Plenty of Water on Mars

http://www.nasa.gov

If humans ever decide to colonize Mars, it appears that there is an abundant water supply; unfortunately, it is not in the form of lakes, rivers, or even underground pools. It’s in the dirt, and eating a handful won’t quench your thirst.

At one time, flowing water was probably plentiful on the planet, but the only immediate water sources found currently are located at the planet’s poles, as ice. Mar’s ‘watery phase’ likely lasted until about four billion years ago.

Mars’ diameter is about half that of the Earth, its mass is about 11% of Earth’s, and its gravity is less than 40% of our planet: all these factors facilitated the loss of the atmosphere’s upper layers as they were blown away by two mechanisms; the impact of meteors, and a natural ‘boiling’ of gasses into space. But a planet’s atmosphere — especially the heavier gasses — can also be absorbed into the soil, which is probably why the dirt of Mars contains such a high percentage of water.

NASA’s Curiosity rover scooped up samples of Martian dirt, deposited the dirt in its oven-abdomen (into SAM, the Sample Analyzer at Mars instrument) and heated the samples to more than 800 ⁰C to drive off and measure the volatiles. Its analysis identified about two percent water by weight, which converts to approximately two pints (1 litre) of water per cubic foot (0.03 cubic meters) of soil.

This discovery leads me to believe that a human settlement on Mars isn’t quite as far-fetched as it seemed a short time ago; additionally, early indications suggest that there is no life on the planet, so a terraforming operation wouldn’t destroy life that was already present.

It also occurs to me that viewing a planet that is devoid of life should make us all realize that we are the custodians of a jewel in space, a remarkable world that is bursting with miracles.

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For more information on Mars and Curiosity:

Volatile, Isotope, and Organic analysis of Martian Fines with the Mars Curiosity Rover

The Petrochemisry of Jake_M: A Martian Mugearite

 Curiosity finds no sign of methane, the gas linked to life

Rover finds evidence Mars lost its atmosphere four billion years ago

Mars Curiosity: Facts and Information

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Supermarket produce can tell time

The vegetables at your local market or grocery store are still alive and can tell time.

A new study (Janet Braam in Current Biology), indicates that the way produce is stored has a significant effect on its nutritional value and health benefits. Fruits and vegetables, like animals, respond to circadian rhythms, and their biology is modified in response to different lighting conditions, a reaction that is programmed to defend against insects. These responses to lighting conditions affect the health value of the produce.  

For example, cruciferous vegetables (e.g.: cabbage), contain glucosinolates, which initiate the secretion of detoxifying enzymes that eliminate carcinogens from an organism (i.e.: cabbage fights cancer). The researchers put cabbage heads into light-dark circadian cycles and found that glucosinolate concentrations were almost twice as high during the day, reaching a peak in the hours just before dusk. The research indicates that it might be beneficial to store produce (at the market, or at home) in light-dark cycles, and consume the produce in daylight (and, preferably, just before dusk). It might also be best to harvest crops, freeze, and preserve them at the appropriate time.

I heard a rumour that the research was initiated because of a random remark by Janet Braam’s son. She was explaining to him that the food value in plants was known to change depending on the time of day. Her son mentioned that perhaps he should time his meals to coincide with the peaks of nutrition. Apparently, nobody had thought to check whether picked produce retained the circadian rhythm of the parent plant, hence the research. I also heard that Janet Braam wasn’t expecting the results that were found, and was pleasantly surprised. Sometimes it helps to think outside the box… 

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A Hurricane on Saturn

http://www.nasa.gov

It has been pretty windy around here lately, but I just read about a storm that defies comparison anywhere on Earth…

Cassini — a spacecraft launched from Cape Canaveral in 1997 — has sent back some dramatic pictures of a colossal hurricane at Saturn’s North Pole.

The eye of the storm is over two-thousand kilometers in diameter, twenty times the size of a typical hurricane on Earth. Scientists believe that the storm has been active for years, with its epicenter anchored at the North Pole where water vapor must be fueling the hurricane. Clouds reach speeds of over five hundred kilometers per hour at the periphery of the hurricane.

