In the Beginning…. WOW! You are about to enter The Twilight Zone…

In the Beginning…

WOW!

You are about to enter

The Twilight Zone…

Happy Thanksgiving!

Detailed Overviewfor Today’s Talk

• Brief political statement

• Some history mixed with some really cool pictures!

• Really cool pictures mixed with some information

What is this?Have you seen it?

What is this?Have you seen it?

Star Parties: a bunch of geeks

staying up all nightto look at the sky

Visit Rose City Astronomer’s web page

(end of brief political statement)

Stepping back a few years…

Ptolemy (83-168AD):Greek philosopher, earth centered universe

If you are aware of the earth and sky, Ptolemy was right! Pretty much

“Science is about becoming less wrong” (Mark Utlaut)

But stepping ahead one and a half millennia…

1543, Nicolaus Copernicus moved the earth: the sun become the center of the universe.

Kepler’s Laws

• 1604 Kepler observed a temporary “new star”– The heavens were not immutable!?

• 1605 Kepler determined the motion of planets around the sun

1610, Galileo provided evidence to support Copernicus …

…oops

Isaac Newton1643-1727

• The same force that causes an apple to fall to the ground makes the moon circle the earth!

• Invented a new telescope design

Skipping ahead a few years…

1910’s• The Milky Way was the Universe

• All fuzzy objects (nebula) were thought to be within the Milky Way.

• The universe was “static” – not changing

• Universe was eternal!

• Einstein believed in a static, eternal universe – modified relativity to match that.

Moon is superimposed, but the scale is correct

in regards to apparent size.

Andromeda is Big.

Andromeda is the furthest “naked

eye” object

Andromeda: galaxy or nebulae?

The Great Debate (1920)

• Harlow Shapley: – Milky Way is the Universe – “Spiral nebula” are nearby gas clouds– Sun is far from the center

• Heber Curtis: – “Spiral nebula” are “island universes” of stars– Sun is near the center of the Milky Way

1920’s Edwin Hubble

• Studied Cepheid variables in “nebula” NGC 6822

• Hubble’s seminal paper: N.G.C. 6822, A Remote Stellar System

• Showed many of the nebula were not in the Milky Way, but are individual galaxies

In a Galaxy Far Far Away!Duhh, they are all far far away

• Cepheid variable stars: brightness increases and decreases periodically.

• True brightness is a function of brightening cycle period

• Used as “standard candles” – Determine true brightness– Measure apparent brightness– Calculate distance

100 Inch Hooker TelescopeMt. Wilson Observatory

Construction of mirror: 1917-1948

Some nebula are extra-galactic:

The Universe got a

LOT BIGGER!

NGC 6822 in Sagittarius

Hubble Space Telescope has:Provided really cool picturesFostered significant scientific advancesAllowed the populous to have a sense of awe about who and where we are!

Red Shift

• Light emitted from stars has specific spectra

• Doppler effect:– Object moving away are “red

shifted” (longer wave length)– Objects moving towards are “blue

shifted”

Red Shift

• 1918 - some spiral nebula were observed to have “red shift” (few had “blue shift”)

• Maybe red shift could be caused by “tired light”• Or red shift can be caused by object moving away

The further distant, the faster it move away!

Big but Semi-Static

• The Universe became BIG with Hubble’s discovery

• But it was still considered to be static– Maybe things move, but don’t really change

• Eternal!– Possibly, new matter is created to fill in voids– Possibly, red shift is “tired light”

• Or maybe…

• Lemaitre…the “new Galileo”?

• Considered “running the expansion clock backwards” which…

• …challenged the norm of an eternal, static universe.

• Replaced it with a universe that had a beginning.

Fr. Georges Lemaitre

1927 paper: A homogeneous universe of constant mass and growing radius accounting for the

radial velocity of extragalactic nebulae

• Lemaitre’s theory is now known as “the Big Bang”

• “Big bang” was the name given to this theory by Fred Hoyle in 1950 – Hoyle was an adamant “static universe” believer

• “The notion of a beginning…is repugnant”– Arthur Eddington

Modern thoughts include

“multi-verses”

1940’s

• Ralph Alpher, under direction of George Gamow, described nuclear physics in the realm of an expanding universe

• If “big bang” is real, what elements would have formed in the beginning?

Ralph Alpher and Robert Herman

• Run the “expanding universe” clock backwards

• The universe compresses and gets very very very hot!

• These conditions are

replicated in particle accelerators.

