The title of this article may come as a shock to those of you who are pretty much interested in physics. Not very often you hear about a physicist hunting aliens, at least not when it comes to someone of the stature of Max Planck. Planck’s contribution to physics will remain immortal because of his contribution that literally gave birth to quantum physics.
His contribution to physics is the famous Planck’s constant (denoted by h), which today is considered as a fundamental parameter in quantum physics and is a universal constant. He was the first person to realize that when it comes to electromagnetic radiations, the only way they can be emitted, absorbed or transmitted are in discreet values that he called quanta or energy packets. Quantum is the singular form of quanta. Energy of a quantum, according to Planck, is measured by the equation, E = hν. Here E represents Energy of quantum, h is Planck’s constant and ν is nu – Greek letter. ν actually represents the radiation frequency of a quantum (also referred to as a photon). This discovery earned Planck the Nobel Prize in 1918.
Quest for communicating with aliens
Though most of us know Max Planck because of Planck’s constant, most of us are not aware of the fact that he was one of the first few people who speculated that communicating with aliens or extraterrestrial life forms was indeed a practical possibility.
Planck was not the first person to think of communicating with aliens or better said, think of the communication language that should be used. There were many other people out there. However, all of them faced one major challenge – finding a universal language for communicating with extraterrestrial life.
One of the long standing views when it comes to communicating with aliens is that mathematics may be the answer. Some say that only a few specific forms of mathematics can help humans achieve this like binary arithmetic. But, there is a small glitch! And what’s that? Well, in case of binary arithmetic we have this habit of drawing reference of some form of physical unit, for example, 6 ounces, 5 seconds, 12 mi/hr and so on. The only problem here is that these numbers are anthropic by nature. Meters, liters, seconds, grams, etc. – all units of Système International are also anthropic.
In case you are not aware of what anthropic means, allow us to explain. Anthropic simply means something related to human beings. These units that we mentioned are all of human origins and we humans don’t find it difficult to comprehend them. Every unit of Système International has been defined in context of planet Earth. For example, mass of a certain water volume was defined in kilograms. Similarly, it was the need for measuring a fraction of rotation period of Earth that gave birth to seconds. Again, the need for measuring a fraction of Earth’s circumference gave birth to the unit called meter.
Thus, all are anthropic, i.e. human related. Now, because we live on Earth and we are quite familiar with it, we don’t find it difficult to understand what these units mean and how we need to use them. What about the aliens? Aliens don’t belong to Earth. They are most possibly not familiar with the planet and hence, it is highly logical to say that they will not even understand the measurement units that were all created in context of Earth and humans.
Search for non-anthropic units
So… way out? Simple! Get your hands dirty with units that are not human or Earth centric. This calls for units that are not anthropic or are non-anthropic (whatever you prefer to call). Good! But there is a teeny tiny problem. What will be the non-anthropic unit? This is where radiations pitch in. There are fundamental particles that make up the whole of universe. These particles are present on every planet in our Solar System and every other celestial body within in the Solar System. Beyond the Solar System, these particles are present in every galaxy in the universe. So, if the aliens come from a different galaxy, they must be aware of these fundamental particles and they must be aware of the fact that these particles have specific masses and that each type of particle actually emits radiation of specific wavelength or frequency.
That’s good thinking! But again, there is a teeny tiny problem! There are several of these fundamental particles and each of them have their own radiation wavelength and mass that differ from every other fundamental particle on the list. The aliens may just end up using any one particular particle while we earthlings end up using some other particle!
It was Max Planck who came up with a nice solution that took a detour from the usual thinking. In 1899 Planck submitted a paper in Prussian Academy of Sciences. It was all about irreversible radiative processes. However, at the very end of the paper, there was a bit on natural measurement units – a proposal actually. Here is a quick extract from the paper he submitted which explicitly mentions the prospect of communicating with extraterrestrials: “Units for length, mass, time and temperature which, being independent of specific bodies or substances, retain their meaning for all times and all cultures, even non-terrestrial and non-human ones.”
Solution given by Max Planck
So, what was Planck’s ground-breaking idea? Planck came up with what he called Natural Units. These are physical units that are used for measurement in Physics. These units make use of 4 other universal constants apart from the Planck’s constant.
The universal constants are:
- G = gravitational constant.
- c = light’s speed in vacuum.
- ħ = reduced Planck’s constant (it is actually derived from Planck’s constant which is represented by h).
- ke = Coulomb constant.
- kB = Boltzmann constant.
These 5 constants were used to derive the Natural Units which are today known as Planck Units. These units are:
- Planck Length
- Planck Mass
- Planck Time
- Planck Charge
- Planck Temperature
When using these physical measurement units, the 5 physical constants mentioned above take the value 1. Interestingly the 5 units mentioned above are the base Planck Units. Several other Planck Units have been derived from these base units. Some of the derived units include Planck Area, Planck Volume, Planck Momentum, Planck Energy, Planck Force, etc.
Now, the interesting thing about the Planck Units is that they are all based on Nature’s properties. Put in other words, they are not anthropic by nature. Because the units actually use properties of our known universe, any intelligent life form or extraterrestrials that have scientific know-how of how the universe works (assuming that what we know is correct) will be able to communicate using these units. So, Max Planck actually gave a practical way of communication with extraterrestrials back in 1899.