Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Slow us down

  1. Sep 29, 2007 #1
    Hi, is it possible in (theory) to somehow combine lots of atoms, protons ect and make a shield that pushes gravity outwards in every direction so the aircraft or whatever was the weightless? if that were possible, would we be able to travel near the speed of light or even 1/4 the speed of light? please anser in detail, thanks
     
  2. jcsd
  3. Sep 29, 2007 #2

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    no you cant sheild gravity, gravity is attractive to all particles, there exist no "negative gravity" as you have in electric charge etc. The only way to not "feel" gravity is to accelerate in opposite direction with equal magnitude (Principle of equivalence).

    In order to travel fast, we need much energy per mass of space craft, so there should exist some limt on travel speed.
     
  4. Sep 30, 2007 #3
    I dont really understand much about science in general, but what is light made of? and why cant we use the atoms or whatever lights made of and use that to help us travel fast? if you understand what I mean please explain on my level lol. no complicated words :P
     
  5. Sep 30, 2007 #4

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    Light has wave and particle properties, but what light IS.. is perhaps noone who can answer.

    But your question "why cant we use the atoms or whatever lights made of and use that to help us travel fast" is really funny and very strange from a scientists point of view.

    We need fuel to travel, and the more power per mass of space craft we can travel fast. According to newtons law: Force = mass*acceleration; the more force per mass -> greater Acceleration and hence greater velocity (now Iam very simplified so that you can understand..) And the most effective power source we know of is fusion (the thing that the Sun gets its energy from). And there is also restrictions on how small the space crafts could be. Due to size of humans, and the container to have the fuel in, and magnets etc that is needed to perform fusion. Fusion on earth has not been made yet, but maybe in 30-50 years, the first fusion reactor is build.

    now back to your question; "cant we use the atoms or whatever lights made of and use that to help us travel fast?" Specify it first, tell me what kind of device you had in mind.
    Well, we can use light as power to travel, if we had a huge sail that uses the momenta of photons to push us forward (not solar cells). But that has been made.. and when we are a certain distance from the sun, the light intesity gets too low to use this effect effective. So best we can use is fusion. As trivia, the space crafts that have been traveling (without humans) to neptune and further, have used nuclear decays for traveling power ;)
     
  6. Sep 30, 2007 #5
    ok I understand (sort of) I have a perfect example, a ship carrys fuel, the ship has to stop every few weeks or so to re-fuel, but a submarine has a nuclear thingy so the sub dont have to stop for 20 years or so? I think scientists need to stop thing of fuel that runs out quickly, if you think about when you turn on a light what propels the light forward? speed your money inventing NEW forms or propulsion.

    Example: I was thinking of something that is either already in space and isnt going to run out, or an engine of some kind that uses an extreme about of thrust and when it shoots out the back it dosent go into the air but can be used again and again? This might seem like a stupid question but to me it seems a possibility.
     
  7. Sep 30, 2007 #6

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper


    but we are looking for new energy sources, the best we know of is fusion, and we are trying to control it. Fission has certain troubles, that it quite dangerous, when we use Uran as fission fuel, but there is reaserch in fission too, how to fission other nucleis than uran more effetive. And you can't just invent ANYTHING, there are constraints that nature gives us.

    What do you mean by "if you think about when you turn on a light what propels the light forward?" ??????????

    A thing that aleady is in space that already exists but does not run out? hehe now you are just guessing, you mean that we can use energy from stars etc? In order to get there, we must first spend approx 1 000 000 years in space travelling there, if you dont mean the sun. And how would you controll that energy from black holes etc? You can't, its just science fiction.

    And an enginge that reuses its thrust over and over again sounds like an "eternal machine" and there is no such, was proved in 19th century by laws of thermodynamics and entropy.. there is always losses. And if you gather all the thrust, what would make the space craft move forward?..

    You have to motivate WHY you think something is possible, othervise it is not worth anything. And you "complained" on scienteist
    "speed your money inventing NEW forms or propulsion" (you must have made a typo); you demanding things that are in contradiction with nature, if you dont know so much about science, why making all these ideas? And complaining? You dont even know what it is you are complaining about.
     
  8. Sep 30, 2007 #7
    lmao, I have an idea and I have just been searching on the net and I didnt belive what I was seeing. this is the sort of idea I had. http://video.google.co.uk/videoplay...=18&start=0&num=10&so=0&type=search&plindex=1 in this video the black thing is floating, cant you make an entire aircraft like this? and if that was possible then the fuel we use would be really good because in the video he says it is extremely easy to accelerate :D

    And when I said what propels light forward, I ment like... when we speek we force the air out, what forces light to move?

