Podcast Reflections

9 10 2009

So a year ago at this time I put out a little blog piece on a question that really caught my attention in college.  I remember that I found it elegant in its simplicity, yet fascinating in the various debates it drew.

When I heard about the 365daysofastronomy project I knew I wanted to be a part of it, I just wasn’t sure what topic I would tackle.  I turned to my blog and looked at some of the things I had already written.  This one on Olbers caught my eye, and I requested his birthday for an air date.  I didn’t get that date, but I got the day after.  Close enough.

Next came the challenge of designing a style for the podcast.  I read through what I had written, and it even put me to sleep.  I mean, I think it reads pretty solid and I certainly don’t hate it, but it just didn’t translate to speech very well.  Hopefully, what I and a few friends came up with will be well received.  And, actually I’m quite proud of it.

I’m very honored to have my podcast played in between some pretty awesome people.  The podcast before mine references Giordano Bruno as a champion for the search for extra-solar Earths.  The podcast after mine is produced by the education officer for the NRAO and, along with an engineer there, discusses how signals are coaxed from the tons of background noise by Greenbank’s staff.  As I look over the calendar I see some folks I know, like Pat McQuillan and Carolyn Petersen, and I see some names that are somewhat famous in the world of astronomy, like Emily Lakdawalla and Martin Ratcliffe.  It’s a pretty special group and I’m so grateful that I got to be part of something together with everyone involved.

So, in looking back at that article from last year, I’ve decided to re-post it in its entirety here.  Any comments about the podcast should be added to this post.

Thanks.

Today is the 250th anniversary of the birth of the greatest of paradox proposers, Heinrich Wilhelm Olbers.  Olbers did a number of things in his life to advance the study of astronomy, but what he is most famous for is the question that bears his name:

If the universe is infinite and stars are distributed evenly throughout, then why isn’t the sky infinitely bright?

Think of it this way, if you were standing in a large forest you wouldn’t be able to see your way out of it.  Near you there wouldn’t be many trees and you could see past them.  Farther away the trees would appear smaller yet more numerous.  This balances out and explains why you can’t look in any horizontal direction and not see a tree.  Now imagine those trees as stars.

This question may not be as well known today, but 100 years ago this was the BIG question.  Last century people wondered about the nature of light, whether matter was continuous or quantized, and what was the source of gravity.  Today we have big questions like “Did we accelerate global warming?”, “What is dark matter?”, and “Do gravitons create the gravitational force?” (I guess gravity may baffle us for centuries to come).  But in social circles people talked about Olbers’ Paradox to stretch their imaginations and to show off for the ladies!  Just like today — the ladies love a man who can discuss the implications of the discovery of the Higgs particle on multi-dimensional physics.  Ummm Hmmmm!

Olbers’ Paradox was originally proposed by my hero, Johannes Kepler, 200 years before Olbers described the argument in 1823.  This argument arises from the idea that the universe is steady-state, meaning that it has always looked like it does today and always will.  Einstein held this belief so strongly that he refused to accept the Big Bang Theory, even though his own equations pointed to that reality.

Here’s the idea in a nutshell.  There were a few generally accepted beliefs among scientists and the majority of the educated population.

1.  The universe is steady-state

2.  Stars are evenly distributed throughout

3.  The universe is infinitely big

If all three of these is true then there would be no line of sight that would not end in a star.  If everywhere you looked there was light coming toward you, then the sky would be infinitely bright.  The only way you would know where the sun was would be to look for the slightly darker area of the sky.  A seemingly ridiculous hypothesis, yet completely logical.

This means, of course, that one of the accepted beliefs was most likely wrong.  Or two.  Or all.  But what is the truth?  There were many ideas — good ideas — suggested by some very smart people to explain our reality.  But many fell victim to Occam’s Razor; they were just too convoluted to be viable.

Strange as it may sound, the first person to publish a correct solution was Edgar Allen Poe.

“Were the succession of stars endless, then the background of the sky would present us a uniform luminosity, like that displayed by the Galaxy –since there could be absolutely no point, in all that background, at which would not exist a star. The only mode, therefore, in which, under such a state of affairs, we could comprehend the voids which our telescopes find in innumerable directions, would be by supposing the distance of the invisible background so immense that no ray from it has yet been able to reach us at all.”  –Eureka: A Prose Poem

What he proposes here (if you can read through all his commas!  Sheesh!  He writes run-on sentences like I write sentence fragments.  –you do read my blog, right?) is that light has a speed limit and the universe is not infinitely old, thus this infinite amount of star light hasn’t reached the Earth yet.  He did not contradict any of the three suppositions, yet his idea of the universe having a beginning gives us a good starting point for the explanation.  He wrote this in 1848, 80 years before Hubble would show conclusive evidence for a beginning to everything.  Odd thing is, no one paid attention to Poe just like no one paid attention to Hubble at first because folks were so convinced that the universe had always been here.

So that’s only part of the explanation.  The rest of the story is that the universe is expanding.  In a not-so-readily-apparent sense, because the universe was smaller in the past it was also brighter.  As the expanding space-time continuum spreads things out, the overall energy density decreases.  (Wow!  That sentence made me feel smart!)  There is a ‘horizon’ to the universe — a boundary which we cannot see beyond.  The expansion is faster than light, which means anything beyond that boundary will never be visible to us because the light from those objects can’t outrun the space-time expansion.  Thereby preventing us from ever knowing how far the universe actually extends.  And keeping the visible universe of limited size.

Also, because of the expansion the stars aren’t uniformly spaced.  They occur in clumps.  These clumps were hypothesized way back in the 1700s by philosophers, but not confirmed by astronomers until the 1920s!  The clumps were given the name galaxies after the Greek word for milk.  Yeah, makes total sense to me too.  Still a cool word, though.

