We need things to be about us in order to care. Thus, in most of our stories about aliens, the aliens come because of us be it to kill, enslave, or study us or to take things that are dear to us. We are also usually the first who make contact with the aliens, and they almost always look something like us or like something familiar to us. However, I don't pay much mind to the little-green-men mythology. I don't think aliens have to be humanoid , carbon-based, or even alive by our definition of alive.
Human beings aren't made to survive in space. If aliens arrive on Earth here, it means they have survived in space and have the means to adapt to our atmosphere. I think it highly possible that they'll be nothing like us. They use matter whatever that matter is and wherever it comes from and they adapt to wherever they are. And their wants and needs and methods of going about their business are wholly foreign to humans.
I don't think aliens have been, are, will be what we are expecting. The street cred: Former chemistry professor , Northeastern University. The chances of anyone alive today seeing or even communicating with them are very slim. However, such problems should not stop us from imagining what they might be like. Of course. You have to see to build a civilization. The squid has better eyes than we do, and the eye seems to have evolved separately a few times at least.
Our alien will have eyes that may only resemble ours superficially. A lens and iris are almost an absolute requirement. The whites do not have to be white. Neither does the iris have to be colored in anything like the way ours are.
How many eyes? One just will not do. Inability to perceive distance will lead to rapid extinction. Unless you can find a good reason for it, extra eyes create evolutionary baggage and will not persist, spiders not withstanding. Eyes being important, they will be recessed and capable of being covered, as necessary. Our aliens are not likely to be bug-eyed, although we cannot totally rule that out. An alien must have the means to breathe. It must be symmetrical.
The nose does not have to be in the middle of a face, although that is convenient for some purposes such as sharing the air pipe with a mouth for times of exertion.
You can imagine other arrangements. Must have means for ingestion of food. All large animals have some means to capture and swallow food. Some masticate it; others do not. Teeth are rather common on Earth but other systems of eating are possible. The problem is that plants and animals have been in an evolutionary war for millennia.
We inherit the outcome of that war. Teeth were necessary to eat plants that became more fibrous, an evolutionary reaction to being eaten. There are other ways to sheer off plant food, such as what birds do. They 'chew' in their gizzards. Most certainly. Other means of locomotion will be relatively slow and be relegated to armored animals and of those living in holes. Neither of these lifestyles will lead naturally to greater intelligence.
How many legs? In our case, we adapted the forelegs for manipulation from animals with four legs. No land animals with endoskeletons have more legs. It may or may not be significant that humans have just two eyes and ears just enough for stereo vision and hearing , and just two legs reduced from the initially more stable four. Many other organs also come in pairs as a consequence of our evolutionarily deep-seated — and perhaps inevitable — bilateral symmetry.
Still other elements of our body plan are probably nothing more than chance. The fact that we have hands and feet with five digits is a consequence of the fixation on five in our early tetrapod ancestors — close relatives experimented with seven or eight.
Untangling the functional from the accidental is one of the big outstanding challenges in evolutionary biology — and may help us better understand how alien lifeforms could differ from us. The main way we now search for intelligent life in space is by listening for radio or gamma transmissions. These efforts are increasingly being concentrated on star systems with Earth-like planets, as these are believed to be the most likely to harbour life.
Portsmouth Climate Festival — Portsmouth, Portsmouth. Edition: Available editions United Kingdom. Become an author Sign up as a reader Sign in. Well, maybe. Matthew Wills , University of Bath. The most important rule is that life arises by natural selection. Life adapts to its environment. Complex aliens will have evolved from simple aliens, to solve the problems on their planet.
These Earthly problems are also problems that need to be solved on alien worlds. And when we look at how Earth animals solve them, we can see how aliens might do it too.
The trick is to think about how aliens live. What do they really need? The first thing is to eat. All life needs energy, and energy comes mostly from two places, from sunlight or maybe other kinds of heat , and from other creatures.
Plants eat sunlight, but animals eat other animals and plants. Titan, conversely, has liquid on its surface, but in the form of liquid natural gas, specifically methane and ethane. Kershenbaum is willing to think creatively about how life may arise elsewhere in the universe. Here on the blue planet, many marine organisms live on the ocean floor and go up to the surface to feed. Kershenbaum is also resourceful in thinking about alien communication. Maybe, he said, extraterrestrial conversation could occur through such diverse ways as sound, light and chemicals, even magnetism and electricity.
We can use this to understand why, where and how it could be [used] on other planets. Part of the book considers more complex forms of alien life such as humanoids and AI. Would you feel comfortable calling them human? They would not be Homo sapiens. The brilliance of Charles Darwin was to understand that every individual on the planet is related to every other, no matter what species.
It does not apply to aliens.
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