Page 1 of 3 123 LastLast
Results 1 to 30 of 61

Thread: The Impossibility of "Gravitational Slingshotting" in escaping the Suns Gravity

  1. #1
    Join Date
    May 2012
    Posts
    23

    The Impossibility of "Gravitational Slingshotting" in escaping the Suns Gravity

    As a member here I realize i am subject to rules of the forum, and will do my best to abide in them, but one thing I will not do is respond to confrontational personal attacks by users or moderators. If you abide in the same rules you set forth for me as a user, by the time I am finished here your entire view of academia and science will be forever altered, as will your perception of reality.

    On my threads the rules are simple, stick to science, keep the personalities out of it, and understand that personal attacks will be completely ignored because I know this is how successful arguments are stifled systematically on forums like this..
    As my username indicates I am skeptical of everything I have been taught that does not stand up to the scrutiny of close examination and the presentation of positive , verifiable and interdependently reproducible proof. These are the basic rules of how true science is conducted. I will answer any on topic question asked of me to the best my ability, but I will not reps pond to sarcastic, derogatory or confrontational retorts. Because "everyone agrees" or 75% of people surveyed believe it is not acceptable as proof.

    This is precisely why I reject the vast majority of mainstream physic, because it's purveyor instead of proving their theories simply add further mathematical and theoretical complication to explain them instead of providing concrete proof that real empirical science demands. . I propose that this is not science, but badly written complex fiction that no two people in the world understand in precisely the same way, making it nothing more than a waste of time.
    Without consensus on what the theory states, you have no theory.

    In this thread I will systematically and by using empirical science and pure physics prove that the concept of gravitational sling-shotting using the gravity of planets is impossible, and violates the basic laws of physics.

    The individuals who claim this as fact have ignored very basic principals involved, I suppose hoping that academia has dumbed down it's students sufficiently that they will never question it.

    The idea of using the orbital velocity of a planet along with it's gravitational attraction to accelerate a space vehicle is not itself flawed, in fact I have no problem believing nor understanding that this is impossible. What I do find impossible is that a net gain in velocity could be achieved.

    Let's try to visualize if we can what these 'scientists' claim is happening. They claim by carefully aiming the trajectory of a space probe they can cause it to come within range of a planets strong gravitational field by coming very close to the planet from behind it's orbital direction. So far, so good, right? The probe is accelerated by being caught in the planet's "gravity well" and 'stealing' a small amount of it's momentum.

    But there is one glaring problem, one that proves that those who believe this idea is possible lack a basic understanding of physics on a fundamental level.(this idea was first brought to my attention when it was featured on an episode of "Star trek" the original series).

    It is proposed that the the probe does not actually come from behind the planet (it could never catch it anyway!), but carefully aimed so that it intersects an area in space slightly behind the planet as it passes in it's orbital path, the probe then being caught in it's gravity, and 'slung' or 'slingshotted' at a higher velocity than it's original velocity.

    Ok, so this seems reasonable so far, right? No doubt about it, it could and would work.

    But now comes the dis-qualifier and the falsification. No matter what angle the probe came in at (we must assume very close to straight across the planets orbital path), it would be 'slung' in a direction that placed it in the planets gravity well for a much longer time that it spent accelerating towards it, with the best case scenario a net gain of zero velocity. Assuming the encounter could be calculated with such perfection that the probe was 'slung; in a direction that sent it back the direction it came from, the net gain is zero. Assuming it could be caught by the planets gravity and accelerated by careful calumniation to go in a basically opposite direction of the planets direction , acceleration would be possible but not in a direction further from the Sun, only in a direction closer to it.
    The basic premise of my argument is that any velocity gained in a direction away from the Sun while accelerating towards the planet would be lost escaping the planets gravity. This is basic orbital mechanics.

    If there is someone here who can illustrate using mathematical calculations of how a net gain in velocity can be achieved, present them. Do not make such claims as the success of the technique with existing probes is proof, because it has never been duplicated independently and only JPL claims contact with these probes, other than a an Santana salesman who presents no proof whatsoever.

    One of the basic laws of physics is the conservation of energy. In such an encounter as an attempted slingshotting using a planets gravity, the planet would have to lose some of it's energy to the probe. but in actual experimentation using magnets to simulate gravity one will find one of two things will actually happen, the probe would be captured by the planet no matter it's velocity and remain in a elliptical orbit, or it would crash into it.

    Show me the math. otherwise the authenticity of all deep space probes has been disqualified.
    I maintain it is impossible, and I've got the experimental method to prove it conclusively.

  2. #2
    Join Date
    Sep 2003
    Location
    The beautiful north coast (Ohio)
    Posts
    39,355
    Totally Skeptical

    First, welcome to BAUT.

    Second, as your thread topic seems to be advocating a non-mainstream idea, your thread has been moved from Science & Technology to Against The Mainstream (ATM). That means, if you wish to advocate this idea here, you have to follow our rules for this forum.

