MELTING, MELTING

By Pam Eastlick

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

I’ve discovered something interesting while surfing the net and talking to people. A lot of people who firmly ‘believe’ that the aliens are here think that global warming is a vast conspiracy promoted by the “government”. Unfortunately for humanity, there’s a lot more proof of global warming that the existence of the aliens. For instance, recent research shows that 2010 set new records for the melting of the Greenland Ice Sheet.

According to Dr. Marco Tedesco, director of the Cryospheric Processes Laboratory at The City College of New York (CCNY — CUNY), the past melt season was exceptional, with melting in some areas lasting up to 50 days longer than average. Melting in 2010 started exceptionally early at the end of April and ended quite late in mid-September.

Also in 2010, summer temperatures up to 5 degrees F. above the average were combined with reduced snowfall. The capital of Greenland, Nuuk, had the warmest spring and summer since records began in 1873. Bare ice was exposed earlier than the average and longer than previous years, contributing to the extreme record. This is bad because bare ice is much darker than snow and absorbs more solar radiation.

The melting of the Greenland ice sheet could have some dire consequences. Scientists at the University of Barcelona have done some studies on how ocean currents in the Atlantic were affected by climate change in the past. Their research shows that there was a period when the flow of deep waters in the Atlantic was reversed.

Ocean currents in the Atlantic Ocean are an important component in the regulation of world-wide weather. Warm currents, like the Gulf Stream transport energy from the tropics to the subpolar North Atlantic and influence regional weather and climate patterns. Once they arrive in the North the currents cool, their waters sink and they transfer atmospheric carbon into the deep ocean.

The Barcelona study shows that ocean circulation was very different in the past and there was a period when the flow of deep waters in the Atlantic was reversed. This situation occurred during the ice age 20,000 years ago. Although this was far back in time the results are relevant for our climate today and in the near future. The new study shows that circulation in the Atlantic Ocean in the past was very sensitive to changes in the salt balance of the water. Similar changes in seawater salt concentration are expected to occur in the North Atlantic in the course of climate warming over the next 100 years.

There is also some thought that massive melting of the Greenland ice sheet will cause cold water to flood into the northern Atlantic, stopping the warming Gulf Stream in its tracks. This would have the effect of chilling Great Britain and northern Europe with unpredictable local and global consequences.

Global warming. It just won’t go away. And it’s a lot more ‘real’ than the presence of aliens.

Life or no Life

By Pam Eastlick

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

I got an e-mail from a column reader last week that said “What methane-based life forms? Do you mean there really are aliens out there?” So I figured we’d talk about what’s happening on Titan besides volcanoes that erupt molten water.

There’s some really complex chemistry happening on the surface of Saturn’s moon Titan. You can explain at least some of it with non-biological chemistry but many scientists think that Titan may harbor a primitive form of life that’s based on the chemical methane.

In recently published papers, scientists with the Cassini mission say that hydrogen molecules are flowing down through Titan’s atmosphere and disappearing at the surface and that there’s no acetylene on Titan’s surface when, given the chemistry on Titan, the surface should be covered with the stuff.

The lack of acetylene is very important because that’s the chemical that would probably be the food source for methane-based life. But that hydrogen flow and disappearance is also important because if you’re going to use acetylene as your food source, you’d have to use hydrogen as well. The hypothetical life forms would use hydrogen just like we use oxygen.

Of course, so far, methane-based life forms are only hypothetical. We haven’t found any here on Earth although there are liquid-water-based microbes here that thrive on methane or produce it as a waste product. Any organism, as far as we know, must have a liquid in which to do their business. On Titan, where temperatures run around 90 Kelvin (minus 290 degrees Fahrenheit), water (our liquid medium) is rocks! At Titan’s temperatures, the list of liquid candidates is very short: liquid methane and related molecules like ethane.

The scientists investigating the data from Titan had expected the Sun’s interactions with chemicals in the atmosphere to produce acetylene that rains down to coat Titan’s surface. But Cassini has detected no acetylene on the surface. In addition, Cassini’s spectrometer detected an absence of water ice on Titan’s surface, but loads of benzene and another material, which appears to be an organic compound that scientists have not yet been able to identify.

These findings lead scientists to think that organic compounds completely cover the solid water ‘rocks’ that make up Titan’s ‘land’ with a film of hydrocarbons that’s at least a couple of inches thick, but possibly much deeper in some places. The ‘land’ remains covered with these hydrocarbons even though liquid methane and ethane flow all over Titan’s surface. If the film were inert, you’d expect the methane and ethane rain to wash it away since these two chemicals create rivers, lakes and seas on Titan much as liquid water does on Earth.

Of course, the absence of acetylene on Titan’s surface could have a non-biological explanation. One possibility is that sunlight is transforming the acetylene in the atmosphere into more complex molecules that would fall to the ground leaving no acetylene signature.

So . . . life or no life? Right now we don’t know, but Cassini has many more flybys of Titan that might help us sort out just what is happening at the surface. For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

A DIFFERENT KIND OF LAVA

By Pam Eastlick

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

It’s been a really long time since we went exploring in deep space and since there is little space left in the space file; it’s time for a little voyage to the outer solar system. We’re headed for Saturn where the space robot Cassini has been sending back remarkable pictures and information about the ringed planet and its many and varied moons.

