Science & Nature Archive

Friday, January 2, 2009

Happy Darwin Year

Charles Darwin as a Young ManSince 2009 marks the bicentennial of Charles Darwin's birth, as well as the 150th anniversary (sesquicentennial) of the publication of On the Origin of Species, many groups have decided that 2009 should be Darwin Year. So, to kick off the year, here are a couple links to good sites dealing with Darwin.

  • Nature's Darwin 200 The prestigious journal has put together a collection of articles, editorials, news stories, and various other essays and features that have to do with evolution in general or Darwin in particular.
  • The Darwin 200 Consortium Hosted by London's Natural History Museum, this site also has a collection of info on evolution, as well as info about upcoming events to celebrate Darwin Year.
  • Another good site with evolutionary info. The events on this site are mostly on or around Darwin Day, February 12th.
  • American Museum of Natural History's Darwin page Yet another good collection of information. This is from the exhibit that ran in the museum from 2005 to 2006.

To give a short taste of the Nature site, they've made freely available, and even encouraged dissemination of (so sharing it here is perfectly legal), an article on 15 Evolutionary Gems, collecting information from articles published in the journal "over the past decade or so to illustrate the breadth, depth and power of evolutionary thinking."

Don't forget to check with your own local museums. Even if they don't have any special events scheduled for Darwin Year, they're always fun to visit, anyway.

Added 2009-01-02 Well, I figure that for the kick off to Darwin Year I might as well post links to the previous posts I've made on evolution or Darwin. If I happen to post anything else on the subject during this year, I'll try to remember to update this list.

Friday, November 14, 2008

The Moon

Speaking of space, my daughter and I broke out the telescope tonight, and I figured that just for the hell of it, I'd try to take a picture of the moon. No fancy equipment - just sticking the camera up against the eyepiece, and doing my best to get it in focus.

The Moon
(click image to enlarge)

If anyone's interested, it was an Astroscan telescope, and the box the eyepiece was in said "Plossl F15." The camera was a 7.2 MP Sony DSC-W80. I probably could have gotten a little better picture if I'd messed around a bit more, but I thought this one still turned out decent.

Thursday, November 13, 2008

The Universe Is Big

Douglas Adams once wrote,

Space is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space.

Phil Plait from the Bad Astronomy Blog recently posted about "the deepest ground-based look into the universe ever undertaken." I've put a compressed image below, but I would highly recommend downloading the 32MB full resolution image (The ESO reorganized their site. The image can now be found here. It's offered in several resolutions, including a gigantic 78.6 MB tiff. You could also use this flickr link instead, for a slightly lower res version). Don't be fooled - most of those smudges of light aren't individual stars; they're galaxies.

Deep Look Into Space

Okay, to give an idea of scale, I've superimposed that image onto the moon, to show how much of our field of view it takes up (If you make a thumbs up sign and hold it at arm's length, the full moon's about the size of your thumb nail). Not just that, but notice that little white square in the top left corner of the superimposed image? Well, I put the full size of that portion on the right. Note that in the image above that that region appears to be pretty empty, but once you zoom in on it, you can see there's still a lot there. And remember, those are galaxies, not individual stars. That's why it's so impresive to download the full size image and just scroll around it.

Image Superimposed on Moon

Okay, to put this into a little more perspective, I did a rough calculation. It seems like people like comparing stars to grains of sand. Well, it's been estimated that our galaxy contains around 100 billion (1 x 1011) stars. For a rough calculation, let's assume we have spherical grains of sand around 0.5mm in diameter (source), or about .02 inches in diameter. I won't bore you with the calculations, but 100 billion grains of sand would have a combined volume of 231 cubic feet. Assuming a 64% packing ratio (because there're going to be air spaces in between the grains), you'd actually need a container of around 361 cubic feet to hold all that sand, which works out to a cube of around 7 ft. per side.

So, the point of all that calculation - if you had a 7'x7'x7' container full of sand, that's about how many stars there are in our galaxy. Assuming we have an average size galaxy (some are bigger, some are smaller), just about every smudge of light in the image above represents around that many stars. I really can't even begin to comprehend that - all I can do is describe it. Scrolling around that full size image gives me butterflies in my stomach thinking about just how big this universe is.

