Living in the Universe

Insanity in Space

Fifth Week of August 2007

In a week which saw former astronaut Lisa Nowak plead insanity in the case where she drove eight hundred miles across the country in a diaper to threaten a rival in love, it seems only natural that we should talk about craziness in space. There’s a book called Diary of a Cosmonaut written by Valentine Lebedev which has exactly two reviews posted on Amazon. One of them calls it a profound book about what it’s like to be in a flying tin can for more than half a year. But the other reviewer would not recommend reading its pages to his worst enemy.

Dr. Lebedev’s tortuous account of increasingly territorial behavior and flagging conversation with his lone colleague on Salyut 7 is a rather boring portrayal of why human space exploration can be pointless, frivolous, and perhaps in the end even dangerous. Dr. Lebedev’s mission would however be trivial compared to a trip to Mars. The round trip, including a stay on the surface, would take about seventeen months which is why it’s surprising, given the hazards and the duress of that voyage, that within a few days of being advertised, more than three thousand people applied to take part in an experiment planned by the Russian Institute for Biomedical Problems and the European Space Agency to simulate such an outing.

The experiment’s popularity is even more bizarre, given that Dr. Lebedev is far from the only astronaut whose space experience has driven them a little crazy. Half of all Russian cosmonauts have developed a condition that their psychologists call asthenization. It’s a condition that American psychologists do not even recognize, characterized by irritability and low energy. Crew members often get on badly with each other. Individuals develop space dementia. Orbiting astronauts have become clinically depressed and have panicked at psychosomatic illnesses. It’s a jungle out there; I’m not signing up any time soon.

Nick Kanas and his colleagues at the University of California in San Francisco have scrutinized seven years of interactions between the crew and the ground staff during missions to most scientists’ favorite white elephant, the International Space Station. Those years included eight missions that maintained, through overlapping stays, at least three astronauts on the ISS at all times. The seventeen crew members involved and the hundred and twenty-eight mission controllers then rated the social climate of the mission and also their own emotional states in weekly questionnaires beginning a month before launch and ending two weeks after a mission returned to the Earth.

Dr. Kanas’s analysis has been published in the June issue of Aviation, Space, and Environmental Medicine. It’s consistent with an earlier small study of missions to MIR, Soviet Union’s first space station. Of the eighty-two person-years spent in space, two-thirds have been notched by Russians. Thus it was the Russian support staff who first learned to monitor their cosmonauts’ speech rhythms for early signs of stress and strain. They would arrange surprise gifts in supply ships and cheery telephone calls from famous people and family members. But presents and real time interactions with Earthlings would be impossible on a Mars mission, which would be much more similar psychologically to heading into the watery sunset with Magellan than with joining a trip to the Moon in Apollo.

The study also uncovered a more worrying finding. As with his MIR study and by all six of his measures, the ISS crew coped with stress by blaming the ground team and perceiving that its members felt negatively towards them, even though the records of mission controllers showed that they did not. This tendency to convert tensions on board into feelings that Earth people do not care is one reason why sending people to Mars would be as much a psychological as a technical challenge.

Paranoia in distant space is an extremely dangerous and toxic emotion. Indeed one of the crews of Skylab, NASA’s first long-lived space mission, became so annoyed with their mission control during their eighty-four days in space that they mutinied, sulked, and eventually turned off all communication. Some psychologists propose sending an all-female crew to Mars. Even if women become irritable, they are less likely to commit suicide or murder each other than men are. Others think that a mixed team would support each other better. But as the European experiment may demonstrate, this does raise the possibility of getting first Martians. Perhaps it is better to stick to more psychologically robust and less libidinous space explorers: robots.

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Microbes in the Deep Freeze

Fourth Week of August 2007

Last week I talked about creating life from scratch in the lab. This week I want to talk about bringing life back into being after it’s been long dead, reanimating life. A recent paper in the Proceedings of the National Academy of Science talks about the DNA of ancient microorganisms which, long frozen in glaciers, may return to life as the glaciers melt.

“This finding is really significant,” according to Kay Bidle, the author of the study and an assistant professor of marine and coastal sciences at Rutgers University, “because scientists didn’t know until now whether such ancient frozen organisms and their DNA could be revived at all or for how long cells are viable after they’ve been frozen.” Bidle and his coauthors melted five samples of ice ranging in age from a hundred thousand to eight million years old to find the microorganisms trapped inside. The researchers wanted to find out how long cells could remain viable and how intact their ice was in the youngest and oldest ice.

