Freebie: This theory is the only candidate way to unify gravity with the quantum forces.

Standard Model Summary

The Standard Model (quarks, leptons, three generations and four currently-distinct forces)

Can explain all known experimental data, from:The birth of the universe (10-12 seconds) to now.Motionless objects, to those traveling at the speed of light.Temperatures from absolute zero to the Big Bang.Lotsa stuff…..

Cannot explainThe very early universe (before 10-12 seconds).Do the forces unify?Are there many particles or just strings?Lotsa stuff…..

Data-Model Comparison

Data-Model Comparison

It is not possible to be ignorant of the end of things if we know their beginning.

-Thomas Aquinas Summa Theologica

www-d0.fnal.gov/~lucifer/PowerPoint/PopTalk_Jan2005.ppt

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