Shape of rolling stones due to turbulence can connect the evolution of biophysics.

Professor Adrian Bejan of Duke University

Have we ever thought why larger animals live longer and travel further? This statement may seem to be quite simple but indeed has a lot of physics behind it and in this article, you will be astonished to know it. This simple law of physics extends to the simplest forms of mass migration on the planet like rolling stones flowing with the fast streams of rivers and the turbulent eddies forming in water and air currents. A research was been carried out at Duke University and the results found is quite fascinating.

After analyzing the results, Adrian Bejan, Professor of Mechanical Engineering at Duke University came to a conclusion that evolution not only applies to biological things but in any other physical system in motion. Bejan has been working in this field for a long time and he has even developed a physical law called the “constructal law“, which states that any flowing system allowed to change freely over time will trend toward an easier flowing architecture.

For the botanical domain of systems like rivers, roots, and vascular systems, this law applies in a way that limited large channels carry massive flows to abundant smaller branches for dispersal. Similarly for the zoological domain of systems like animals, a few large species with widespread, long-range influences on the environment act together with many smaller species touching smaller regions, but in greater numbers.

In his latest paper, Bejan illustrated that this idea can be generalized even further. He postulates that the most basic processes that have shaped the planet’s landscape for billions of years like rolling stones and turbulent water currents can also adhere to these physical laws.

Theory of Evolution

Bejan said, “I’m defining evolution literally to mean what the word implies, which is continuous change in a discernible direction over time.” What Darwin imagined for animals and called ‘evolution‘ is actually a physical description, and it applies to everything else that morphs freely while flowing, whether it’s biological or not. So my ‘aha’ is that evolution is everything because everything is in motion and is free to change while moving.”

Bejan solved a series of simple physics equations to prove his theory that both the time spent moving and the distance traveled of a rolling stone should increase with its mass. He further compared ” an eddy of turbulence” with the “fluid eye rotating in a fluid socket” and concluded that its lifespan and traveling distance also increase with its size.

Both processes have been responsible for moving objects across the Earth’s surface for billions of years. Bejan also points out that rolling stone evolve to have less friction so that they can travel further. That is, they become rounder over time.

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Previously Bejan worked on animal size, lifespan, and travel distance and established a fact that, despite the differences, all animals should have roughly the same number of breaths per lifetime. Comparing his previous theory on animals, Bejan injected the analyzing results in his new work and clinched that all other things being equal, all rolling stones and eddies have the same number of revolutions before their energy dissipates through friction.

Bejan further added, “These three characteristics,life span, life travel and the constancy of the number of breaths or revolutions of bodies that move mass, unite the animal, the eddy, and the rolling stone. Traditional camps believe that evolution is only biological and has already been explained to the hilt. I’m showing that evolution is actually based in physics and that it is simply designed change over time. To the origin of life in non-living matter, abiogenesis, rolling stones and turbulence add the physics of evolution.”

Well, this experiment may seem simple but its importance is undoubtedly significant in environmental science. This experiments will help us further in understanding the infinitesimal fundamentals of biophysics along with Charles Darwin’s theory of evolution proposed almost 150 years ago.


Will the discovery of Gravitational waves ever help us detect the ripples of Big Bang?


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Detecting ripples in a space-time was not an easy task, after-all it took 50 years of trial and error, and 25 years perfecting a set of instruments so sensitive that could finally show a distortion in space-time millions of light years away. The discovery of gravitational waves have stirred the whole world of astronomy and have posed all sort of fascinating questions for astronomers regarding binary black-hole systems. Perhaps in a way it has opened a new field of gravitational physics which will revolutionize our understanding of the universe during its infancy.

The game has just started and now that we know how to measure gravitational waves, experiments like LIGO can be further enhanced to have a broader view of events happening in and around the cosmos that we have never been able to see before, such as mergers of super-massive black holes in the early universe. But the utmost question is that how far back can we really go? What about the gravitational waves that occurred moments after the big bang, will LIGO’s discovery help us catch those?

Let us take a step back in time, we are now in an era where the masses involved in the events are large by stellar standards, they are dwarfed by the super-massive black holes that scientists believe are present at the center of almost every galaxy. Our very own galaxy, the Milky Way, hosts a hole of about 4 million sun masses, detected through the motions of stars orbiting it.

There are yet a lot to discover about these super-massive black holes. We presently understand them through the immense amounts of electromagnetic radiation, like visible light and X-rays, produced by gas cascades into them. We know the likeliness of the process of formation of black holes, where some gasses are too slow and near and others are too fast and away for the black holes to capture it. So, the intriguing questions are that how could they get so big?

The answer could be that collisions between these super-massive holes helped to grow them, particularly when they were comparatively young and had not yet gained much gas. However, a collision between two super-massive black holes can probably only happen if the two galaxies hosting them collide and merge too. But these event is impossible to happen in the current time as because galaxies are far away from each other. But what if we go back in time, a time when the universe was much younger and the galaxies were very nearer to each other.

So detecting gravitational waves from such collisions means going back in time and analyzing the most distant galaxies giving us direct traces about how important these events were in growing super-massive black holes early in their lives and in turn unraveling the truth of mystery about the universe.

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But the collision of super-massive black-holes is not the end. The Big Bang, and particularly the eon of very rapid expansion dubbed inflation with enormous masses moving with almost light speed producing powerful gravitational waves are the goal we are looking forward to achieve. However, the most powerful signal comes from masses whose size is comparable to the scale of the universe itself. Since gravitational radiation has a typical wavelength larger than the masses emitting it, the “wavelength” of this radiation is itself similar to the entire size of the universe. So LIGO, or any other experiment that is smaller than the universe, will not be able to detect it.

The challenge is extremely difficult but a positive result could give evidence for the popular inflation theory, and offer explanations for several baffling features of the universe, such as why the distribution of matter is so standardized. Although finding such a signal is a colossal challenge, so was the direct detection of gravitational waves when first proposed half a century ago.