9/12/2018

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Burkey- ESS

QUIZ Thursday

At the instant of the Big Bang,

all the matter, energy, time, &

space in the Universe was

condensed into a single, tiny

point. We call this Singularity.

Doppler Effect

Occurs when the source of sound waves

moves towards or away

Sound moving TOWARDS

Sound waves compressed

Higher frequency

Shorter wavelength

Sound moving AWAY

Sound waves stretched out

Lower frequency

Longer wavelength

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“Doppler Effect” with Light – is

called Red Shift

Red Shift

This change of light to longer wavelength

Light moving away

This is moving to the red-end of the light spectrum,

not that it’s necessarily red.

Blue Shift

This change of light to shorter wavelength

Light moving towards

This is moving to the blue(violet) end of the light

spectrum, not that it’s necessarily blue.

Radial Velocity

the speed at which objects are

approaching or receding from an

observer

+Positive that it

is receding

-Negative that it

is approaching.

Hubble’s Law

Galaxies that are moving AWAY from us are shifted to the RED end of the spectrum at a speed that is proportional to their distance.

Galaxies that are moving TOWARD us are shifted to the BLUE end of the spectrum

v = radial velocity Ho = constantd = distance to galaxy

v = H0 d

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NOW….

The Big Bang Theory

prevailing cosmological model that explains the

development of the Universe

abundant evidence has been uncovered in support

of the model

~13.75 billion years ago (also the

estimated age of our Universe)

Earth Space Big Bang Theory

I. The Universe was once in an extremely hot and

dense state which expanded rapidly.

II. In an instant, the universe expanded very quickly

III. Then it settled down to a slower rate of expansion,

cooling all the time

IV. After a few minutes it had cooled enough for

protons to form

Big Bang Theory (continued)

V. Hydrogen and helium were the raw ingredients

that were available for making stars

VI. Heavier elements were made inside stars dying

and exploding.

VII. Then newer stars created, many of them like our

solar system with abundance of complex

elements.

Evidence for Big Bang

**ALL was observational

“the four pillars of the Big

Bang theory“ the evidence to

support the theory.

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Evidence #1

The Universe is expanding

As the distance between galaxy clusters is

increasing today, it can be inferred that everything

was closer together in the past. *Red shifting by

Huble’s Law and a dark night sky.

What color is the sky at night?

DARK at night (Olber’s Paradox)

IF the universe were infinite in size, eternally old, and if stars shine all the time, then…

everywhere we look at night, we SHOULD see a star…but we DON’T.

the sky should be as bright as the Sun’s surface all of the time…but it’s NOT

We are surrounded by a cosmic particle horizon beyond which we can’t see.

Solution to Olber’s Paradox:

1. Much of the light is red-shifted

to the extent that the energy is

undetectable in the visible

spectrum..

2. Universe is not eternal. Light from

the most distant galaxies hasn’t had

time to reach us.

Will talk about the 4 pillars tomorrow.

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Edwin Hubble•Observed that nearly all galaxies are moving away from us with red shifting.

Therefore….The universe is expanding.

Hubble’s Law – from this guy!

1929

But, if all the galaxies are

moving away from us,

doesn’t that make us the

center of the universe???

Raisin Bread explains it all…

Cosmological Principle

From every galaxy, at

every time, the universe

looks the same in all

directions. Every galaxy

seems to be at the center

of the universe.

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Evidence #2

Cosmic Background Radiation

The bright intense light from the Big Bang - 13.7

billion years ago, still bathes the cosmos.

Space has a 2.7 Kelvin uniform background radiation temperature

•Wilson & Penzias at 1st thought it was background or “static” •It is believed to be microwave radiation left over from the Big Bang because it is isotropic (everywhere)

Color indicates temperature

http://map.gsfc.nasa.gov/universe/bb_tests_cmb.html

Evidence #3

Universe Composition

The Universe should be in abundances of lighter

elements.

Universe is ~75% Hydrogen, ~24% Helium

Evidence #4

Evolution of the Universe

The Universe is moving and changing. Something

must have started the movement.

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Everything is moving, orbiting,

rotating around and around.

Objects in motion stay in

motion.

Whatever it is, it doesn’t emit or absorb light like normal matter

So we’re calling it dark matter

We think it accounts for 23% of all the matter in the universe

We only can measure ~4%

Pie of matter and energy

[NASA]

Dark Matter – What is it??

So how do we know it’s there?

Dark Matter is such a

huge mass it bends

light. Only know

material.

Acting kind of like a

lens curling light

around it and altering

our view of distant

galaxies.

I LOVE memes!