NASA constructed a video (with informative audio) from the images gathered by Cassini

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Where in the world is the North Pole?

physics.hku.hk

It’s not like I was planning a vacation (but you never know); I was just curious, and decided to find out exactly where on the planet the North Pole is. The answer wasn’t as easy as I thought…

As a matter of fact, there are several ‘North Poles’ (the following is somewhat ‘borrowed’ from a Scientific American article…):

• North Pole, Alaska. This town isn’t close to any of the other North Poles in this post, but the town gets a lot of mail just prior to Christmas every year.
• Geographic North Pole, the point where all the lines of longitude of a map meet: known as true north to cartographers.
• Celestial North Pole, a whimsical point that is defined by extrapolating the Earth’s axis of rotation into the heavens. If we imagine the celestial North Pole as a hub, the universe of stars — the celestial sphere — rotates around it. This is an important point for the set-up of sundials (Polaris — the North Star — is located surprisingly close to the Celestial North Pole).
• Instantaneous North Pole, where the Earth’s rotational axis meets its surface. The instantaneous North Pole is not a fixed point: it whirls in an erratic, spiral dance called the Chandler wobble (i.e.: the Earth wobbles, as discovered in 1891 by Seth Carlo Chandler).
• The North Pole of Balance is defined as the center-point of the Chandler wobble (see above).
• Magnetic North Pole, where the Earth’s magnetic field is vertical (also called ‘the magnetic dip pole’: if you stand at this point, a compass needle will try to point (dip) straight down). Similarly to the instantaneous North Pole, the magnetic North Pole is not a static point; it moves as much as fifty kilometers per year. Currently, the magnetic North Pole is moving from northern Canada toward Siberia. And, to be factual, the magnetic North Pole is somewhat of a misnomer because it actually behaves like the south pole of a magnet (by definition, a magnet’s flux lines describe a vector away from the north pole and toward the south pole: the opposite of Earth’s north/south pole magnetic field vectors).
• Geomagnetic North Pole is an attempt to treat the complexity of Earth’s magnetic field as a dipole bar magnet. Geomagnetic north is of little use to navigators — magnetic north is much more useful — but if you happen to be a space physicist, geomagnetic north might interest you because the further you travel from our planet the more it approximates the characteristics of a dipole bar magnet.

In summary, I have no idea which North Pole Santa calls home; also, if you’re planning a trip to the North Pole, you’d best decide which one you want to arrive at before setting out.

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What is Time?

So, what is time? It strikes me as an elusive, nebulous concept.

Einstein’s theory states that space-time is malleable; it can be manipulated, bent and twisted. Is there any possibility that time could be distorted in such a way that paradoxes would not occur and we could travel into the past? Most physicists say no, but they have found no mathematical proofs that rule out the possibility.

Travel into the future is certainly possible; we’re relentless time-travelers, but is it possible to accelerate (or decelerate) the process?

Why is time linear? Why do we remember the past, but not the future? Why does the arrow of time point inexorably toward tomorrow? We take the arrow of time as a given, but what makes it so?

One way of explaining time — at least our perception of it — is through the second law of thermodynamics: entropy (disorder) increases as time passes: the universe, once very ordered, is becoming increasingly disordered with the passage of time (you can scramble an egg, but unscrambling it back into its original egg-form is much more difficult). We can perceive changes in entropy, so perhaps the passage of time is a concept that is defined by consciousness.

Time seems to be a fundamental law of the universe; but, according to physicists, the flow of time, as we perceive it, is not a fundamental law. There is even speculation that our section of the universe might be unique, and other fundamental laws might apply in another corner of the universe. Perhaps there is a place where entropy is decreasing; perhaps time runs backward to a being in this place, and they would think it was odd that we perceive it else-wise. Some physicists have posited a multiverse, like a tree that branches with each decision node; these branches occur at certain nodes of time. Perhaps this is why time, for us, travels forward: we cannot travel back through these nodes.

[I feel the need to digress…

Am I only taking my own life in hand when I make my decision to not look both ways before crossing the street? If I fail to look and other factors conspire against me, I might not get to the other side alive. But if I do look, or if there were no cars zooming along the pavement, I will get safely to the other side. There are many different possibilities: I may even decide not to cross the street. The multiverse theory postulates that the universe splits at these nodes, and all possibilities take place: there are an infinite number of universes, some of which contain me (in many different forms), and in other universes I do not exist. I think it is incumbent on me, as a custodian for my future doppelgängers in those other universes, to ensure I look both ways before crossing the street.]

