What Don’t We Know About Gravity? Answer: Everything

Nobody knows what gravity is, and almost nobody knows that nobody knows what gravity is. The exception is scientists. They know that nobody knows what gravity is, because they don’t know what gravity is. – Richard Panek

Yesterday, I wrote a post, A Tale of Two Brains, where I mentioned that scientists don’t know what gravity is. I thought I should add a separate note about it because most people are unaware how much mystery there is in the subject and I thought I should provide a reference to back up that shocking admission of scientific failure.

Richard Panek has written an interesting book on the history of our study of gravity. He also writes about the how most people do not know that science is not as certain about its understanding of how the universe as we think.

In the first pages of his book, he writes of typical conversations he has with the general public and with scientists about gravity. He says that they fall into two categories:

Category One:

ME: Nobody knows what gravity is.
CIVILIAN: (Pause.) What do you mean, nobody knows what gravity is?
ME: I mean nobody knows what gravity actually is.
CIVILIAN: (Pause.) Isn’t it a force of nature?
ME: Okay, fine – but what does that even mean?
CIVILIAN: (Silence.)

Category Two:

ME: Nobody knows what gravity is.
SCIENTIST: That’s right.

We call gravity a force and we say it takes the form of a field, but we only say this because we don’t know how the force of gravity exerts its force over a distance. We can calculate its strength, but beyond that we don’t understand how it interacts with matter at all. Still, the general public thinks scientists know all about it.

We live in a time where scientists write all our new mythologies. That is an interesting thought because the purpose of mythology is to explain things that we cannot know for certain about our lives and the world around us. But, the people who come to believe these same stories don’t seem to know that scientists aren’t writing about what they know, but what they don’t know. And it’s well known that scientists are notoriously imprecise with their use of language. Good with math, not so good with words.

So, it’s a very curious thing that we live in a time where the storytellers are scientists and it’s even more curious that there is so little curiosity about it.

Looking Into the Abyss: Is The Universe Doomed to End In Heat Death Or Is That A Scientific Myth?

Spoiler Alert: It’s a myth.

The Heat Death of the Universe was first proposed by Lord Kelvin in the late 19th century. It is a conjecture that the universe is expanding and will continue to expand until all the thermal energy of the universe is expended causing all physical processes to cease.

This faulty and uninspiring mental image of the universe has been a part of the cultural milieu of the scientific community for so long that it has become a part of the popular culture’s understanding of Reality and is rarely challenged.

This apocalyptic vision originated from the observation of physical and chemical processes under specific, local conditions and then extrapolated to include the fate of the entire universe.

Just the Abyss - Ellis Rosen - The New Yorker

“It’s just the abyss, dear. Try not to gaze into it”

We call this kind of analysis empiricism, which is a bottom-up approach to knowledge. While empiricism is a powerful scientific tool, it has its limitations.


the theory that all knowledge is derived from sense-experience. Stimulated by the rise of experimental science, it developed in the 17th and 18th centuries, expounded in particular by John Locke, George Berkeley, and David Hume.

Google definition

Physics gives us knowledge when observing concrete (physical), local systems. We can control and submit these local systems to scientific experimentation. We fail sometimes to realize how little we can observe about the universe. From our tiny perch on this small planet whirling about in the vastness of space what can we really know for certain about the fate of the universe?

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