The Morning Text 11/02

An Educational Newsletter

GOOD MORNING!
Welcome to The Morning Text!

Someone asked me what makes me qualified to write a newsletter and talk about things in which I have no degrees. My answer is: I don’t need qualifications to write about things I think are fascinating. And I definitely don’t need to be “qualified” to share my opinion on those subjects. All I need is the desire. So if anyone wants to write and share what they have written but is too worried about not having the “qualifications,” do it anyway. You don’t need qualifications.

Good, now that that’s done. This morning text will come in two parts, part one today and part two tomorrow. 

Anyway, Lets talk about astrophysics. Specifically, gravity. Gravity is a force that is caused by the unequal distribution of matter and energy in the universe. These unequal distributions bend the spacetime continuum. In short, gravity is caused by matter and mass. Matter is something with substance, everything we can think of is made up of matter except space which is in fact void of matter. Even light, in theory, is made up of matter. Mass is the existing body of matter. All matter creates some bit of gravity. Although it may not be enough to bend the spacetime continuum like a star does, even you create gravity. 

If you don’t understand “bend spacetime continuum” don’t fret. It may be an intimidating phrase but it can be explained. Imagine a flat, undisturbed trampoline. That trampoline is space. Now let’s take a bowling ball and place it on the trampoline. Notice that this heavy object is bending the trampoline downwards. Assuming this trampoline is space, that bowling ball is bending the space time continuum. Now let’s take a baseball and place it on the same trampoline, it would immediately roll toward the bowling ball, right? That’s what gravity is like. If you imagine the bowling ball as the sun and the baseball as earth, then it all makes sense. 

But wait, why doesn’t the earth fly into the sun like the baseball does to the bowling ball. Well imagine taking that baseball and rolling it sideways across the edge of the trampoline. Notice that the baseball will roll around the bowling ball over and over again. That baseball is now orbiting the bowling ball. And the baseball would go on forever if it wasn’t for the fact that the friction between the baseball and the trampoline tarp caused the baseball to slow down. Space of course is void of matter, so there is no friction to slow the earth down. So the earth will continue orbiting the sun forever (in theory). 

Now add something to the trampoline. Take the baseball off of the trampoline, leaving only the bowling ball. Now add a marble to the story. Take the baseball and the marble and roll them onto the trampoline side by side at the same time. That marble will now orbit the baseball which is of course orbiting the bowling ball. That is like our moon orbiting the earth as the earth orbits the sun. And then the sun is orbiting our galaxy.

So now we know how gravity affects the three spacial dimensions. To complicate things further, we know of four dimensions. Unlike the first three, the fourth is not spacial. In fact, the fourth is more closely related to time (but is not technically time). So I’ll explain it with another analogy. Imagine a large white bed sheet spread over an empty area (a few feet of air below it). Now imagine a ladybug is trying to crawl from one side to the other. The side from which the insect is crawling we are calling point A, and the other side is point B. It may take the ladybug 20 minutes to cross the sheet. So let’s go grab our bowling ball and place is in the middle of this big sheet. Now instead of holding the sheet tightly by the corners, let it bend. With the bowling ball in the middle of the sheet, the two ends of the sheet will come together and touch. This would enable the ladybug to crawl from one end of the sheet to the other end in just a few steps. That is how gravity affects time. It been the space time continuum shortening the distance between point A and point B. Also, a lighter ball (lighter source of gravity) would cause less of a bend in the sheet (spacetime continuum). This of course is a two dimensional analogy of a fourth dimension. In reality, gravity having effect in all four dimensions of space, we would see that the closer you are to gravity, the slower time moves. Our watches will even tick just a little slower when we go up in the elevator!

Tomorrow’s will be about a concept that has boggled the minds of astrophysicists since the 1930’s.

Challenge of the Day: Choose a planet in the solar system and look up how heavy you would be on that planet. For instance, my favorite planet is Mars and I would weigh 52.7 lbs on the surface. I’ll provide a link to a calculator for the challenge below

That’s it for today! Please don’t hesitate to provide feedback so that I can better cater to your interests. If you believe you have received this message in error and no longer wish to receive them, please notify me. If you would like to view previous Morning Texts please visit themorningtext.com 

Have a wonderful day.

Written by Caleb Gibbons

Sources:

https://www.exploratorium.edu/ronh/weight/

http://physicsbuzz.physicscentral.com/2010/09/time-moves-faster-upstairs.html?m=1

Where Does Gravity Come From?

1 thought on “The Morning Text 11/02”

  1. Your trampoline example got me distracted thinking about scale. Here’s what I found out: if the sun was a bowling ball, the earth would be something like a piece of #10 shot. (Imagine a grain of rice trimmed down until it is a sphere.) The moon would be a grain of sand, on the course side. The earth and the moon would be a little over two inches apart, and their orbit would be on the edge of a trampoline that fills up about half of a football field.
    Also, if you put your bowling ball and baseball in space, with the same distance between them (assuming the baseball is close to the edge of the trampoline) it would take the baseball about six days to complete a stable orbit.

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