    Heres another adea of what I've been thinking about http://news.bbc.co.uk/media/images/38164000/gif/_38164768_anti_gravity_gra2300.gif
     
    Last edited: Sep 30, 2007
  9. Sep 30, 2007 #8

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    That is called Meissner effect, and we can use it to move trains without friction. But we need to cool the material to very low temperatures. Or invent superconductors in room temperature... But you cant accelerate things with it. And yeah, the "black thing" is an ordinary ferromagnet.

    In space, you have no friction, so the Meissner effect is just good here on earth ;)

    and i dont know what is meant by "force the air out". Light is light, energy conservation from atomic transitions etc creates light.. light is among the most strange things in nature...
     
  10. Sep 30, 2007 #9
    ok, sorry to keep throwing things at you but im extremely intrested, I found another thing on the net about anti-gravity ect http://www.ufoevidence.org/documents/doc1064.htm theres a few lines in it that says..... "examine possible uses for such a technology". Applications, the company says, could include space launch systems, artificial gravity on spacecraft, aircraft propulsion and ‘fuelless’ electricity generation — so-called ‘free energy’.

    What you think about this?
     
  11. Sep 30, 2007 #10

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    ufoevidence.org... not a source I would trust;) I mean, does this page or the guy the refer to present their methods etc? No.. because it is secret, very secret.. hehe.. just to fool peaplo that is not into physics, so that they will not trust real phycisists nomore. Because real physics is relly complicated formulas etc, but in this pseduoscience, you can just write some nice words so that people can understand and be admired.. I say crap :)
     
  12. Sep 30, 2007 #11
    just one more question, is there "anything" anywhere in the universe that we know about, that would repel gravity... ie inject these "things" into a golf ball for example and the throw the golf ball up into the air and it would just keep going and keep gaining speed and never stop or loose speed? if the answer is yes, I have faith in travel to diffrent solor systems, if the answer is no, we are never going to get diffrent solor systems in a decent amount of time, the one thing that is stoping us is speed, lol i no you new that :P any ideas
     
  13. Sep 30, 2007 #12

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    look at my first post regarding "negative"

    Gravity is the conection between space and time, as inteprented by Einsteins General Relativity, behaves very strange around and inside black holes.

    To learn more about this, I suggest you go to the sub forum of astrophysics instead.
     
  14. Sep 30, 2007 #13
    ok, malawi glenn id like to thank you for answering all my stupid questions, but i understand a little, just one more question, were does anti-matter and or dark matter exsist? what is it, thanks for you time, ;)
     
  15. Sep 30, 2007 #14

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    What Dark matter is, no one knows yet. It is matter that dont interact with light in ordinary manner. It is proven that dark matter is sourronding galaxies and hopes of galaxies.

    Anti-matter exists only a fraction of a second, in laboratories and in processes such as decays of nuclei and particles, but are almost directly beeing annihilated (meet corresponding particle) and disapear and leaving photons left.

    Have you tried read about this on wikipedia or hyperphysics?
     
  16. Sep 30, 2007 #15
    no, I dont really understand when I read it on the net anyway, well im going to stop thinking about this sort of stuff now, and hopefully in the next 50 years we will see how much progress we have made with speed and distance travel.

    Cya malawi glenn and thanks for answer all my q's
     
  17. Sep 30, 2007 #16

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

    okay, is this way better to let a guy who meets non-physicts maybe once a month to explain to a guy who himself says he dont understand much about science? :P
     
  18. Sep 30, 2007 #17
    oh, i just remembered my mate told me that light has been slowed down to just 60mph before???? true? and once it reached 60 mph when it was finished being slowed down would it resume its normal speed 186,000 miles per second lol, still cant get my head round that, or would it stay at 60 mph?
     
  19. Sep 30, 2007 #18
    oh, i just remembered my mate told me that light has been slowed down to just 60mph before???? true? and once it reached 60 mph when it was finished being slowed down would it resume its normal speed 186,000 miles per second lol, still cant get my head round that, or would it stay at 60 mph?
     
  20. Sep 30, 2007 #19

    malawi_glenn

    User Avatar
    Science Advisor
    Homework Helper

  21. Oct 1, 2007 #20
    Didn't you already have one thread locked due to a link to a crackpot UFO web site on "anti-gravity" and a complete lack of actual physics?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Slow us down
  1. Why no down/anti-down? (Replies: 10)

  2. Up and down quarks (Replies: 8)

  3. Slow neutrons (Replies: 3)

  4. Up+down scalar meson (Replies: 2)

Loading...