    Quote Originally Posted by Totally Skeptical View Post
    On my threads the rules are simple, stick to science, keep the personalities out of it, and understand that personal attacks will be completely ignored because I know this is how successful arguments are stifled systematically on forums like this..
    Let me make it simple, you do not get to set the rules here. I VERY STRONGLY suggest you read our Advice for ATM Idea Advocates and the Rules for this forum as you will be expected to follow them. If you are not prepared to follow our rules, then this thread will be closed.
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  3. #3
    Join Date
    Jan 2005
    Location
    New Zealand
    Posts
    9,646
    Quote Originally Posted by Totally Skeptical View Post
    ...

    If there is someone here who can illustrate using mathematical calculations of how a net gain in velocity can be achieved, present them. Do not make such claims as the success of the technique with existing probes is proof, because it has never been duplicated independently and only JPL claims contact with these probes, other than a an Santana salesman who presents no proof whatsoever.

    One of the basic laws of physics is the conservation of energy. In such an encounter as an attempted slingshotting using a planets gravity, the planet would have to lose some of it's energy to the probe. but in actual experimentation using magnets to simulate gravity one will find one of two things will actually happen, the probe would be captured by the planet no matter it's velocity and remain in a elliptical orbit, or it would crash into it.

    Show me the math. otherwise the authenticity of all deep space probes has been disqualified.
    I maintain it is impossible, and I've got the experimental method to prove it conclusively.
    I would add (it's in the advice threads, but needs to be made explicit) that as you are the person trying to overturn physics, it's up to you to prove it. All you've got so far is a story, which is how you in turn dismiss 70 or so years of space science.

    It is not up to anyone to show you the math to prove you wrong. It's up to you to present your math for discussion.
    I don't see any Ice Giants.

  4. #4
    Join Date
    May 2012
    Posts
    23
    It is not I who is trying to overturn physics, that would be NASA. If this thread doesn't belong where I posted it I would like a better explanation than it goes against the mainstream, because actually mainstream physics is what I intend to us to prove gravitational slingshotting is impossible.

    You buried my thread, it's censorship plain and it's unethical and it is childish. You did it simply because no one can show the math and prove it is possible, and because I am correct. . Put the thread back where it belongs and quit making up your own definitions. Are you a moderator or NAZI censor?

  5. #5
    Join Date
    May 2012
    Posts
    23
    Your rules are simple, comply. Look where that's got us , sunshine.

  6. #6
    Join Date
    Jan 2005
    Location
    New Zealand
    Posts
    9,646
    Quote Originally Posted by Totally Skeptical View Post
    It is not I who is trying to overturn physics, that would be NASA.
    NASA does not hold a monopoly on space science*. Rather than bring this conspiracy angle into the discussion, just get to the science.

    (* from wikipedia: "The gravity assist maneuver was first used in 1959 when the Soviet probe Luna 3 photographed the far side of Earth's Moon. The maneuver relied on research performed at the Department of Applied Mathematics of Steklov Institute")


    Quote Originally Posted by Totally Skeptical View Post
    If this thread doesn't belong where I posted it I would like a better explanation than it goes against the mainstream, ...
    It is your unique claim that slingshotting doesn't work. Yours is clearly the non-mainstream position.

    Quote Originally Posted by Totally Skeptical View Post
    ... because actually mainstream physics is what I intend to us to prove gravitational slingshotting is impossible.
    When you are, please just get on with that, and leave out the complaining.

    Quote Originally Posted by Totally Skeptical View Post
    You buried my thread, it's censorship plain and it's unethical and it is childish.
    Your thread is not buried, it is here for anyone on the internet to read it. As for what's childish, we'll let the reader determine that.

    Quote Originally Posted by Totally Skeptical View Post
    You did it simply because no one can show the math and prove it is possible, and because I am correct.
    Give it a little time. If anyone wants to show the math, they can, but give it some time. This is a voluntary membership discussion forum. To argue no one can provide the math just a few hours after starting the thread is silly. Besides, you've not yet provided your math.

    Quote Originally Posted by Totally Skeptical View Post
    Put the thread back where it belongs ...
    This is exactly where it belongs.

    Quote Originally Posted by Totally Skeptical View Post
    ... and quit making up your own definitions.
    I'm not entirely sure what you mean here, unless it's about the "mainstream" "non-mainstream" distinction. Well, I think it's clear what the mainstream view is. In any case, a distinction needs to be made and the people who run the forum make that distinction. Decision can be queried, politely.

    Quote Originally Posted by Totally Skeptical View Post
    Are you a moderator or NAZI censor?
    Sigh. Nobody is censoring you.

    -----

    Quote Originally Posted by Totally Skeptical View Post
    Your rules are simple, comply. Look where that's got us , sunshine.
    Arguing moderation in thread is against the rules. It's disruptive. If you wish to complain about moderation, report a post to send a message to all of the moderators at once.
    I don't see any Ice Giants.

