Sentience - A Natural Result?

Reports in The Ecologist and National Geographic reports that crows are carrying walnuts in their beaks to intersections, wait for the traffic light to turn red, drop the walnuts and after the cars run over the nuts, fly down and pick out the walnut meat. The National Geographic continues, stating that crows can make tools - and not just by accident. They create two different tools, depending upon the need. Apparently crows are as smart as chimpanzees, and studies seem to show that actually, crows are better at making tools than chimpanzees.

In addition, studies show dogs can map language. Great apes have been taught to communicate using sign language. We know that some animals can lie (recall, for instance, the article "Lemurs can be liars, if they think you want their food" in the May 2006 issue of Monitor on Psychology).

So, if planets are a natural consequence of the laws of physics (especially gravity) given a debris field, and life a natural consequence of the laws of physics and chemistry given liquid water, common basic organic molecules (found everywhere in space, from nebulae to comets), and an energy source, is sentient life a consequence of the laws of biology given a "boring" enough environment (see "Universal Biologies - Order from Chaos," and "Sentient Life" post)?

This is not to say that the universe is teeming with sentient life. While life is probably fairly common, most of it will be microbial type. Even with Earth's history, microbes account for most of the timeline for life. While catastrophic events can (and have, on the Earth) wipe out larger life forms, microbial forms are the most likely to survive.

Microbes can even survive being blasted into space; for example, if a large meteor hits a planet, large chunks of the planet can be launched into space. If one of those chunks hits another planet - life may be seeded there. Some feel that maybe that has happened between Mars and the Earth: some say life may have started on Mars first, then spread to the Earth (making Mars the garden of eden, and it did have a much wetter and warmer past), others say the reverse.

In addition, some environments are probably too harsh for large, complex life forms to evolve, or greatly slow down the evolutionary process (increasing the chances for a large enough catastrophe to set the evolutionary clock back).

But, life will find a way, and where there is life, there is hope. Thus, I believe sentient life is a natural potential - it will result if given a chance. But it won't be as common as, well, "common," or lower, life forms.

References:

Dingfelder, S. "Lemurs can be liars, if they think you want their food." Monitor on Psychology. Vol 37, No. 5 (May 2006). 10. Can also be found at <http://www.apa.org/monitor/may06/lemurs.html> (as of 1 December 2007).

Owen, James. "Crows as Clever as Great Apes, Study Says."
National Geographic News. 9 December 2004. 1 December 2007. <http://news.nationalgeographic.com/news/2004/12/1209_041209_crows_apes.html>

Pickrell, John. "Crows Better at Tool Building Than Chimps, Study Says." National Geographic News. 23 April 2003. 1 December 2007. <http://news.nationalgeographic.com/news/2003/04/0423_030423_crowtools.html>

Planets, planets everywhere

Watching the "Alien Planets" episode of the History Channel's Universe program, we learn an interesting discovery: planets around a pulsar (for example PSR B1257+12). That should be impossible - a pulsar is what is formed after a massive supernova explosion, an explosion so powerful that any planets should be destroyed. However, three small rocky planets were found. What they now hypothesize is that these are planets that formed from the debris of the destroyed orignial planets. If this is so, then this is more proof that planets can form even under extreme conditions; gravity wants to clump debris together, it is a natural consequence of matter and gravity. Thus, planets are probably very, very common.

By the way, life on a planet around a pulsar is very unlikely - there is far too much radiation flooding the system, especially if the planet happens to be in the way of the emission beams from the pulsar's magnetic poles.

Reference:

Pennsylvania State University. "Scientists announce smallest extra-solar planet yet discovered." 10 February 2005. 29 November 2007. <http://live.psu.edu/story/10180>

Wolszczan, A. (1994). "Confirmation of Earth Mass Planets Orbiting the Millisecond Pulsar PSR B1257+12". Science 264 (5158): 538 – 542.