And there you have it! All three postulates failed and the paradox is now moot.  The scientists who proposed the problem knew that something was wrong with popular opinion, they just weren’t sure where the answer lied.  It took a lot of looking, a lot of thinking, and a lot of technological advances to put the pieces together, but today we have a pretty clear view of our place in the universe.

So, Happy Birthday, Heinrich!  Of all the science you brought us, you showed that sometimes it’s more important to ask the right questions.

[BTW, while double-checking all my facts on the intertubes I found countless articles that were just plain wrong or else written so poorly that I could barely read them.  Honestly, I’m going to have to side with Wil Wheaton on this and say that these days the ability to spell is a superpower.  And do they just let any idiot with a library card have a blog?  <checks library card>  Oh, yeah… guess they do.]

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Small Article

8 10 2009

So the state paper interviewed me and another teacher a couple of weeks back.  The interview was published in the local edition of the paper today.  You can read it online here.  I’m not sure how long they keep articles archived, so it may be gone soon.  I’ll keep a copy and post it here if they take it down.  In the meantime, I don’t think they’ll mind if I steal their photo…

paper picture

I wish the article had focused more on student projects.  I really love it when students want to build stuff and do investigations and play with big physics toys.  I brought Adam’s Tesla Coil up to the school primarily so my current students could see it before I gave it away to UCA, but also because I wanted the newspaper photographer to take this picture. In the interview, I talked for over a half hour about what projects my students have done in the past and what a current one will be doing this year.  Alas, she decided to keep the article focused on the workshop I attended.  Well, at least she quoted me right.  :o)





LCROSS to attack the Moon!

7 10 2009

So when I was in college, I had a professor named Dr. Eldridge who spent some time with Dr. Oppenheimer, and therefore said things in an odd way.  (Look, I don’t know if Oppenheimer had *anything* to do with Eldridge’s odd metaphors, but it adds to the story, ‘k?)  And when we would talk about the innards of the atom he would always say,  “Well, you know the best way to see what’s in your Christmas present.  Blast it with a shotgun and see what flies out.”  It was his way of explaining Rutherford’s gold foil experiment.  Or any other experiment involving subatomic particles.

Looks like NASA has taken his cue in looking for water on the moon.  This Friday, early morning, the American satellite LCROSS is going to slam into the southern side of the moon while scientists watch the resulting dust cloud for evidence of water.  The impact won’t (shouldn’t) be visible to the unaided eye, but perhaps a 10-in. scope can pick it out.

crash1

A computer visualization of LCROSS hitting the Moon on Oct. 9th. Credit: NASA/Ames

The impactor is huge!  At almost 5000 lbs, it’ll strike the moon with the energy of a small atomic bomb.  Shortly after, the booster rocket, which weighs in at 1500 lbs itself, will strike a short distance away.  There are a ton of websites with lots of good information about this all over the net.  This is a good place to start.  There’s information there for folks who’d like to observe or even submit images of the event as well.

And, just because it gives me yet another chance to post this image, here’s what it should look like through the right telescope.





Podcast This Saturday

7 10 2009

So the podcast that I wrote and produced for 365daysofastronomy.org is being released this Saturday.  I worked pretty hard on it, and I don’t hate it, so I think you’ll enjoy it.

Some details:

  • It’s about Olbers’ Paradox which asks the question, “If the universe is infinite and stars are evenly distributed, then why isn’t the night sky bright with star light from every direction?”
  • It’s written in the spirit of NPR’s Car Talk where I and my ‘brother’ take calls from people with astronomy questions.
  • The first call we take is just for the funny, but it is based on an actual event in England a few years back!
  • The podcast had to be less than 10 minutes in length.  The script, as originally written, took over 16 minutes of recorded audio to get through.  I spent one night re-writing and re-recording some things with Jeremy and James to compact it .   And I spent one night whittling out some more dialogue — and a few jokes that I really hated to cut — in order to get everything under the time limit.
  • I had to cut out all of Kathleen’s lines as well.  Kathleen, I am so sorry for that.  I left you in the credits anyway, if that helps…  (I am so sorry!)
  • To make this sound semi-professional, I had to use two sound cards (one for recording through Skype and one for multi-channel ASIO format) and a slew of effects to clean up bad VOIP audio or to dirty up in-house audio that was too clean sounding.
  • I had a couple of other things I wanted to do with the audio, but time was short so I kissed my baby goodbye and upped it to the servers, only 2 days later than my deadline.  :o)

I can’t thank those involved enough for their time and patience helping me with this.  They are, Jeremy ‘Indiana’ Lusk, Lauren ‘The Annihilator’ Jacobs, Kathleen ‘Action!’ McMurray, James ‘Drill-Bit’ Tidwell, Jenny ‘Why-do-I-have-to-be-the-stupid-one’ Temple, and Dr. Jim ‘That’s-gonna-need-some-editing’ Ross.  And double thanks to Jeremy and Lauren for helping flesh out some major points and helping with the writing style.  And triple thanks to Jeremy for the two times he had to come out to my house to record his parts.  I’d also like the thank the good folks at 365days for getting this awesome brainstorm and then allowing me to participate, especially Davin Flateau for putting in a good word for me.  After hearing his podcasts, I really didn’t want to let him down!

If you don’t get a chance to catch the piece on Saturday, it’ll be up for the rest of the year.  Get by the website and take a listen.  And check out some of the other pieces people have contributed.  I find myself listening to one after the other.  Astronomy is such a broad field, and I love listening to people who are passionate about their specific area.  All the really cool stuff people post reminds me of a great saying that seems to fit quite appropriately here…

“The universe is full beyond measure of elegant truths of exquisite interrelationships of the awesome machinery of nature.”  — Carl Sagan