  7. #7
    Join Date
    Jun 2003
    Location
    SE Michigan
    Posts
    2,896
    I cannot provide any figures, as my last physics class was in high school, decades ago. Therefore, you may ignore this post as being not technical enough. Be that as it may...

    As I understand it, saying that "a net gain in velocity could be achieved" is inaccurate. Consider, rather than velocity, momentum, mass times velocity. The change in momentum of the spacecraft is countered by an equal and opposite change in momentum of the planet. As planets are many orders of magnitude more massive than spacecraft, a small, even unmeasurable, change in the planet's momentum results in a very large and measurable change in the spacecraft's momentum. Since the masses of the two bodies do not change, the velocities must. Add everything up, and it all balances.

    Such momentum transfer can be used either way. MESSENGER used the opposite technique in order to arrive at Mercury. It lost momentum to Earth, Venus, and Mercury in order to reduce its velocity to a level where it could then enter Mercury orbit.

    Laugh if you wish, but I was first exposed to this by the following passage in a rather famous SF novel:
    Quote Originally Posted by Arthur C. Clarke, in 2001: A Space Odyssey
    [The ETA at Saturn] was within a minute of the estimate; the fly-by had been carried out with impeccable precision. Like a ball on a cosmic pool table, Discovery had bounced off the moving gravitational field of Jupiter, and had gained momentum from the impact. Without using any fuel, she had increased her speed by several thousand miles per hour.

    Yet there was no violation of the laws of mechanics; Nature always balances her books, and Jupiter had lost exactly as much momentum as Discovery had gained. The planet has been slowed down -- but as its mass was a sextillion times greater than the ship's, the change in its orbit was too small to be detectable. The time had not yet come when Man could leave his mark on the Solar System.
    As for your model using magnets, it is only a model. Have you accounted for all other forces involved besides magnetism -- in particular, friction? In real life, it is almost impossible for one body to gravitationally capture another without other forces being involved: A third body, which gains the momentum that the captured body loses; an atmosphere used for aerobraking; reaction motors (rocket engines) used to slow the captured body. An extreme case is lithobraking, as experienced by meteorites. In most two-body encounters, the orbits are only slightly changed. In the rest, the less-massive body's orbit is profoundly changed, or the two collide.

    All that said, can you "illustrate using mathematical calculations" your ideas, and show exactly where the mainstream view is wrong? I will not be able to evaluate them, but there are others here who can.

    Fred
    "For shame, gentlemen, pack your evidence a little better against another time."
    -- John Dryden, "The Vindication of The Duke of Guise" 1684

  8. #8
    Join Date
    Nov 2002
    Posts
    6,238
    Quote Originally Posted by Totally Skeptical View Post
    But now comes the dis-qualifier and the falsification. No matter what angle the probe came in at (we must assume very close to straight across the planets orbital path), it would be 'slung' in a direction that placed it in the planets gravity well for a much longer time that it spent accelerating towards it, with the best case scenario a net gain of zero velocity. Assuming the encounter could be calculated with such perfection that the probe was 'slung; in a direction that sent it back the direction it came from, the net gain is zero. Assuming it could be caught by the planets gravity and accelerated by careful calumniation to go in a basically opposite direction of the planets direction , acceleration would be possible but not in a direction further from the Sun, only in a direction closer to it.
    The basic premise of my argument is that any velocity gained in a direction away from the Sun while accelerating towards the planet would be lost escaping the planets gravity. This is basic orbital mechanics.
    Then you should have no problem presenting the equation showing exactly this. When can we expect to see this? I was going to comment on something else, but pzkpfw beat me to it. Probably better that way.

    Quote Originally Posted by Totally Skeptical View Post
    If there is someone here who can illustrate using mathematical calculations of how a net gain in velocity can be achieved, present them. Do not make such claims as the success of the technique with existing probes is proof, because it has never been duplicated independently and only JPL claims contact with these probes, other than a an Santana salesman who presents no proof whatsoever.
    Actually, you do know that while they communicate with JPL, two of the deep space antennas are not located in the US. There is also the Chinese, Indian, Japanese and European Deep Space Networks that could, if they so wanted, track the craft that took advantage of the slingshot maneuver. It's not like hiding the information of where they are at. Here is the location of voyager 1. for instance.

    Quote Originally Posted by Totally Skeptical View Post
    One of the basic laws of physics is the conservation of energy. In such an encounter as an attempted slingshotting using a planets gravity, the planet would have to lose some of it's energy to the probe. but in actual experimentation using magnets to simulate gravity one will find one of two things will actually happen, the probe would be captured by the planet no matter it's velocity and remain in a elliptical orbit, or it would crash into it.
    There are several problems with this. I'll use Pioneer 10 around Jupiter to Illustrate. The difference in mass between the Pioneer 10 and Jupiter was on the order of 1025 kg. Did the magnets in the experiment you mention have that mass difference? Also, the difference in force between gravity and magnetic force is on the order of 1039. Was that taken into account in the experiment you mention. If neither the difference in mass or in force was part of the experiment, the experiment has no bearing on actual astronomical slingshot maneuvers.