First they asked if they could detect organisms at all, and they did detect more in the young ice than the old. The group tried to grow them in media and the young stuff grew very effectively. They recovered the microorganisms easily, and they could plate them and isolate colonies which doubled every couple of days. By contrast, the microorganisms from the oldest ice samples grew very slowly, only doubling only every sixty or seventy days. Not only were the microorganisms in the oldest ice slowest to grow, the researchers were unable to identify them as they grow because their DNA deteriorates.

In fact DNA in the five samples examined showed an exponential decline after one million years and according to Bidle this constrains the geological preservation of microbes in icy environments and the possible exchange of genetic material to the oceans. He said, “There’s still DNA left after a million years, but a million years is the half life. That is, every one million years the amount of DNA gets chopped in half.” Bidle said the average size of DNA in the old ice was two hundred and ten base pairs. That is two hundred and ten units of genetic code strung together. By contrast, the average genome size of the simplest bacteria is three million base pairs. Two hundred and ten base pairs is not a viable organism, although actually the smallest possible replicating piece of genetic code is about that size.

These researchers chose the Antarctic glaciers for their research because the polar regions are subject to more cosmic radiation than the rest of the planet, and they contain the oldest ice on the planet. It’s this cosmic radiation that’s blasting the DNA into pieces over geological time, and most of the organisms simply can’t repair that damage. Because the DNA had deteriorated so much in the old ice, the researchers concluded that life on Earth, however it arose, did not ride in on a comet or other debris from outside the solar system. According to Bidle again, “The preservation of microbes and their genes in icy comets may have allowed the transfer of genetic material among planets. However, given the extremely high cosmic radiation flux in space, our result suggests it’s highly unlikely that life on Earth could have been seeded by genetic material external to this solar system.”

So a small, localized study on the Antarctic glaciers has produced a result that has serious and important implications for how life arose on Earth and, by implication, how life may transmit and arise in other solar systems. Since interstellar travel times of rocks ejected by meteoric impact are likely to be millions of years, it’s very unlikely that life primitive life could hitchhike between the stars.

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The Rise of Artificial Life

Third Week of August 2007

We don’t know exactly how life started on Earth. It’s one of the biggest questions in science, and we may never know exactly because much of the evidence has been lost with time. But in the lab scientists are trying to create artificial life to show the possible pathways by which simple chemicals could have arranged themselves into the first cells. Around the world, a handful of bold scientists are trying to create life from scratch, and they’re getting closer. Experts expect an announcement within three to ten years from someone in the little known field of “wet” artificial life.

Listen to Mark Bedau, chief operating officer of a company called ProtoLife based in Venice, Italy. “It’s going to be a big deal, and everyone’s going to know about it,” he said. We’re talking about a technology that could change the world in pretty fundamental ways, in fact, in ways that are impossible to predict.” That first cell of synthetic life made from the basic chemicals in DNA might not seem like much to non-scientists. For one thing, you’ll need a microscope to see it.

Creating proto-cells does have the potential to shed new light on our place in the universe because it will remove one of the few fundamental mysteries about the creation of our role in the universe. Several scientists believe that man-made life forms will one day offer the potential for solving a variety of problems from fighting diseases, to locking up greenhouse gases, to eating toxic waste. Bedau figures there are three major hurdles to creating synthetic life. First, you need a container or membrane for the cell to keep bad molecules out, allow good ones in, and the ability to multiply. Each cell is like a tiny chemical factory. Although the nutrients necessary for life exist in sea water or in a pond, they’re not concentrated sufficiently for the vital chemical reactions to take place with sufficient speed.

Second, you need a genetic system that controls the functions of the cell, enabling it to reproduce and mutate in response to environmental changes. That’s tricky because this has to occur naturally. Scientists don’t believe that an intelligent designer created the genetic system. They believe that it occurred by chance in a process of unguided evolution. In the lab, scientists will have to simulate this type of unguided process and yet produce an outcome that has function and form built into a biological system.

The third requirement is a metabolism that can extract raw materials from the environment as food and change it into energy. That’s key, although it’s not the hardest part actually, because in nature there are many ways that energy changes hands, and there is much raw available energy in the environment. So the energy requirement for life is easy to meet, and life on Earth has found many different ways to harness energy from the environment.

One of the leaders in this field, Jack Szostak, who works at the Harvard Medical School, predicts that within the next six months scientists will report evidence of success in the first step, creating a cell membrane, since that is, as he puts it “Not a big problem.” Scientists are using fatty acids in that effort, and in fact Szostak, who’s usually modest about his efforts, is perhaps the world leader in creating a cell in the laboratory. He’s been working more than ten years at it, and he’s made major strides towards concentrating the nutrients in naturally occurring containers or vesicles.