The Big Bang (some 14 billion years ago) may not have been a beginning; rather, a node in the multiverse.

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Further reading/viewing…

Time’s arrow and Boltzmann’s entropy

Einstein’s Dreams, a novel by Alan Lightman

What is time?

Salvador Dali on What’s My Line?

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Radioactive Orchestra

I found the YouTube video below (recently demonstrated at TEDxGöteborg) and thought it was interesting enough to share.

Swedish scientists have created a musical instrument that uses a photon detector as a pulse generator (high energy particles yield a high note; low energy particles yield a low note). Some interesting science and theory is explained at the beginning (not too technical, easy for non-scientists to follow), but if you just want to hear the sound/music that is produced, fast forward to about the eleven minute mark of the video. Enjoy…

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The Anthropocene: the New Man Epoch

economist.com

A new geological epoch, the Anthropocene (the New Man Epoch), may have begun; which, according to predictions, will include the sixth mass extinction in Earth’s history.

A paper has been written (The New World of the Anthropocene) in which the authors claim “…that recent human activity, including stunning population growth, sprawling megacities, and increased use of fossil fuels, have changed the planet to such an extent that we are entering a new geological era. Since the Industrial Revolution, humans have wrought such vast and unprecedented changes to our world that we actually might be ushering in a new geological time era, and changing the course of the planet’s geological evolution for millions of years.” The authors of the paper are Jan Zalasiewicz, Mark Williams, Will Steffen, and Paul Crutzen (who was awarded the Nobel Prize in Chemistry for his study of atmospheric ozone).

Currently, fertilizer factories are account for the fixation of more nitrogen (the conversion of more nitrogen to a biologically useable form) than all land-based plants and microbes. The runoff from fertilized lands triggers oxygen-depleting algal-blooms in river deltas around the world.

Poor forest husbandry practices have caused devastating erosion and an alarming increase in sedimentation (and giant dam projects cause the opposite, holding back sediment that would naturally be washed out to the seas of the world). The loss of forest habitat is predicted to cause mass extinctions, which are already occurring over a hundred times quicker than at any time during the previous half-billion years; and, if trends persist, the rate of extinctions may rise by a factor of thousands.

But the largest geological effect is the change in the atmospheric composition; namely, an increase in carbon dioxide (and other greenhouse gasses) as a result of the use of fossil fuels, which are causing a warming effect that could raise temperatures to levels not felt on our planet for millions of years. There is evidence that plants and animals are already migrating toward the Earth’s poles. Many species will not survive. It is predicted that sea levels will rise six meters (twenty feet), or more. Carbon dioxide will eventually acidify the oceans to the point that corals will not be able to build reefs (there is evidence that this process is already occurring, and by the middle of this century it may cause devastation to corral reefs). Reef gaps are a consequence of the previous five major mass extinctions; the most recent mass extinction was approximately sixty million years ago, possibly due to the impact of an asteroid. To the geologists of the far future (assuming homo sapiens survive), our footprint will look eerily similar to the devastatingly sudden consequences of an asteroid striking the planet. I wonder how we will be viewed by our distant descendants, but I imagine it will not be with approval.

There is still debate that the increased carbon dioxide in the Earth’s atmosphere is a naturally occurring phenomena (although the gasses are increasing at an unprecidented rate of over ten times the speed of previous epochs, mainly driven by human activity); however, these arguments, to me, seem moot: does it really matter? Is it morally acceptable to continue to belch and leach poisons into the atmosphere and waterways? I think we’ve become inured to the problem; apathy reigns, and I admit that I, alike millions upon millions, am caught in the lethargy of our society. This is what scares me: the ennui of apathy.

Paul Crutzen, who coined the term Anthropocene, has said that his “…hope is that the term Anthropocene will be a warning to the world.”

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Faster-than-light Warp Drive

Image Credit: Dr. Harold ‘Sonny’ White

I read an article the other day that awoke my inner geek (and made me wonder, yet again, where my Buck Rogers’ ray gun and Starship Troopers’ space cadet cap got to).

