1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Is there any way that we can defy gravity?

  1. Dec 19, 2011 #1
    Will we be able to defy gravity sometime in the future? Like, 1000 years from now?
     
  2. jcsd
  3. Dec 19, 2011 #2

    Pengwuino

    User Avatar
    Gold Member

    We do it right now.

    DeltaII.jpg

    Actually we've been doing it for a long time

    WRBR_375x180%20First%20Flight%20Dec%2017%201903.jpg
     
  4. Dec 19, 2011 #3
    In case the original poster meant a human defying gravity without needing to climb into a huge vehicle, we also do that right now.

    http://martinjetpack.com/app_images/gallery/_martinjetpack006.jpg [Broken]
     
    Last edited by a moderator: May 5, 2017
  5. Dec 19, 2011 #4

    olivermsun

    User Avatar
    Science Advisor

    We sure can, but I'm not sure gravity cares.
     
  6. Dec 19, 2011 #5

    phinds

    User Avatar
    Gold Member
    2016 Award

    Yes, that was going to be my point as well. I frequently tell gravity to go to hell. That makes me feel better mentally, but has never succeeded in making me lighter.
     
  7. Dec 20, 2011 #6
    Would this be an accurate rephrasing of your question?

    "Is there any way to nullify gravity so that the amount of force needed to prevent acceleration at a given point in a gravitational field is reduced?"

    If that is what you meant to ask then the answer is unknown. Gravity has been very well described by general relativity. To my knowledge there is no solution to general relativity that would constitute an anti-gravity device. However, General relativity is not compatible with quantum mechanics. One or both of them must be wrong in some situations.

    If you are unfamiliar with the quantum double slit experiment then I suggest you read about it. one thing that is fascinating about it is that you can actually reduce the illumination of some parts of the screen by opening up the second slit. Without a quantum understanding of gravity it is impossible to say if wave-like destructive interference is possible with gravitons.
     
  8. Dec 22, 2011 #7
    If you mean reduciung gravity without reducing mass, as opposed to overcoming gravity, then that is a harder thing to do (if at all possible). In electrostatics, we can block the electrostatic force of a large charged object simply by standing behind a large grounded conducting wall, which acts as a shield. Could you line your kitchen floor with some material that shields gravity, so that when you step into the kitchen, you begin to float? Probably not. Electromagnetic shielding occurs because there are negatively charged particles that can respond to fields produced by positive charges and cancel them out. In the realm of gravitational forces, there are no negative mass objects. The gravitational force is always attractive, and never repulsive because there is only positive mass. To shield gravity, you would need a wall made out of negative mass material. Such material has never been observed (antimatter has positive mass) and I don't believe is predicted by current theory. But it's a strange universe. Who knows what we'll find in the next 100 years.
     
  9. Dec 22, 2011 #8
    Seeing as mass and acceleration are the same thing according to general relativity, all you need is to speed up the earth's spin.
     
  10. Dec 22, 2011 #9
    What is going to happen when earth rotates with more speed?

    I saw this video on youtube:
    https://www.youtube.com/watch?v=v=G7ysnXH53Wo

    After seeing the video, I am guessing that, the neodymium magnet is acted upon by some forces when it is inside of that copper pipe. Now, if we want to fly for real without using any engines or anything all I need to do is make some invisible force(unknown(?)) act upon me which could help me fly!? No?
     
  11. Dec 22, 2011 #10

    berkeman

    User Avatar

    Staff: Mentor

    Science fiction thread is closed.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook