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Univ. of St. Andrews photoillustration
On a world that spins around two dim suns, the vegetation may well look black to human eyes.
Researchers suggest that vegetation on an alien planet like Tatooine in "Star Wars" might well look black or gray to human eyes. But they probably wouldn’t seem devoid of color to the eyes of the aliens — assuming they have eyes, that is.
The conjecture comes from a paper presented by the University of St. Andrews' Jack O'Malley-James at the Royal Astronomical Society's National Astronomy Meeting in Wales. O'Malley-James is working on a Ph.D. project to assess the potential for photosynthetic life in multiple-star systems with different combinations of sunlike stars and red dwarfs.
On Earth, the leaves of plants generally look green because two types of chlorophyll absorb the reddish and bluish wavelengths in the visible-light spectrum. Those red and blue wavelengths drive the photosynthetic process by which plants convert the sun's energy into chemical energy. In contrast, the green wavelengths are reflected into the RGB optical sensors known as our eyes.
Scientists surmise that the birds and bugs may see plants quite differently, with greater sensitivity to different shades of green and the ability to sense ultraviolet wavelengths as well.
O'Malley-James suggests that in different corners of our galaxy, plants could evolve to take advantage of different combinations of wavelengths, depending on the light coming from their parent sun ... or suns. The possibilities become particularly intriguing for a planet in a multiple-star system — like Tatooine, Luke Skywalker's fictional home planet in the "Star Wars" movie saga.
J. O'Malley-James / Univ. of St. Andrews
On planets orbiting red-dwarf stars, the vegetation may have more photosynthetic pigments in order to make use of a fuller range of wavelengths, giving them a "black" appearance. Here are some earthly examples of dark plants and flowers.
"If a planet were found in a system with two or more stars, there would potentially be multiple sources of energy available to drive photosynthesis. The temperature of a star determines its color and, hence, the color of light used for photosynthesis. Depending on the colors of their starlight, plants would evolve very differently," he said in a news release.
Statistics show that more than 25 percent of sunlike stars and 50 percent of the red dwarfs in our galaxy are found in multiple-star systems. Armed with such statistics, O'Malley-James and his colleagues ran computer simulations to determine the optimal strategy for photosynthesis over a wide spectrum (heh, heh) of planetary alignments.
“Our simulations suggest that planets in multi-star systems may host exotic forms of the more familiar plants we see on Earth," O'Malley-James reported. "Plants with dim red dwarf suns for example, may appear black to our eyes, absorbing across the entire visible wavelength range in order to use as much of the available light as possible. They may also be able to use infrared or ultraviolet radiation to drive photosynthesis. For planets orbiting two stars like our own, harmful radiation from intense stellar flares could lead to plants that develop their own UV-blocking sunscreens, or photosynthesizing microorganisms that can move in response to a sudden flare."
But even if the plants reflected none of the visible-light wavelengths, extraterrestrial gardeners might well have their own special appreciation for an ultraviolet bloom, or leaves that are variegated in the thermal infrared.
I know it sounds like a flight of fancy, but this is just the kind of flight I enjoy the most. The subject reminds me of the scene from "Battlestar Galactica" where Brother Cavil complains about the "ridiculous gelatinous orbs" in his head. "I want to see gamma rays!" he shouts. "I want to hear X-rays!" Which new senses do you think the aliens might have ... and which do you wish you could have? Feel free to weigh in with your own conjectures in the comment section below.
More about alien perspectives:
- Want to call E.T.? Keep it simple, stupid Earthling
- Rare exoplanet has 'Star Wars' twin sunset
- How to find aliens: Follow the photosynthesis
- Alien plants get new twist in world of 'Avatar'
- Plants on other planets might not be green
O'Malley-James' supervisors on the Ph.D. project include Jane Greaves of the University of St. Andrews, John Raven of the University of Dundee and Charles Cockell of The Open University.
Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about my book on Pluto and the search for planets, check out the website for "The Case for Pluto."
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I've always been curious to hear (see?) what kind of music aliens would play. An intergalactic 4-piece probably has some good jams... even if a lot of the notes are in a register too low or high for me to hear.
Ultrasonic hearing like the hearing which bats possess could be very advantageous. So would low light level night sight like that which nocturnal animals possess. Even infared or UV spectrum sight would also be helpful, too. All of these senses and more are to be found right here on our planet Earth in other species. I hope that one day soon mankind will be incorporating genetic improvements into our own genome structure which already exist right here on Earth in other species. Like high density retinas of the kind that eagles possess, or an olfactory sense of smell on the order of that which bears possess. But I would also expect advanced ETs would likely do the same as well, using other species which exist in their home worlds, long before they make it out into the distant cosmos to visit other alien worlds like our Earth. There are a very large number of genetic advancements right here on Earth which can greatly enhance our own human genome structure, and I hope over time we will be availing ourselves of these advancements in other species and even more, if our own Earth doesn't suffer a future mass extinction due to our own callous indifference and ineptitude. - Rick Carter
Don't forget about the use of bionics as a possibility, too, when it comes to enhanced senses in aliens. This would also include the bionic equivalent of telepathic thought. - RC
Bionics? I played Mass Effect 2 as well, but come on, that was just a game.
It can and will happen. There are already prosthetics (sp?) that respond to thought impulses the way your natural arm woud and exoskeletons that are help parapelegics walk again.
Ghost in the Shell is not as far in the future as you would think. Well, maybe the brain box is... But cybernetic implants, not so much.
It goes without saying that whatever primary characteristics ET possess will be a direct result of their environment.
Take the liquid moon of Europa for instance. With a continual heat source, and an "atmosphere" consisting of 50 miles of ice protecting it from space, who knows what has been stewing under there for millions of years....you can bet the creatures there (I have no doubt there is life on Europa) are very similar to some of the creatures of the deep we are just discovering in our oceans, now. Artificial sources of light would be paramount.
Also, if aliens can "see" unltraviolet light wavelengths, they may not be able to see our wavelengths, or at least not all of them. And if they could "see" infrared, they may only have the lower part of our spectrum, if at all. The same thing for hearing.
Could aliens possess other senses? Not ESP, I'm tired of all the movies showing them with telepathy and telekinesis, but what if they had a sense, similar to touch, sound or sight (or smell or taste, even), but registering some other input? Would we recognize it as such, or would we compare it to ours?
Perhaps aliens who have made the long trek into their future without blowing themselves or their planet up, have shed their corporal bodies for some sort of bio-mechanical 'vessel'. The repository of their individual knowledge and remembrances would be with them AND be stored in a central repository where every new thought, the scent of a flower or travel into space would be captured by the microsecond. No doctors. No lawyers, no death. No need for any of those things we need to sustain us through an aging life. If the alien body is damaged or destroyed, a new one is instantly reproduced with the complete memory up to the microsecond before. A society traveling through space with the vast knowledge of the Universe would need only one thing to sustain them with so much power and knowledge. Thirst for more of life's adventures and experiences provided by the memories of other planetary civilizations. Perhaps shared. Perhaps taken! A Universe as one gigantic Netflix Store to be uploaded and stored in the Central Repository!
We are the Borg. We will add your biological and technological distinctiveness to our own. You will be assimilated. Resistance is futile.
You got it tony!
HUGE points for the author, mentioning Number One's great rant from BSG. One of the greatest moments in scifi TV history, and so very right for the piece.
I could not resist....the alien trees just might look black, and straight at ya too, or even sideways.....
I think the aliens of the darker worlds may just have thicker skin and double eyelids as a result of the higher energy radiation, on the larger superearths, I can expect the worms and fish to be much larger than here, different methods of photoreception are almost an evolutionary decree, and being that some of the darker worlds are much older star systems, we can expect speciation to of favored a more choosey, and discerning predator with a bit of wisdom we do not usually attach to primal animals....we can also expect a stark contrast amonst the survivers of the predatory beasts, a race of beings with a set of survival instincts we will have a difficult time comprehending, the question is, will knowledge be an evolutionary trait, or just a waste of time.
Ah, speculation!! isn't it just what scientists do? I find the ideas/theories presented to be logical, cogent. But until we figure a way to travel outside the space/time continuem(sp?) we'll never find out. I also agree that our senses leave MUCH to be desired.
ETs and their plant life…..hmmmm.
What kind of talk is this? Aren’t we supposed to be the only planet in the universe with life? Aren’t we supposed to be alone? God only appeared to us here on Earth. He didn’t go to other planets. How can those ETs be saved? Aren’t we supposed to hate those darned Aliens anyway who are evil and obviously want to eat us?
Be careful with this kind of talk ….I don’t think we are ready for this. People might start to riot in the street. Orthodox religious traditions might be in jeopardy. Large energy corporations might fail knowing that there is cheap energy available outside of oil, gas and coal.
Please stop this…..We can’t let anybody know about this.
:)
Sarcasm? I hope.
You forgot the sarcasm font <sarcasm> </sarcasm>
I don't think they'd look black or gray because that would mean the plants employed multiple methods of capturing solar energy (reducing reflection) and that would require a large energy investment in the cells building many different complex chemicals and the integration of a lot of different mechanisms of photosynthesis.
How would all these different reaction sequences be regulated? If all wavelengths are working and producing exothermic reactions (as normally would occur), how does the plant regulate transpiration and keep itself from drying out? Again, more energy investment.
The multiple mechanisms may take advantage, at peak opportunities, of the many wavelengths of solar energy possible, but at low-energy opportunities, it seems to me that the plants most likely to survive and reproduce would be those that required the least energy to keep working under low-energy conditions - and that would be those plants with simplified photosynthetic pathways utilizing a limited set of wavelengths.
On Earth, all plants use all forms of blue light to grow in size. They also use the green spectrum for growth. The red spectrum is used for flowering/blooming, so is orange. Add in the factor that plants also use the rest of the color spectrum because there is no complete blocking of it available unless you set up an indoor, controlled room and you provide the artificial sunlight as I do in my experiments with horticulture. Now, on the other hand, if you give light 24 hours a day, seven days a week...all you get are longer cycles of growth or flowering. You can give the plants blue and red light at the same time and get the plant to vegetate and bud at the same time. I've done that. Regarding having extra starlight such as two suns, it still is okay because all you get is increased growth or flowering. If the two suns provided too much heat, the atmosphere would be loaded with CO2 and that would permit the added heat. That happens naturally on Earth around the equator.
At first glance I thought the article said "Trees that look back!" Plants with eyes? Why not? Plants have sensory perceptions we humans cannot fathom. Plants have no cpu...no brain, so how do they 'know' anything, up from down, night from day, how do they sense and follow the Sun? Although rooted, plants move all the time, yet they have no muscles. Regardless, they are also exceptionally strong and powerful, enormously prolific and sexually successful. Not all plants here on Earth process photosynthesis in the same spectra, look how many varieties have red or varigated red/green leaves. We humans cannot directly use solar energy, we must have plants do it for us. And how about longevity? No human can begin to match a sturdy oak, fir, cedar or redwood. Let alone bristlecone! If you haven't read "The Secret Life of The Plants" so very popular in the '60s, check it out this weekend from your public library. Life on this 'lonely planet' is incredibly varied, endurant, and exists just about everywhere. No doubt extraterrestial life with be just as astounding as morning glories, moon jellies, chambered nautulli, hummingbirds, or grizzly bears!
And that has WHAT to do w/the topic at hand?
Wow, the trees on Mars are black!!!!! No wonder we are spending 2.5 BILLION to go there again. How many are we going to bring back this time????
