Posted on by Paul Scott Anderson

Microscopic Worms May Help to Colonize Mars

A Caenorhabditis elegans worm. Credit: Creative Commons

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Once the realm of science fiction, the prospect of colonizing other planets is getting closer to reality. The most logical first place, besides the Moon, has always been Mars. Venus is a bit closer, but the scorching conditions there are, well, much less than ideal. There is still technology that needs to be developed before we can send humans to Mars at all, never mind stay there permanently. But now there may be help from an unlikely and lowly companion. – worms.

Ok, not the kind of worms you find in your garden, but tiny microscopic worms called Caenorhabditis elegans (C. elegans). Similar biologically to humans in some ways, they are being studied by scientists at the University of Nottingham in the UK to help see how people are affected by long-duration space travel.

In December 2006, 4,000 of them were sent into orbit aboard the Space Shuttle Discovery. This was followed by another mission in 2009. The scientists found that in space, the worms develop and produce progeny just as they do on Earth. The research has been published in the November 30, 2011 issue of Interface, a journal of The Royal Society.

According to Dr. Nathaniel Szewczyk of the Division of Clinical Physiology in the School of Graduate Entry Medicine, “While it may seem surprising, many of the biological changes that happen during spaceflight affect astronauts and worms and in the same way. We have been able to show that worms can grow and reproduce in space for long enough to reach another planet and that we can remotely monitor their health. As a result C. elegans is a cost-effective option for discovering and studying the biological effects of deep space missions. Ultimately, we are now in a position to be able to remotely grow and study an animal on another planet.”

He added: “Worms allow us to detect changes in growth, development, reproduction and behaviour in response to environmental conditions such as toxins or in response to deep space missions. Given the high failure rate of Mars missions use of worms allows us to safely and relatively cheaply test spacecraft systems prior to manned missions.”

So while a manned space mission to Mars is still a ways off, some lucky worms may get there first, making the voyage of a lifetime, even if they don’t realize it!

Posted on by Paul Scott Anderson

Could Curiosity Determine if Viking Found Life on Mars?

The landing site of Viking 1 on Mars in 1977, with trenches dug in the soil for the biology experiments. Credit: NASA/JPL

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One of the most controversial and long-debated aspects of Mars exploration has been the results of the Viking landers’ life-detection experiments back in the 1970s. While the preliminary findings were consistent with the presence of bacteria (or something similar) in the soil samples, the lack of organics found by other instruments forced most scientists to conclude that the life-like responses were most likely the result of unknown chemical reactions, not life. Gilbert V. Levin, however, one of the primary scientists involved with the Viking experiments, has continued to maintain that the Viking landers did indeed find life in the Martian soil. He also now thinks that the just-launched Curiosity rover might be able to confirm this when it lands on Mars next summer.

Curiosity is not specifically a life-detection mission. Rather, it continues the search for evidence of habitability, both now and in the past. But is it possible that it could find evidence for life anyway? Levin believes it could, between its organics detection capability and its high-resolution cameras.

The major argument against the life-detection claims was the lack of organics found in the soil. How could there be life with no organic building blocks? It has since been thought that any organics were destroyed by the harsh ultraviolet radiation or other chemical compounds in the soil itself. Perchlorates could do that, and were later found in the soil by the Phoenix mission a few years ago, closer to the north pole of Mars. The experiments themselves, which included baking the soil at high heat, may have destroyed any organics present (part of the studies involved heating the soil to kill any organisms and then study the residual gases released as a result, as well as feeding nutrients to any putative organisms and analyzing the gases released from the soil). If Curiosity can find organics, either in the soil or by drilling into rocks, Levin argues, that would bolster the case for life being found in the original Viking experiments, as they were the “missing piece” to the puzzle.

So what about the cameras? Any life would have to be macro, of visible size, to be detected. Levin and his team had also found “greenish coloured patches” on some of the nearby rocks. (I still have a little booklet published by Levin at the time, “Color and Feature Changes at Mars Viking Lander Site” which describes these in more detail). When as a test, lichen-bearing rocks on Earth were viewed with the same camera system using visible and infrared spectral analysis, the results were remarkably similar to what was seen on Mars. Again, since then though, those results have been widely disputed, with most scientists thinking the patches were mineral coatings similar to others seen since then. Of course, there is also the microscopic imager, similar to that on the Spirit and Opportunity rovers, although microorganisms would still be too small to be seen directly.

