Category Archives: planetary science

A Lesson in Earth Science

And Climate Change

Sometimes you can’t keep ahead of the news. Especially in science.  As I was working on the climate change exhibits for California Academy of Sciences earlier this year, I’d keep tabs on research and discoveries in Earth sciences, particularly Earth’s atmosphere and oceans. And, as fast as I’d write up something from peer-reviewed science, there’d be more information and discoveries coming in.  Which is great, but when it comes to climate change, it seems like it might be chronicling drastic change that we neither need nor want.  But, that’s the nature of science research — it reports on what’s happening and tries to find out why it’s happening.If we’re smart, we heed what we see and take action.

Tomorrow there’s a peer-reviewed science paper coming out that I wish had come out earlier, since it would make a striking addition to the exhibits. It states that as Earth’s oceans absorb more carbon dioxide generated by human consumption of fossil fuels and other activities (which warms up oceans and causes them to become more acidic), sounds will travel farther underwater. What’s the big deal, you might ask.  Well, noisier oceans affect marine mammal, for one thing. And, there are likely other effects that reverberate throughout the ocean environment.

Image credit: (c) 2008 MBARI (Base image courtesy of David Fierstein). This illustration shows how increasing carbon dioxide in the atmosphere leads to an increase in the acidity of seawater, which in turn allows sounds (such as whale calls) to travel farther underwater.
Image credit: © 2008 MBARI (Base image courtesy of David Fierstein). This illustration shows how increasing carbon dioxide in the atmosphere leads to an increase in the acidity of seawater, which in turn allows sounds (such as whale calls) to travel farther underwater.

This projected impact on ocean sound is the result of calculations by Keith Hester and his colleagues at the Monterey Bay Aquarium Research Institute (MBARI) in Moss Landing, Calif. Their paper is coming out in tomorrow’s (October 1, 2008) issue of  Geophysical Research Letters, a journal of the American Geophysical Union (AGU).

So, what does it mean? Ocean chemists know that as seawater chemistry changes, its ability to absorb sound changes. As sound moves through seawater, it causes groups of atoms to vibrate, absorbing sounds at specific frequencies. This involves a variety of chemical interactions that are not completely understood.

The overall effect is strongly controlled by the acidity of the seawater. The bottom line is this: the more acidic the seawater, the less low- and mid-frequency sound it absorbs.

As the oceans become more acidic, sounds will travel farther underwater and the level of underwater noise will rise. This change in chemistry will have the greatest effect on sounds below about 3,000 cycles per second (two and one half octaves above “middle C” on a piano).

This range of sound includes many of the underwater noises generated by industrial and military activity, as well as by boats and ships. Such human-generated underwater noise has increased dramatically over the last 50 years, as human activities in the ocean have increased. For marine mammals that also use this range of sounds to communicate, it’s like having your neighborhood go from one of relative quiet to one where the neighbors are blasting their stereos and revving their engines all the time.

The MBARI researchers say that sound already may be traveling 10 percent farther in the oceans than it did a few hundred years ago. However, they predict that by the year 2050, under conservative projections of ocean acidification, sounds could travel as much as 70 percent farther in some ocean areas (particularly in the Atlantic Ocean). This could dramatically improve the ability of marine mammals to communicate over long distances, but, on the down side, it could also increase the amount of background noise that they have to live with.

There are no long-term records of sound absorption over large ocean areas. However, the researchers cite a study off the coast of California which showed an increase in ocean noise between 1960 and 2000 that was not directly attributable to known factors such as ocean winds or ships.

Hester’s research shows how human activities are affecting the Earth in far-reaching and unexpected ways. As the researchers put it in their paper, “The waters in the upper ocean are now undergoing an extraordinary transition in their fundamental chemical state at a rate not seen on Earth for millions of years, and the effects are being felt not only in biological impacts but also on basic geophysical properties, including ocean acoustics.”

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Planetariums Foolish? Not so Much…

It’s a Place of Science Learning, John, Not Uninformed Posturing

So, last week there was a kerfuffle, as they like to say, over a U.S. presidential candidate’s using planetarium funding as a weapon against his opponent. It was silly and, in my opinion, made the guy who complained about the funding look pretty foolish and ignorant (and, as Phil Plait suspected, anti-science). I suppose you could conclude that the candidate hates science education, but I suspect in reality, he had no clue of what he was talking about and just grabbed the first thing he could think of to throw back in his opponent’s face. It backfired, as it should have. Sensible teachers routinely flunk students who wing it like that, particularly in science where there’s little tolerance for making up facts to suit an argument. There’s no reason we should put up with a candidate for president of the U.S. who doesn’t do his homework.

I don’t want to get into the various specifics of the argument, mostly because we already hashed it out over at Phil’s Bad Astronomy Blog. I’d rather talk about what good planetariums are.

I’ve been involved in planetarium show production for a long time, both as a lecturer and as a content creator. To me, a planetarium is a great gateway into the world of science. Astronomy itself is a great entry into other sciences. Point yourself in any direction in the sky and the list of sciences you can use to explain what you see is a long one:  physics, astrophysics, chemistry, biology, atmospheric science, planetary science, geology… just to name a few. And, the beauty of a planetarium is that you can teach all that stuff on the dome, simply by looking at stars, planets, and galaxies.

Sure, you might not end up in astronomy as a career, but a number of scientists cite their first visit to a planetarium as something that got them started in science. In fact, it goes beyond scientists — I recently read about an environmental lawyer who fertilized his interest in science by lecturing at his local planetarium. I guarantee you that a good planetarium production will ignite your interest in astronomy, an interest you can take with you wherever you go.

I remember MY first visit to one when I was in 7th grade. I couldn’t believe such a cool place existed. It took a few years before I got back to one, and even a bit longer before I got into creating shows for such places. I spent some time just before graduate school lecturing in one, sometimes several times a day. It never failed to amaze me how cool the visitors thought the experience was. Oh sure, there were always a few slouches who came in and tried to be disruptive. But, for the most part, the visitors were thrilled to be there and learn something about astronomy.

In the U.S., we need more and better science education — it leads to critical thinking and better-informed citizens, methinks (which, come to think of it, might scare a certain subset of politicians (and others) who thrive on having ignorant voters…)

If a planetarium can help spur kids into studying science and having fun with it, it ADDS to taxpayer literacy in our country, and money spent on education (if done wisely) can come back to us in the form of better educated teachers, more scientists, and involved, engaged citizens. So, I kind of have to wonder: what’s so bad about that?  And, why is attacking a planetarium’s funding (which was a very small amount of money compared to the money that the attacker has wasted or misspent through his actions over the decades as a senator, and certainly is well below the amount he has sunk into all his seven or eight homes) somehow a sign of political virtue?  Especially since there are bigger budgetary oxen to be gored. I just don’t see how huffing and puffing about a planetarium is anything but a nonstarter, unless the candidate is a supporter of decreasing science literacy for all of us.