Szostak’s also optimistic about the next step, getting nucleotides, the building blocks of DNA, to form a working genetic system. His idea is that once the container is made, if scientists add nucleotides in the right proportions, then Darwinian evolution could simply take over. The question is how did nature add nucleotides in those right proportions? Perhaps if it did happen by chance and Darwinian evolution takes over, the correct proportions of nucleotides would come to dominate all the other proportions, thereby explaining how life came to be the way it is. Szostak says, “We aren’t smart enough to design these things. We let evolution do the hard work, and then we figure out what happens.”

In Gainesville, Florida, Steve Benner, a biological chemist at the Foundation for Applied Molecular Evolution, is attacking that problem by going outside of natural genetics. Normal DNA consists of four bases, adenine, cytosine, guanine, and thymine, known as A, C, G, and T, molecules that spell out the genetic code in pairs. Benner is now trying to add eight new bases to the genetic alphabet. Bedau says there are legitimate worries about creating life that could run amok, but there are ways of addressing it, and it will be a very long time before that is a problem. As he says, “When these things are created, they are going to be so weak. It’ll be a huge achievement if you can keep them alive for an hour in the lab. But the idea of them getting out and taking over, never in our imagination could this happen.”

It’s a good cautionary note to end on because many things that couldn’t occur in the imagination of scientists actually do end up happening. So as artificial life moves from hypothesis to reality, scientists will have enormous pressure to be cautious about what happens with their creations.

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Ice in the Outer Solar System

Second Week of August 2007

We all know about global warming, and most people suffering through the summer will recognize that it’s one of the hottest on record, perhaps the hottest on record. You probably don’t have it as bad as we do in Arizona. Up the road in Phoenix, this year so far they’ve had twenty-one days with a high temperature above a hundred and ten degrees. That’s three times more than the largest number ever on record. In Tucson we consider we’re lucky if we get away with a hundred degrees, and this year we may have a hundred days over a hundred degrees. It’s pretty nasty here. Humans are not really built for such heat.

What better than to think of the coolest place possible? No, not your swimming pool or freezer. I mean the outer parts of the solar system, the coolest place there is. So let’s talk about the distant realms of the solar system, Pluto and its small moon Charon. I know, Pluto’s not even a planet anymore; it was demoted a year or so ago so it’s almost beneath our respect, but it sure is a nice, cold place. So let’s talk about ice.

Charon is like an ice machine sitting in the outer part of the solar system. Recent observations have shown that frigid geysers spew material up through the cracks in the crust of Pluto’s companion and recoat parts of its surface in ice crystals that could make this little distant world into the equivalent of an outer solar system ice machine. The evidence for these ice deposits comes not from any spacecraft, although there is a spacecraft on the way to Pluto, but from a ground-based telescope at the Gemini observatory in Hawaii. It’s their adaptive optics system coupled to a near infrared instrument called NIRI. These observations were made with the 8-meter telescope on Hawaii’s Mauna Kea, and they showed that spectral fingerprints of ammonia hydrates and water crystals are spread in patches across Charon and have been described as the best evidence yet for the existence of these compounds on tiny worlds such as Charon.

The observations suggest that liquid water mixed with ammonia from deep within Charon is pushing out onto the ultra-cold surface. This action could be occurring on timescales as short as a few hours or days and at levels that re-coat the little moon to a depth of one millimeter every hundred thousand years. This discovery will have implications for other cold worlds in the outer solar system, particularly in the Kuiper Belt, which is a region of the solar system that extends beyond the orbit of Neptune and contains a number of small bodies, the largest of which include Pluto and Charon. It also, famously, includes several objects that are larger than Pluto, hence the demotion of Pluto from planet status. Jason Cook, a graduate student on the project who works up the road at Arizona State University, says, “There are a number of mechanisms that could explain the presence of crystalline water ice on the surface of Charon, but the most interesting explanation points to cryovolcanism which brings liquid water to the surface where it freezes into ice crystals, and that implies that Charon’s interior possesses liquid water.

Liquid water is essential for life as we know it, and understanding the distribution and behavior of liquid water beyond Earth can help scientists understand where to search for habitable environments.” To reach the conclusion that cryovolcanism was producing ice on Charon, Cook and his collaborators studied all the possible mechanisms that could explain water ice. The crystals are unlikely to be made of primordial ice from the time the solar system formed, because such ice would become amorphous, that is it would lose crystalline appearance in a few tens of thousands of years due to solar UV radiation and cosmic ray bombardment. Processes that create fresh, icy patches on other worlds, such as impact gardening by meteorites and convection of subsurface materials to the surface, are not supported by the particular chemical fingerprint they saw.