This is why I love to come to COSMIC LOG. My tiny monkey brain may not be able to absorb all the technical language or theories but I can certainly appreciate pieces of information like this article.
I sometimes wonder what kinds of different life might be out there in the universe. Methane breathers? Ultra-violet light vision. Non-color or super color vision. Enhanced smell, or hearing? Living rocks or sentient aquatic life?
Anything and everything is possible and an article like this one really makes you think about the endless possibilities.
HEY! Maybe the cities on Mars can ONLY BE SEEN IN ULTRA-VIOLET? Or maybe some sub-atomic spectrum not even known to man! It's like bone-less chicken, it's mind-boggling.
Thanks COSMIC LOG.
When I read this piece, while I applaud the thinking process, I can't help but think this is another physicist out of their element--pun intended.
The reason why the specific wavelengths of light here on earth are utilized is a function of how they ultimately contribute to carbon chemistry. Visible wavelengths are "Goldilocks" so to speak--not too low energy, like infrared, and not too high energy, like ultraviolet, but rather just right. And not all visible wavelengths are suitable for photosynthetic chemistry either. That's why many photosynthetic organisms create pigments which help to either convert unusable photosynthetic wavelengths to useful ones or to disperse this energy as heat. So, while it is possible an organism could try to cover all the possible wavelengths of light and be black, not all of them are equally useful. Plus, things which are black tend to get very hot when in sunshine and very cold when they are not. This can be a very big problem for biological systems.
This report is as fascinating as science fiction and should be taken as such. The student in question would be better off conjecturing life on distant worlds isn't carbon based before they get into the sticky business of deciding which bits and pieces of biology they choose to believe may be amenable to change.
Also, the PI of this student should be ashamed of themselves for allowing such drivel to be released publicly. Is this what passes for science in "astronomy" these days?
A couple of things I'd like to say here.
1) Thank you for your thinking on the usability of wavelengths. It seems that only specific wavelengths have the energies required to initiate the different chemical reactions involved in photosynthesis, so certain wavelengths may only be usable, however, the article (why does that word look wrong?) specifically references dim red dwarfs, which may only produce a limited set of wavelengths. the question is, which wavelengths can the stars in question produce and which are absorbed for heat, for conversion, or for photosynthesis.
2) Things here that are black tend to be hot to the touch because they are absorbing the sunlight and not converting much of it to chemical reaction. Whereas plants hypothesized to be black in color, may be converting much of the sunlight they absorb into usbale energy and growth. Thus, the energy is being expelled in a manner other than heat.
3) Yes, this is what "passes for science in 'astronomy' these days". Namely, in the search for life, we most likely will not be sent smoke signals, let alone see giant smoke stacks and billboards. Different planets will have different living conditions tailoring it's theoretical life. This will help us spot the evidence of that life as we scan the Universe for neighbors.
Wouldn't it be possible for someone to do a test here to prove or disprove this? Get some plants and stick them in a room with no windows and have a lamp that produces light in both infrared and visible spectrums (or ultra-violet), and regulate the amount of time the light is on (producing day and night). Cross pollinate the plants to try and see what remains after x-number of generations... or something along those lines?
Maybe, I doubt such an experiment has ever been tried.
When there is a food/energy source something will evolve to exploit it. A close look at life here on Earth should reveal all the ways Carbon based life, (in an aqueous medium, such as the inside of cells), can use light for energy. Just look for environments where the available light is the same as the planet in question. If no such environment exists, create it in the lab, by stages, while growing algae, until such an organism evolves.
I've always had trouble imagining a planet with enough of a radiation shield and orbital stability surviving in a multiple sun system. I don't know but it seems improbable. Anyone ?
As h.c.petley pointed out, That would depend on the configuration and type of stars, and their
distance from the planets involved. The popular image of a double star planet is the Tatoine of
Star Wars fame. Two sun like stars in appearance.