The Meanings of Color

© DigitalBlasphemy.com

Some more contemplations on color and culture. Color can be useful for helping to distinguish between unripe, ripe, and overripe fruit; threaten or warn; distinguish between types of prey (which kind of beetle is tastier); and attracting mates; to mention but a few uses, and thus reasons for, the ability to see in many colors. For creatures who can see in color and find it useful, and who develop advanced sentience (including the ability to think in abstract terms), there is a probability that they will assign metaphorical meanings to color as well.

Some of this was mentioned in the Color of Life post; think of what various colors mean to us: yellow means warmth, light, day, energy - it is a positive color; red is connected to blood, and often means life, and from spilled blood, sacrifice or death; blue is a color of coolness, water, and sky; black is the color of night, mystery, and death, and of course green is for food, sustenance, fertility, serenity, and life.

Around different stars, these colors could easily take on other meanings. Around a hot blue star, blue may not be a color of coolness. The sky may very well be blue, with a brighter blue spot for the sun - which could be interesting. Think about what if our sky was yellow? Our yellow sun would be this bright part of the yellow sky, a bright spot that moved. Maybe we wouldn't be able to tell exactly the boundaries of the sun and so not, at first, recognize it as a self contained body circling the Earth, but instead just a brightness that moves across the sky.

So too, possibly, for some planets circling a blue star (a B class star - O class stars are also blue, but being the most massive stars in the universe, nd can not form planets due to the photoevaporation effect). Blue stars tend to be extremely hot and bright - the star would be this large very bright blue spot in the sky, the sky being a gradient from somewhat darker blue at the horizon, moving to lighter and brighter blue at the center of the bright day light. The world would be bathed in blue. Plants could be fuchsia, or even purple, in color. Oceans would have fuchsia or purple algae like plants in it, giving the seas there a violet or purple tint.

It is possible that some planets around F-stars would be home to plants with blue and blue related hues. Creatures trying to conceal themselves would develop blue skin colorations (Andorians?). That could either elevate blue to some mythic status, or because it is so common, other, more rare, colors would hold greater value.

Another possible result may be that some creatures, especially the carnivores, may find being color blind an advantage - with everything awash in blue, the ability to detect differences in brightness and texture would become more important than color itself (see the post Color Blindness Advantages - What Drives Color Range? for more information). Maybe blues would be seen in grayscale, while the other, more rare, colors are seen as they are. To such beings, the day time sky would appear a bright light grey, with the night sky black - and as the day turns to night, the sky changes in a sliding gradient from very light grey to ever darkening grey, and finally to black.

On a planet with black plants (possibly on a planet circling a dim, red class M star, the most common star in the universe), black could come to represent life (literally to the primitive sentient mind and metaphorically to the advanced sentient mind) - the opposite of how many Earthlings view the color. And if black was food, sustenance, fertility, and thus life - then what of the black night sky? Think of how such a planet would look to human explorers - say a somewhat dim red sun in the sky (giving the appearance of constant approaching evening), in a crimson, fuchsia or magenta sky (*), bathing black plants with reddish light - what a demonic place it would appear to human eyes, a Dante planet. Yet, to the natives, those would be the colors that would bring peace, and calmness - it would be the colors of home. Red would mean life, as well as black. The night sky would be as important, color-wise, as the day sky. Space would always have this connection to plants, to food, to sustenance - even if subconsciously. So maybe such creatures would be less fearful of space - they would find a comfort being surrounded by the blackness like some people on Earth feel when in a heavily forested mountain, or dense tropical jungle - surrounded by the color of life.

Would primitive aliens on such a planet think of the night sky as being a large plant leaf that blocks the sun (but, like all leaves, has imperfections, imperfections that allow some light to sneak through - star light)? One of their gods could then be a plant god. And since plants need the sun, this is not an evil god, just one that is taking its turn soaking up some sun. Or maybe it is an evil plant-god (some plants are poisonous, after all) fighting with the planet's creatures for the life-giving rays of the sun, a battle that occurs every day-night cycle (ancient humans thought somewhat similar battles went on between the Sun and the Moon - brought to terrifying climax with solar eclipses, which gave the appearance of the Moon eating the Sun, and to which primitive humans tried to help the Sun by banging on drums or shooting arrows in the air at the Moon to drive the Moon away - which of course always worked!)


