Does invisible ALIENS really exist among us? An Astrobiologist reveals her research // servicebloggers.com

Does invisible ALIENS really exist among us? An Astrobiologist reveals her research
Author: Pradeep   Date: Jan 2020

So could aliens be among us? I don’t believe that we have been visited by a life form with the technology to travel across the vast distances of space. But we do have evidence for life-forming, carbon-based molecules having arrived on Earth on meteorites, so the evidence certainly doesn’t rule out the same possibility for more unfamiliar life forms.

Life is pretty easy to recognize. It moves, it grows, it eats, it excretes, it reproduces. In biology, researchers often use the acronym “MRSGREN” to describe it. It stands for Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition.

But Helen Sharman, Britain’s first astronaut and a chemist at Imperial College London, recently said that alien life forms that are impossible to spot may be living among us.

Does invisible aliens really exist among us? An Astro-biologist reveals her research

How could that be possible, aliens living among us?

While life may be easy to recognize, it’s actually notoriously difficult to define and has had scientists and philosophers in debate for centuries. For example, a 3D printer can reproduce itself, but we wouldn’t call it alive. On the other hand, a mule is famously sterile, but we would never say it doesn’t live.

As nobody can agree, there are more than 100 definitions of what life is. An alternative (but imperfect) approach is describing life as “a self-sustaining chemical system capable of evolving. The lack of definition is a huge problem when it comes to searching for life in space. Not being able to define life as we are truly limiting ourselves to geocentric, possibly even anthropocentric, ideas of what life looks like. When we think about aliens, we often picture a humanoid creature. But the intelligent life we are searching for doesn’t have to be humanoid.

Extraterrestrial life, but not as we know it on Earth;

Sharman says she believes alien life exist and “there’s no two ways about it”. Furthermore, she wonders: “Will they be like you and me, made up of carbon and nitrogen? Maybe not. It’s possible they’re here right now and we simply can’t see them.”

Such life would exist in a “shadow biosphere”. By that, I don’t mean a ghost realm, but undiscovered creatures probably with a different biochemistry. This means we can’t study or even notice them because they are outside of our comprehension. Assuming it exists, such a shadow biosphere would probably be microscopic.

Does invisible aliens really exist among us? An Astro-biologist reveals her research

So why haven’t we found it? We have limited ways of studying the microscopic world as only a small percentage of microbes can be cultured in a lab. As we have seen a illustrate of CGI in 'Hollywood movie ANT MAN'. This may mean that there could indeed be many life forms we haven’t yet spotted. We do now have the ability to sequence the DNA of acculturate strains of microbes, but this can only detect life as we know it, that contain DNA.

However, If we find such a biosphere, how we name it's life form “extraterrestrial origin” or simply “unknown life form”.

Does invisible aliens really exist among us? An Astro-biologist reveals her research

Silicon-based life

A popular suggestion for an alternative biochemistry is one based on silicon rather than carbon. It makes sense, even from a geocentric point of view. Around 90% of the Earth is made up of silicon, iron, magnesium and oxygen, which means there’s lots to go around for building potential life.

Silicon is similar to carbon, it has four electrons available for creating bonds with other atoms. But silicon is heavier, with 14 protons (protons make up the atomic nucleus with neutrons) compared to the six in the carbon nucleus. While carbon can create strong double and triple bonds to form long chains useful for many functions, such as building cell walls, it is much harder for silicon. It struggles to create strong bonds, so long-chain molecules are much less stable.

What’s more, common silicon compounds, such as silicon dioxide (or silica), are generally solid at terrestrial temperatures and insoluble in water. Compare this to highly soluble carbon dioxide, for example, and we see that carbon is more flexible and provides many more molecular possibilities.

Life on Earth is fundamentally different from the bulk composition of the Earth. Another argument against a silicon-based shadow biosphere is that too much silicon is locked up in rocks. In fact, the chemical composition of life on Earth has an approximate correlation with the chemical composition of the sun, with 98% of atoms in biology consisting of hydrogen, oxygen and carbon. So if there were viable silicon lifeforms here, they may have evolved elsewhere.

That said, there are arguments in favor of silicon-based life on Earth. A few years ago, scientists at Caltech managed to breed a bacterial protein that created bonds with silicon – essentially bringing silicon to life. So even though silicon is inflexible compared with carbon, it could perhaps find ways to assemble into living organisms, potentially including carbon.

And when it comes to other places in space, such as Saturn’s moon Titan or planets orbiting other stars, we certainly can’t rule out the possibility of silicon-based life.

To find it, we have to somehow think outside of the terrestrial biology box and figure out ways of recognizing life forms that are fundamentally different from the carbon-based form. There are never ending researches going on like the caltech one.

Regardless of the belief held by many that life exists elsewhere in the universe, we have no evidence for that. So it is important to consider all life as precious, no matter its size, quantity or location. The Earth supports the only known life in the universe. So no matter what form life elsewhere in the solar system or universe, we have to make sure we protect it from harmful contamination – whether it is terrestrial life or alien life forms.