The Big Bang Evidence - PowerPoint PPT Presentation

1 / 19
About This Presentation
Title:

The Big Bang Evidence

Description:

The Big Bang Evidence. The Science of Creation. 19. Goals. What is ... It pervades all space. It has reflected in every direction over the age of the universe. ... – PowerPoint PPT presentation

Number of Views:244
Avg rating:3.0/5.0
Slides: 20
Provided by: JulieAR9
Category:
Tags: bang | evidence

less

Transcript and Presenter's Notes

Title: The Big Bang Evidence


1
The Big Bang Evidence
  • The Science of Creation

2
Goals
  • What is the evidence for the Big Bang?
  • What predictions does the Big Bang theory make?
  • What observations can we make?
  • How good of a theory is the Big Bang?

3
Cosmological Principle
  • Isotropy The view from here is the same in all
    directions. (observation)
  • Homogeneity We live in an average place the
    same as any other. (statistics)
  • This is the cosmological principle.
  • Implies
  • Universe has no edge!
  • Universe has no center!

4
Olbers Paradox
  • Why is it dark at night?
  • In an infinite and unchanging universe
  • Every line of sight should end at the surface of
    a star.
  • Either
  • Universe has edge.
  • Universe has a beginning.

5
Concept Test
  • Olbers paradox asks why the night sky is dark,
    when every line of sight must eventually fall on
    a star. Which of the following reasons would best
    explain the darkness at night? It is because the
    universe is
  • Infinite and mostly empty.
  • Clumpy, so not every sightline intercepts a star.
  • Expanding, so distant stars are red-shifted.
  • Young, so there are only stars to a finite
    distance.
  • None of the above.

6
Scientific Evidence
  • A scientific model must do two things
  • Explain what is seen.
  • Predict what will happen accurately.
  • Or, predict what can be seen before one thinks to
    look.

7
Cosmic Microwave Background
  • The Big Bang
  • Massive amount of energy.
  • Very high temperature ? thermal radiation
  • As Universe expands
  • Temperature cools ? thermal radiation gets
    redder.
  • or
  • Cosmological redshift ? same thing.

8
Origin of the CMB
  • Once cool enough for atoms, radiation could move
    freely through space.

9
The Temperature of Space
  • After 500,000 yrs T3000K
  • lpeak a 1/T
  • lpeak near infrared.
  • The Universe was red.
  • After 16 billion yrs
  • Universe 1000x bigger.
  • lpeak 1000x longer.
  • lpeak microwaves (radio).
  • T 3K!

10
Where do you look?
  • Recall Lookback time.
  • Universe is a time machine.
  • Look beyond the youngest galaxies.
  • Look everywhere.

11
What We See
12
Cosmic Microwaves
  • Big Bang theory predicted cosmic microwave
    background.
  • In 1965 discovery of radio waves (microwaves)
    from sky.
  • Prediction confirmed.

13
COBE
  • Early 1990s
  • NASA Cosmic Background Explorer
  • Measure the intensity of radiation at many
    wavelengths.
  • 3K thermal emission!

lpeak (3 x 10-3 m/K) / 3 K 0.001m 1mm
14
COBE cont.
  • Also measure the (temperature) intensity and
    wavelength in various directions.
  • Look for fluctuations out of which galaxies came.

V 600 km/s
15
COBE cont.
  • Also measure the (temperature) intensity and
    wavelength in various directions.
  • Look for fluctuations out of which galaxies came.

V 600 km/s
16
(No Transcript)
17
Large Scale Structure
18
Concept Test
  • The cosmic background radiation is visible in
    every direction because
  • We are at the center of the universe.
  • It is just now passing by us at the speed of
    light.
  • It pervades all space.
  • It has reflected in every direction over the age
    of the universe.
  • All of the above.

19
Evidence of Eras
  • Cant see what happened before origin of CMB.
  • Can estimate given change of temperature and
    density with time.
  • Look for Proof.
  • CMB (Age of Nuclei)
  • Ratio of H/He and Li (Age of Nucleosynthesis)
  • Weak Bosons (Electroweak Era)

20
A Good Theory?
  • The Big Bang is a very successful theory.
  • Makes predictions
  • CMB.
  • Hydrogen, Helium, Lithium abundances.
  • Formation of structure.
  • Expansion of Universe.
  • Are other Creation theories
  • Scientific?
  • Successful?

21
Homework 19
  • For Monday, read NY Times article plus WMAP
    website http//map.gsfc.nasa.gov/m_mm.html
  • Answer the following
  • What is the inflation theory?
  • What new observations support the theory?
  • How does this theory change/help/augment the Big
    Bang theory?
Write a Comment
User Comments (0)
About PowerShow.com