* Depending upon how much blue light the star also radiates, and how much ozone is in the atmosphere to scatter that blue light- while an M-star radiates red most strongly in the visual range, it doesn't mean it does not radiate any other color.

References:

Berman, Bob. "Sky Lights." Discover Magazine. 23 Feb. 2007. Web. 22 Nov. 2007. <http://discovermagazine.com/2003/jun/featsky>.

"Breakthrough Method System for Understanding Ocean Plant Life." Earth Observation News. 1 Mar. 2005. Web. 22 Nov. 2007. <http://news.eoportal.org/research/050301_unicalifornia.html>.

"Extraterrestrial Landscaping." Discover. July 2007. 15. Print.

Meadows, Vikki. "Colors of Alien Plants." Astrobiology Magazine. 1 Oct. 2007. 22 Nov. 2007. <http://www.astrobio.net/news/article2477.html>.

Vu, Linda. "Planets Prefer Safe Neighborhoods." Spitzer Space Telescope. Spitzer Science Center. 3 Oct. 2006. Web. 23 Aug. 2008. <http://www.spitzer.caltech.edu/Media/happenings/20061003/>.

The Lost Regeneration

Most members of the animal kingdom can regenerate lost body parts at some (or all) of their life cycle. Mammals aren't one of those animals. Yet, scientists say the pathway (called the Wnt pathway) still exists, untapped, in mammalians.

Before we start speculating on alien sentient beings being able to routinely sprout new appendages (or like Jeebs, the hapless alien in MIB I and II, a new head), the question that first needs to be pondered is why have mammalians lost, or suppressed, this ability. On the surface, it seems like it would be evolutionary advantageous to retain this ability. Yet apparently it was also advantageous to lose it. Even among creatures that can regenerate, many of them can not do so when adults. This seems to indicate that there must be some problems with regeneration, especially with advanced life forms.

It is obvious we do not fully understand all the parameters regarding regeneration. However, the fact remains the Wnt pathway still exists, latently, but exists in at least some higher mammals. Thus, maybe it is not far-fetched to think there could be sentient aliens with at least some regenerative abilities. In addition, since Earth scientists are looking to restart this latent ability (and have had some success with adult frogs and chicken embryos), it is a distinct possibility that other alien sentient beings could work on restarting any latent regeneration they may have, and may be successful, either as medical procedure, or as a full time reacquired ability.

However, the more advanced the creature, the more there are limitations to the regeneration - that only makes sense. Simple structures are easier to rebuild, with less chance for mistakes. Not so for complex structures. Simple structures require less energy to rebuild than complex structures. Simple structures can rebuild faster. And finally, simple creatures tend to less centralized, the less centralized they are, the easier they can live without a part of themselves. Complex creatures tend to have rather centralized controls. Which brings us to an important point: there are structures that just can't be regenerated - such as a heart, or brain. How can a mammalian body naturally survive a missing heart even if it has the ability to regenerate? The body cannot survive long enough without a heart to give time enough for another heart to regenerate. Same with a brain - if the entire brain is dead or missing, the body cannot continue functioning long enough to allow for regeneration to complete (and even if a creature could regenerate a new head, ala Jeebs in MIB, how could it retain all its knowledge and memories?).

So, how would this affect culture, if we could routinely regenerate missing ears, noses, arms, or legs? For one, it would prolong life - for instance, amputations due to illness would be a temporary set back as the body regrows a healthy new appendage. Maybe more people would be greater risk takers, since the risk of death or permanent dismemberment or disfigurement is lowered (cosmetic surgery? Just remove the offending area, and let a new area grow back). But it also may make war or violence even more common place, since soldiers could be more easily resent back into battle (wars of attrition would take much longer). Of course repeated violence, repeated being torn apart and regrowing must have an affect on the brain, especially on the mental "adaptation" to such a "life." This would also affect culture.

