Another question on Gravity

[Zachary Smith]

Relax, I'm not accusing you of anything, it was more of a compliment really. I considered myself a very smart person until I started seeing some of the things being posted here.

One need not necessarily have any great facility with mathematics to be "smart". I'm miserable with equations--don't even bother to look at them actually--but I think I'm not half bad with concepts.

 

[Shaw]

I considered myself a very smart person until I started seeing some of the things being posted here.

Well that is almost worse!

If your feelings are indicative, I really failed in what I was hoping for. The last thing you want in a topic like this is people questioning themselves in that way. The topic should be inclusive.

Think about it, Zachary Smith has actually put forward some of the best thought provoking ideas and he flatly admitted to not understanding the math. I didn't want the math to act like a barrier to entry in the discussion, just an alternate idea to the normal analogies that are used.

I wasn't actually thinking that the equations should be deeply understood by everyone, what I was hoping would be noticeable was their similarities to each other (sort of like different shades of the same color). Even seen as just a bunch of squigglies, I was hoping that the similarity in their structures was conveying how they are all related to one another.

I can see now that I underestimated the impact of equations popping up in the middle of a thread. And like I said, I really hope that no one saw them and turned away from the discussion as that was not my intent.

 

[Jadzia]

if one were to somehow build a tower somewhere along the equator, a VERY tall tower with a room at the top, what altitude--if ANY--would there be a "zero-G effect" in the room?

The point of equilibrium is at the geostationary altitude. Below it you'll be on the floor and above it you'll be on the ceiling.

Yes, the earths spin creates a centrifugal force, that counters gravity to some extent. The faster the spin the more it counters gravity. The further up the tower you go, the more it counters gravity (and additionally the weaker gravity becomes). If the earth spun fast enough, things on the equator would be thrown into orbit. The Earth's bulbous shape has an effect on local gravity too.

Similarly, on top of a mountain, the centrifugal forces are higher than at sea level, so up there you weigh less. The difference is about 1 part in 200. (1 pound in 200 pounds)


If scientific weighing scales are ever made abroad, they have to be recalibrated when they arrive at their destination because of the gravitational and centrifugal changes. Some manufactuers make these changes themselves if they know where the scales will end up. It is called latitude correction.

So if you buy bathroom scales made in Taiwan, intended for general export and you happen to live in Norway, the scales would tell you that you were heavier than you really were.

External reading

Also, this is why space shuttle launch pads are as close to the equator as possible. The Earth's spin and reduced gravity makes it a little easier to launch into orbit, because the rotational velocity on earth becomes part of the rocket's orbital velocity once it's up there. So less rocket fuel is needed, which means less weight to carry on the rocket, which means less fuel is needed.

 

[TerriO]

#4:

LOL! You seem to be either:

1. Showing off, or

2. Demonstrating that even smart people can be surprisingly dumb. How dumb do you have to be to fail to explain your terms clearly to your audience? Hawking understands that blinding his audience with equations is mere obfuscation or technobabble, that without explanation, it fails to illuminate.

Based on the amount of effort you've expended with Photoshop to make a pretty presentation, I vote for #1.

I vote for #3. People actually being willing to admit there are people in this forum more intelligent or more experienced with a field than they are, and attempting to participate in an intellectual discussion instead of mocking other posters for their efforts to actually educate someone on a topic instead of just appealing to the lowest common denominator. I've received more than a few PMs from people I'd consider our "brain trust" posters that are concerning me and I apologize profusely to them for not addressing the issue sooner. RL got in the way in a manner that I never could have anticipated.

This isn't a forum where you're naturally going to be spoken down to. I hate that when it's done to me, and I don't want anyone here feeling as though they're being spoken down to, either. If you want something in layman's terms, all you have to do is ask for it. Otherwise, how are the people you're asking questions of going to know your level of expertise? This isn't remedial chemistry/physics/electrical engineering/etc., nor should it be treated as such on a blanket level.

Yes, there are going to be people in here who talk on a level that's over other posters' heads. We've got a lot of highly-skilled people who post here. I'm grateful to all of them for taking their time to help others understand the world around us. I'd highly suggest folks learn to accept that and move on, instead of referring to these folks as "showoffs." They're not showing off, they're just talking on a level that might require some folks to work to understand them. Goddess forfend that anyone posting on a science fiction BBS might want to understand the science behind that fiction at some point.

This is a science and technology forum, folks. It's my fondest hope that we can learn from each other, not just sit here and do the old "*chuckle* *point* Geek" at people who are honestly trying to help others understand the high-concept stuff in this universe. Are there discussions that I don't get? Oh, yeah. But I have my areas of expertise, as does every other person posting here. If you don't get something, and you want to understand it, ask. This isn't high school. You're not going to get made fun of for not knowing something. I promise all of you that I'll make sure of that.

If you don't understand a point someone's trying to make, by all means, ask. Never be afraid to ask questions. There are no such things as stupid questions as long as I'm running this forum. By asking questions, we learn. And if you haven't come in here to learn, please, ask yourself what have you come in here for?