    Quote Originally Posted by Totally Skeptical View Post
    Show me the math. otherwise the authenticity of all deep space probes has been disqualified.
    Here is one example. Here's another Mathpages has this page . There is a tutorial here by Dr. James Van Allen (yes, that Van Allen). Unfortunately, if you don't have a subscription, you will have to buy the tutorial for $30. There are a few others I can point you to, again for a fee of $30 dollars, if you don't have subscriptions.

    Quote Originally Posted by Totally Skeptical View Post
    I maintain it is impossible, and I've got the experimental method to prove it conclusively.
    Yeah, but I have a strong suspicion your experiment is wrong. Can you provide the parameters used in the experiment, you say proves it is impossible conclusively?

  9. #9
    Join Date
    May 2005
    Posts
    5,704
    Quote Originally Posted by Totally Skeptical View Post
    You did it simply because no one can show the math and prove it is possible, and because I am correct.
    The second link that appears in this quote from Tensor's post is a no-cost pdf without too much complication.
    Quote Originally Posted by Tensor View Post
    Here is one example. Here's another Mathpages has this page .

  10. #10
    Join Date
    Jun 2005
    Posts
    8,863
    Quote Originally Posted by Totally Skeptical View Post
    Your rules are simple, comply. Look where that's got us , sunshine.
    The use of "sunshine" seems sarcastic to me, and I thought your own personal rule was not to use it.

    I read through your idea briefly. Aren't you confusing speed and velocity? I gather you were trying to say that a probe approaching a planet cannot then move away from the planet at a different speed than it approached it. Absolutely true, but that's not the point of a slingshot maneuver.
    As above, so below

  11. #11
    Join Date
    Jan 2005
    Location
    New Zealand
    Posts
    9,646
    Jens, please don't try to moderate threads. The poster has already been infracted, no need to comment on that line too.
    I don't see any Ice Giants.

  12. #12
    Join Date
    Jul 2006
    Location
    Seattle, WA
    Posts
    1,402
    Totally Skeptical, I don't have the math background to debate the physics of gravity assist with you but consider the following:

    This graphic shows Cassini's speed at any given point in time from when it was launched until arrival at Saturn. The spacecraft's speed and location were easily tracked through radio navigation technology.

    From this website, the following graphic and quote cites details of the flybys:

    Launched on October 15, 1997 from the Kennedy Space Center in Florida, the Cassini-Huygens probe took a very long and indirect path to reach Saturn. This path was necessitated by the heavy weight of the probe - over six tons, including propellant. Lacking a strong enough booster, NASA devised a flight path that utilized the gravitational forces of Venus, Jupiter, and the Earth to create a slingshot effect to generate the necessary velocity to reach Saturn.



    Four gravity assists were required to hurl the spacecraft to Saturn. Cassini used an interplanetary trajectory that took it by Venus twice, then past Earth and Jupiter. After flying past Venus twice, first at an altitude of 284 kilometers (176 miles) on April 26, 1998 and again on June 24, 1999 at 600 kilometers (370 miles), the spacecraft then swung past Earth at an altitude of 1,171 kilometers (727 miles) on August 18, 1999. Given these three gravity assists, Cassini finally had enough momentum to reach the outer solar system. The fourth and final gravity assist was from Jupiter on December 30, 2000, at an altitude of 9,723,890 million kilometers (6,042,145 million miles) boosting Cassini all the way to Saturn. After a nearly seven-year journey covering 3.5 billion kilometers (2.2 billion miles), Cassini arrived at Saturn on July 1, 2004.

    There is no question those flybys actually occurred. That means, for your proposal to be correct, we must either assume NASA and JPL had no clue what they were doing, or that some incredible conspiracy was taking place, both of which are ludicrous proposals.

    Do you accept that Cassini couldn't have made it to Saturn without the assists? If so, then the flybys must have worked. If not, it would mean that the four flybys were unnecessary and that would require explaining why they would have taken the time and trouble to employ them.

    Which of the above do you believe?.... and please give details to back you up.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	CassiniFlybys.jpg 
Views:	51 
Size:	104.0 KB 
ID:	16952   Click image for larger version. 