• 0.01 seconds after the “beginning” the universe was about 1010K (a.k.a. hot).

• Neutrons, protons and electrons formed from quarks

• 7 protons for every 1 neutron

Race Against Time

• For the next few minutes fusion combined protons and neutrons into atomic nuclei

• After a few minutes, expansion cooled the universe such that no more fusion could occur. All matter was done forming!

• Created 75% H and 25% He

25% He and 75% H!!!!

• Knowledge gained in particle accelerators predicts the universe would produce 25% helium and 75% hydrogen in the first few minutes of creation. Nothing else.

• These are stable – these proportions remain today.

• Observations show the universe is now about 24% He, 74% H, 2% everything else

• What about “everything else?

1930’s-1950’s• Hans Bethe studied stellar fusion

• Nuclear reaction: Elements are fused inside stars to form heavier elements from hydrogen

• Along with others, it was shown that the abundance of elements in the universe can be explained mostly by stellar fusion…

Margaret BurbidgeGeoffrey Burbidge

Willy FowlerFred Hoyle

Bethe – every thing else?

• Hans Bethe et al., showed elements such as oxygen, carbon and nitrogen are created inside stars.

• What about other elements? (stay tuned)

Two Successes!

• By late 1950’s the “Big Bang” theory was supported by two significant observations:– Red shift shows the universe is expanding– Actual observed He/H ratio is what it should be

if the “big bang” is real

• Still, many physicists not convinced…

Interesting coincedence

• Three of the physisists involved with nuclear fusion were:

• Ralph Alpher

• Hans Bethe

• George Gamow

More from and

• Alpher and Gamow also predicted that the heat present during the first few minutes is still present in the universe

• The universe should have now expanded and be on average only a few Kelvins hot

• The wave length of this radiation should be in the range of microwaves

Black Body Radiation

• The wave length of “light” emitted from matter is proportional to temperature

• Very cold: radio wave length

• Room temperature: infrared

• 1500C: glowing orange (visible)

• Very hot: x-ray

Persistence Pays Off…

• 1964, Arno Penzias and Robert Wilson

• Microwave work with Bell Labs

• Observed “hiss” in their detector that they could not explain

• Since it was isotropic – it seemed to be noise.

• They persisted…

Their “Telescope”

David Wilkinson (?), et al.

• Meanwhile, in Princeton (?) the design of a microwave detector was underway - Trying to find the left over light from the big bang.

• Then the phone rang…it was Penzias and Wilson…they had a problem they didn’t understand…oh what a lucky problem!

Wilkinson knew…

• Penzias and Wilson won the Nobel Prize in 1978 for detection of the Cosmic Microwave Background radiation!

• The universe is glowing at 2.73K

• This was the Third Great Observation to nail down the Big Bang as real!

One last problem: isotropy

The temperature appeared to be perfectly uniformHow could stars and galaxies form if mass

was perfectly distributed?

Wilkinson Microwave Anisotropy Probe (WMAP)

Problem solved:Almost perfectly uniform…but not quite…

Temperature variations (Temp ~ 0.005°C) indicates “clumping” of matter which resulted in galaxy formation

High resolution cosmic background radiation image from WMAP (Wilkinson Microwave Anisotropic Probe)

Big Bang Data• Red Shift

– further objects recede faster (raisin bread)

• Universe consists of ~75% H and 25% He• Cosmic Background Microwave Radiation

– black body radiation• Characteristic black body distribution at 2.7 Kelvin

– isotropic, homogeneous (smooth, uniform)

– variations (0.005°C) are thought to be galactic “seeds”

Big Bang Theory• Not an explosion in the universe• Universe itself started at a “singularity”

– not static– expands “into itself”

• Very firmly established theory (mid 20th) – only existing theory that explains the data

• red shift, H/He ratio, Cosmic background radiation

• Still being modified (ex. inflation theory, multiverses…)

Big Bang - Events

• Prior to 10-6seconds, no matter, only energy

• 10-6 seconds - quarks formed

• By 1 second - all matter created– Tuniverse=1010 K

– 7 protons for every 1 neutron– This results in 75% H and 25% He

In the beginning (well, after 3 minutes at least):•All of the protons and neutrons that exist today were formed.•Matter consisted of 25% helium and

75% hydrogen•Trace amounts of lithium and beryllium•Nothing else!

There is more to life than hydrogen and helium!

Thank your lucky stars!

Elements lighter than iron are created inside stars by fusion.

But how did it get here?