In reality, consider the Alpha Centauri system. A triple star system, but if you were on a
planet in orbit around the main component, alpha Centauri "A". An earthlike planet at a similar
distance from the "A" star...the "B" star would at times be as far as Saturn or Uranus from Earth.
The "B" star is a nearly sun like star but some ten times the distance from the "A" star.
On this hypothetical world, two suns could appear in the sky at certain times of the year
and the "B" star at the closest point in its orbit would appear as a disc roughly 1/10th
the diameter of the sun. It would be as bright as probably several hundred full moons if
it happened to be the only star visible in this planets sky.
Plants on such a planet would have to deal with more than just two suns in the sky. There
would be times when only one of the stars or the other might be visible for instance. As for
the third star...Proxima Centauri...it is too far away to be anything more than an extremely
dim point of slightly reddish light in Alpha Centauri planetary skies in earthlike orbits around the "A" or even "B" star. Prox may not even be visible without binoculars or telescopes from such a world.
I think plants could survive and adapt to this kind of scenario pretty well.
The survival of a planetary biosphere in a multiple star system would depend on the proximity of the stars involved (such as the alpha centauri system in our own S. hemis sky, featuring Alpha, Beta and Proxima) If the stars are close enough to orbit one another, yet not too close to disrupt each other, then a planet with a biosphere orbiting one or the other could survive in a delicate gravitational balance. Solar energy from close additional stars could give life on said planet an extraordinary jolt. Would there be night? Maybe on a very long periodicity, maybe not at all. There could be stupendous tides if an ocean existed. Multiple star systems are common throughout our Galaxy and can be considered to exist apriori in all others. There is a high probability that planets do orbit stars that are twins or triplets or are members of a multiple group; consider for a momemt star clusters, which are also very common. Our star is pretty much a loner and our planet-with-biosphere unique in this system. Our principle light and heat source gives us a certain spectrum of radiation and we have evolved in it. Other stars with different radiation emissions would most likely, again apriori, produce life that is also very different. So black or very dark purple vegetation could very well exist. So could H.P. Lovecraft's "Color Out of Space" which an interested reader can find in a variety of old scifi anthologies.
Sol might not be as alone as you might think, assuming the search for the disruption of Ort Cloud comets ends with a brown dwarf or some similar stellar companion. I think it's extremely interesting to think our system might be a binary and we just don't know it yet.
They have found stars orbiting very close to each other. Assume a small star orbiting where Mercury is, or a little further out. Then assume an Earthlike planet orbiting those about Mars to Jupiter orbit. Further from the Suns, but increased energy.
Would love to see it.
I think it's a fair guess to say if there is light there are eyes.
This guy is going to get a phd in stupidity and he is getting help from three other people. Between them they should know the trees would not be black. What are they racist.
Maybe the plants are intelligent and will come here to occupy Earth or enslave us.
Maybe they will try to enslave our trees? Or liberate them from our animalness?
I think darthdon hits close to the underlying thesis, if there is food or energy available, life will evolve to exploit it. A grand excersise to all those that have contributed, as pointed out, we barely even know our own oort cloud, let alone our neighbors planetary system, but if we are to use near earth detection systems these thought experiments very well may help in allowing the instrument designers to optimize the as yet designed equipment to a peak sensitivty to wavelengths and chemicals more apt of an "alien" environment. It is all to easy to project our frame of reference upon the subjects of remote detection, but that is surely a naivity of mankind in general. We say people, but cannot fathom a brain inside a stationary plant, so we expect aliens to be huminoid and bipedal, yet dolphins and whales seem to have every bit the brain capacity of us, or at least of bumpy powers. The speculation is good, and thought provoking, as long as we know it's got purpose. Imagine what we may have missed had we never built a gamma ray telescope!!...someone had to of taken the leap of logic and assume that something relevant and worthwhile would be detected by said telescope. Party on dudes, and leave the naysayers in the dust, once again.
Nice post, Ray.