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dstebbins

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Posts posted by dstebbins

  1. probably not.

    a quark perhaps?

    it has the advantage of existing over a very small portion of the force gradient.

     

    Okay, would you care to explain your mathematical logic here? In order for an object to escape the event horizon of a black hole, it has to move faster than the speed of light, which, according to Einstein, is impossible, and has yet to be disproven. We've detected high-velocity particles at damn-near the speed of light, but not equivalent to it, and certainly not greater than it. Therefore, your theory that an object with enough kinetic energy can escape the event horizon of a black hole is not only practically impossible, but theoretically impossible as well, since theoretical physics dictates that it is impossible to go faster than light.

  2. Express "tons and tons" (actually ~4e9 kg) as a fraction of 10^30 kg and you'll see.

     

    Done. I know see that, if the time the measurement was taken were placed at zero years, with all time beforehand being negative years, the sun would burn out in the year 2.19 x 10^25.

     

    But then why do we say the Sun only has a few billion years to go?

  3. Now I see. The radius of the earth was just an estimate.

     

    One last question (for the time being, at least): On that Wikipedia page, it says that the mass of the sun, aka the "solar mass," is 1.9891 x 10^30 kg, but how can they be so sure? The sun forces tons and tons of Hydrogen to undergo nuclear fusion every second, meaning it's mass is constantly decreasing. How can they give such a precise measurement for a star?

  4. Is ALL of the mass 1 m away?

     

    An application of Gauss's law shows that for a uniform mass distribution, you can treat all the mass as if it were at the center-of-mass location, for r > R (i.e. all mass "below" you behaves as if it were at the center of the sphere)

     

    I'm aware of that. Don't you know that 100% of Newtonian physics is based on the assumption that the conditions are ideal? For example, when we say that the free-fall acceleration due to gravity is 9.8m/s/s, that's assuming (emphasis on that last word) that A) The object is EXACTLY at sea level, B) the portion of the earth directly beneath you is the same size and density as the average size and density of earth, and C) the object is accelerating in a vacuum, so air resistance can be ignored. Therefore, it is safe to assume that the person is the same density throughout, the earth is the same density throughout, and so on. Yes, 1m is not right at sea level, but the difference that one meter makes is negligible in the equation.

     

    EDIT: Nevermind. I now see what you're saying. Let me rework my calculations.

     

    According to ask.com, the radius of the earth is about 4000mi. That's approximately 6667km, or 6.667*10^6m. Square that, you get 4.445*10^13 m^2. Since the weight of a 100.0kg object is 980N, that means that means that the numerator in this equation is equal to 4.356*10^16. The denominator stays the same at 6.674*10^-9, so compute that, and I get 6.527*10^24, and it STILL comes out wrong! WTF?

  5. Okay, let's put this theory of universal gravitation to the test. My hypothesis (since we are, technically, scientists) is that the mass of the earth will be an unimaginatively large number of kilograms.

     

    A 100.0kg person standing 1.000m above sea level on Earth weighs approximately 980.0N. By that logic, the mass of the earth should be equal to M in M=(d^2F)/(Gm) where d=distance between the objects, F equals force applied by one object on the other object, G is the gravitational constant, and m is the mass of the person. Therefore, plug amounts into the proper places, and you get (1.000^2 x 980.0)/(6.674*10^-11 x 100.0), or M= (980.0)/(6.674 x 10^-9). This means that the mass of the earth equals approximately 1.468 x 10^11. So my hypothesis was kind of right and kind of wrong, since 1.468 x 10^11 is not a very small number, but isn't a very large number either.

     

    Does that sound right to you guys?

     

    Edit: Don't answer that. I looked it up on ask.com, and I found here that the mass of the earth is 5.97 * 10^24 kilograms. What gives with this? Where did I go wrong?

  6. Just to say (yes I know this is going WILDLY off topic) that I've spoken to Athiest quite a lot, and I would not read it sarcastically at all.

     

    In that case, I apologize. I just hate it to the bone when someone thinks I'm stupid just because I don't know how to change a u-joint on a car or suchlike. It's not a fact that I'm stupid; it's the fact that I've never been taught.

  7. I looked it up: The value on Wikipedia is pretty much correct; the 1.667 is wrong (I misread Klaynos' post and took the "1." as part of the value). Since you´re obviously not a stupid bimbo, you should be able to figure out all the rest yourself.

     

    I swear, I used to have respect for you, but if that last comment is meant sarcastically, you can kiss my hairy caucasion ass.

  8. I don´t know many high school students such as yourself (I don´t even know what "high school" is) but there you go: [math] G= 0.00000000001667 \frac{N m^2}{kg^2} [/math] (value copied from Klaynos' post without verification).

     

    High school means grades 9-12. Where are you from? Africa?

     

    So what you're saying is that the constant is (5/3)*10^-11 J^2/kg^2. Is that it?

