Which moon? Earth's moon -- the one that is fairly prominent in the sky.

I'll agree that the fastest baseball ever pitched was something like 46 meters per second. But that's on EARTH.

Throwing a baseball on Earth runs into a number of problems, most notably the air resistance and relatively high gravity.

Now, the fact points out that if the that baseball pitcher would then pitch on the moon, that they would not encounter such encumberances to their throwing. So, without air resistance, and with only 1/6th the gravity, if a professional pitcher were to thow the ball at an appropriate angle (I think 36 degrees from the horizon was calculated to be the best, not 45 degrees, due to the arrangement of muscles in a human arm), then there would be enough force to get the baseball into orbit.

Just based on the gravity calculation alone, if one can throw 46 mps on Earth, then at 1/6th the gravity, one could throw at a rate of the square of the relative gravity faster. Namely, 46 mps * 6², which works out to be 1656 mps. And then throw in the lack of air resistance, and that's probably at least another factor of 2, bringing us up to 3312 mps, which is far more than the 1000 mps that you state as a requirement for orbital velocity.

But of course, no one has actually tried this on the moon, so I'm not saying that it can actually happen. But they did calculate it and say that it was possible. And these are the same scientists at NASA who can get a rover safely onto Mars after a journey of about 150 million miles.

Maybe it's you who should provide the source for saying that the fact isn't true? After all, who should we believe, you or those NASA scientists? (I know who I'd put my money on...)

I guess we'll have to just agree to disagree, then.

I've seen this assertion a number of times over the years. Most recently from Chris McKay from NASA Ames (he's a great guy; I've seen him talk a bunch of times) at a talk about robotic retrieval of lunar samples and how to get them back to Earth.

And as to your statement that "initial speed doesn't depend on gravitational force", it most certainly does in this example. Imagine throwing a baseball on Earth -- easy. Now imagine if you were in an extremely high gravitational field, such as on Jupiter or something -- you wouldn't even be able to pick up the baseball, and thus, the initial speed would be 0.

But what was wrong with my calculations? I showed them in the previous post, and I think I came up with a pretty good estimate which was 3 times the velocity that is needed. I think that my formula just falls our from your formula for relative gravitational fields.

And while I couldn't get a NASA source on this, I did a quick Google search, and it seems that the general consensus is that the golf ball that was hit by one of the moon astronauts did actually go into orbit. So why is it that you'll believe it for a golf ball but not a baseball? Is it that you're an empiracist and you don't believe it until you see it? Or are you denying the golf ball as well?

Oh well. I'm spent...

To start with, I'd like to say that I have nothing but the utmost respect for cadet, as I have read many of his posts and find them to be extremely well worded and the math to be of the highest quality. That said there are some things which I’d like to point out.
First, a baseball has the same mass no matter where in the universe you are. 100 grams on earth is 100 grams on the moon (I’m sure this is something that does not need to be pointed out to you). The same amount of work is needed to be done on the ball in order for it to reach a certain velocity. The kinetic energy of the ball will be the same at a specific velocity no matter what planet it is on. So in effect, throwing a baseball on the earth has very similar kinetics as throwing a baseball on the moon.
But not exactly the same. Everyone in this discussion has been making this problem much simpler than it really is and ignoring many aspects. First, a pitchers arm moves in a circular path as it throws a ball, so as the pitcher throws it, he is also lifting it away from the surface of the moon. So, less energy is going into increasing the balls gravitational potential energy, and more energy is going into the kinetic energy. This would increase the maximum velocity. There is also the lack of an atmosphere, which also makes it easier to throw the ball. There are also many other factors to consider, like a human muscle can only physically contract at maximum rate, and the large amount of power that it would take to get a ball to move that fast.
Here are some quick numbers. Assuming that a typical baseball averages 142 grams, and that the ball needs 1000m/s in order to reach orbit, the ball needs 71 KJ of energy. Now, assuming that the pitcher’s throwing motion is roughly 2.5meters (I’m stretching it here, but I’m just trying to make a point) and the pitcher’s force on the ball is roughly constant through out the delivery, the pitcher needs to exert a constant force of 28400 Newtons. A power of 14.2 mega watts (19306 metric Hp) would be needed to launch a baseball 1000m/s in 2.5 meters at constant acceleration.
I don’t know if this is possible, but I’m sure going to believe NASA engineers over anything that I can compute on my own. There are so many factors that come into play here, and others that other people brought up that really don’t matter as much.
That’s my two bits anyways.