The tougher question is how would it affect theology? What kind of theology would an alien race that had strong natural regenerative powers have?

Reference:

Casselman, Anne. "How to Grow a New Limb." Discover. October 2007. 17.

Astronomers Say Moons Like Ours Are Uncommon - How Important is That?

The Uncommon Moon?

ScienceDaily (2007-11-22) -- The next time you take a moonlit stroll, or admire a full, bright-white moon looming in the night sky, you might count yourself lucky. New observations suggest that moons like Earth's -- that formed out of tremendous collisions -- are uncommon in the universe, arising at most in only five to ten percent of planetary systems.

<http://www.sciencedaily.com/releases/2007/11/071121184530.htm>

A Large 5 Percent

Though 5 to 10 percent of billions of planets is still a large number of planets with large moons (the size of the Moon is so large in comparison with the Earth, it leads some to speak of the Earth and the Moon as a Earth-Moon system, or a double planet).

However, this is an important issue when discussing, speculating, on alternative extrasolar biological, psychological, theological and societal realities that could exist.


Protector Moon


Firstly, how important is a large moon to the rise of, and sustainability of, life on a planet? Some say the moon, by its size, helps protect the Earth from large meteor bombardment. That is debatable. One could actually argue that the Earth protects the Moon more than the Moon protects the Earth since the Earth is larger than the Moon, and hence a bigger target and a larger "attractant" due to its larger gravity. Also, one could also argue that the Moon also increases the chances of meteors coming close, by adding its gravitational pull (think of the Earth and Moon as one system: add up the gravitational attraction it would have on passing meteors). Additionally, while the Moon is large, it is separated by 250,000 miles. The further away you hold a large shield from you, the less of a shield it becomes. When a meteor heads towards the Earth, the Moon would have to be pretty much in the direct path. Remember, the gravity pull of the Earth is several times larger than the Moon's - in a tug a war between the Earth and the Moon over a meteor, I would lay bets on the Earth "winning."

So while the Moon may give the Earth some protection, it may not give us as much as we think. But, it may have been enough. Let us say that without the Moon's protection, we would've experienced only one additional large meteor impact over the history of the planet to date. That one additional impact would easily change the course of sentient development on Earth - most likely delaying it by millions of years. And quite possibly changing the final face of the sentient creature that did eventually evolve.




Stabilizer Moon


Secondly, the size of the Moon does help keep the Earth from being too wobbly on its axis. This helps keep the seasons from being overly dramatic, which would make it more difficult for complex life to arise (though, I would argue, not impossible, but probably would prolong its rise, and thus delay the rise of sentient life).



Tidal Moon


Thirdly, the Moon affects the tides on Earth. A smaller moon would have a much smaller effect, and without a moon, there would be an even small effect (the Sun would have an effect, but only 1/3 of the effect the Moon presently has). The tides have profound effects on the Earth - mainly from erosion which helps mix chemicals, especially for the young Earth (when the Moon was closer and had a much more dramatic effect on the tides).

By the way, did you know that this tidal affect is also responsible for pushing the Moon slowly away from us? The Earth is rotating faster (essentially 29 times faster) than the Moon orbits around it. This causes the high tide to move ahead of the Moon. Recall that a high tide is a bulge in the oceans of the Earth facing the Moon (and directly opposite of it). This bulge has mass, and thus gravity; this added gravity tugs on the Moon - but since it is slightly ahead of the Moon (due to the Earth rotating faster than the Moon orbits) - this tiny gravitational tug pulls on the Moon, accelerating it. The result of this constant tug is that the Moon is slowly accelerating, and thus spiraling away from the Earth. As time passes, the Moon will get further and further away (though as it gets further away, the Moon will have lesser effect on the tides, which will thus mean that the resulting acceleration would decrease - but not to zero, the Moon will continue to spiral away). So for those that remark at how miraculous it is that the Moon is the same apparent size in the sky as the Sun need to recall that it hasn't always been that way, nor will it stay that way (plus the Moon isn't exactly the same apparent size as the Sun - but it is very close to it).