     

    EDIT: Hold the phone. That link that Klaynos gave me suggests that the constant isn't what you claim. Wtf?

  9. I shall provide a link because it goes into far more depth than I can possibly do:

     

    http://en.wikipedia.org/wiki/Gravitational_constant

    Thanks. I'll check it out when I have more than five minutes.

     

     

    1. 6.67*10^-11m^3kg-1s-2 (Nm^2kg^-2)

    Can you put that in a number and unit combo that a high school student like myself can understand?

     

    2. I can't remember the derivation offhand, any good low level university text book should have one in it... If I remember tomorrow I shall have a look.

    Thanks for that. Science like this drives me nuts.

     

    3. The GR theory of gravity is used more than the newtonian one, which also uses the constant. But the way it works is you put the experimental evidence into some equations and the results of these says that there should be a very large mass at the centre of the galaxy, on investigation and other evidence it is surmissed that this mass must be in the form of a blackhole.

    That's not exactly what I'm talking about. What's their mathematical reasoning? Suppose I was a science professor grading these scientists' exams. If they were to show all their work, what would it look like?

  10. My high school physics teacher says that, when Newton invented the laws of universal gravitation, he devised a constant to be implemented when considering the gravitational relationship between two spacial bodies. According to my teacher, it was using this constant that was used to "find" the supermassive black hole in the center of the galaxy (by studying the behavior of the stars around it). He says that this constant's unit is kg^2/m^2 (kilgrams squared per meters squared); however, that's as far as his knowledge goes. He remembers virtually nothing about this constant, not even the numerical value of it, so I'm turning to you guys.

     

    1. What is the numerical value of this constant? Is it in decimal form or fraction form?

     

    2. How did Newton come up with this constant? What was his mathematical reasoning?

     

    3. How is this constant utilized in things like the discovery of a supermassive black hole?

     

    Thanks ahead of time.

  11. I saw the same show, and I don't remember them talking about any such equation for theory of everything. What they did talk about was whether or not it was even possible, and the many issues regarding the Hawking Paradox, such as the destruction of information. I think the equation you saw was the equation for the Hawking radiation emitted from a black hole.

     

    That wasn't the only place I heard it. I was also watching the Weakest Link on GSN and one of the questions was "What wheelchair-bound physicist wrote the London Times Best Selling book 'The Theory of Everything?'" The answer was, indeed Stephen Hawking.

  12. I heard this on the science channel, on a documantary called the "Hawking Paradox." This was a side note from the main point of the documentary, and it stated that Hawking had developed a single, elegant theory that summed up everythin in our universe. To do this, he took bits and pieces of other famous equations, such as e=mc^2, and simplified where units cancled, and the equation that he developed when he finished was so simple that you could count the number of variables on one hand.

  13. I heard somewhere that Stephen Hawking had developed a theory of everything, and then wrote a book about it. The thing that seperated this theory from all the other "theories of everything" is that it is literally so simple that a high school student can memorize and compute it with a cheap, one dollar calculator in a matter of minutes.

     

    Personally, I have to see this to believe it. Can anyone give me a link. Wikipedia was no luck to me.

  14. I apologize if I made you feel that way, I was just making a point so that it doesn't confuse anybody.

     

    Personally, I think the hawking paradox could be an alternative to dark matter. Supposedly, there is not as much matter and energy in the universe as there was immediantly after the Big Bang, so scientists proposed dark matter and dark energy, or matter and energy that can't be detected with the five senses, to explain this. Personally, I think that's BS, simply because there's no way to prove it. Scientific truth is greatly, if not completely dictated by observation, which cannot take place without the senses, so by proposing dark matter, you're proposing something that cannot be proven.

     

    Alternatively, the Hawking Paradox could explain why this lack of matter and energy exists. I don't propose that, when something enters a black hole, it disappears, but travels to another universe, parallel to our own. It has long been theorized that an infinite amount of such universes exist, making up the multiverse, so why not? Black holes are also a source of expelsion as well as suction, because when matter from another universe enters a black hole, out of sheer chance, it enters our universe in the form of hawking radiation, which used to be matter, but underwent nuclear fusion due to the black hole's gravity.

     

    I know, it all probably sounds completely bogus, but I still have yet to get to college. I'm pretty sure I'll learn enough to come up with a legitemate theory then.

  15. The "Hawking Paradox" refers to the apparent destruction of information when it falls into a black hole. The idea behind it is that since light cannot escape a black hole, any information about what falls into it, or the shape of the body itself, is lost. However, since black holes evaporate over time, there has been a debate about whether the information would leak out with it, or if it would be destroyed all together. It is called a paradox because the destruction or loss of that information violates one of the fundamental principles of science, that information cannot be destroyed.

     

    Uh, dude, here's a crazy thought: If you're gonna start accusing me of crap, at least get your facts straight.

     

    I know what the Hawking Paradox was about. What do you think I am? A child? The point of a free-fall was made only as a side topic, completely digressing the main point of the show, but it was there.