Regardless, Levin feels that Curiosity just might be able to vindicate his earlier findings, stating “This is a very exciting time, something for which I have been waiting for years. At the very least, the Curiosity results may bring about my long-requested re-evaluation of the Viking LR results. The Viking LR life detection data are the only data that will ever be available from a pristine Mars. They are priceless, and should be thoroughly studied.”

Posted on by Paul Scott Anderson

Life on Alien Planets May Not Require a Large Moon After All

Earth and Moon. Credit: NASA

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Ever since a study conducted back in 1993, it has been proposed that in order for a planet to support more complex life, it would be most advantageous for that planet to have a large moon orbiting it, much like the Earth’s moon. Our moon helps to stabilize the Earth’s rotational axis against perturbations caused by the gravitational influence of Jupiter. Without that stabilizing force, there would be huge climate fluctuations caused by the tilt of Earth’s axis swinging between about 0 and 85 degrees.

But now that belief is being called into question thanks to newer research, which may mean that the number of planets capable of supporting complex life could be even higher than previously thought.

Since planets with relatively large moons are thought to be fairly rare, that would mean most terrestrial-type planets like Earth would have either smaller moons or no moons at all, limiting their potential to support life. But if the new research results are right, the dependence on a large moon might not be as important after all. “There could be a lot more habitable worlds out there,” according to Jack Lissauer of NASA’s Ames Research Center in Moffett Field, California, who leads the research team.

It seems that the 1993 study did not take into account how fast the changes in tilt would occur; the impression given was that the axis fluctuations would be wild and chaotic. Lissauer and his team conducted a new experiment simulating a moonless Earth over a time period of 4 billion years. The results were surprising – the axis tilt of the Earth varied only between about 10 and 50 degrees, much less than the original study suggested. There were also long periods of time, up to 500 million years, when the tilt was only between 17 and 32 degrees, a lot more stable than previously thought possible.

So what does this mean for planets in other solar systems? According to Darren Williams of Pennsylvania State University, “Large moons are not required for a stable tilt and climate. In some circumstances, large moons can even be detrimental, depending on the arrangement of planets in a given system. Every system is going to be different.”

Apparently the assumption that a planet needs a large moon in order to be capable of supporting life was a bit premature. The results so far from the Kepler mission and other telescopes have shown that there is a wide variety of planets orbiting other stars, and so probably also moons, which we are now also on the verge of being able to detect. It’s nice to think that more of the terrestrial-type rocky planets, with or without moons, might be habitable after all.

Posted on by Paul Scott Anderson

Does Pluto Have a Hidden Ocean?

Credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)

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In recent years, it has become surprisingly apparent that, contrary to previous belief, Earth is not the only place in the solar system with liquid water. Jupiter’s moon Europa, and possibly others, are now thought to have a deep ocean below the icy crust and even subsurface lakes within the crust itself, between the ocean below and the surface. Saturn’s moon Titan may also have a subsurface ocean of ammonia-enriched water in addition to its surface lakes and seas of liquid methane. Then of course there is another Saturnian moon, Enceladus, which seems to not only have liquid water below its surface, but huge geysers of water vapour and ice particles erupting from long fissures at its south pole, which have been sampled directly by the Cassini spacecraft. Even some asteroids may have liquid water layers beneath their surfaces. There is also still a chance that Mars might have subsurface aquifers.

But now there is another contender which at first thought might seem to be the most unlikely place to find water – Pluto.

Inhabiting the bitterly cold, lonely outer reaches of the solar system, this dwarf planet would hardly seem to be a good place to look for liquid water, but new research is indicating that, like the other moons already mentioned, it may yet surprise us. It is now being suggested that a subsurface ocean is not only possible, but likely.