Stellar Evolution

• Stars convert H in to He at their core

• When hydrogen is depleted– gravity overcomes thermal forces

• core shrinks rapidly

– outer shell expands 50X– Red Giant with helium core– Helium starts to “burn” (nuclear fusion)

Stellar Evolution

• Helium core reactions:– He+He creates Be, Be+He creates C, C+He creates O

– Carbon and oxygen are stable

– Variation by 0.5% of the Strong Force renders this unstable – we couldn’t exist

• When helium is depleted– Red Super Giant with C & O core

– Outer shell is cast out (planetary nebula)

– Carbon, etc., is shed to the universe

Stellar Evolution

• Massive stars– very large stars repeat this process– convert heavier elements into still heavier– outer shell cast out periodically– the nucleus of iron is most stable (lowest free

energy). To fuse heavier elements requires energy input.

– Some heavier elements (>Fe) may form

Now, more really cool pictures, less science/history…

Outer shell of star is cast out in to the universe.Star still burns at the center. Star will become a white dwarf.

Planetary Nebula(Cat’s Eye Nebula - 3000 Light years away)

Light elements: C, N, O

Cats Eye Nebula

Okay, so…

•Big Bang: H and He

•Inside Stars: C, N, O, etc.

•Trace amounts of some heavier elements

•So what about the other stuff (Cu, Au, Pb, etc)?

Stellar Death

• Death of a very large star (> 8 solar mass):– fusion in the core ends (no more fuel)– no more thermal energy to prevent collapse– collapse occurs in 1/10 of a second!– Super Nova Explosion

• For weeks the star is 109 brighter than the sun

• Releases its heavy elements

• Explosion energy fuses the heaviest elements

Crab Nebula (Super Nova Remnant)Super Nova of 1054 AD, visible in daylight for 23 days,

6000 light years distant, now 10 light years across

X-ray (Chandra) Infrared (Spitzer)

Crab Nebula

The Crab Nebula spans about 10 light-years. In the nebula's very center lies a pulsar: a neutron star as massive as the Sun but with only the size of a small town. The Crab Pulsar rotates about 30 times each second.

Cassiopeia ASupernova of 1667 or 1680

Closest SNR to Earth

Veil Nebula (shock wave interacting with interstellar medium)

Supernova in many galaxies

Supernova to be: Eta () Carinae

Supernova to be: Eta () Carinae

Supernova to be: Eta () Carinae

Supernova to be: Eta () Carinae

GRB 080319B

Gamma Ray Bursts: *brightest objects in universe*Thought to be collapsing stars (>30solar mass)

March 19, 2008 – above GRB was a naked eye objectBut is over 7 Billion light years distant!100 times brighter than all stars in Milky Way combined!

Okay, stuff gets “blown out”Then what?

Dust (C, Fe, etc.)

Gas and dust swirl around Combines with new gas and dustGravity creates new star forming

regions

Eagle NebulaPillars of Creation

Pillars of CreationIn the Eagle Nebula

Orion Nebula

Orion Nebula

Pleiades (very tiny dipper) – Subaru (Japanese)

Star Clusters

Globular ClustersSurround Galaxies

What about galaxies?

Looking at galaxies IS looking back in time!

Milky Way – Center contains massive black hole (>106 solar mass)10,000 light years to the middle, 100,000 light years across

Andromeda Galaxy

2,200,000 light years away

Hubble Ultra-deep field. Everything shown is a galaxy

Billions of light years distant

Colliding Galaxies Antennae Galaxies Colliding

• Stephan’s Quintet

• 300,000,000 light years

Artistic drawing of Andromeda colliding with Milky Way

Fomalhaut is believed to be a young star, only 100 to 300 million

years old 25 light years distant

Hubble, Chandra, Spitzer, Swift, etc.

Next: James Webb

Keck Observatory

Subaru

Arecibo

Very Large Array

HAPPY THANKSGIVING!

References

• Astronomy Magazine: Oct 2007, Nov 2007• http://www.nytimes.com/2002/10/29/science/space/

29COSM.html?pagewanted=2• I. Iben Jr., A. Tutukov, The Lives of Stars, Sky and

Telescope, Dec. 1997• Scientific American, October 2001• Scientific American, Life in the Universe, 1995• Hogan, The Little Book of the Big Bang, Capernican Press• Photo’s from Astronomy Picture of the Day:

http://antwrp.gsfc.nasa.gov:80/apod/astropix.html• All photos shown in this presentation are from various

websites. Thanks Google, et al.