by Robert Rickover
In the course of my “bio-gravity investigations,” I’ve become fascinated with gravity more generally. All I can recall from my undergraduate days as a physics major (way too many years ago!) is that gravity is an attractive force that can be measured with a high degree of precision. I don’t remember any explanation for how that force was created.
The basic story was that Newton got hit on the head with an apple and then figured out that a force must have caused the apple to fall. He then went on to develop his famous laws of motion based on the existence of that force. As far as I could see, physicists had not gone much past that, at least as far as ordinary objects are concerned.
I do remember that it is remarkable how weak the gravitation force is compared with the other major forces of nature – the force that binds the nuclei, and the electromagnetic force. That may seem strange to hear because our primary experience with gravity is the gravitational force that comes from our nearest neighbor – the earth – which of course is a lot bigger than us. Compare that to the situation of two people in the same room who also generate an attractive gravitational force on each other. In that case it is so weak that they don’t notice it.
From what I know, the extreme weakness of the gravitational force has been a major problem in theoretical physics. An additional problem is that unlike the other three natural forces, it cannot be described by quantum mechanics.
In recent years, Lisa Randell, a well known Harvard string-theory physicist has proposed a model which, if I understand it correctly, suggests that the gravity we experience on earth is a very, very weak modification of “real gravity.” Presumably other planets get their own planet-specific version of this “real gravity.”
I like that model a lot because if the force of earth’s gravity were to change even a little, it would pretty much mean the end of life. For example, a little less gravity, and our atmosphere would drift off into space. A little more and many plants wouldn’t be able to emerge from the ground.
Another respected string-theory physicist, Erik Verlinde, argues that gravity doesn’t exist at all, that we’ve been mistaking something else for gravity!
There are lots of other interesting ideas about gravity out there and I’d love to include them, or maybe links to them, on this page. Please contact me here if you have any interesting gravity ideas to share.
In the meantime, consider these factoids: If you climbed a mountain, you would weigh less than you do at sea level. If you could travel to the exact center of gravity of the earth, you would be…weightless – just as you would be in outer space.
Here’s an audio interview about gravity:
Image courtesy of Nutdanai Apikhomboonwaroot / FreeDigitalPhotos.net