big bang, black holes, no math - texas a&m...

IntroductionTopic 3: Going Small

Big Bang, Black Holes, No Math

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ASTR/PHYS 109Dr. David Toback

Lecture 4



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Prep For Today (is now due) – L4If you just joined the class, welcome. Send me an email if you need an extension. All this is posted in the lecture notes!!• Reading:

– BBBHNM Unit 1 (Chapter 1-4): Was due already – Recommended Reading (not required): BHOT: Chap. 1-3, SHU: Chap. 1-

2, TOE: Chap. 1• eCampus Stuff

– (Warm-up Quizzes Parts 1 & 2)– Warm-up Quiz Part 3 (Requirements): Was due before class– Extensions granted if needed. [email protected]

• Pre-Lecture Reading Questions:– Unit 1 Quizzes:

• Two parts A & B. Will assign today• Will open after you finish Warmups Parts 1-3.

• End-of-Chapter Quizzes:– End-of-chapter quizzes 1 and 2: Was due before class

• Honors Section:– Start working on Stage 0. Need to hear from you at least once every 7

days



Next Topic: Going Small• Finished looking at various things in the universe going from the sizes we know to the VERY big

• Next we do the very small• Why? If we want to understand the universe we need to know what’s in it and what its made of

• Then we can get to the “Why and how did it get to be the way it is?” 4



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Starting out with small things

10 centimeters, or 0.1 meters, or 10-1 meters.About 3 inches

A baseball is a size we know from everyday experience



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Getting smaller

Something smaller you can see with your eyes

0.01 meters, (10-2 m) or 1 cm, or about a 1/3 of an inch



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Much smallerA simple dust mite is barely visible with the naked eye

Into the realm of biology10-3 metersor 1 millimeter



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A human hair

Looking at the side view of a single hair

10-4 meters



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Closer still…A single red blood cell

10-5 meters



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Further still

An HIV virus which is one of the bigger known viruses

10-6 meters



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Small VirusA polio virus which is known to be one of the smaller viruses

10-7 meters



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The Double HelixA close up of the helical structure of DNA

Starting to get into Chemistry

10-8 meters



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An Atom

10-9 meters or 1 nanometer

10 million in a cm

•What we’re seeing is the electron “cloud” as it goes around the atom• Kinda like the blades of a fan

•The realm of Physics



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Inside an Atom

•Snapshot in time of 2 electrons “orbiting” the nucleus

•Atoms are “composite” things, not fundamental

10-10 meters



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The Central Part of the Atom• The electrons are outside our field of view

10-11 meters



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Homing in on The Nucleus• Still zooming into the center of the atom

• The atom is mostly empty space

10-12 meters



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The Structure of the NucleusCan just start to see the “stuff” inside the nucleus

The nucleus is not fundamental

10-13 meters



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Protons and Neutrons• A carbon atom has 6 protons (blue) and 6 neutrons (grey)

• VERY tightly packed

10-14 meters



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Inside the ProtonThree quarks inside the proton–Protons are composite

–Quarks are fundamental

10-15 meters



Other Fundamental Particles?• Electrons and quarks (as far as we know) are fundamental

• Lots of other fundamental particles

• Recently discovered the Higgs Boson

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Anti-Matter Each fundamental particle has an anti-matter

version which is also fundamental

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Protons are stable live foreverNeutrons outside a nucleus are unstable

can decayNeutron Proton + Electron + Neutrino

Stable and Unstable Particles

Neutron

ProtonDecay Electron

NeutrinoNote that this only happens when Neutrons

are by themselves (not in an atom)



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Questions…

• How large are electrons and quarks?–We don’t know… that’s what I (and others) do for a living…

• Are we SURE they are fundamental? Could they made of something smaller? Strings?

• Are there other fundamental particles we haven’t discovered?



Lecture on Chapter 3 now complete

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IntroductionTopic 4: Scientific Methods


Next Topic: Scientific MethodsUnit 1:1. Introduction Done2. Going Big Done3. Going Small Done4. Evidence and the Scientific

Method TodayToday we move on to the Questions

and How we go about answering them

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Plan for the Next Few Weeks1. More on the Questions

and How we go about answering them

2. Some of the history to teach us about the method

3. Need to learn some physics

Today

} Unit 2 (Chapters 5-9)



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Next few Weeks Continued… The tools in our toolbox… Learning some PhysicsTo learn Cosmology will need to learn a bit about:1. Light and Doppler Shifts 2. Gravity, General Relativity and Dark

Matter3. Atomic Physics and Quantum

Mechanics4. Nuclear Physics and Chemistry5. Temperature and Thermal Equilibrium

Won’t spend too long on these, just enough to get back to the big picture…



Prep For Next Time – L4If you just joined the class, welcome. Send me an email if you need an extension. All this is posted in the lecture notes!!• Reading:

– BBBHNM Unit 2 (Chapters 5-9):– Recommended Reading:

• See P3 of http://people.physics.tamu.edu/toback/109/Syllabus.pdf• eCampus Stuff

– (Warm-up Quizzes Parts 1-3)– Warm-up Quiz Part 4 (Peerceptiv): Will assign next time– Extensions granted if needed. [email protected]

• Pre-Lecture Reading Questions:– Unit 1 Quizzes: Two parts A & B: Due before next class

• Will open after you finish Warmups Parts 1-3– Unit 2 Text Submission: Not yet assigned

• Submit to TurnItIn on eCampus. • Submit ONLY 4 questions, need all 4 to be excellent to pass• Pass/Revise assignment. If you don’t pass we will set up dates for Revisions after you get Feedback

– Unit 2 Quiz: Not yet assigned• End-of-Chapter Quizzes:

– Chapters 1-3• Honors Section:

– In a heavy reading stage, submit a draft of Stage 0, if you haven’t yet. Need to hear from you at least once every 7 days

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big bang, black holes, no math - texas a&m...

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