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Gravity of the Sun?

  1. May 2, 2003 #1
    I am missing something here. In old Star Trek episodes, Captain Kirk and Captain Picard were often caught in the gravitational pull of a nearby sun and had to really turn on the engines to escape this terrible force.

    Where on earth did this concept of the sun’s gravity come from?

    In case we have forgotten, the Sun is an enormous explosion. To say that it has gravity is inconsequential to the outward forces it exerts on the planets. It would seem to me that trying to measure the gravity of the Sun would be like trying to measure the gravity of an atomic bomb as it explodes. The gravitational field of the bomb casing is nothing compared to the outward force that the bomb produces.

    The Sun’s gravitational field is negligible compared to the outward (anti-gravity) forces that it exerts on the planets that travel around it.

    So, if the Sun is essentially pushing the planets out into space, how do the planets stay where they are in orbit about the Sun?

    Iron, the metal that comprises at least some portion of the core in any planet, is attracted to electricity. The primary output of the Sun is electricity! The planets stay in orbit around the Sun due to the attraction of the planets to the Sun and not the gravitational pull of the Sun!

    From time to time, you can visit the vacuum cleaner department of a major department store and see that they will have a beach ball floating in the air that is being exhausted from the vacuum. This is not proof that the vacuum cleaner is any better than any other vacuum, since it does not take a lot of air pressure to cause the beach ball to float, but it is an attention grabber to get you to notice the vacuum cleaners.

    The beach ball is affected by the gravitational pull of the earth, yet it is suspended in space by the force of the air exhausting from the vacuum. The picture this produces is exactly the same way the planets and the Sun are related. The planets are attracted to the electrical output of the Sun, yet the Sun is forcing the planets into space by the sheer force of its’ explosive power.

    A number of interesting observations can be made when viewing the relationship of the Sun to the planets in this manner.

    First of all, the collapse of the Sun will occur much sooner than previously estimated. As the force of the Sun diminishes over time, Mercury will enter the outer edges of the Sun, and, if the surface of the Sun is not hot enough to vaporize the entire planet and blast its’ element back into space, Mercury will then initiate the collapse of the Sun. If the Sun is strong enough to blast the Mercurial elements into space, then Venus may be the culprit to cause the collapse.

    Secondly, it is easy to calculate the density of a planet, thereby calculating the gravity of the planet. The surface area of a planet, in conjunction with its’ distance from the Sun can be used to determine the gravitational field of the planet. A planet with less surface area but a higher level of iron will be closer to the sun than a planet with a greater surface area and a lesser amount of iron.

    It is not reasonable to use the same formulas that are used to calculate the moon’s travel round the earth when calculating the forces that cause the planets to travel around the Sun.

    Where can I go to find more information concerning this subject?
  2. jcsd
  3. May 2, 2003 #2
  4. May 2, 2003 #3
    Yeah, what he said.

    Someone will correct me if I'm wrong, certainly...

    Gravity is related to MASS, is it not? I was always taught that gravity was a force of attraction between any two massive bodies, which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

    So, the sun has mass, doesn't it? The planets have mass, don't they? So should there not be a gravitational attraction between the massive object (sun) in the center of the solar system and the massive, but less so, objects in orbit around it (planets)?

    As far as comparing the sun to an atomic bomb, what is the mass of the explosion of an atomic weapon at it's peak? How long does that peak last? For that period of time, would the atomic weapon not have a gravitational effect on the Earth in relation to that mass?
  5. May 2, 2003 #4
    So - it appears that this is an incomprehensible topic? Something no one has considered? That is bizarre! It makes perfect sense that the Sun is pushing the planets into space.
    The Sun is a gaseous object. How much mass can there be in that?
    When I was at the planetarium in Boston, the scientist said that if one atom of iron materialized in the Sun, the Sun would collapse in seconds. Is there truth to that?
  6. May 2, 2003 #5
    1.989e30 kg, it contains over 99% of our solar systems mass.
    Last edited: May 2, 2003
  7. May 2, 2003 #6
    That, I wouldn't know.