Probably the most intriguing Saturnian satellite is Titan, the second largest moon in the solar system. Titan is the only other rocky solar system body besides Earth and Venus to have a thick atmosphere. You couldn’t breathe Titan’s air, even though it’s mostly nitrogen just like Earth’s air because Titan’s air has no free oxygen.

Cassini landed a probe on Titan several years ago and has been using radar to penetrate the thick clouds and map Titan’s topography for seven years and we’ve discovered many interesting things. One is that Titan apparently has volcanoes. But these volcanoes probably don’t erupt lava, which is molten rock. Read on!

Researchers from the USGS office in Flagstaff Arizona examined the 3-D radar maps generated of Titan’s surface and they were amazed by the resemblance of a mountain on Titan called Sotra Facula, to some of Earth’s volcanoes, like Mt. Etna in Italy and Mt. Laki in Iceland.

Scientists have been debating for years whether ice volcanoes, also called cryovolcanoes, exist on ice-rich moons, and if they do what their characteristics are. It’s assumed that some kind of subterranean geological activity warms the interior enough to send slushy ice through an opening on the surface.

Of course, ‘slushy ice’ gives you entirely the wrong idea. It’s COLD on Titan. The Moon has an average surface temperature of -300 F, which considerably colder than your freezer, trust me. And at those temperatures, water ice isn’t the familiar stuff in the cooler.

At Earth temperature and pressure, solid water floats on liquid water. This is truly remarkable and water is one of handful of compounds where this is true. And if it wasn’t true, you and I wouldn’t be here because if ice sank, the oceans would have frozen solid from the bottom up and life-as-we-know-it wouldn’t be possible on Earth.

But at the temperatures and pressures on Titan, water ice isn’t ice-like at all. It’s much more like the rocks we’re familiar with here on Earth. And when it’s melted by that geological activity, it doesn’t make icy slush. It makes molten water, or water lava. I think that’s such a cool concept!

Equally cool (or cold) is the fact that Cassini scientists have also discovered that there isn’t nearly enough hydrogen or acetylene in the atmosphere of Titan. Now you know acetylene as torch material, but in the extremely cold oxygen-free conditions on Titan, acetylene is the best energy source for . . . (wait for it) . . . methane-based life forms.

I’m out of space (pun intended) but maybe we’ll talk one day soon about those possible methane-based life forms and about the fact that whatever the aliens look like, they will NOT look like humans dressed up in alien suits!

For more information about the Cassini mission, visit: http://www.nasa.gov/cassini

This image is based on data from NASA’s Cassini spacecraft and shows a flyover of an area of Saturn’s moon Titan known as Sotra Facula. (Credit: NASA/JPL-Caltech/USGS/University of Arizona)

IT’S REALLY BORING!

By Pam Eastlick

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.

Greetings everyone! Well, today the animal file won out and we’re going to talk about some sea animals that are familiar to most of us; the sea urchins. Probably the most familiar one is the black spiny sea urchin Diadema, that got that common name for a very good reason. Many of us have inadvertently stepped on one or backed into it and had to deal with the spines. Generally you can’t pull them out and the best way to deal with them is to club them with something blunt so that they’ll break up and your body can eventually deal with the debris.

But I’m not talking about Diadema. I’m talking about the ones that you may have never noticed. They’re common on Guam. All you have to do is find a large rock sticking out of the water and look on the seaward facing side near the bottom. Chances are you’ll see a smallish hole filled with spines.

I saw a little girl discover one of these ‘enclosed’ urchins once and she looked at her daddy and said “It’s moving Daddy! How did it get in there?” She was a budding scientist, because that is a very good question. The answer may one day help you carve a better steak.

Many sea urchins live in the tidal zone and protect themselves from predators and the crashing surf by literally eating into the rocks. This rock-boring behavior is pretty awesome, but what’s truly remarkable is that despite the constant grinding and scraping on stone, urchin teeth never, ever get dull. Now a team of scientists from the University of Wisconsin-Madison has peeled back the toothy mystery.

It seems that sea urchin teeth are quite complex and are one of the very few structures in nature that self-sharpen. The teeth, which are always growing, are made from calcite crystals in two forms: plates and fibers. They’re arranged crosswise and cemented together with super hard calcite cement. Between these crystals are layers of organic materials that are weaker than the calcite crystals.

The organic layers are the weak links of the chain and the teeth break at predetermined points. It’s like perforated paper in the sense that the tooth material breaks at these predetermined spots. The outer portion of the tooth sloughs away at these points revealing the new, fresh and sharp surface.

The scientists say that since they’ve discovered how urchins keep their teeth sharp, they may be able to adapt these techniques to create tools for humans that actually sharpen themselves with use.

Of course, I’m not really sure that would help you carve a better steak. First, you wouldn’t want your knife shedding used parts all over your steak and you’d also have to figure out how to accomplish the ever-renewing part that the living urchin manages so well. But for big jobs like mining, where the drills have to be periodically replaced anyway, the urchin’s secret may make the job easier.

Next time you’re at the beach, see if you can find a rock-drilling urchin. Tell them we’ve finally figured out how they do it!

The teeth of a living sea urchin. Scientists have recently discovered why a sea urchin’s teeth are always sharp, despite constant grinding and scraping to create the nooks that protect the marine animal from predators and crashing waves. (Credit: Photo courtesy of Pupa Gilbert)