Warp drive, the faster-than-light-travel I first heard about in the original Star Trek series, may be more realistic than I ever imagined. The ‘real-life’ spacecraft design is quite different, but the general concept is the same… 

In 1994, theoretical physicist Miguel Alcubierre proposed a real-world design for a warp drive. The proposed spacecraft was football-shaped and was attached to a flattened ring that encircled it (the ring was to provide the warp-drive phenomenon). Unfortunately, when Alcubierre did his calculations, the energy required to power his ship was enormous  (equal to the mass-energy of Jupiter). Recently, however, Dr. Harold ‘Sonny’ White (of NASA) reworked the design — replacing the flattened ring with a rounded doughnut — and the recalculated energy requirement is comparable to the mass-energy of NASA’s Voyager 1 probe (Dr. White suggests that further energy reductions are possible with the integration of oscillating space-warps). This may bring the idea of faster-than-light-travel out of the pages of the science fiction books of my teenage years and into reality!

The proposed warp drive does not contravene the theoretical universal speed-limit (as per Einstein’s Special Theory of Relativity); rather, the manipulation of space-time provides an escape clause.

The encircling doughnut-shaped ring produces a warp in space-time around the spacecraft: space in front of the craft contracts, and space behind expands, but the spacecraft remains within a cocoon of non-warped, ‘flat’ space-time and surfs the wave within the warp field. Apparently, the spaceship could theoretically approach a ‘virtual’ speed ten times faster than the speed of light. The math is impenetrable (at least to my thirty-years-in-the-past university calculus, which is, alas, not powerful enough to probe the magic); nevertheless, the important concept is that matter cannot go faster than the speed of light, but the fabric of space — space-time — can, and the spacecraft-cocoon will travel within warped space-time, which will deliver the craft to its destination faster than light can travel.

The ring that creates the warp field will probably require exotic matter (uncommon states of matter that have unusual properties, but are within the sphere of conventional physics). The generation of sufficient amounts of exotic matter to create and sustain the ring for the warp drive is currently speculative, but future advances in quantum mechanics may resolve this issue.

Dr. White, and associates, have set up an experiment — the White-Juday Warp Field Interferometer  (note: this link contains a lot of information on warp mechanics: for the experimental set-up, see p.8 of the pdf) — in an attempt to “…perturb space-time by one part in ten million.” Dr. White admits it’s a humble experiment, but is an important test of principles.

According to the Star Trek canon, warp drive was (will be) invented in 2063. Only time will tell if the prediction comes true…

Warp seven, Scotty; and Sulu, plot a course toward the “…second star to the right, straight on ’til morning.”.

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The Selfish Gene, a book review

Richard Dawkins became famous due to the success of The Selfish Gene (1976), which is now a classic popular science book. Its main theme is that natural selection develops at the gene level, not at the level of the individual. In fact, he goes as far as to say that “…we, and all other animals, are machines created by our genes.” [p. 2]. The replicators (the genes within DNA) developed longevity, fecundity, and high-fidelity, and  they drive the robotic machines.

The ‘selfish’ aspect of Dawkin’s thesis is meant in a metaphoric sense: genes are not consciously selfish, but it would appear as though they are to an outside observer. And, indeed, Dawkins points out that altruism is a required element for the continuance of the replicator (Dawkins biggest hurdle with many critics was the term selfish; in retrospect, he admits — in the introduction to the 30^th anniversary edition — that The Immortal Gene may have served him better as a title).

Later in the book, Dawkins explains that the evolution of the brain has created beings that are able to rise above the control of the ‘selfish gene’, and he coins another term for beings that have attained this level of evolution: the selfish meme.

Dawkins is a persuasive writer and he builds his case well by using scientific examples in layman’s language, but at times his tautologies feel top heavy, as if they were built on an invisible foundation (a certain behavior must be due to selfish genes because all behavior is due to selfish genes).

There are some fascinating facts sprinkled throughout the book and there is an abundance of food for thought, but I cringed when Dawkins began to philosophize (he admits he is not a philosopher, yet this does not stop him from moralizing); in particular, I found his diatribes against religion off-putting. I’m not going to spend time here arguing for (or against) religion, but I think Dawkins could have let his thesis stand on its own (he should have made his points and moved on) without attacking a belief system that is not truly disprovable; after all, Dawkins’ theory is really just another belief system.