    2 x 10^30 kg

    How did I come up with that? I didn't. I used this link as a reference.

    Incomprehensible to me, yes, but maybe I'm just dumb... If you want to go back to your atomic bomb theory, take a look at the blast area near where an atomic bomb has been detonated. Trees, phone poles, and remnants of building structures are all leaning TOWARD the epicenter of the blast, not away. Yes, the blast pushed them out, but the air rushing back after the blast dissipated pulled them back in. If the sun is pushing the planets out, as you say, then all of the other stars in the rest of the universe are pushing the planets in, and I would think that they should be able to push them into the sun or crush them where they stand (orbit, whatever).
  8. May 2, 2003 #7


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    The topic isn't incomprehensible. Your idea is simply completely wrong. But what is incomprehensible is where the idea came from.
    You must have misunderstood.
  9. May 2, 2003 #8
    You can't simply say my idea is wrong! That is analogous to ad hominem arguing! I need you to prove me wrong! I want to know why it is wrong! Just because you were taught that the Sun has this tremendous gravity doesn't mean that it is right! It may be tremendous gravity, but, the explosive force far outwheighs the gravity!
    So what if the atomic bomb analogy isn't exactly right. There are different factors at work in space. The force from the Sun is constant, whereas, a bomb produces high pressure and low pressure events.
  10. May 2, 2003 #9


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    Ok, consider this for a moment - where does most of the destructive power of a nuclear bomb come from?

    Radiation? No.
    Heat? No.

    The power of the nuclear bomb comes from the shockwave it creates in the air when it explodes. This shockwave travels at the speed of sound, and that is what pushes apart buildings, flattens people against walls and other morbid things like that. Without the air to transmit the force, the only way bombs kill would be to incinerate you, or irradiate you.

    Now let's look at the sun. Space has no air. Hence, it is impossible for the reaction that is the sun to generate a shockwave. It cannot exert the pushing force in this way. Heat similarly cannot be conducted or convected to us. The only thing that remains is radiation.

    The sun does emit charged particles, which we call the solar wind. You can observe in in Auroras. But this effect is extremely weak, even on a body as large as the earth. Perhaps a few million newtons. The other source is direct photon pressure from the light hitting us. Given the intensity of the solar radiation, this is also tiny. Both of these are several orders of magnitude too small to be compared to the power of gravity, which is easily observable in earth's orbit.
  11. May 2, 2003 #10
    FYI - gravity is related to the density of an object rather than the mass of an object. Mass calculations cannot be used to determine the gravity of a planet. Just because Mars is bigger than the earth does not mean its' gravity is greater.

    Also, we must consider relativity in all of this. We say that the force of the Sun is weak but in relation to what?

    While you may speak of particles emitted by the Sun which you call Solar Wind, the earth is constantly bombarded by electrons from the Sun in the form of waves. Do you refer to these electrons as particles? Or, by particles, do you mean the protons of an atom? Or, are the particles simply free electrons that are not associated with a wave? I really don't know what is meant when someone refers to a particle.
  12. May 2, 2003 #11
    Related maybe, attributable to, I don't think so.

    Unless I missed the mark, Newton's law of universal gravitation looks like this:

    F = GMm/r2

    and F = ma


    ma = GMm/r2

    The little m's cancel out and the acceleration of gravity at some distance r from the center is equal to GM/r2.

    If the massive body were more dense, the surface would be closer to its center (i.e. r would be smaller), so you'd be dividing by a smaller number (r2 would be smaller) and the acceleration at the surface would be greater.


    edit// punctuation
    Last edited: May 2, 2003
  13. May 2, 2003 #12
    Bill your making Newton toss in his grave!

    Also electromagnetic waves are composed of photons, not electrons.
  14. May 2, 2003 #13
    OK - you got me with Newton's Law - but Newton came up with his law before the dicovery of Black Holes - didn't he?

