Structure & Fate of Universe

8/22/2019 Structure & Fate of Universe

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Structure and Fate of the

Universe


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Penzias & Wilson

Technicians for Bell Laboratories

Couldnt get rid of hiss (interference) in

Bells new, expensive dish antenna.

Hiss turned out to be microwave

radiation interference.

Energy remnant of the Big Bang!


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How do they know these are

The BIG BANG microwaves? They FILL the universe -- come toward Earth

from all directions.

Means it is not being generated by a pointsource.

You can turn away

from a point sourcelight..

Penzias and Wilson couldnt get away from the microwaves

interfering with their antenna


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The Singularity Expands300 million years: Gravitational attraction between bits of

matter causes clumping of matter.

First stars form (very dense clumps of matter).

Stars clump into Galaxies.

Galaxies clumped into Superclusters.

Q. What matter makes up the stars? What element(s)?


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The Singularity Expands9 billion years after Big Bang

which is 5 billion years ago from today: Our sun forms.

Planets in our solar system forming too.

Remember the History of Life Timeline?

Q. How old is the Earth?

Answer: ~4.6 billion years old.


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What does the Universe

LOOK like?


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No Center No Edge

Matter clumped into galaxies

Galaxies clustered intosuper-clusters

Super-clusters connectedby strings of matter.

with Voids in-between


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What is the overall shape?

If density of matter inuniverse is low =

saddle shaped

If density of matter in

universe is moderate

= flat sheet

If density of

matter in

universe is high

= spherical


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Fate of the Universe determined

by the amount oftotal matter inthe universe

It is a competition between the force ofgravity and the force ofexpansion.


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Gravity

Strength of gravitys pull based on

distance between objects and size.

Gravitational pull has slowed

down the rate of expansion

Gravitys pull is also based onvelocity of moving objects.

Recall - the distance between objects in universe is

expanding as space stretches. Gravitys effect is reducing.


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To know fate of universe, must know:

rate of expansion and

how much matterthere must be tocounteract that rate.

how much matter there IS.


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We knowrate of expansion

So can calculateexactly how much matterthere must be to counteract expansion andremain inequilibrium.

Fate of the Universe depends on the ratio between

amount ofmatter actually IN the universe vs critical mass

needed to counteract expansion.

critical mass

Omega(Actual matter/Critical mass)


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Compare actual average mass density of

the universe to critical mass

If Omega = 1 (amt of matter = critical mass)

If Omega > 1 (amt of matter > critical mass)

If Omega < 1 (amt of matter < critical mass)

Equilibrium

Gravity wins

The Big ChillExpansion wins

The Big Crunch


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SO, how much mass is

there in the universe??

Amount of visible matter is less than

10% critical mass .

Dark matter brings us closer 90% of

all matter is dark matter.

suggests big

chill

suggests big

crunchBut Wait . New discovery throws us into disarray!


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Dark Energy discovered!

When density of matter is low enough,

Dark Energy acts like an anti-gravity.

So universe expansion might speed upas density decreases .

New possib i l i ty :

TheBig Rip!


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Superclusters get pulled apart

Galaxies get pulled apart

Stars get pulled apart

Atoms get pulled apart

The Big Rip

Structure & Fate of Universe

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