The only mechanism that could explain the data is cryovolcanism, which is the eruption of liquids and gases to the surface in an ultra-cold environment. It seems now that cryovolcanism is a fairly common occurrence in the outer solar system. Enceladus, a tiny moon of Saturn, and Europa, which orbits Jupiter, both show evidence of water ice oozing or spewing out from beneath their surfaces. The so-called tiger stripes on Enceladus were reported in 2006 by Carolyn Porco. They may have been created by geysers that send water out through surface cracks. Similar markings are seen on the Uranian moon Ariel in Voyager 2 flyby images.

Enceladus and Europa are tidally squeezed by the gravitational forces of their giant planets and in some cases by large nearby moons. This squeezes the water through the cracks. Ariel may have been affected by tidal squeezing in the past. By contrast however, Kuiper Belt objects such as Charon, Quaoar, Orcus and others are not tidally squeezed, and yet they seem to show evidence of cryovolcanism as well. In the case of Charon, it’s thought that heat from internal radioactivity creates a pool of melted water mixed with ammonia inside the ice shell. As the subsurface water cools and approaches the freezing point, it expands into the cracks in the ice shell above it. Due to the expansion, even a small vertical crack of half a kilometer in the base of the ice will allow material to propagate to the outer surface in a matter of hours. As the water sprays through the crack, it freezes and immediately snows back down onto the surface creating the icy patches that can be distinguished in near infrared light. Well, that’s the explanation from theory. The real proof will come from the deep space NASA probe New Horizons which will arrive at this system in 2015 and send back images to verify what’s been seen from the ground.

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Phoenix Soars for Mars

First Week of August 2007

This weekend was a great success for planetary science in general, exploration of Mars, and my university in particular, the University of Arizona. The Phoenix Mars Mission blasted off aiming to arrive at the red planet on May 25 next year to closely examine the northern polar region. Sitting atop a Delta II rocket, it left Cape Canaveral Air Force Base at 5:26 am on Saturday morning. It was a very exciting launch for anyone who was there to witness it.

The principal investigator of this mission is my colleague Peter Smith from the University of Arizona’s Lunar and Planetary Laboratory. The spacecraft launched flawlessly and established communications quickly with its ground station in Goldstone, California. Phoenix will be the first mission to touch water ice on Mars. Its robotic arm will dig into an icy layer believed to just lie below the surface. The mission will study the history of the water in the ice, monitor weather in the polar region, and investigate whether the subsurface environment in the far northern plains of Mars has ever been favorable for sustaining microbial life.

People shouldn’t get the wrong impression. This mission was never designed to look for life itself. It has no detailed biological analysis facility, but it will produce enough diagnostics to show whether this very promising region of Mars, just under the surface and therefore protected from the extreme cold, vacuum, and ultraviolet radiation of the surface itself, is potentially a place that could sustain life or has sustained it in the past. As Peter Smith says, “Water is central to every type of study we will conduct on Mars.” Phoenix is the first of NASA’s competitively proposed and selected Mars scout missions, designed to supplement the agency’s core Mars mission, with the theme: “follow the water.” The University of Arizona was selected to lead the mission in August 2003, and now we are the first public university to lead a Mars exploration mission. The grant that supports this mission was three hundred and thirty million dollars which is also the largest grant the U of A has ever had.

Phoenix uses the main body of a lander originally made for a 2001 mission that was canceled before launch, hence the name Phoenix. During the last year before launch Phoenix was run through a rigorous testing regimen for people who wonder about using a failed mission. The spacecraft and its instruments went through actual mission sequences allowing them to assess the entire system through the life of the mission while here on Earth. In fact there’s a test rig, a facility built in an empty warehouse just down the road from the U of A where they’ll simulate, recreate the Martian surface and run the Mars lander through its paces of landing and sampling soil, and people will be able to go down the road and watch it.

Samples of soil and ice collected by the lander’s robotic arm will be analyzed by instruments mounted on the deck. A key instrument will check for water and carbon containing compounds by heating the soil samples in tiny ovens and examining the vapors that are given off. Another will test soil samples by adding water and analyzing the dissolution products. There are cameras and microscopes to provide information on scales spanning ten powers of ten from features that could fit into hundredths into a period at the end of a sentence, microns, to the aerial view it will take during descent. There will also be a weather station to provide information on atmospheric processes in the arctic region.

The Phoenix Mars Mission will not answer the question of whether there’s life on Mars. It will take a more sophisticated series of missions later in the decade, but it’s going to be an exciting new insight on to the one place we think might have life in the solar system.

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