    I really did not want to go this deep - but - I guess I have to in order to explain this.

    Newton's Law cannot be used to determine the gravity of the Sun, since the Sun is an explosive force that exerts pressure on the objects around it.

    The opposite of the Sun is a Black Hole which exerts a gravitational field.

    I have often read, although I cannot confirm it, that a teaspoon of the substance that exists after the collapse of a star would weigh a million pounds, or, something of that magnitude.

    Now if Newton's Law were correct in all cases, how does the density of this substance since its' mass is so small gain such a weight?

    And what is this substance?

    And, isn't the weight of an object related to its' gravitational force?

    If I could achieve a temperature that is lower than absolute zero (-451 F), which appears to be possible in space, I could strip the electrons from the proton of a hydrogen atom. What would I have if I could strip the electrons from a massive number of hydrogen atoms (which would happen if I went below absolute zero)? I would simply have the protons of the hydrogen atom left. What would happen then? Would the protons then bond? Since there are no electrons to keep them apart? Would I create a new element? Would I create a Black Hole?

    Remember a cardinal rule of atomics; "Electrons flow from a greater concentration to a lesser concentration through the path of least resistance." Given that, electrons are primarily the anti-gravity part of the atom. They are held in place by the force exerted on them by the proton (and you can call that + or - I don't really care). They also insulate the proton from coming in contact with another proton.

    If they were not caught in the gravitational pull of the proton, they would be heading into space as fast as possible.

    I propose that; the protons of an atom are the substance that comprises the heart of a Black Hole which is colder than we can imagine. Far colder than Absolute Zero! And you can't pass through it, as has been recently proposed, without being disassembled! Element by element!
  15. May 2, 2003 #14


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    first off, saying you are wrong is not an ad hominem argument. Saying someone is wrong because they beat their wife (e.g.) is an ad hominem.

    The sun is a giant ball of hydrogen. It has a mass of ~2*10^30kg. That is HUGE. Earth's mass is 6*10^24, 1000000 times less.

    The vast majority of the sun's mass is not 'an explosion'; the only part which is 'exploding' is the core. It is happening because the sun's gravity is pulling all of the hydrogen in on itself until it gets hot enough with enough pressure for the individual atoms to start merging into helium. That is what a fusion reaction is. The fusion reaction in the core 'pushes' outward, which keeps the star from collapsing in on itself.

    The sun glows because the energy (in the form of photons) released from the center excites the hydrogen on the way out, which then re-releases them. Eventually, they get out of the sun's surface and travel to us.

    The thing you heard about iron is correct, but for a different reason:

    It is related to the life cycle of stars. When a star is born, it has well over 99% hydrogen. As the star ages, that hydrogen turns into helium. As the hydrogen in the core gets used up, the star grows into a red giant. When the hydrogen in the core is all gone, then the helium stars to fuse together into larger atoms. When the helium gets used up, the next largest atoms start to fuse (the larger the atom, the harder to fuse). This process continues until you reach iron in the core. Fusing iron together takes more energy than it releases. That means that there is no way for the star to get energy from the fusion, so there is nothing left to hold it up. Game over. The core collapses, the star around it starts to collapse. When the core collapses all the way, the sudden impact of all the mass causes an explosion called a supernova takes place. Depending on the size of the initial star, a white dwarf (our sun), a neutron star, or a black hole will form in the 'rubble'.

    The particles from the sun in the solar wind are usually ions (atoms with too few or too many electrons). Those are completely different from light, which is photons.

    No, gravity is related to mass. If it were related to density, the Earth would have a much stronger force of gravity than the sun and all the Jovian planets as well. Giant gas balls are not very dense.

    BTW, Mars is about 40% smaller than Earth.

    Don't take Star Trek as fact. Sci-fi shows would have you believe that you'll fall into a black hole just by being near it. If the sun turned into a black hole tomorrow, we'd still happily orbit it the same as we always have been (only we'd be a lot colder).
    Last edited: May 2, 2003
  16. May 2, 2003 #15


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    Some ideas are so plausible that one needs to prove them wrong to be confident in dismissing them. Some ideas are so clearly, unambiguously wrong that any intelligent person would realize going through a formal proof would be a waste of time.

