Flamsteed Astronomy Society

Flamsteed Star Lecture — May 29, 2006

Sir Arnold Wolfendale

The Origin of the Universe

IIn the absence of conclusive  evidence to choose between these alternatives, Sir Arnold took a vote among the audience and concluded that the Perfectly-tuned Universe had won by three submissions or a knockout (Fix! Fix!).  He presents three arguments in support of the perfectly-tuned universe:

1. The Universe seems to have close to zero total energy (potential + kinetic = 0).  The entire shooting match could be powered by energy borrowed from the quantum vacuum.

2. The ‘fine tuning’ of the big bang expansion is close to perfect.  A ratio of normal to dark matter of 1:20 is very close to 1 (!).  1 second after the big bang, the velocity of expansion was within 10 –17 of perfection

 

3. Dark matter seems to be necessary for other reasons eg the formation of large scale structures.

Prof. Wolfendale took us for a gallop through the development of the Universe in the split seconds after the big bang and looked at how irregularities of 10 parts per million in the early universe must have existed to result in the galaxies and larger structures we see today.  These early variations have been detected by the COBE and WMAP satellites in the CMB and lead to today’s standard model :  5% ordinary matter; 25% dark matter; 70% vacuum or ‘dark energy’.

 

The 14th Astronomer Royal, Sir Arnold Wolfendale, presented the 2006 Flamsteed Star Lecture on the subject of ‘The Origin of the Universe’.  Nothing small.    The event saw an excellent turn-out with about 90 present in the audience including many non-members.  They were treated to a most entertaining exposition in Sir Arnold’s pithy style and dry wit.   He included several unique anecdotes giving us unrepeatable insight into the ways of the establishment.

Sir Arnold let slip that the 14th AR has something in common with the 1st, John Flamsteed himself :  after Newton and Halley ‘hijacked’ Flamsteed’s work and published the ‘Pirate’ catalogue of 1712, a furious Flamsteed was left to recover 300 undistributed copies which he burned in Greenwich Park;  over 300 years later, the 14th AR was left to corner the market on the tragically remaindered copies of his book on cosmic rays.  He bought up numerous copies of the 10/6d volume at 6d each.   According to Sir A. both works are now collectors’ items.  Plus ca change …

We began with a quick tour out from the Earth :  Jupiter, 5 times more distant from the Sun; the orbit of the Ulysses satellite, out of the plane of the solar system; the disk of the Milky Way; the Magellanic Clouds, our nearest galaxy neighbours; the Andromeda galaxy, 2 million light-years distant and the farthest object visible with the Mark-I eyeball; out to galaxy clusters many billions of light years distant; to the HDF super-clusters, the beginning of time.

When we study galaxies and larger structures a pattern seems to emerge :   we don’t see enough matter out there to explain the observed motions.  Galaxies and clusters are rotating and moving faster than we can explain using good old Isaac Newton’s laws of gravitation.  There is ‘missing mass’ of somewhere from 4 to 20 times the visible mass.  The missing mass is called Dark Matter and we don’t know what it is.

Back to the basis of today’s ‘standard’ cosmology model, the Big Bang —

1929 Edwin Hubble and Milt Humason study the redshifts of many galaxies and deduce the Hubble expansion

1965 Penzias and Wilson stumble over background radiation coming from everywhere in the sky, equivalent to 2.7 degrees K. — the CMB cosmic microwave background radiation.  The residual echo of the big bang, redshifted into the microwave after almost 14 billion years.

The universe is expanding.  Galaxies are flying further and further apart.  But what will happen?  They may continue to fly further apart, called an ‘open’ universe; they may eventually stop and the start falling inwards back toward each other, called a ‘closed’ universe; or the acceleration may just gradually slow towards a halt after an infinite time, the perfectly-tuned or just-right universe, Goldilocks.

What are the possibilities for the future expansion of the Universe?  There are four :

1. An Open Universe in which the expansion continues forever and the Universe undergoes ‘heat death’

2. A closed and oscillating Universe in which the expansion reverses at some point, and the Universe contracts to a Big Crunch followed by another Big Bang ad infinitum.   In this model there is no ‘before the Big Bang’ avoiding difficult questions.

3. A Time Reversal in which time runs backwards after the big crunch.  The Universe in this phase would appear to be expanding to an observer inside.

4. The perfect Universe. Expansion continues but slows down, coming to a standstill after infinite time.

We were left with the four big unanswered questions :

What happened during the Big Bang before 10 –43 seconds?

 

What is Dark Matter?

Is Dark Energy real?

Where are we going?  Why?  Do I care, and who the hell am I anyway?

On a previous occasion Sir Arnold was asked what God was doing before the big bang. “Madam” he replied.  “God was making hell ready for people who ask questions like that”.