Tuesday, July 27, 2010

The Big Bang One More Time

I heard the question:  “What came before the Big Bang?  What exploded?”

Here's an attempt at a brief explanation.

Einstein's general relativity explains gravity in terms of geometry.  Instead of a force, objects move they way they move because mass changes the geometry of spacetime.

Taking the earth as an analogy, we understand the geometry of a ball.  By studying the geometry of the surface of the earth we can easily conclude that we live on a sphere.  Along with that comes the inescapable conclusion that the earth has a center.  We can't go to the center of the earth, but we know its there.

When we we try to determine the geometry of the universe, we find that it's space-time  “shape” implies a center, but one that is in the past.  At this center in the past, the scale of space goes to zero.

We can also use the earth as a different analogy.  If people set out from the equator in the Americas, in Europe and Asia, all travelling north, they will arrive at the north pole.  It doesn't make sense to ask what is beyond the north pole, if you are travelling north on the surface of the earth.

In the same way, the question of what comes before the big bang doesn't make sense in light of the implied geometry of the universe.

There's not an explosion in the they way most people think of.   If you go back in time in the above model, space is smaller and densities are higher.   The temperature and energy density are necessarily higher and, mathematically, go to infinity at the “center.”

That high-temperature past serves a useful purpose for physicists.  It provides another way to answer questions about high energy states of matter and its structure in addition to the large accelerators we've built.

From the point of view of creation, there's nothing that says God couldn't create a full-grown universe as described here just like he created full-grown people.

Saturday, July 24, 2010

Perpetual Calendar

I had a subscription to Popular Science around 1970 for a few years and, I think, as part of that had this little perpetual calendar on a card that I carried in my wallet for decades.  It was only recently that I removed it and today I found a photocopy I'd made of it.

Here's the same calendar as part of an on-line auction.  It's good through 2059.

Facebook Friend Suggestions

Arg!  Facebook strikes again, i.e., it's just another day.  I thought I was accepting friend requests when, in fact, I  was clicking on friend suggestions and ended up sending out  friend requests.

It's not a huge deal since they were people I know.  My usual practice is to just receive requests.  Then, if they are from folks I know, I'll usually accept them.  However, I rarely send them out.

The moral is, always pay attention to the labels.  Yes, they are clearly marked, actually.

Thursday, July 15, 2010

Jupiter's South Equatorial Belt is Gone!

I was looking at some of the amazing images on Brian Combs' web site and noticed that Jupiter's South Equatorial Belt is gone!  The article in Sky and Telescope mentions that this has happened recently, to a lesser degree.   I know that Jupiter's clouds change over the years, but didn't remember an equatorial belt completely disappearing.

One nice side effect is that the Great Red Spot is now easier to see, maybe for the first time since the 70s (when it was very red).

Article at Astronomy.com

Image linked to at Sky and Telescope

Froyo's Color Trackball LED

Heh, when I received Google Voice mail yesterday, my track ball flashed green!  That's the first time I've ever seen it any color other than white.  That's another small but neat feature of Froyo.

Wednesday, July 14, 2010

Blogs to Facebook (Update)

Removing and re-adding the import seems to have fixed it.  What a pain.

Let's see if this one appears.

(Update) Yep, it worked.  I suspect they wanted me to click the policy/agreement acceptance check box and click the Confirm button again, but I don't recall ever receiving a request to do that.  It just quit.  Ah, well.

Tuesday, July 13, 2010

Blog Gateway to Facebook

It seems that my blog posts are not being picked up by Facebook again.  I wonder why.  Let's see if this one works.  Maybe it eschews the shortened links I include sometimes.


Amazing starry sky, planetarium in your computer software!

It seems I've never mentioned Stellariium here.  This free, open source software is amazing!  It's as nice, and as nice looking, as any planetarium program I've tried.

Friday, July 09, 2010

TWiT Cottage Studio Rewired

Here's a neat time-lapse video of the TWiT cottage studio being rewired.

Thursday, July 08, 2010

Friday, July 02, 2010

Those Annoying Horns

Didn't we have these horns, years ago in high school, at football games and such?  It seems like they were sort of red and plastic.  Of course we didn't suffer everyone blowing them incessantly.