    Bottom line: we don't have to thoroughly investigate every idea pushed by every crackpot. Nearly all of them are in fact worthy of quick, thoughtless dismissal -- yours included.
    The thing he heard, "if one atom of iron materialized in the Sun, the Sun would collapse in seconds," is in fact not at all true, enigma. Iron is important in stellar physics because it is the most stable nucleus -- but the presence of iron in a star has no consequence. Only when the core is predominantly iron is there a problem.

    Point of fact, our own star, among many many others, has some iron in it.

    - Warren
  17. May 2, 2003 #16


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    The explosion of a bomb expands. If the gravitational force of the sun is negligable, then why does the sun not expand?

  18. May 2, 2003 #17


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    Newton's Law can be used to determine the gravity of the Sun, but only inderectly by observing the rates that things orbit around it. The formulas are actually derivations of Newtons Laws done by Kepler.

    No, the black hole is what remains after a superlarge star dies.

    That is neutron star material. After a star collapses, what is left behind depends on the mass of the initial star. If the star is small, there isn't enough gravity to keep a lot of the initial mass around. Most gets blown away in the supernova, leaving a white dwarf, which is a hot ball of whatever reached the center of the supernova first (some iron, some hydrogen, etc.)

    If the mass was bigger, then the gravity holds onto the stuff through the supernova explosion, and it falls into itself. Since there is no material left to do any fusion reactions, it collapses, and collapses, and collapses, until the pressure is so big that the atoms themselves cannot hold themselves up. The electrons collapse into the protons, the space between the atoms vanishes, and you end up with a ball of neutrons the size of a large city (IIRC on the size).

    If the mass was even bigger still, then there is enough mass neutrons such that the neutrons cannot even hold themselves up. They compress down and down and down until the force of gravity is so strong in the proximity to it, that light cannot escape. That fact means that the event horizon forms, and we have a brand new black hole.

    I stated it above, but I'll just go through this last post of yours. Newtons Laws are correct in all cases. The mass is huge.

    Hydrogen, some helium, some trace other elements

    The mass is. The weight is how much the gravity pulls that mass, and is equal to m*g

    You can't go lower than absolute zero. You can't even reach absolute zero. Absolute zero means there is absolutely no energy present. It is impossible to pull further thermal energy out, and keeping something at absolute zero anywhere near (like... in the universe) something not at absolute zero will cause the energy to leak into the Ab 0 substance.

    A whole bunch of hydrogen ions. :wink:

    Not unless you heated them up to a few million degrees. The + charges repel (a LOT), and it takes a lot of thermal energy (which is just an average of the individual molecules kinetic energy) to get them to overcome that.

    The electrons don't keep them apart. The electrons balance the charge, and allow complex molecules to form by electron 'sharing' between them.

    That is not how QM or atomic reactions work, but the actual effects are out of my realm of knowledge.

    It's actually the coulomb (electrical) force which keeps the electrons close by. Gravity is way too small to hold an electron near. The reason it holds planets in an orbit is because A) it acts over much larger distances than electricity, and B) It always attracts. Electricity both attracts and repels.

    You can't pass through a black hole.
  19. May 2, 2003 #18


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    I know that, warren. I did explain the phenomena, didn't I?

    I also know that he misunderstood or misenterprited what was told to him, and a previous poster said that there was no truth to it at all, which is incorrect.
  20. May 2, 2003 #19
    remember, newtons laws of motion (F=ma) break down at high speeds and ALL laws of physics break down at the singularity. we simply don't know what exactly is going on past the event horizon of a black hole (but we make a lot of guesses :wink:).
  21. May 2, 2003 #20


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    Non-magnetic objects (asteroids without metal in them, big balls of water-ice, old astronaut gloves)orbit the Sun, the same way planets do.
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