january 2009 david toback, saturday morning physics 1 prof. david toback texas a&m university...

January 2009 David Toback, Saturday Morning Physics

1

Prof. David TobackTexas A&M University

January 2014

Dark Matter and the Big Bang

Theory

Overview


2

Two of the most exciting topics in all of science are Dark Matter and the Big Bang

Start with questions: • What IS Dark matter and what is the

evidence for it? • What IS the Big Bang Theory?• What does Dark Matter have to do

with the Big Bang? • What are scientists doing today to

discover Dark Matter? Final Thoughts

What is Dark Matter?


3

Dark Matter


4

What is some of

the evidenc

e for Dark

matter?

How stars move in galaxies


5

• Start by considering the case that there IS no Dark Matter in galaxies

• Can use laws of gravity to predict the orbits of planets and stars as they move around the solar system and galaxy

• For the solar system, the data agree perfectly, but for the outer part of galaxies it should look like stars in orbit around a massive center

• Problem: This isn’t what the data shows


6

http://people.physics

.tamu.edu/toback/Talks/

Video/Lab4_SS1_vide

o.swf

As the Galaxy Turns

http://faculty.physics.tamu.edu/toback/Talks/Video/

Lab4_GX1_video_slow.swf


7

Data well explained by lots of “Dark Matter” we can’t

seeThis is where it gets its

nameIn some sense, the name is a statement of almost all

we know about it (it doesn’t interact with light,

and it has mass)January 2014 David Toback, Saturday Morning

Physics8

Our Place in the Universe

You are here In some ways, Dark Matter

surrounds the galaxy like the

water in a fishbowl

surrounds a fish in the middle of

the bowlNot exactly the

same… denser in the middle

because of the pull of gravity

What is the Big Bang Theory?


10

Not that Big Bang Theory


11


12

A Big Bang Occurred… Then What?The Story of the Universe

since the Beginning


13

Observe lots of galaxies with the world’s best

telescopeWe notice that All the far

away ones are moving away from us VERY

quickly

So What?


14

All the stuff in the galaxies appears to have come from a single point

in space ~13.7 billion years ago

Name this time The Big Bang

A moment of Creation

What happened in the past? Run the clock backward in time

Slightly more complicated than that…

• As best as we understand the Universe began with a Big Bang–A REALLY Big Bang

• Then what?• How did we get from the bang to the Universe we have today?


15

March 2011David Toback, Texas A&M University

Davidson Scholars 16

A Brief History of Time• Zero

• One millionth of one second after the Bang

• A few minutes

• A few hundred thousand years

• 100 million to 1 billion years

• 9 billion years

• ~13.7 billion years

• The Big Bang produces lots of particles

• Quarks combine to form protons and neutrons

• Protons and Neutrons combine to form the nucleus of an atom

• Nuclei and electrons combine to form atoms

• Atoms combine to form Stars and Galaxies

• The Earth and our solar system forms

• You listen to me talk

May 2009 David Toback, Texas A&M University 17

Artists Conception of the Big Bang


The very early UniverseLots of free particles just hanging

around…Universe is so hot that quarks can’t

combine to make protons/neutrons


Later, Quarks Combine to Form Nucleons

Quark

Quark

ProtonNuclear Reaction

Quark

qqq Proton


A Millionth of a Second after the Big Bang

The quarks have combined to form Protons and Neutrons

Creating Heavier Nuclei


21

Proton

DeuteriumNuclear Reaction

Proton + Proton Deuterium


22

A couple hundred thousand years later: Atoms

Proton

Electron

HydrogenAtom

ElectroMagnetic Reaction


Wait a Billion Years

After about a billion years,

because of gravity atoms

combine to form the first stars

and galaxies

Our galaxy, the Milky Way

http://cmsdoc.cern.ch/cms/TRIDAS/html/CollisionSide.html


After about 9 billion

years our solar

system and the Earth form

http://cmsdoc.cern.ch/cms/TRIDAS/html/CollisionSide.html


Recent History: Life on Earth

• Earth is about 4 or 5 billion years old

• Evidence that microbial tracings existed on Earth about 3.5 billion years ago

• Humanoids, like “Lucy” existed a mere 3 million years ago

• Homo-sapiens at around 100,000 years ago

What does Dark Matter have to do with the Big Bang Theory?


26

The Known Particles


27

– No known particles have the properties of Dark Matter

– Other reasons to believe there are new fundamental particles to be discovered–For example, we just

discovered the Higgs Boson

– Maybe Dark Matter is a New Particle!


28

Hypothesis: The Dark Matter in the Universe is made up of LOTS of

particles that we haven’t discovered yet!

Best Guess: Huge numbers got created in the Early Universe like everything else and are still here

today!

Big Bang!

Then Universe gets bigger

What IS the Dark Matter?We don’t know…

Today: Observe 5 times more Dark Matter than Atoms in

the Universe

What are scientists doing today to discover Dark Matter?

Just mention two of the fun experiments being done here at

Texas A&M!


29

Some Sources of Dark Matter are Cheap


30

You are hereOur Sun is

Moving through our

Galaxy… Lots of

Dark Matter is hitting the Earth

every second

Experiment


31

Dark Matter Particle

Atom in Detector

Detector

Ping

I saw it! Eureka!

Can we Make and Discover Dark Matter?


32

• High energy collisions between particles in the Early Universe

• Recreate the conditions like they were RIGHT AFTER the Big Bang

• If we can produce Dark Matter in a collision then we can STUDY it

October 2011David Toback, Texas A&M University

Research Topics Seminar 33

More Expensive Dark Matter? High Energy Collisions Dark Matter

ParticlesLHC ≈1 ps after the Big Bang

Dark M

atter P

article

Dar

k M

atte

r Pa

rticle

Detector

Proton Proton

Ok… Its more complicated than this

since Dark Matter Particles don’t easily

interact with detectors…

Nor do we usually produce them directly


Aerial View of the LHC

CMS

ATLAS

27 km in Circumference!

One of the largest and the most complex scientific

instrument ever conceived & built by humankind

pp

Collides high energy protons

Two huge detectors

Lake LemanGeneva Airport


35

How does it do it? Accelerates protons to REALLY high energies, then bashes them togetherhttp://people.physics.tamu.edu/

toback/Talks/Video/particle_event_full_ns.avi

Final Thoughts


36


37

Interested in learning more?

• Physics department now offers a course entitled “Big Bang & Black Holes”

(ASTR/PHYS 109)– Covers Stephen Hawking’s

“Brief History of Time”– Origin and Evolution of the

Universe– How do stars form?– What is Dark Matter? Dark

Energy?– What are Black Holes?– General Relativity & Quantum

Mechanics– Particle Physics

– High School Students: • Get your school to get involved

with the Talk Science Program http://faculty.physics.tamu.edu/toback/109/

http://people.physics.tamu.edu/toback/TalkScience/

Conclusions


38

• It’s an incredibly exciting time to be a scientist!

• Astronomy, Cosmology and Particle Physics are all coming together!

• Starting to understand the role of Dark Matter in the Universe since the Big Bang!

• If our understanding is correct, a major discovery may be just around the corner!

Wanna join us? We need your

help!


39

january 2009 david toback, saturday morning physics 1 prof. david toback texas a&m university...

Documents