T-shirt,

not true actually. Work done = Force x distance, and while the masses may be the same, their weights arent.

This question is not high school math either (atleast not american high school it isnt). I do not care to spout numbers right now, but my guess is that a pitcher would be mentally deficient in working out the exact angle and velocity he needed to throw the ball to get it in orbit.

plus a pitcher would not be able to throw a ball as fast as he could on earth. why? because hes wearing a freakin space suit.

edit:
it appears the lad above me just made the same point.

Well, I would not be so arrogant as to assume that. On the other hand, just because they are older scientists than I does not mean that they will necessarily always be right. Being from NASA does not help your cause.

I'm not going to pass judgement on their calculations because they are most probably correct. However, I do think that they neglected some lateral thinking when they made that 'statement', as I have said. First, the pitcher is wearing a space suit, and secondly he needs to be extremely accurate in his pitch (both in terms of speed and direction).

Yes, that is a suspiciously round number...

Target, I'd like to know how you calculated the escape velocity of the moon? Wikipedia states earth's escape velocity is 11.2 km/sec. I trust this article. The moon has 1/6th the radius, so we divide by 36 (radius squared) to arrive at 311 m/sec = escape velocity on the moon.

on a sidenote, how fast and far would you need to throw a kitten on the moon to get it into orbit?

now think about that one for a while.

What kind of spacesuit would be needed to allow a kitten to live on the moon, not to mention have the mobility to throw a baseball. And ofcourse that a kitten has no thumbs to grip the baseball to throw it anyway.

Okay, zguess. A (an) opossum, permanently juxtaposed with a buttered slice of bread. Opossae have opposable thumbs, and they're akin to cats.

leggie, remember equal and opposing forces! the kitten has nothing to prevent momentum changes relative to the moon while in mid-air.

Posted By: cadet

I'm sorry Target, but your calculations are just way off target... As a physics major at a leading american university i can say that Taed's calculations (which I helped him derive using calculus) are 100% true.

And besides that, his logic is also much more correct than yours. Gravity will affect a pitcher no matter how you slice the problem. Are you saying that you couldnt throw a 100 gram rock faster than a 600 gram rock? Because if you are, then you must be weak like a kitten. Even kittens, if on the moon, would be able to throw a baseball and would be even cuter.

And by all of these pieces of evidence we can deduce that Taed's calculations and logic are far superior to yours. I think you may want to do some more extensive research on the subject.

What is up with this strange obsession about kittens throwing baseballs, I've seen it in other threads. It's quite odd and physically impossible!

I love that theory where if you put a piece of buttered toast on a cat's back and drop it from a height, it will start spinning around endlessly because cats always land on their feet and toast always lands buttered side up

But seriously. Baseball on the moon, people.

Sorry, I don't have that memorized. You're probably right, since you have an idea about it. It's on some other thread..

After watching the Detroit Tigers play tonight, I would have to say that Joel Zumaya could potentially get the hypothetical ball into orbit, even with a buttered kitten tied to it.

I just have to say it, because I've been waiting for the perfect opportunity to use this smilie - the Tigers totally the Yankees today!

yeah, the 1000 figure is escape velocity, not orbital velocity. also, i think he fergot to take into account the odd orbiting habits of the moon. the precesion of the earth moon orbiting pair has a heavy effect on anything orbiting the moon. basically, the earths gravitaitonal pull adds velocity to anything in orbit around the moon, a lot like a hula hooper bumping the hoop with their hip for some extra speed.

Posted By: MrFingers

hahahaha, wow. just wow. talk about an inferiority complex!

