Popular Physics Myths

Many legends have arisen over the years in regards to physics and physicists, some of which are quite false. This list collects some of these myths and misconceptions, and provides further information to try to clarify the truths behind them.

Clocks against a black background, warped and distorted as they combine together in center of image.
Conceptual image of relativity. Images Etc. Ltd./Getty Images
In the postmodern world, many believe that Einstein's Theory of Relativity says that "everything is relative" and it has been taken (along with some elements of quantum theory) to mean that there is no objective truth. In some sense this couldn't be further from the truth.

While it does talk about how space and time change depending upon the relative motion of two observers, Einstein viewed his own theory as talking in very absolute terms - time and space are completely real quantities, and his equations give you the necessary tools to determine the values of those quantities no matter how you are moving. More »

There are several aspects of quantum physics which easily lends it to misinterpretation. The first is Heisenberg's Uncertainty Principle, which very specifically relates to the proportional relationship of quantities - such as position measurement and momentum measurement - within a quantum system. Another is the fact that quantum physics field equations yield a range of "probabilities" of what the outcome is. Together, the two have led some postmodern thinkers to believe that reality itself is completely random.

In fact, though, the probabilities go away when you combine them and expand the mathematics into our own macroscopic world. While the tiny world may be random, the sum of all that randomness is an orderly universe. More »

Albert Einstein, 1921. Public Domain
Even while he was still alive, Albert Einstein was confronted by rumours, both informal and published in the newspaper, that he had failed in mathematics courses as a child. This was patently not true, as Einstein had done fairly well in mathematics throughout his education and had considered becoming a mathematician instead of a physicist, but chose physics because he felt it led to deeper truths about reality.

The basis for this rumour seemed to be that there was one mathematics exam required for admission into his university physics program which he'd not scored high enough on and had to retest ... so he had, in a sense, "failed" that one mathematics test, which covered graduate level mathematics. More »

Sir Isaac Newton (1689, Godfrey Kneller).

There is a classic story that Sir Isaac Newton came up with his law of gravity when an apple fell on his head. What is true is that he was on his mother's farm and watched an apple fall from a tree onto the ground when he began to wonder what forces were at work to cause the apple to fall in that way. He eventually realized that they were the same forces which kept the moon in orbit around the Earth, which was his brilliant insight.

But, so far as we know, he was never hit in the head with an apple. More »

of 09

The Large Hadron Collider Will Destroy the Earth

View of the YB-2 in the cavern of the CMS experiment. LHC/CERN

There have been concerns over the Large Hadron Collider (LHC) destroying the Earth. The reason for this is that there have been some proposals that, in exploring high energy levels through particle collisions, the LHC may create some microscopic black holes, which would then draw in matter and devour the planet Earth.

This is unfounded for several reasons. First, black holes evaporate energy in the form of Hawking radiation, so the microscopic black holes will quickly evaporate. Second, particle collisions of the intensity expected at the LHC happen all the time in the upper atmosphere, and no microscopic black holes formed there have ever destroyed the Earth (if such black holes form in collisions - we don't know yet, after all).

The concept of entropy had been used, especially in recent years, to help support the idea that evolution is impossible. The "proof" goes:

  1. In natural processes, a system will always lose order or stay the same (second law of thermodynamics).
  2. Evolution is a natural process where life gains order & complexity.
  3. Evolution violates the second law of thermodynamics.
  4. Therefore, evolution must be false.
The problem in this argument comes in step 3. Evolution does not violate the second law, because the Earth is not a closed system. We gain radiated heat energy from the sun. When drawing energy from outside the system, it is in fact possible to increase the order of a system. More »
The Ice Diet is a proposed diet in which people say that eating ice causes your body to spend energy to heat the ice. While this is true, the diet fails to take into account the amount of ice required. Generally, when this is considered feasible, it does so by mistakenly calculating gram calories in place of the kilogram Calories which are what is talked about in reference to nutritional Calories. More »
of 09

Noise Travels in Space

The cover of Don't Try This At Home!: The Physics of Hollywood Movies by Adam Weiner. Kaplan Publishing

Perhaps not a myth in the proper sense, because no one who thinks about physics for even a minute believes this happens, but still it's something which shows up in popular culture all the time. In the book Don't Try This at Home!: The Physics of Hollywood Movies by physics teacher Adam Weiner, this is listed as the biggest, most common physics error in movies.

Sound waves require a medium through which to travel. This means they can travel through air, water, or even solid objects, such as a window (though it gets muffled), but in space it is essentially a complete vacuum. There are not enough particles to transmit sound. So, no matter how impressive the space-ship explosion, it will be completely silent ... despite Star Wars.

A photograph of Niels Bohr. public domain from wikipedia.org

There are likely a few different ways that this argument plays out, but the one I've heard most frequently centers around the Copenhagen Interpretation of Quantum Mechanics. This is the interpretation developed by Niels Bohr and his colleagues at his Copenhagen Institute, and one of the central features of this approach is that the collapse of the quantum wavefunction requires a conscious "observer."

The argument that comes out of this is that since this collapse requires a conscious observer, there must have been a conscious observer in place at the beginning of the universe in order to cause the wavefunction to collapse prior to the arrival of human beings (and any other potential observers out there). This is then put forward as an argument in favor of the existence of some sort of deity.

The argument is unconvincing for a number of reasons. More »