The New Horizons spacecraft is scheduled to fly by Pluto in 2015, and it may be able to confirm the existence of the ocean if it is actually there. As it is understood right now, Pluto has a thin shell of nitrogen ice covering a thicker shell of water ice. But is there a layer of liquid water below that? The way for New Horizons to help to determine that is to study the surface features and shape of Pluto as it passes. If there is a noticeable bulge toward the equator, then that means that any primordial ocean or liquid layer probably froze a long time ago, since a liquid layer would tend to cause the surface ice to flow, reducing any bulge. This is based on the fact that a spherical body, as it rotates, will push material toward the equator by angular momentum. If there is no bulge, then any liquid layer is probably still liquid today.

The surface itself can also provide clues about what lies beneath. If there are large fractures, as there are on Europa and Enceladus, their characteristics can be an indication of whether there is an ocean down below. The fractures are caused by surface stresses; tensional stresses would result from icy water beneath the outer ice shell while compressional stresses would indicate a solid layer instead. The long fractures on Europa are particularly reminiscent of the cracked ice floes in Antarctica on Earth where an ice layer covers the sea water beneath it. If geysers similar to those on Enceladus were to be seen on Pluto, that would also of course be good evidence for an ocean.

There is also, inevitably, the question of life. If Pluto’s rocky interior contains radioactive isotopes such as potassium, as seems likely, they could provide enough heat to maintain an ocean. “I think there is a good chance that Pluto has enough potassium to maintain an ocean,” said planetary scientist Francis Nimmo from the University of California at Santa Cruz, who is involved with the new studies. And if you have liquid water and heat… Pluto, however, is thought to lack organics, which would be necessary as a starting point for life.

A Plutonian ocean? Who would have ever thought? When New Horizons finally reaches Pluto in 2015, we should hopefully have a better idea one way or the other regarding this intriguing possibility.

Posted on by Paul Scott Anderson

Is There a Methane Habitable Zone?

A sunlight glint off a methane lake near Titan’s north pole (infrared image). Credit: NASA/JPL/University of Arizona/DLR

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For a long time now, we have heard the mantra “follow the water” when it comes to searching for life elsewhere. Life as we know it here on Earth requires liquid water, whether it is tiny microbes or elephants. It has thus been assumed that carbon-based life somewhere else that is basically similar to ours in its chemical makeup (another assumption) would also require water for its survival and growth. But is that necessarily true? In recent years, more consideration has been given to the possibility that life could develop in other mediums as well, besides water. A liquid is still ideal, for allowing the necessary molecules to bond together. So what are the alternatives? Well, one of the most interesting possibilities is something we have already seen now elsewhere in our solar system – liquid methane.

It should be noted that the importance of water cannot be overlooked. According to Chris McKay, an astrobiologist and planetary scientist at NASA’s Ames Research Center, “We live on a planet where water is a liquid and we have adapted and evolved to work with that liquid. Life has very cleverly used the properties of water to do things not just in terms of solution, but in using the strong polarity of that solution to its advantage in terms of hydrophobic and hydrophilic bonds, and using the very structure of water to help align molecules.”

But McKay also published a paper In the journal Planetary and Space Science last April, postulating how life on some worlds could use liquid methane in place of water. There could be planets orbiting red dwarf stars, which are smaller and cooler than our Sun, and could have a “liquid methane habitable zone” where methane could exist as a liquid on the surface of planets orbiting within that zone. They could also exist around Sun-like stars, although they would be easier to detect around the smaller, dimmer red dwarf stars. But there is already one methane world that we know of, much closer to home…

Orbiting the sixth planet out from the Sun, Saturn, is a moon which in some ways is eerily Earth-like, with rain, rivers, lakes and seas – Titan. It is the first world we’ve found so far that has liquid on its surface like Earth does. But there is one major difference; the liquid is not water, it is liquid methane/ethane. With temperatures far colder than anywhere on Earth at –179 degrees Celsius, water cannot exist as a liquid, it is frozen as hard as rock. But methane can exist as a liquid under those conditions and indeed does on Titan. Beneath an atmosphere that is thicker than ours (but also made primarily of nitrogen), the surface of Titan has been modified in much the same way as Earth’s; liquid methane plays the same role there as water does here, with a complete hydrological cycle. It is like a familiar-looking but colder version of our planet, which has raised the question of whether an environment like this could even support life of some kind.

