Why is there only an up and down on Earth and not out in space? 

There’s no gravity in space. On a planet like ours, down is always toward the center of gravity.  Up is always the opposite of the center of gravity. Drop a ball, it goes down. Up is the opposite.

In space if you let go of a ball it stays where you let go of it (as long as you weren’t moving your hand, that is.)

Your personal sense of up and down is caused by your inner ear. In space, however, sometimes people feel sick because it feels like they’re falling all the time (and in fact, when in orbit you are falling all the time).

Lose weight with less gravity!

You weigh less on the Equator than at the South Pole.

I saw a show once about a science researcher that traveled the globe with a small scale and an ordinary garden gnome, you know, like the one on Travelocity TV commercials.

At one point he weighed the gnome at the south pole and it weighed 309.82 grams. At the equator the gnome weighed 307.86 grams. The gnome was 0.6% lighter at the equator, which is further from the center of the earth’s core than the south pole.

The further you go from the core of the earth, the less gravity you experience. So if you want to lose weight without dieting or exercise, go to the equator!

Here’s the scientist himself weighing the gnome.

What percentage of the earth’s water is tied up in the atmosphere (clouds)?

Great question and I don’t know. But this graphic will help us understand together:

Here you can see that there’s not much water on Earth. Basically the earth has high and low areas. The low areas have water. To us the oceans seem deep – 7 miles, maybe more, but overall, compared to the size of the planet, it’s really not much water. We can also see from the image above that we really don’t have a lot of air.

That being said, common sense tells us that not all the water is in the atmosphere. Only some, otherwise we’d have no lakes, rivers or ocean! So I’m going to guess – that’s scientifically called an educated guess, not a large percentage of Earth’s water is tied up in the atmosphere.

Now we could research this more with some Google searches, but my answer is just about common sense. I don’t think that much of our total water is in our atmosphere. There’s some, but we still need some left over to fill the lakes, rivers and oceans too.


How Big does a Moon Have to Be?

Not very big! It would just have to be natural. Not made by man! And it wouldn’t have to be there for very long either. Just long enough for it to be in orbit.

The astronomical community doesn’t have a definition for moon other than it has to be a natural object. Thus captured asteroids can be moons. It’s even possible for a moon to have a moon!

Mars has two moons, neither of which are large enough to be round. Objects in space get round due to their own gravity. The first image above is Deimos and the second is Phobos, the Martian Moons. Deimos (top) is the smallest. It has a mean radius of 3.9 miles.

What’s the real reason we haven’t sent someone to Mars yet?

A question people ask.

We really want to send somebody to Mars. Why?

The answer to the question is that it’s a long way away, it moves all the time (sometimes it’s a very long way away on the other side of the sun), it’s expensive, it’s very dangerous, it’s a dead planet, there’s nothing humans can do there that our less expensive rovers can’t do, we can’t breathe the air, we can’t grow anything there, there’s no legitimate scientific reason to go and last but not least nobody would fund it, especially Congress.

Solution to Joe Drops the Ball

In two previous blog posts about Newton’s Cannon and Joe Drops the Ball I posed the question: If falling objects go faster and faster, why don’t orbiting objects fall out of orbit and crash to the ground?

The question is legitimate and also has a perfectly legitimate explanation.

The rate of a falling object is 32.2 feet per second per second, i.e. it goes faster and faster as it goes down. It accelerates on the way to the ground. So the first question is this: 1) Is an object in orbit in free fall? The answer is yes. 2) Do falling objects accelerate as they fall to the ground? The answer is yes. 3) Do orbiting objects accelerate and thus fall to the ground? The answer is no.

It’s all in the definition of accelerate. Acceleration is a change in velocity not just a change in speed. Velocity is the speed in a given direction, but because an object in orbit is always changing direction it is technically accelerating even if it’s speed isn’t changing.JoeDropsBall5

The force of gravity bending the forward motion of the orbiting object changes the direction of the object. The object is accelerating even if it’s speed isn’t changing, because it is constantly changing direction.

This is alternatively explained in the article I wrote called The Little Rocket that Was.

Joe Drops the Ball

Because of Joe’s ball, the Earth may fall into the sun and the moon may fall from the sky.

Meet Joe. Joe has a ball, and his ball is a great problem for the whole world.

Because of Joe’s ball, the Earth may fall into the sun and the moon may fall from the sky. That’s a big problem for a small ball in Joe’s hand.

Joe tosses his ball to the side
Joe tosses the ball

The problem is that Joe drops his ball and then tosses it to the side (see illustration at right).

You see, when Joe drops his ball it accelerates at a spectacular rate of 32.2 feet per second per second.

Joe’s ball, as does any falling object, doesn’t just drop. It drops faster and faster, whether he just drops it, or tosses it to the side! If he tosses it to the side, it will hit the ground at the same time as if he just dropped it. The forward movement of the ball doesn’t slow down the downward acceleration of the ball toward the ground. (We are assuming here, that there’s no wind or air to slow it down, okay? Just leave that out for now.)JoeDropsBall3

Now, Let’s say Joe has a bullet in his hand and drops his bullet. Like the ball, the bullet’s gonna fall to the ground at the same rate the ball did.

Let’s next give Joe a gun, and have him shoot the bullet. The bullet is going forward, just like the ball that Joe tossed. But the forward movement of the bullet from the gun barrel doesn’t slow the downward acceleration of the bullet as it falls to the ground. It just falls to the ground a ways off because the bullet was going fast.JoeDropsBall4

Finally, Sir Isaac Newton shoots a cannon. And his cannon is very powerful. The cannonball goes so fast, so far, that as it falls to the ground, the ground curves away underneath it, and it goes around the world in an orbit.

JoeDropsBall5But why? Both the ball and the bullet fall to the ground at 32.2 feet per second per second. They accelerate toward the ground, but Isaac Newton’s cannonball doesn’t. Satellites stay in orbit, the moon stays in orbit, the Earth stays in orbit, and they don’t accelerate toward the ground. How come?