Another result of the above is that the energy for the acceleration of the Moon comes at a cost to the Earth: it's angular momentum decreases. The result for this is a lengthening day. Some calculate that billions of years ago the Earth spun much faster, and without any moon, a full day today would be around 8 hours instead of 24. This faster spinning Earth could also have much stronger winds as well. Life would look a bit different on a planet that had stronger winds, a shorter day, and smaller (but more frequent) tides.

Moon Cult(ure)

Not having a moon would definitely have affects on the culture and theology of a sentient race. Think of how strongly our Moon plays into many of our primitive theologies and myths. But another consideration is how the dark skies would affect the alien race as well: darker skies would mean more attention paid to the stars, but I think an even stronger effect is that having a large moon so close to us may have encouraged us as a species to think about exploring space sooner than we would've otherwise. Without a moon, there is nothing close enough to explore - for thousands of years, the planets were just thought of as wandering stars. The only other physical body was the moon. Without the Moon, it would be quite some time before we would realize there are other physical bodies besides the Earth. Without a moon, there would not be that stepping stone that we enjoy - going to the Moon is far easier than going to Mars. It gives us a chance to learn, experiment, and gain experience before heading off to more arduous and more difficult explorations.

Habitable Moons

One way a habitable planet may have some of the benefits of a large moon without having a moon orbiting it, is for the planet to be a large moon itself, and circling a gas giant. While that gas giant would surely attract more than its share of meteors, the orbiting moons are so very small compared to the parent planet, that most would probably miss the moons. Not all, of course, but no planet or moon is totally safe from meteors.

Let's say a planet about the size of the Earth was circling a planet the size of Jupiter. There would definitely be tides! And as we see with our own system, giant planets are like a solar system themselves: ringed by many captured moons. A habitable "moon" circling such a gas giant would have many near by physical neighbors to visit, explore, and colonize (or base stations on). Such a civilization may be more even encouraged to explore space than our own.

Gas Giant Theology

And what a god the gas giant would probably play in their primitive theologies! Would they look up in the sky filled, at times, completely by the gas giant, and think "is that heaven" or "is that hell?"

A Downside

Actually, that may be a downside - orbiting such a large planet would mean periods where the sun would be blocked by the gas giant, and day and night would both be dark (with part of that darkness without even any nighttime stars). Though the times the moon was in front of the gas giant (between the planet and the sun), the night would be ruled by the reflected sunlight off of the planet's cloud tops. Life has adapted to life above the arctic and antarctic circles here on Earth, with their months long days and months long nights, so life could easily adapt to orbiting a gas giant - though the orbiting moons may well have such fast orbiting periods (for one thing, as big as Jupiter is, it is still much smaller than the sun) that these periods of full light and full darkness would be short - Io orbits Jupiter in under two days, while Europa orbits in under 4 days. Leda and Himalia have the longest orbiting periods for a Jovian moon: just over 238 days for Leda and 250 for Himalia. Nights (where the sun is totally blocked by Jupiter) on those moons are probably around one or two months long (haven't worked out the exact numbers; the distance from Jupiter is a factor - a theoretical moon with an orbit of 250 days at 600,000 Km from Jupiter would have a longer day long nights than another moon with the same orbit, but at 11,480,000 Km away. The shadow of a planet is not a cylinder, but a cone, it gets more narrow the further out it goes).

The Phase Lock Waltz

Another thing to consider is if the orbiting moon is in phase lock with the planet - the rotation period the same as its orbital period, thus ensuring one side always facing the planet it is orbiting. Our Moon is like this - we only see one side of the Moon from Earth. Those living on the far side of the orbiting moon would never see the gas giant (well, if they stayed near the equator. If they moved some distance north or south of the equator, they would begin to see the top, or bottom, of the gas giant over the horizon). They would have a long day, followed by a long night. Those on the near side would always face the gas giant. Most of their daylight would be the reflected light off the gas giant, though as the moon orbited the planet, those living on the near side would get short glimpses of the sun - it wouldn't rise high in the sky, however. And then they would experience a starless night (though for the same reason they would get a short glimpse of the sun before or after night, they would get a short glimpse of a star filled night sky after or before night).

