(almost) in the beginning

I love it when a scientist or science writer gives  jargon-free explanations.  Carl Sagan, Stephen Jay Gould, E.O. Wilson, Jane Goodall  and Neil deGrasse Tyson come over as superstars and  a handful of new stars have emerged on YouTube.  The work of these explainers is important to society going well beyond science education.  

 

 

A few days back I was given a new cosmology book aimed at a general audience.  The writing was almost jargon-free and respected the audience.  The artwork was outstanding as was the layout of the book.  But I had to give it up.   There were a couple of glaring errors so large to be a post-worthy.  I'll write about the one that bothers me most.

 

You probably learned the Universe began with an event called the Big Bang.  The evidence goes back a long way.   About 90 years ago it was discovered that most of the Universe was moving away from us and that the further away something was, the faster it was moving.  The idea of a static steady-state Universe was in serious trouble.   If everything was expanding it implied they were closer in the past..  much much closer in the very distant past.  It implied a beginning .. perhaps a beginning time.

 

As the Universe expands it stretches the wavelength of existing light.  Blue light becomes redder.  The energy of a photon - the particle of light - depends on it's wavelength.  The shorter the wavelength, the higher the energy.  Going backwards in time photons of existing light were more energetic.  The Universe was hotter.  As you go back in time it gets so hot atoms can't form.  Keep going and you get to a singularity - a super dense and hot region at the beginning of time.   The Big Bang happens and a Universe is set in motion.  You should be able to look in the sky and see the remnants of this event.  By now the expansion had been so great all that was left over was a cool glow of microwave radiation a few degrees warmer than absolute zero^.1  Two Bell Labs astronomers detected it in 1964 and the Big Bang was accepted.  The steady state Universe was dead.

 

There were some curious technical problems left to describe.  In the late 70s the notion of inflation came about to explain them.  Explaining cosmic inflation is a big too much for now, but think of it was the Universe expanding from an tiny size at an unbelievably fast rate for a short amount of time. Much faster than the speed of light (which turns out not to be a problem as information isn't exchanged between parts of the inflating Universe).  

 

The explanation was satisfying and compelling.  Now the Big Bang was seen as a singularity.. essentially a mathematical point of infinite density.  It happened and then the Universe inflated followed by the comparatively gentle expansion we see today.  Nobel prize worthy observations shortly afterwards dispelled that notion.  Inflation had to come first.  The Universe didn't begin as a superhot, superdense point, but more likely began without matter or radiation.  All of the energy was in the fabric of space-time itself - what physicists call a vacuum energy.  After about about a trillionth of a trillionth of a trillionth of a second,  inflation came to an end with the energy converted to matter and radiation somewhere between the size of a grape and a volleyball.  That glob and the expansion that immediately followed was the Big Bang.    

 

You might ask what set off inflation at the beginning of time?  Or was there a beginning of time? Or is was there time?   There are conjectures, but they're just that - conjectures.  There's nothing that can be addressed by physics (yet).   More to learn.

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¹ This background radiation fills the Universe.  If you have an old non-digital TV and tune it to an unused UHF channel, about one percent of the snow on the screen is that leftover from the Big Bang.  It's not from the Big Bang directly, but rather from the time when the Universe cooled to a point where it first became transparent..  about 380,000 years after the Big Bang. 

 

 

Comments

[Jheri]

when they say that CERN is looking at the early universe with their accelerator do they mean just a high temperature?

The video is great!!

[steve crandall]

Exactly Jheri. The particles are moving with a lot of kinetic energy. You can speak of the temperature of tin terms of energy.. In a gas temperature is closely related to the kinetic energy of the bits that make it up. So the early universe had enormous energy and thus was very hot.

It may seem strange but particle accelerators, looking at the smallest bits of matter, are windows into the early Universe.