Name:	flight.jpg 
Views:	43 
Size:	20.6 KB 
ID:	16953  
    "There are powers in this universe beyond anything you know. There is much you have to learn. Go to your homes. Go and give thought to the mysteries of the universe. I will leave you now, in peace." --Galaxy Being

  13. #13
    Join Date
    Oct 2001
    Posts
    29,139
    Quote Originally Posted by Totally Skeptical View Post
    No matter what angle the probe came in at (we must assume very close to straight across the planets orbital path), it would be 'slung' in a direction that placed it in the planets gravity well for a much longer time that it spent accelerating towards it, with the best case scenario a net gain of zero velocity.
    The net gain is zero, but the net is calculated relative to the planet, which is moving around the Sun. Therefore, relative to the Sun, there is a net acceleration.

    One of the basic laws of physics is the conservation of energy. In such an encounter as an attempted slingshotting using a planets gravity, the planet would have to lose some of it's energy to the probe. but in actual experimentation using magnets to simulate gravity one will find one of two things will actually happen, the probe would be captured by the planet no matter it's velocity and remain in a elliptical orbit, or it would crash into it.
    I'd be interested in hearing more details about these experiments. If you're using two magnets to simulate gravity, that's not going to work because they follow an inverse cube law, unlike the inverse square law of gravity. It's actually not possible for a single object to capture another object gravitationally since if it's coming in at escape velocity it will leave at the same escape velocity. Additionally, if the magnet representing the planet isn't moving, it is likewise not an accurate representation of the actual situation.
    Everything I need to know I learned through Googling.

  14. #14
    Join Date
    Dec 2004
    Posts
    12,552
    Quote Originally Posted by Totally Skeptical View Post
    ... in actual experimentation using magnets to simulate
    gravity one will find one of two things will actually happen,
    the probe would be captured by the planet no matter it's
    velocity and remain in a elliptical orbit, or it would crash
    into it.
    Obviously. That's one way in which magnetism is starkly
    different from gravity. You didn't really think gravity could
    be modelled with magnets, did you? Anyone can see that
    would never work.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  15. #15
    Join Date
    Oct 2006
    Posts
    3,767
    Quote Originally Posted by Totally Skeptical View Post
    Show me the math. otherwise the authenticity of all deep space probes has been disqualified..
    The mathematics of gravity assists is clearly and simply played out here : http://en.wikipedia.org/wiki/Gravity_assist : How or why you would get to your conclusion without coming across this most basic of search results is baffling.

    Have you not seen that page? If you have - where and why does it fall short in correcting your most basic of misconceptions?

    But - if you are right - then you have many questions an answer. If all those missions are faked - then that's a colossal conspiracy you're alleging - one that involves tens, if not hundreds of thousands of people.

    What was the actual fate of the launches of Pioneer 10, 11, Voyager 1, 2, Galileo, Cassini, New Horizons, Stardust, NEAR, Deep Impact, Dawn and so on then?

    Are you suggesting that all of their data is somehow faked?

    If so, by whom, and how?

    How do you account for the receipt of radio signals from these spacecraft by ham radio enthusiasts?
    http://www.southgatearc.org/news/april2006/voyager1.htm and http://www.uhf-satcom.com/amateurdsn/ for example. Where are those signals actually coming from? Are ham radio enthusiast around the world a part of the conspiracy as well? If all the spacecraft didn't go where they should..what are they listening to.

    Also - the deep space network. I've seen the antennae at Goldstone. They're real. They're also tracking 'things' in the sky. What ARE they tracking if not these spacecraft BEO?


    Rockets were launched. Were they carrying these spacecraft or not?

    I work at JPL and was involved in realtime predicted simulations of the Stardust-NExT and EPOXI missions in Eyes on the Solar System..... am I part of the conspiracy to fake this, or is it somehow higher up? All the spacecraft I listed above are represented. We went to great lengths to show their trajectories and they include many many gravity assists. Is the trajectory data at NAIF all faked? Who made it? The Stardust mission used gravity assists to get to a comet...and then return samples TO THE EARTH....are the samples faked? Many people watched the re-entry at a velocity that was clearly not from Earth orbit - so it went SOMEWHERE... where?

    Several spacecraft have been imaged by amateurs doing these flybys - such as http://www.astronomyforum.net/amateu...setta-fly.html What - exactly - are these amateurs seeing if not spacecraft doing gravity flybys?

    You allegation leaves so MANY questions to be answered.
    Last edited by djellison; 2012-May-29 at 04:49 AM.

  16. #16
    Join Date
    Jun 2005
    Posts
    8,863
    To be a bit more generous, I understand the problem that the OP is having. It appears that he (if it's a he) recognizes that the probe might lose velocity by coming up from behind the planet and then departing in the other direction, but can't accept that the opposite might happen, that it might come from in front of the planet and then be slingshot out in front of it. To be honest, I can understand why it's difficult to grasp that; I have the same problem trying to visualize it, though thinking it through rationally makes it possible to get it.
    As above, so below

  17. #17
    Join Date
    Sep 2003
    Location
    The beautiful north coast (Ohio)
    Posts
    39,355
    So as not to burden the OP with too much of a backlog, I am closing this thread.