Phase Lock Theologies

It would be interesting to entertain what kind of mythologies would arise on the near side and on the far side of such a world. For the near side, a massive god before them, and a bright god that flirtatiously appears once during the short year, and a star filled sky half a year later. For the far side, the bright god of the day, but this looming god just over the horizon, peaking over. And then there's the many small moons whizzing by, some below, some above the world - what to make of them? Also, would such a world figure out sooner than we did that the universe doesn't orbit around the habited world?

More Downsides

Another downside to orbiting a gas giant could be the intense radiation belt surrounding the giant planet. Io, a moon of Jupiter, orbits closer to the Jupiter's cloud tops than the Moon orbits the Earth. Jupiter has massive radiation belts, and Io cuts through them, causing Io not only to be bathed in high levels of dangerous radiation, but creating huge currents of electricity that flow along Io's own magnetic field (bathing the moon in auroral glow).

Another downside is that such a "moon" would have greater tides. The closer it circles the gas giant, the greater the tidal forces. It is thought that the tidal energies experienced by the moons orbiting Jupiter and Saturn are keeping the cores of the moons heated. There is direct evidence of geological activity at work on many of the moons. For instance, it is thought that tidal forces are what are causing the volcanic activity on Io, and is one of the mechanisms thought to create liquid oceans under the frozen surface of Europa (also a moon of Jupiter).

References:

Comins, Neil F. "What if the Moon Didn't Exist?" The Universe in the Classroom. Astronomical Society of the Pacific. Winter 1996. 25 November 2007. <http://www.astrosociety.org/education/publications/tnl/33/33.html>

"Solar System." Jet Propulsion Lab. 25 November 2007. <http://www.jpl.nasa.gov/solar_system/>

University Of Arizona. "Astronomers Say Moons Like Ours Are Uncommon." ScienceDaily. 22 November 2007. 25 November 2007 <http://www.sciencedaily.com/releases/2007/11/071121184530.htm>

Tiny DNA Molecules Show Liquid Crystal Phases, Pointing Up New Scenario For First Life On Earth

ScienceDaily (2007-11-23) -- Scientists have discovered some unexpected forms of liquid crystals of ultrashort DNA molecules immersed in water, providing a new scenario for a key step in the emergence of life on Earth.

<http://www.sciencedaily.com/releases/2007/11/071122151148.htm>

A key missing step in the process has been discovered - it is felt that the formation of full DNA molecules by random chemistry is essentially impossible, and thus scientists have been searching for more primitive and simpler molecules that would self organize. These, then, could lead to DNA.

This discovery of liquid crystal form of self organizing ultrashort DNA is an amazing discovery. Small repeating patterns combine to build larger repeating patterns which combine to build even larger and more complex patterns. Evolution works fairly quickly with simple organizations, and slows for more complex organizations, as we've seen in a previous post (Sentient Evolution ).

This helps support New York University chemist Robert Shapiro's earlier statement that life began from cyclical reactions involving small molecules: "these reactions would produce compounds that would feed back into the cycle, creating an ever-growing reaction network" (Schirber, Par. 13). The cyclic reactions from the small molecules would eventually create more complex molecules that would be more efficient, replacing the smaller molecules: "the system would learn to make slightly larger molecules" (Schirber, Par. 15). This is the "metabolism first" hypothesis of how life began (the other main thought is that RNA came first).

However life started, there is evidence it started 3.7 billion years ago, and fossilized bacteria found as old as 3.5 billion years. There is evidence that some form of photosynthesis began nearly at the beginning, if not at the beginning. This may indicate yet again that photosynthesis may be one of the more common energy sources for life, especially early life - may even be a common, almost universal, part of the rise of life; thus, the most common life form in the universe may well be simple plants. When the writer of Genesis says God created plant life first, and far before animal life, that writer was right - He didn't dally with the plants.

