omenti

after a fall

a quick minipost

 

Or after THE fall..  

 

The Olympics can brings years of effort into very sharp focus for some of the best athletes in the world.  A decade or more of hard work and sacrifice can fall one way or another in under a second.  By any rational measure they're all amazing to get as far as they have.   And of course the athletes don't buy that - at least not initially.

 

A few people have recommended a new book on regret.  I haven't read it, but getting the recommendations while the Olympics are underway seems natural.  I don't consider the phrase no regrets to be useful.  Regret can be a powerful motivator, teacher and catalyst for self-reflection.

 

Every successful group and organization I've been around holds postmortems for projects independent of outcome.  In large particle physics experiments it's common to hold internal and external postmortems.  These are particularly important where the culture and institutional memory are long term goals.  External postmortems are held for other experts - often competitors - and are important for ferreting out and fixing issues that hadn't been considered. (Feynman frequently said ~ The first principle is that you must not fool yourself, and you are the easiest person to fool...)  Of course there are regrets and people can feel a bit stupid, but you learn and grow.

 

At a personal level regret can be a highly motivating teacher.   With enough reflection you become much better at making decisions and you get better at what you're doing.    And sometimes life's big decisions come into clearer focus.  Are you really doing what you like?  Are you doing what you should be doing? Should you change your goals or invent completely new ones?   A life with a singular focus can lead you down a path that you realize all too late was the wrong one.  The self reflection of regret seems like a mechanism to make midcourse corrections, learning and growing as you travel.

 

I've had wonderful failures and mostly useful regrets.  To some I may seem like a failure, to others a success, but to myself I'm lucky enough to still be learning - plus -  all of my fingers and eyelashes are still intact.

 

how big is it?

Two days ago I was on a call with one of you.  Somehow "how big is the Universe?" came up.  I spent ten or fifteen minutes talking about it at a very high level.  Here's roughly what I think I said. A few of you worry about this and I'd be interested in comments if this is a good layperson's explanation. 

__________

 

Start with the fact that the speed of light is finite and fixed. That you see the Sun as it was about 500 seconds ago, the moon 1.3 seconds and your ring a handful of nanoseconds in the past. The farthest star you can see with the naked eye on a dark and clear night is about 16,000 light years away and the most distant object is the Andromeda galaxy at something over 2 million light years off.

In the past two decades the age of the universe has been pinning down at around 13.8 billion years. Since light travels at the speed of light one might conclude the universe has a diameter of 27.6 billion light years.

But the universe isn’t static. In the late 1920s it became clear it was expanding everywhere.  The farther something is, the faster it's moving away.  The hypothesis that it may have come from something very small was a natural conjecture.  It became known as the Big Bang.  

What a terrible name!  Bang invokes explosion.  Instead it's an expansion of space everywhere.  A neat thing about relativity is that “nothing moves faster than light” only applies to light and matter, and not to space. Space isn't breaking any rules when its expand faster than the speed of light. Distantly separated objects may not be moving much relative to the space immediately around them, but the space between them is expanding and distancing them.

The universe was initially a hot opaque plasma that cooled as it  expanded. Finally, at about 380,000 years, it chilled to about 3,000° K - chilly enough that electrons and protons in the plasma became hydrogen atoms and the universe was transparent to light for the first time. The first color isn’t far from the orange you see on the filament of an old incandescent light - so orange everywhere.  The what might be called the observable universe  had expanded to a sphere with radius of about 42 million light years. We can still see that initial event.  Light coming towards us was encountering an expanding distance to travel and has finally made it here after 13.8 billion years.

So re-stating.... The remnant of that first light that we currently see on earth comes from a sphere that was 42 million light years in radius when it started. Light seen on Earth yesterday was from a slightly smaller sphere, light seen tomorrow from a slightly larger one. The expansion of space has stretched out (red shifted) the wavelength of that light with an initial wavelength of about a half micron to the point where it’s now a microwave with a wavelength of about 1.9 mm. Those primordial photons still light up the universe.. there are about 400 of them per cubic centimeter of space.

Expansion continues. That first glow - the cosmic microwave background - we observe is 13.8 billion years in the past, its sphere has continued to expand (at a slower rate) and is now about 46 billion light years away from us.

So this is the known universe, much of which we can’t observe.

Immediately preceding what is now known as the hot big bang may have been an incredibly rapid inflation. It explains much about the structure of the universe but hasn’t been found in direct observation (yet). It also sets a lower limit on the size of the universe at about 125 million times larger (by volume) than the 92 billion light year universe we sort of know.  It could be much much larger. There’s no reason to think we’re special. It seems likely that volume is filled with stars, galaxies, black holes and (my gut feeling) intelligences beings thinking about this too.