McKay had also previously suggested that methane-based life could consume hydrogen, acetylene and ethane, and exhale methane instead of carbon-dioxide. This would result in a depletion of hydrogen, acetylene and ethane on the surface of Titan. Interestingly, this is just what has been found by the Cassini spacecraft, although McKay is quick to caution that there could still be other more likely explanations. There is still a lot we don’t know about Titan. Whatever the explanation, there is some interesting chemistry going on.

At the very least, Titan is thought to represent conditions similar to those on the early Earth, a sort of primordial Earth in deep-freeze. That alone could provide vital clues as to how to life took hold on our planet. If there are other planets or moons out there that are similar, as now seems likely, they could also reveal valuable insights into the question of the origin of life, whether there is anything swimming in those cold lakes and seas or not. While water is still considered the primary liquid medium of choice, liquid methane could be the next best thing, and if we have learned anything, it is how amazingly adaptive and resourceful life can be, perhaps even more than we think.

Posted on by Paul Scott Anderson

‘Sweet Spots’ for Formation of Complex Organic Molecules Discovered in Our Galaxy

Credit: NASA

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Astrobiologists have discovered regions in our galaxy which might have the greatest potential for producing very complex organic molecules, the starting point for the development of life. We’ve heard before about “follow the water” in the search for life; in this case it may be “follow the methanol”…

The scientists involved, from Rensselaer Polytechnic Institute in Troy, New York, began a search for methanol, a key ingredient in the synthesis of organic molecules. According to Douglas Whittet, lead researcher of the study, “Methanol formation is the major chemical pathway to complex organic molecules in interstellar space.” The idea is to look for areas where there is rich methanol production occurring. In the large clouds of dust and gas that give birth to new stars, there are simpler organic molecules like carbon monoxide. Under the right conditions, carbon monoxide on the surfaces of dust grains can interact with hydrogen, also found in the clouds, to create methanol. Methanol can then become a steppingstone to create the more complex organic molecules, the types needed for life itself. But how much methanol is out there, and where?

It appears to be most abundant around a small number of newly-formed stars, where it makes up to 30 percent of the material around those stars. In other areas though, it is in much smaller amounts, or none at all. In the cold dust and gas clouds that will eventually produce new stars, it was found to exist in the 1 to 2 percent range. Hence, there appear to be “sweet spots” where conditions are suitable for the chain reactions to occur, depending on how fast the needed molecules can reach the dust grains. It can mean the difference between a “dead end” for additional development or an “organic bloom.” As described by Whittet: “If the carbon monoxide molecules build up too quickly on the surfaces of the dust grains, they don’t get the opportunity to react and form more complex molecules. Instead, the molecules get buried in the ices and add up to a lot of dead weight. If the buildup is too slow, the opportunities for reaction are also much lower.”

So some places may be much more likely to have the conditions necessary for the development of life than others. What about our own solar system? How does it compare? By studying the methanol amounts in comets, relics from the beginning of the solar system, the scientists have concluded that the methanol abundance back then was about average. Not a dearth of the stuff, but not a “sweet spot” really, either. Yet here we are… or, as Whittet put it, “This means that our solar system wasn’t particularly lucky and didn’t have the large amounts of methanol that we see around some other stars in the galaxy. But, it was obviously enough for us to be here.”

The paper, titled “Observational constraints on methanol production in interstellar and preplanetary ices,” will be published in the Nov. 20 edition of The Astrophysical Journal and is a collaboration between Rensselaer, NASA Ames Research Center, the SETI Institute and Ohio State University.

Posted on by Paul Scott Anderson

Looking For the City Lights of Alien Civilizations

Artist's conception of city lights on an alien planet. Credit: David A. Aguilar (CfA)

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When most people think about the search for alien life, the first thing that usually pops into mind is SETI (Search for Extraterrestrial Intelligence). Primarily a search for extraterrestrial radio signals, another more recent facet of SETI is now looking for laser pulses as a conceivable means of communication across interstellar distances. But now, a third option has been presented: looking for sources of artificial light on the surfaces of exoplanets, like the lights of cities on Earth.

According to Avi Loeb at the Harvard-Smithsonian Center for Astrophysics, “Looking for alien cities would be a long shot, but wouldn’t require extra resources. And if we succeed, it would change our perception of our place in the universe.”

Like the other SETI initiatives, it relies on an assumption that an alien civilization would use technologies that are similar to ours or at least recognizable. That assumption itself has been the subject of contentious debate over the years. If an alien society was thousands or millions of years more advanced than us, would any of its technology even be recognizable to us?

That aside, how easy (or not) would it be to spot the signs of artificial lighting on an alien planet light-years away from us? The suggestion is to look at the changes in light from an exoplanet as it orbits its star. Artificial light would increase in brightness on the dark side of a planet as it orbits the star (as the planet goes through its phases, like our Moon or other planets in our own solar system), becoming more visible than any light that is reflected from the day side.

That type of discovery will require the next generation of telescopes, but today’s telescopes could test the idea, being able to find something similar as far out as the Kuiper Belt in our solar system, where Pluto and thousands of other small icy bodies reside. As noted by Edwin Turner at Princeton University, “It’s very unlikely that there are alien cities on the edge of our solar system, but the principle of science is to find a method to check. Before Galileo, it was conventional wisdom that heavier objects fall faster than light objects, but he tested the belief and found they actually fall at the same rate.”

The paper has been submitted to the journal Astrobiology and is available here.

Posted on by Paul Scott Anderson

NASA Developing Real-Life Tractor Beams

Artist's conception of a future space probe using a tractor beam to gather samples of material from an asteroid. Credit: NASA

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If you are a Star Trek fan, you will of course be familiar with “tractor beams,” those cool-looking laser beams that can grab an object in space and it pull backwards toward the source of the beam (including trapping spacecraft as evil aliens would often do). They are another long-running staple of science fiction that is now closer to science reality. NASA is now working on developing just such technology, which would help primarily in obtaining material samples in real-life space missions, such as on Mars or an asteroid or comet.

A $100,000 study to look at three possible methods has been awarded to NASA’s Goddard Space Flight Center by the NASA Office of the Chief Technologist (OCT). According to Principal Investigator Paul Stysley, “Though a mainstay in science fiction, and Star Trek in particular, laser-based trapping isn’t fanciful or beyond current technological know-how.”

The methods being developed can trap and move particles of matter or even single molecules, viruses or cells, using the power of light – maybe not another spacecraft yet, but the principle is the same.

NASA has used various methods of sample-retrieving, all with great success, including aerogel on the Stardust spacecraft to obtain dust samples from the comet Wild 2 and scoops, brushes and rock abrasion tools on various Mars landers and rovers to retrieve rock and soil samples. On the next Mars rover, Curiosity, which is due to be launched later this month, there will be a scoop as well as a drill. It will also feature a laser beam to zap rocks so the resulting particles can be analyzed; not quite the same as a tractor beam but still cool.

The first technique being studied is the optical vortex or “optical tweezers” method which uses two counter-propagating beams of light. Particles are confined to the “dark core” of the overlapping beams. Particles can be moved along the ring’s centre by alternating the strength or weakness of one of the beams. The only catch with this method is that it requires an atmosphere to work. Ideal then maybe for on the surface of Mars or Titan for example, but not for an asteroid or other airless body.

The second technique uses optical solenoid beams, where the intensity peaks spiral around the axis of propagation. Particles can be pulled backwards along the entire length of the beam, and it can operate in a vacuum, no atmosphere necessary.

Both of those techniques have been tested in the laboratory, but the third method, as of yet, has not. It uses what is known as a Bessel beam, which, when projected onto a wall for example, features rings of light surrounding the central dot of light. The effect is similar to looking at ripples surrounding the spot where a pebble has been dropped into a pool of water. Other types of laser beams do not exhibit that however, appearing only as a single point of light. Such a beam could induce electric and magnetic fields in the path of an object, which could then pull the object backwards.