Added 2008-11-14 Okay, that assumption about our galaxy being typical has been bugging me a bit. I still haven't been able to find a good source showing the distribution of sizes of galaxies (admittedly, I haven't looked very hard), but Wikipedia says that most galaxies range in size from 10 million to 1 trillion stars. So, repeating the calculations I did earlier with that star count, it would take a 15x15x15 ft cube to hold a trillion grains of sand, and a 4x4x4 inch cube to hold 10 million. Now, a 4" cube may not be all that big compared to the 15' one, but that's still a lot of grains of sand.

Now, just to add one more bit of comparison, if you're in a dark area on a clear night, you could probably see around 2000 individual stars with your naked eye (since you can't resolve individual stars in the Milky Way or 3 three galaxies you can see with the naked eye, the Andromeda Galaxy, The Large Magellanic Cloud and the Small Magellanic Cloud - source1, source 2). It would only take a 1/4 inch cube to hold that many grains of sand.

So now, when you look at the picture, you'll have a slightly more accurate guess of how many stars each one of those smudges of light represents.

I'll also add that after working on this entry yesterday, and then staring up at the night sky with a near full moon for comparison, it made me feel tiny.

Friday, May 16, 2008

Global Warming - It's Real, And We're Causing It

Global WarmingI was with a group of people yesterday, and one of them brought up the recent news of the U.S. listing polar bears as a threatened species under the Endangered Species Act, due to their expected decline as global warming melts the arctic sea ice they depend upon for survival. And of course, this got the conversation going on global warming. Out of the six of us, one guy thought that scientists just didn't know what the hell was going on with the climate, that there wasn't any real consensus on global warming at all, and that even if global warming were real, which he doubted, polar bears would find a way to survive, anyway. Another guy seemed more open to the idea that global warming could be happening, and could be human caused, but wasn't entirely convinced. I tried my best to defend the science, while the other three people stayed pretty quiet on the subject (although from a previous conversation, I think that one of them at least accepts that global warming is happening). Later on, when I told another guy about this conversation, he seemed to think that the current global warming might just be a natual cycle, and that it's not human caused. So, out of 7 people, I was the only one to strongly accept that current global warming is human caused.

Now, I'll admit I'm no expert on global climate. Not only am I not involved with the field at all, but I haven't really studied it in depth on a lay level, either, like I have other fields such as evolution. So, I guess I need to ask myself, how can I go on accepting that humans are causing global warming, and that it is a major problem?

First, I'll defer to the experts. I realize this isn't exactly a sound logical approach - after all, evidence is evidence no matter who discovers it. But, in the same way that I'll take my doctor's advice on what effects different medicines and procedures have, I'll put a fair amount of weight on the statements of the people who devote their careers to studying climate.

Continue reading "Global Warming - It's Real, And We're Causing It" »

Friday, March 28, 2008

A (Somewhat) Brief Introduction to Evolution

Evolutionary TreeThe other night, we went out to eat with some friends. I forget why, but for whatever reason my daughter was going through, with our help, trying to think up a mammal for every letter of the alphabet (aardvark, bear, cat...) Well, for P she picked platypus, so when the game was all over, it got us to talking about them. And I foget exactly how the next part came up, but the guy I was talking to brought up that he couldn't see how they were related to other mammals, and that he really doubted the whole theory of evolution. I tell ya what - get a couple beers in me and then tell me you don't accept evolution, and just see what type of conversation gets going. Boy, was it fun. Unfortunately, I don't think I did much convincing. It had nothing to do with the beer, but a whole lot to do with the fact that discussions like that are basically my word vs. your word. Considering that I'm not a biologist or in any related field, and it makes my word worth that much less. So, I decided to write up an e-mail to send him, along with links to lots of sources backing it up. Once I got through with typing it, I figured that it made for a decent general introduction to evolution. Maybe at some point I'll clean it up and make a good essay out of it, but even in its rough e-mail form, I figure it makes for a decent blog entry. So, if you want to read it, go head below the fold.

Continue reading "A (Somewhat) Brief Introduction to Evolution" »


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