    Totally Skeptical, when you return from your suspension, if you wish to continue this discussion, please Report this post (the triangle with the ! in the lower left corner, and ask for it to be reopened. The moderator advice given to you in this thread so far, with regard to polite behavior and the rules of this forum, will still stand.

    (Mod Note: Thread reopened at OP's request.)
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  18. #18
    Join Date
    May 2012
    Posts
    23
    Quote Originally Posted by Jeff Root View Post
    Obviously. That's one way in which magnetism is starkly
    different from gravity. You didn't really think gravity could
    be modelled with magnets, did you? Anyone can see that
    would never work.

    -- Jeff, in Minneapolis
    The simple fact is that what JPL is claiming is physically impossible. The idea of amateur radio enthusiasts receiving signals from a probe a billion miles away is ridiculous, too ridiculous to require response. On this forum is required that I prove my disqualifications, and IMHO I already have. Having a thick skull is not my problem. The idea of using gravity from a planet to accelerate a space vehicle is not in question, but a net gain in relative velocity is impossible, since it violates the laws of physics. No matter what angle or what finagling you can dream up, as much velocity is lost escaping the planets gravity as being accelerated by it.

  19. #19
    Join Date
    Oct 2010
    Posts
    136
    Quote Originally Posted by Totally Skeptical View Post
    The idea of amateur radio enthusiasts receiving signals from a probe a billion miles away is ridiculous, too ridiculous to require response.
    No, it's not ridiculous. You don't get to dismiss it without showing us the exact reasons why it's impossible.
    On this forum is required that I prove my disqualifications, and IMHO I already have.
    You haven't shown anything, so now would be a good time to start with the math.
    The idea of using gravity from a planet to accelerate a space vehicle is not in question, but a net gain in relative velocity is impossible, since it violates the laws of physics.
    No laws of physics are being violated. I say that as a physicist.
    No matter what angle or what finagling you can dream up, as much velocity is lost escaping the planets gravity as being accelerated by it.
    It seems that you don't understand how it works. I'd recommend actually familiarizing yourself with the problem before criticizing it, as your ignorance will just make you look rather foolish, when it becomes apparent that you don't know what you are talking about.

  20. #20
    Join Date
    Mar 2004
    Posts
    17,307
    Quote Originally Posted by Totally Skeptical View Post
    The simple fact is that what JPL is claiming is physically impossible.
    You haven't demonstrated why.

    The idea of amateur radio enthusiasts receiving signals from a probe a billion miles away is ridiculous, too ridiculous to require response.
    It's ridiculous because you say so? Why should we care what you believe? An argument from personal incredulity is useless. Demonstrate why it is physically impossible or withdraw the claim.

    The idea of using gravity from a planet to accelerate a space vehicle is not in question, but a net gain in relative velocity is impossible
    Velocity relative to WHAT? The velocity relative to a planet is not the same thing as the velocity relative to the sun.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  21. #21
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    4,395
    Show me the math. otherwise the authenticity of all deep space probes has been disqualified.
    Tensor showed you the maths in post 8 as you requested - what is your response to that? Do you now admit you are wrong or have you spotted a flaw in the maths? Argument by assertion or from personal incredulity do not count.
    The idea of amateur radio enthusiasts receiving signals from a probe a billion miles away is ridiculous, too ridiculous to require response.
    With a 20m dish: Voyager 1 at 14.7 billion km
    With a 3.5m dish: Mars Express at 100 million km
    Another group working with Mars Express
    Please respond.

  22. #22
    Join Date
    Oct 2006
    Posts
    3,767
    Quote Originally Posted by Totally Skeptical View Post
    The idea of amateur radio enthusiasts receiving signals from a probe a billion miles away is ridiculous, too ridiculous to require response
    Then you have to explain what those amateurs who have published their results online are doing. Faking it? Part of a conspiracy? For what purpose, exactly?

    I've watched a ham radio enthusiast listen to the EPOXI spacecraft from a parking lot near Guildford in the UK. Then he did the same with MRO. Are you saying he was faking it, or lying to me? There were a dozen other people, most VERY advanced Ham Radio enthusiasts there, and they all saw it as well.

    Moreover - you are yet to answer my questions regarding all the spacecraft that have used gravity assists to get to their targets. What you are stating is that these missions can not possibly be where NASA, ESA, JAXA and others say they are....so...for these missions (most of which have international science teams)...

    Pioneer 10
    Pioneer 11
    Voyager 1
    Voyager 2
    Galileo
    Cassini-Huygens
    Ulysses
    Juno
    Messenger
    Hayabusa
    Rosetta
    Stardust
    EPOXI
    Akatsuki
    Genesis
    Stereo-A
    Stereo-B

    For all those missions, please tell us...

    What was in the rocket
    Where did it go
    How were the images and other data made
    By whom.
    Who does and doesn't know that it's all faked....

    All have used gravity assists as part of their mission. If what you say is true - that gravity assists are impossible - then all these missions must have been faked.


    Moreover - I showed you the Wiki page that demonstrates the simple math that explains how these assists work. Are you ignoring it, rejecting it, and if so - why. Why is it wrong. (saying that it's wrong just because it's on Wikipedia is not enough)

  23. #23
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    3,995
    If a cricket ball encounters a moving bat, it rebounds with more energy and speed than it had before but in another direction because it picked up momentum from the bat. The same would happen if the ball was magnetically linked or gravitationally linked to the bat and instead of colliding was "captured" temporarily. You can see this happening in magnetic pendulum toys where the bobs are not allowed to touch. The cricket ball does not violate any laws of physics and nor do the planetary slingshots. This was all discussed in an earlier slingshot thread.

  24. #24
    Join Date
    Oct 2009
    Location
    a long way away
    Posts
    8,801
    I would like to thank Totally Skeptical as I have never quite got my head round how this worked. Thanks to the great explanations here, it all now makes perfect sense.

  25. #25
    Join Date
    Dec 2004
    Posts
    12,552
    Quote Originally Posted by Totally Skeptical View Post
    Quote Originally Posted by Jeff Root View Post
    Obviously. That's one way in which magnetism is starkly
    different from gravity. You didn't really think gravity could
    be modelled with magnets, did you? Anyone can see that
    would never work.
    The simple fact is that what JPL is claiming is
    physically impossible.
    What makes you think that? I know you are wrong,
    but you must have some reason for thinking that it
    is physically impossible. What is that reason?

    Do you agree that your comparison of the action of
    gravity to the action of magnets was a mistake?
    Do you see how different the two forces are, and
    agree that those differences completely invalidate
    the comparison?

    If not, why not? It is very obvious to everyone else
    who has ever experimented with magnets.

    Quote Originally Posted by Totally Skeptical View Post
    The idea of amateur radio enthusiasts receiving signals
    from a probe a billion miles away is ridiculous, too
    ridiculous to require response.
    It does seem unlikely, because such a *very* large
    concentrating reflector is needed for the antenna to
    get a strong enough signal to detect. Just how large
    a reflector is needed? How large a reflector did the
    amateurs use?

    I've watched amateur radio enthusiasts set up small
    portable antennas and receive signals from satellites
    in low Earth orbit. I looked at the images from those
    satellites as they were received. Why couldn't other
    amateurs using much larger antennae receive signals
    from much more distant spacecraft?

    Quote Originally Posted by Totally Skeptical View Post
    On this forum is required that I prove my disqualifications,
    and IMHO I already have. Having a thick skull is not my
    problem.
    Everyone makes mistakes. You were mistaken about
    using magnets as an analogue of gravity. Clearly you
    are also mistaken about the impossibility of the
    gravitational "slingshot" maneuver. What it looks like
    is that you got the idea that it couldn't work, but you
    haven't actually analyzed the physics sufficiently to
    know, and are instead sticking with your impression
    and assuming that your impression isn't mistaken.

    I make that kind of mistake a lot.

    Quote Originally Posted by Totally Skeptical View Post
    The idea of using gravity from a planet to accelerate a
    space vehicle is not in question, but a net gain in relative
    velocity is impossible, since it violates the laws of physics.
    Can you show that? I know you can't, but it would be
    a good idea for you to try to show it. If it were true,
    it would be fairly simple to show mathematically.

    Quote Originally Posted by Totally Skeptical View Post
    No matter what angle or what finagling you can dream
    up, as much velocity is lost escaping the planets gravity
    as being accelerated by it.
    Relative to the planet, yes. The thing is, the planet is
    orbiting the Sun, and the spacecraft approaches the
    planet with one velocity relative to the Sun and leaves
    the planet with a different velocity relative to the Sun.
    That velocity can be either lower or higher speed than
    the speed of approach to the planet relative to the Sun.

    I bet you've never worked any of this out. Have you?
    I think it's pretty neat. The same thing happens with
    stars in globular clusters. It redistributes the stars in
    a way called "virialization", in which the more massive
    stars tend to end up near the center of the cluster,
    and less massive stars tend to end up spending most
    of the time in orbits near the outside of the cluster.