According to team member Barry Coyle, “We want to make sure we thoroughly understand these methods. We have hope that one of these will work for our purposes.” He added, “We’re at the starting gate on this. This is a new application that no one has claimed yet.”

A more technical overview of the practicality of tractor beams is here.

Posted on by Paul Scott Anderson

Kepler Space Telescope Mission Extension Proposal

Artist's conception of the Kepler 16 system, where the planet Kepler 16-b orbits two stars, much like Tatooine from Star Wars. Credit: NASA/JPL-Caltech/R. Hurt

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Some potentially good news for exoplanet fans, and Kepler fans in particular – Kepler scientists are asking for a mission extension and seem reasonably confident they will get it. Otherwise, funding is due to run out in November of 2012. It is crucial that Kepler receive renewed funding in order to continue its already incredibly successful search for planets orbiting other stars. Its primary goal — and the holy grail of exoplanet research — is finding worlds that are about the size of Earth, orbiting in the “habitable zone” of stars that are similar to our Sun, where temperatures could allow liquid water on their surfaces.

But finding those ideal smaller planets requires several years of observations, in order for Kepler to confirm a repeated orbit as a planet transits its star. The larger the orbit, the longer the observation time needed to view multilple transits. Most of the planetary candidates found already orbit much closer to their stars, hence taking less time to complete an orbit, and can more easily be detected within the first few years of the mission.

Kepler has already obtained very compelling data on a wide variety of planets since it was launched in 2009, with 1,235 candidates found so far (about 25 of which have been confirmed to date), but further refining of the data will take more time; a few more years would do just fine. The exciting trend has been that smaller, rocky planets appear to be much more common than gas giants; good news for those hoping to finds worlds similar to Earth that could be habitable (or, of course, inhabited!).

It is estimated it would cost about $20 million per year to keep Kepler functioning past 2012, which doesn’t sound too bad considering that about $600 million has already been invested in the mission. NASA’s budget, like everyone else’s, is tight though these days, so it isn’t a done deal yet.

The proposal will be submitted in January, with an answer expected by next April or May.

Posted on by Paul Scott Anderson

To Boldly Go Where No Beer Has Gone Before

Credit: Vostok Pty Ltd.

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For those who aspire to be a space tourist and who also love their beer, this story is for you. A company in Sydney, Australia wants to be the first to offer specially-made brews just for space travel. If they get their wish, you may soon be able to relax in your space taxi or in an orbiting hotel and have your favourite beverage as you enjoy the view.

This is the dream of Jason Held, an American aeronautical engineer who has worked on NASA’s Hubble Space Telescope and Jaron Mitchell, who owns a pub in Sydney, 4 Pines Brewery. They’ve come up with an original craft beer called Vostok 4 Pines Stout, named after the rocket which took the first man into space, Yuri Gagarin, in 1961.

Note the logo! Credit: Vostok Pty Ltd.

But there are certain challenges unique to developing space beer, namely delivery to space via a rather violent rocket launch with all that shaking going on. Then, there’s the effect of drinking beer on the human body in zero gravity. Both of these problems are still being tested, with a focus on finding a way to deliver the beer to orbit as a liquid, since most space drinks until now have been in powdered form (think Tang). Making a glass of beer from a powder just won’t do.

They also had to increase the flavour and decrease the carbonation to make the beer suitable for zero gravity, since tastebuds on the tongue lose sensitivity in a weightless environment. Burping a highly carbonized drink would result in bubbles of liquid being regurgitated and floating around – not very appealing, but comical at the same time. So then what about the future of Coke or Pepsi in space, I wonder?

Jaron Mitchell, left, and Jason Held. Credit: John Kung for Bloomberg Businessweek

Some don’t see beer or dining in general as being a high priority for space tourists though, as noted by Stephen Attenborough, director of Virgin Galactic. “Frankly, we suspect that few if any will want to spend the precious flight time worrying about food and drink,” he said.

But Held sees it differently, saying, “A space hotel without a space bar without space beer. I can’t see it happening.”

All in all, it sounds like a good idea to me (and wine would be nice too), but after the fun, maybe wait a while before driving any space taxis!