  16. Do you have any sources for that? I'm pretty interested in the subject and I've just been reading A brief history of time, so far what I've read contradicts your post.

     

    My source is a Science Channel documentary called "The Hawking Paradox." If anyone would like to vouch for me, that would be great.

  17. If the only force on this object is gravity (since it is in a vacuum, I assume that you wanted to neglect all drag), you have to remember gravity is a force that pulls on all objects to the center of mass. If we assume that the only two obejcts in existance are this object and the earth, yes, the earth's gravity pulls on the object, but the object's gravity also pulls on the earth. It is just that the force of gravity, which is small, does not move a large mass like the earth very far at all. Like 10^-20 or 10^-30 m.

     

    But, the force of gravity is equal in both directions.

     

    and p.s. your signature at the moment is very obnoxious.

     

    but that doesn't make sense to me, and I'll explain why.

     

    I understand that the object is pulling on the earth, but by that logic, five pounds in one direction and five pounds in another direction should cancel each other out, and there should be a net force of zero, meaning no acceleration, but the object does accelerate at 9.8m/s/s, so the net force isn't zero.

     

    I don't know how to explain my confusion any more clearly. And btw, how exactly should I phrase what my sig is saying and still get my point accross?

  18. Ordinarily I'd beat drochaid over the head for that comment, but it makes the point so well...

     

    The advantage of forums is that you can respond to posts whenever you want. This isn't a chatroom or, God forbid, an actual meeting of people, so you're not obligated to respond to everybody. Please remove your obnoxious signature.

     

    it's not just that. When twenty people respond, each with their own way of explaining my inquiry, it's a really hard time to figure out what the similarities are between them and who's right with the differences.

  19. Newton's 3rd law of motion states that for every force, there is a force equal in magnitude and opposite in direction. For example, when a five pound book lays on a desk, it exerts five pounds downward on the desk. At the same time, the desk pushes upward on the book five pounds.

     

    But what about when the net force is not zero? For example, a free-falling object in a vacuum. Where is the equal and opposite force there?

  20. Have you looked up the term "gravitational field"? Since I seem to be a bit lonely with my view that the term "gravity" does not mean "gravitational force", let me briefly present what I consider gravity:

     

    Gravity is the concept that explains the observed attraction between massive bodies (the gravitational interaction).

     

    Clasically, theories of interactions consist of two parts:

    - The field equation that defines the field (the gravitational field, here) as a function of its sources (mass, here) - and describes its dynamics, but that´s not important, here.

    - The part that defines the influence of the field on other particles. This part comes as an additional term to the equation of motion of those particles. In Newtonian Gravity, this additional leads to the equation of motion of a particle to alter from [math] a=0 [/math] to [math] a = \frac{m}{m} g [/math], where g is the gravitational field (I´ve explicitely written m/m as a hint on the problem with massless particles, which cannot be described with Newtonian physics, anyways).

     

    So now back to your original post: Whether the term gravity really is defined as the gravitational force or not seems pure semantics to me. What you seem to be bothered about is why the gravity of earth (whatever that is) is not constant but depends on the object it acts on (if it is the gravitational force). My point is quite simple: There is an object (a concept) associated to gravitational interaction, the gravitational field, that has exactly the property you are missing in the gravitational force: It only depends on the source, not on the object it acts on.

     

    quick question:

     

     

    Wtf?

  21. According to Stephen Hawking, the only reason we consider the possibility of "spegetification," or however it's spelled, is because that's what it would look like to the outsiders because spacetime is distorted to our vision. According to Hawking, if a satient person were to actually enter a black hole, they would experience a common free-fall; nothing more, nothing less. Their body would appear to be spread out over the black hole only because Einstein's Theory of Gravitational Distortion suggests that large quantities of gravity have the potential to distort spacetime, which explains why light heads for a black hole even though it has no mass and thus is unaffected by gravity (it's following a straight path, but the path is distorted by the black hole, causing what appears to be a change in direction).

     

    Hopefully, I'll learn more about this in college in the coming months. Until then, idk.

  22. Hey hey hey hey HEY! One at a time, folks. I can't talk to everyone at once. What do you think I am, a computer?

     

    Anyway, when I say "constant force," I mean suppose the earth's gravity was a force of 2.00 x 10^20 N (I came up with that number out of the blue. It's so large because I imagine the earth would have a large force). That means that an object with a mass of 1.00kg would accelerate to the earth at a rate of 2.00 x 10^20 m/s/s. Likewise, if an object had a mass of 2.00kg, it would accelerate in free fall at a rate of 1.00 x 10^20 m/s/s. It's called inverse proportionality. If c is a constant, then c=xy, or in this case, f=ma. The force formula is just an example of inverse proportionality with different variables. F is constant, so if mass goes up, acceleration must go down.

     

    But that's not the case. The acceleration is constant, so gravity is more like a=fm. That's not the equation for force, so can gravity really be considered a force at all?

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