Archive for March, 2010

Remember the Cassini probe? If words like “Saturn” and “Titan” and “hydrocarbons” are floating around your grey matter right now, then you definitely do! Cassini-Huygens was a probe designed, funded, and built by NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI). Launched in 1997, the probe set out to explore Saturn, its moons, and its ring system. Cassini is actually the larger portion of the probe (from NASA), and the part that is still functioning. It arrived in orbit of Saturn in the summer of 2004.

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My earlier post bemoaning the Pacific Northwest’s lack of preparation for a megathrust-style earthquake led to a long description of the basics of plate tectonics. Revisit that post to remind yourself how Earth’s tectonic plates move, sliding past one another, moving apart, or colliding head on. Over our short lives, we see only a tiny bit of evidence of this awesome process. But, over the hundreds of millions of years that life has been thriving on this planet, the face of Earth has changed dramatically.

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The above image is the Korean Peninsula at night, via satellite. If the Korean coastline isn’t very familiar to you, there’s a daytime image after the jump.

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Geologists and engineers in the Pacific Northwest are analyzing the damage and devastation in Chile from their recent earthquake, and they don’t like what they’re seeing. An op-ed in this weekend’s New York Times argues that the Pacific Northwest population centers, and the Puget Sound metropolitan region in particular, are entirely unprepared to face future earthquakes and associated hazards. Their evidence? American building and infrastructure codes, and the unique example of Chile: a developed country prone to similar types of earthquakes seen in the Pacific Northwest.

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While I was enjoying the gorgeous views of British Columbia’s Sunshine Coast from the many ferry rides it took to get to Texada Island on Thursday, Andrew Revkin posted new findings concerning climate change and ocean currents on the New York Times blog Dot Earth.

A short summary: ocean currents as they’re currently set up help distribute warmer waters from equatorial regions toward the poles, and bring cold water back to the equatorial regions to be heated. This planet-wide circulation pattern has tremendous effects on local climates. One famous result of these current networks is that northern Europe’s climate is kept much warmer than it would otherwise be based solely on its latitude.

For several years now, scientists have worried that these circulation patterns in the north Atlantic Ocean could be disrupted by climate change. The problem centers on melting ice: rising temperatures may shrink or completely melt the massive ice sheet covering Greenland, discharging huge amounts of cold freshwater into the north Atlantic. As a result, these ocean circulation networks in the north Atlantic could slow down (a bad event) or break down entirely (a topic of the disaster film The Day After Tomorrow). While the sudden collapse of the north Atlantic circulation pattern was a highly unlikely scenario, even the current’s slowdown could cool northern Europe to a climate not seen in recorded history.

However, new research from NASA’s Jet Propulsion Laboratory measuring has added silver lining to the climate change cloud. Sure, parts of the Greenland ice sheet are melting, but so far the speed of the north Atlantic currents has remained stable since the 1990s. Currents keep bringing warm water up from the equatorial regions, and transporting cool water down to be re-heated, despite the increasing discharge of freshwater.

Many questions remain:

  • How fast is the Greenland ice sheet melting, and will it melt entirely?
  • What about the potential loss of sea ice from the Arctic?
  • Could there be other sources of freshwater discharge into the north Atlantic and Arctic, such as increasing stream and river discharges from a warmer Canada or Russia?
  • Will the currents still remain stable in the coming decades?

And of course, even if all these melting events don’t slow ocean circulation patterns significantly, there’s another major problem we still have to deal with: all these melting glaciers and ice sheets are going to raise global sea levels.  It’s not a matter of “if,” but “how much?”

Video of ocean current circulation patterns courtesy of NASA’s Goddard Space Flight Center.

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Sine Qua Non

For those of you who have become loyal readers over this science blog’s brief life, an announcement:

I journey today to Texada Island in the Strait of Georgia to attend the Texada Stickleback Group meeting. I’ll likely have no mobile phone service after crossing the Canadian border (something I’ve never understood about mobile phone service with the closest economic and political ally of the United States), and sparse internet access on Texada. Thus, no new posts until next week!

Until then, read some science news on your own:

Happy trails!

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The geologic processes that shape Earth’s interior and exterior seem to crawl along at a snail’s pace, at least from the perspective of a single life. Sure, in the scope of the planet’s 4.6 billion year existence, Earth has changed quite a bit. But, for the handful of decades we can collect observations, we may be lucky to collect some observations: erosion of a hillside, extension of a glacier, or shift in a river’s channel. For us, we still often have to wait decades to see Earth’s evolution in action.

However, sometimes these processes occur quickly. Rather than waiting decades, drastic changes can occur in a year, a month, or even the blink of an eye. The violent eruption of Mt. St. Helens on 18 May 1980 changed the mountain and the surrounding landscape in a single day. My biochemistry professor in college remembers how her parents had to climb up onto the roof of her house near Tacoma, Washington to push away the ash that was piling up after the eruption.

The recent earthquake in Chile shows us two examples of the big and small changes (by human standards) that geologic events can bring. For the huge change: the city of Concepcion (the closest major urban area to the earthquake) moved a full 10 feet to the west due to the release of energy and the violent shaking that accompanied it. Other cities moved smaller distances (the Argentine capital moved less than a foot), but 10 feet is a pretty significant move by human standards. For the small change: a day on Earth is now 1.26 microseconds shorter.

The recent earthquakes in Chile and Haiti made me wonder about other geologic events that have shaped our environment in the blink of an eye. Earthquakes? Volcanic eruptions? Erosion? Those are the primary examples I could come up with. But, there’s one more category I can think of: volcanic births. An eruption? Yes. But, a very special type of eruption: the eruptive activity that gives birth to a brand new volcano.

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