References:

Genesis 1:10-20.

Schirber, Michael. "How Life Began: New Research Suggests Simple Approach." Animals. Live Science. 9 June 2006. <http://www.livescience.com/animals/060609_life_origin.html>

University of Colorado at Boulder. "Tiny DNA Molecules Show Liquid Crystal Phases, Pointing Up New Scenario For First Life On Earth." ScienceDaily. 23 November 2007. 25 November 2007 <http://www.sciencedaily.com/releases/2007/11/071122151148.htm>.

Color Blindness Advantages - What Drives Color Range?

© DigitalBlasphemy.com

Color Blind Advantages

A short article in the October issue of Discover explains that sometimes being color blind isn't a bad thing. It was discovered that color-blind capauchins (a species of monkey native to S. America) were more successful at hunting camouflaged insects than capauchins with broader color vision. One hypothesis is that color-blindness actually helps improve the ability to notice differences in texture and brightness, thus being able to better detect camouflaged insects. As a hobby artist, I find that black and white photos sometimes show me more than a full color photo, especially in looking for differences in contrast or brightness - sometimes full color sends too many signals to the brain.

So, in addition to possible alien sentient beings able to perceive only or mainly in the UV range (see previous posts with the tag "alien senses"), or in the infrared, some aliens may see within our range, but be color-blind compared to the average human. Of course, we woul'd be UV-blind (though there have been rare instances of humans being able to see partially into the UV range).

What drives color range?

Sex and food primarily, and possibly detection of enemies. For instance, some researchers feel that first color vision arose because those who evolved the ability to see color were better able to distinguish ripe fruit. As the primates developed, and then improved, their ability to see red and orange, the primates began to develop orange and red hues to their hair and skin (or maybe more accurately, those few primates that had orange or red hair stood out from the others and thus were favored by the primates that were more successful in finding ripe fruit).

Color Tracking, Sports, and Church

Interestingly, humans can normally only keep track of three items at once, but if groups of items are of the same color, then we can keep track of three groups, or sets, of items, and thus keep track of many items at once - as long as the items are grouped in no more than three sets of colors (thus, one reason for team uniforms). Not sure what the benefit is of only three. Why not four or five? But at least our minds can use the "trick" of color to get around that limitation somewhat. Maybe humans hunted packs of animals in packs themselves, but also needed to keep track of their human pack leader (the "alpha wolf"). Thus, team uniforms are very advantageous for the spectator: with the two opposing teams in different colors, and the referees in yet a third color, the spectator can keep track of what is going on far better than if everyone wore whatever they wanted, with no player having the same color scheme as any other player on the field. Sports may not have been the evolutionary pressure to develop this ability to track three sets based on color, but instead an example of how the modern mind takes advantage of the situation.

But if we could answer the question, why three, we may be able to determine the conditions needed for an alien species to develop the ability to track four or five (or just two). The ability to track different items will affect the alien civilization's social, cultural, and theological realities; think about the three again: humans have trouble tracking more than three items at once, and three seems to be a holy number for many of our theologies - coincidence? Maybe for aliens that can track four items at a time with ease, four would be their common holy number. And maybe they would have games involving three teams at once.

References:

American Institute of Physics. "Tracking Your Team." Science Daily. 1 December 2006. 25 November 2007. <http://www.sciencedaily.com/videos/2006/1202-tracking_your_team.htm>

Barone, Jennifer. "The Upside of Color Blindness." Discover. October 2007. 17.

John Hopkins University. "What Are Uniforms Uniform? Because Color Helps Us Track Objects." Science Daily. 24 July 2006. 25 November 2007. <http://www.sciencedaily.com/releases/2006/07/060724105951.htm>

Ohio University. "Color Vision Drove Primates To Develop Red Skin And Hair, Study Finds." Science Daily. 25 May 2007. 25 November 2007. <http://www.sciencedaily.com/releases/2007/05/070524155313.htm>