Why do you say that? I'm sorry - we Michiganders are awfully excited about our baseball team right now. Actually, it was really cool - I won tickets on the radio to go to Saturday's game where we kicked Yankee butt and took names! It was great!!

OOPS!!

Sorry - I thought that since you live in New York, maybe you were a Yankees fan.

Hmm... I suspect the fuse might ignite but a match would not, due to the oxygen vacuum.

not to barge in but i was wondering does a baseball have air inside it or is it solid? because air would probably make the baseball very big on the moon with no presure and all, so the bat would probably blow it :) also i'm curious what would happen to the pitcher after a swing like that how fast would he turn around and around and how long would it take for him to stop?

A baseball is completely solid, its center looks like string balled up and covered in glue (my dogs chew stuff). And to answer how fast he would have to be going, the ball would have to travel 385000 km and would have to maintain at least a speed of 9.8 meters per second. Which means, at the slowest, it would take almost 11 hours for the baseball to reach the moon. So the batter would have to swing the bat at least 26657 mph, and would spin for about 15 minutes. As for the pitcher he would probably just watch in amazement.

Dear "My Dad Is A Professor":

This is science. You can't argue science.

Love and kisses,
"My Dad Can Out-Profess Your Dad"

The idea that one could throw a baseball into orbit strains credulity. One of the people said that because of the differences on the moon, one could infact throw a ball 1,000 m/s, and it was claimed that was the escape velocity, or velocity necessary to get it into orbit. I asked my dad, he said getting into orbit is 1/Squareroot(2) compared to the escape velocity. It is an extraordinary claim, that because of 1/6 gravity, the muscles (actin + Myosin) could cause that kind of contraction. The question is, what kind of force is the arm capable of giving to the ball in kinetic energy, and what kind of velocity that would create on the moon. Then the question is, what kind of velocity would cause it to not come back down to the surface, but stay in orbit.

Taed says that
'Just based on the gravity calculation alone, if one can throw 46 mps on Earth, then at 1/6th the gravity, one could throw at a rate of the square of the relative gravity faster. Namely, 46 mps * 62, which works out to be 1656 mps. And then throw in the lack of air resistance, and that's probably at least another factor of 2, bringing us up to 3312 mps, which is far more than the 1000 mps that you state as a requirement for orbital velocity.'.

He's essentially saying that a human can throw a ball on the moon 3,312 meters/second. That is faster then the fastest fighter jets. Muscles (based on the contraction of actin-myosin fibrils) are able to give a certain force in the form of muscle contraction, which is what causes the arm to move, and propel the ball. So the Force that they give, is not going to change. Because what is giving it the force is the same. Gravity accelerates downward on Earth 9.8 m/s^2. And 1.66 m/s^2 on the moon. When the arm is fighting gravity, when the pitcher's arm is going upward, that means that there is 1/6 the Newtons on arm, meaning conceivably, it might be able to accelerate faster on the upward portion, possibly 6 times as fast (which is overlooking that the body might not allow that kind of motion). Then lets add no air resistance, even faster. Taed says that the difference in velocity would be 6^2. But Force in Newtons is the amount needed to accelerate 1 kilogram 1m/s^2. Since the mass of the arm and ball on the Earth and moon is the same, what has changed do to gravity is the acceleration by a factor of 6. Which means the force needed to cause the same acceleration on the arm and ball only in the upward direction is 1/6 as much. Since the Force should be the same, the acceleration could conceivably be 6 times as great. A great throw, 90 MPH, *(1600/3600) would be roughly 30 mps. If he can muster 6 times the velocity on the moon, he could throw 180 mps. I don't believe it would make that much difference.

Escape velocity on moon:
http://www.idialstars.com/evmc.htm

Here's one place that discusses it's methods. It says 1.47 miles/second. That would be over 2 kilometers/second. Or over 2,000 meters/ second. Arm can potentially throw 180 mps (very generously) on the moon. Escape velocity is 2,000 mps. Getting into orbit Escape Velocity/ Squareroot(2) is still greater then 1,000 mps. Still far short. i.e. it is impossible for a human to throw a ball into orbit on the moon.

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