    -- Jeff, in Minneapolis

    .
    Last edited by Jeff Root; 2012-Jun-03 at 12:31 AM. Reason: added missing preposition
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  26. #26
    Join Date
    Sep 2003
    Location
    The beautiful north coast (Ohio)
    Posts
    39,355
    Quote Originally Posted by Totally Skeptical View Post
    If there is someone here who can illustrate using mathematical calculations of how a net gain in velocity can be achieved, present them. Do not make such claims as the success of the technique with existing probes is proof, because it has never been duplicated independently and only JPL claims contact with these probes, other than a an Santana salesman who presents no proof whatsoever.
    The gravity assist maneuver was first used in 1959 when the Soviet probe Luna 3 photographed the far side of Earth's Moon. The maneuver relied on research performed at the Department of Applied Mathematics of Steklov Institute.
    LINK

    A more recent non-JPL example:
    Over the next eighteen months ESA’s lunar scout SMART-1 will become the first spacecraft to use gravity assists in conjunction with a revolutionary propulsion system, the solar-electric ion engine.
    LINK
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  27. #27
    Join Date
    Jul 2003
    Location
    SW of the town of Maricopa, AZ. This is in the southern Arizona desert.
    Posts
    1,432
    Quote Originally Posted by Totally Skeptical View Post
    ... The idea of amateur radio enthusiasts receiving signals from a probe a billion miles away is ridiculous, too ridiculous to require response. ...
    Speaking as an amateur radio operator, I take exception to this comment. We (historically as a group) have done things with radio signals that you would be amazed by. Receiving signals from "billions" of miles away is really no big deal.

    Having said that, I request that you present proof that supports you contention that this idea is "too ridiculous". Failing that, I expect you to retract this idea.

    And yes, this does require a response.
    problems worthy of attack prove their worth by hitting back (Piet Hein)
    I cook with wine, and sometime I even add it to the food. (W.C. Fields)
    I don't ask stupid questions. I just make stupid statements!!!
    Experience is a wonderful thing. It enables you to recognize a mistake when you make it again.
    All truths are simple to understand, once they are found. The challenge is finding them. (attrib. to Galileo)


  28. #28
    Join Date
    Oct 2001
    Location
    Clear Lake City, TX
    Posts
    9,042
    Quote Originally Posted by AstroRockHunter View Post
    ... And yes, this does require a response.
    Totally Skeptical, as a reminder, the Rules for Posting require that all pertinent questions be answered in a timely manner. Since your last post you have been asked reasonable, direct and pertinent questions. Please answer them
    Never attribute to malice that which can be adequately explained by ignorance or stupidity.
    Isaac Asimov

    Moderation will be in purple.
    Rules for Posting to This Board

  29. #29
    Join Date
    May 2012
    Posts
    23
    Quote Originally Posted by amazeofdeath View Post
    No, it's not ridiculous. You don't get to dismiss it without showing us the exact reasons why it's impossible.
    It is impossibles because it violates the basic physical law of conservation of energy. Furthermore , if it were possible for close passing celestial objects to slow the orbits of planets, their orbits would have in the past 4 billion years decayed. We don't see any such indication. Do the math for any approach angle and ee if you can come up with a het gain in velocity. This is not star trek.




    Quote Originally Posted by amazeofdeath View Post
    You haven't shown anything, so now would be a good time to start with the math. No laws of physics are being violated.
    Yes sir, they are . Being educated is not synonymous with being knowledgeable or intelligent. This forum has the unusual rule that I must show my proof, my proof has been presented, no mattr what angle you approached the planet the net gain in velocity would be zero. This is simply because any velocity gained by the gravitational contraction of the planet approaching it would be lost departing it. This is why no one can show a single article or paper proving the idea. It;s not that hard t understand, which is what baffles me as to how anyone could argue it is impossible.
    Quote Originally Posted by amazeofdeath View Post
    I say that as a physicist. It seems that you don't understand how it works. I'd recommend actually familiarizing yourself with the problem before criticizing it, as your ignorance will just make you look rather foolish, when it becomes apparent that you don't know what you are talking about.
    Why don't you enlighten me, i want to know how it is possible. Your supposedly a physicist, it should be easy to explain. But you cannot.

  30. #30
    Join Date
    May 2012
    Posts
    23
    Quote Originally Posted by Shaula View Post
    Tensor showed you the maths in post 8 as you requested - what is your response to that? Do you now admit you are wrong or have you spotted a flaw in the maths? Argument by assertion or from personal incredulity do not count.

    With a 20m dish: Voyager 1 at 14.7 billion km
    With a 3.5m dish: Mars Express at 100 million km
    Another group working with Mars Express
    Please respond.
    SHow proof that holds up to the scientific method. You cannot.

Similar Threads

  1. The Impossibility of "Gravitational Slingshotting" in escaping the Suns Gravity
    By Totally Skeptical in forum Science and Technology
    Replies: 0
    Last Post: 2012-May-28, 05:26 PM
  2. NatGeo: Known Universe 6/19/11 "Escaping Earth"
    By bunker9603 in forum Small Media at Large
    Replies: 0
    Last Post: 2011-Jun-12, 08:33 PM
  3. Replies: 1
    Last Post: 2008-Jun-10, 11:02 AM
  4. Replies: 68
    Last Post: 2007-Jan-31, 08:11 AM
  5. Hubble Captures a "Five-Star" Rated Gravitational Lens
    By Kullat Nunu in forum Space Exploration
    Replies: 9
    Last Post: 2006-May-24, 12:45 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
here
The forum is sponsored in-part by: