Book Thursday. Universe. Nutshell.

: Cover of The Universe in a Nutshell

A number of years ago, I started giving books almost exclusively for presents.

I love to read, shop for, and get books for presents.

I keep a running Wish List on amazon.com, as do several others in my family. My secret vice is that it is a rare bookstore visit when I am shopping for gifts that I do not also find a book or two for myself.

In my continuing quest to understand the world that I studied only briefly in school, and that we know more about in the intervening 50 years, I am now struggling through Steven Hawking’s The Illustrated A Brief History of Time, that is combined with The Universe in a Nutshell, which I found at a bargain price and is available through amazon.com for $18.44.

Everything you need to know about time.

Once before I’d tried to read one of Hawking’s books, abandoning it as too hard.

This time, he has added tons of illustrations to demonstrate the concepts. And, the book is mostly about how scientists built on what was known to take the next leap.

Einstein famously said he stood on the shoulders of giants, but I’d never read any explanation of why his thinking about time, space, and the speed of light were the next logical step for an imaginative thinker.

Hawking explains that a British physicist, James Clerk Maxwell, predicted in 1865 that light travels at a fixed speed.

American physicists Albert Michelson and Edward Morley demonstrated this in an experiment in 1887. Dutch physicist Hendrik Lorentz tried to explain that clocks might slow down.

And, in 1905, Einstein published a paper suggesting that time was not absolute, but mass and energy were interchangeably related, and the speed of light was constant, no matter where it was being observed from, or how fast the observer was moving, as he summed up in his equation E=mc2 (E stands for energy; m for mass, c the speed of light).

Hawking also explains that curious phenomenon about a bowling ball and a feather landing on earth at the same time if dropped from a high point.

It just makes no sense.

And, apparently, you can’t even conduct this experiment very easily on earth to prove it, because wind currents slow the fall of the feather.

But, he shows a photo of an astronaut doing it on the moon, where there is no wind.

Very cool.

I also found a video of it being demonstrated on earth, presumably in a vacuum chamber.

It appears that the weight of the ball actually slows down its fall, relative to the feather, because the larger mass offers resistance, or inertia, just like a big, heavy car doesn’t move as fast with a 250-horsepower engine, as a small, sleek sports car does with the same engine.

So, the mass of the ball cancels out the light weight of the feather and they reach the ground at the same time.

Another explanation has it that the force of gravity’s pull is constant, no matter the size or weight of the falling object, so any two objects, regardless of size or weight, will hit the ground at the same time if dropped from the same height.

Even if the second one is shot some distance from where the first is dropped. They both land at the same time. Cool, huh?

Turns out, it is kind of fun to keep learning, assuming that what we learned in high school or college 50 years ago either has changed, or we didn’t have enough time to really understand it, just learn enough to pass the tests. Now, we have time.

Carol Covin, Granny-Guru

Author, Who Gets to Name Grandma? The Wisdom of Mothers and Grandmothers

http://newgrandmas.com