If you plan to read the book I would recommend acquiring at least the second edition (updated with corrections and extra material, including excellent Endnotes), which enriches the reading experience.

The Selfish Gene is an enjoyable read, with a few sections I had to slog through, and some unfortunate sections I could have done without, but it was intellectually stimulating.

Recommended.

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The Caddis Fly Larvae

I spent a great deal of my childhood hiking through the rainforest on the side of Grouse Mountain. In particular, my friends and I explored the areas around Mackay Creek, a small stream that burbled over a rocky bed. The creek was filled with small trout, crayfish, and caddis fly larvae (apparently a sure sign of pollution-free water: we often drank the cold, clear water in cupped hands with no noticeable deleterious effects). About a decade ago I visited my old stomping grounds and I was so distressed with the loss of habitat to the burgeoning suburbia that I haven’t been back since; fortunately, my memories are, for the most part, intact.

Remarkably, the caddis fly larvae left one of the greatest impressions on my memory. I didn’t know what the creatures were at the time (I had no idea they were a larval form of a flying creature: to me they were aquatic bugs), but they fascinated me, and it was the caddis fly larvae, I think, that helped spark my life-long interest in biology (and, now that I think about it, the time I spent peering into the crystal water — long after my friends had gone home — was possibly my initiation into meditation).

There are over a thousand species of caddis fly in North America, and the Pacific Northwest is home to nearly two-hundred, but there is a particular species that attracted my attention.

Caddis fly adults are nocturnal and look like small moths with long antennae and silken hair on their wings; but they are not moths, they are in the Order Trichoptera (from the Greek for hair and wings). The adults are a favored snack of trout and are commonly used as models for fly-fishers. The caddis fly’s adult life is brief, just long enough for reproduction. Some adult female species deposit their eggs on the surface of the water and others dive underwater to lay their eggs.

As I mentioned, it was the larvae stage that fascinated me as a boy. A caddis fly larva is a long, segmented creature: its head and six legs are packed into its anterior end and two grasping hooks are situated at the posterior end.

Some larva species live like underwater spiders, spinning webs as a home and as a means to gather food, but most species build homes around their bodies. The habitats are constructed from various materials; some use slivers of wood, tree needles, or grains of sand, but there is a small group of species that uses miniature stones to create a cylindrical structure (the larvae secret a cementing chemical and laboriously build a house of pebbles around themselves), and it is this variety — two or three centimeters long (about an inch) and about a half-centimeter in diameter — that caught my attention while wading in and around Mackay Creek.

Using the grasping hooks at their anterior end, they hold fast to rocks in the stream and maneuver about using their six legs. I studied the creatures and, though they were all obviously quite similar in structure, each home was composed of tiny pebbles that were unique in color, size and shape. I tried to imagine each tiny creature choosing pebble fragments as they flowed downstream within reach: the creature would presumably grasp a stone, turn and spin it this way and that, and then mysteriously fasten the stone to the outside of its body (perhaps they forage for construction material and assemble their homes in an area of the creek that has no current, but I preferred the image of creatures plucking boulder-sized (to them) rocks from the stream’s current). I suppose the construction is instinctual, like a spider’s web, but it baffled my young mind.

At a glance they appeared to be sessile creatures, but I watched long enough to observe them as they crawled across small boulders in the middle of the current. I marveled at their tenacity: their petite black heads could be observed bobbing out the top of their homes, and their dark legs moved slowly and carefully across the rock surface: it appeared as though the legs helped anchor the larva for motility in the current. The cylindrical structures waggled in the current, but I never saw one lose its grip (I tested their resolve by plucking some of the creatures off of their boulder: they held on tenaciously, but I was able to tear them off. I tried to place them back on the boulder, but they had retracted their legs, probably fearing the worst. I have no idea whether I had injured them; I hope not).

Apparently, the larvae writhe inside their home, which enables oxygenated water to flow through fissures in the pebble-structure and along the gills that are located on the creature’s abdomens.

Before pupating in late summer, the larva attaches itself to a rock and seals its casing; within two weeks an adult emerges from the pupal enclosure, makes its way to the water-surface and searches for a mate in order to continue its genetic heritage by contributing to the succeeding generation.

I’m almost curious enough to go back to Mackay Creek and check for larvae, but I think my memory will suffice.

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