1. Post #321
    I am a moderator.
    Swebonny's Avatar
    August 2006
    12,837 Posts
    I remember seeing similar pictures a few years back. Makes more sense now:


    Edit:
    I'm glad only things we're doing in physics are about particles and waves.
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  2. Post #322
    Yep. Light cones in that picture are at upward 45 degree angles. So a light beam in the right exterior region can only travel into the black hole or along the event horizon to end up on the event horizon of the other hole along the boundary of the other space time region, but can never actually enter it.
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  3. Post #323
    Meow :3
    Ac!dL3ak's Avatar
    July 2005
    6,043 Posts
    How do you even wrap your head around that
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  4. Post #324
    Gold Member
    Alan Ninja!'s Avatar
    February 2009
    1,848 Posts
    JohnnyMo1 posted:
    PHYSICS
    Oh dear, perhaps I should have been a criminal-justice major after all.
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  5. Post #325
    Oh dear, perhaps I should have been a criminal-justice major after all.
    It's hard, but I find GR really really interesting once you understand it. Like earlier today I was reading about the Penrose process, by which you can steal energy from a black hole by robbing it of some of its angular momentum.
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  6. Post #326
    I am a moderator.
    Swebonny's Avatar
    August 2006
    12,837 Posts
    Funny, I was dealing with angular momentum too, although on a much smaller scale (hydrogen atom). Big boys getting all the large angular momentums, unfair!
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  7. Post #327
    Gold Member
    Alan Ninja!'s Avatar
    February 2009
    1,848 Posts
    I honestly love physics; what could be cooler than learning how the universe works?    nothing    Problem is, I'm becoming increasingly worried about whether or not I can actually do the math it requires. I'm barely getting though Calculus II as it is, and its only going to get worse.
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  8. Post #328
    I am a moderator.
    Swebonny's Avatar
    August 2006
    12,837 Posts
    I honestly love physics; what could be cooler than learning how the universe works?    nothing    Problem is, I'm becoming increasingly worried about whether or not I can actually do the math it requires. I'm barely getting though Calculus II as it is, and its only going to get worse.
    Are you actually spending time doing your math? I really learned it the hard way that if you want to understand, you have to spend time trying to understand. It's kinda like a language. You have to keep using it to not lose your knowledge. Something that I fail to do. I'm already a week behind schedule in my Calculus III.
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  9. Post #329
    I honestly love physics; what could be cooler than learning how the universe works?    nothing    Problem is, I'm becoming increasingly worried about whether or not I can actually do the math it requires. I'm barely getting though Calculus II as it is, and its only going to get worse.
    I assume you're at a university? Look up good references for whatever is confusing you online, see if the library has them.
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  10. Post #330
    HQRSE FUCKER
    ief014's Avatar
    September 2009
    3,045 Posts
    Brought home a Canon SX40HS camera today. Gonna try some sky shots this weekend when I'm out of the city.
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  11. Post #331
    Gold Member
    DesolateGrun's Avatar
    July 2008
    6,242 Posts
    Firstly, I made no claim that it was necessarily true. Secondly, how much do you know about GR and white holes? That is not at all the justification for it.
    Absolutely nothing! All I know is the reasoning behind white holes is that the matter that goes into black holes cannot be lost if we follow the law of conservation of mass and energy? But other than that I am un aware of anything else to that.
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  12. Post #332
    Absolutely nothing! All I know is the reasoning behind white holes is that the matter that goes into black holes cannot be lost if we follow the law of conservation of mass and energy? But other than that I am un aware of anything else to that.
    No, that's not the reasoning behind it. The energy goes into the black hole anyway. It's not lost.
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  13. Post #333
    Gold Member
    DesolateGrun's Avatar
    July 2008
    6,242 Posts
    No, that's not the reasoning behind it. The energy goes into the black hole anyway. It's not lost.
    aw man
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  14. Post #334
    Falubii's Avatar
    May 2010
    3,387 Posts
    I want to be Gordon Freeman someday.
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  15. Post #335
    I want to be Gordon Freeman someday.
    I want to publish a paper called "Observation of Einstein-Podolsky-Rosen Entanglement on Supraquantum Structures by Induction Through Nonlinear Transuranic Crystal of Extremely Long Wavelength (ELW) Pulse from Mode-Locked Source Array" and see if anyone gets it.
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  16. Post #336
    Falubii's Avatar
    May 2010
    3,387 Posts
    I want to publish a paper called "Observation of Einstein-Podolsky-Rosen Entanglement on Supraquantum Structures by Induction Through Nonlinear Transuranic Crystal of Extremely Long Wavelength (ELW) Pulse from Mode-Locked Source Array" and see if anyone gets it.
    I certainly don't.
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  17. Post #337
    I certainly don't.
    It's Gordon's doctoral thesis.
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  18. Post #338
    Gold Member
    DesolateGrun's Avatar
    July 2008
    6,242 Posts
    I want to publish a paper called "Observation of Einstein-Podolsky-Rosen Entanglement on Supraquantum Structures by Induction Through Nonlinear Transuranic Crystal of Extremely Long Wavelength (ELW) Pulse from Mode-Locked Source Array" and see if anyone gets it.
    Well his proffesor should have failed him because tge resonance cascade was mentiones NOWHERE throughout the whole thing
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  19. Post #339
    Gold Member
    FunnyBunny's Avatar
    December 2006
    4,724 Posts
    Fuck yes, just found out SpaceX is giving a talk at my school next week.
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  20. Post #340
    Gold Member
    DesolateGrun's Avatar
    July 2008
    6,242 Posts
    Fuck yes, just found out SpaceX is giving a talk at my school next week.
    What the fuck let us I'm on this
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  21. Post #341
    OvB
    Facepunch resident scientist
    OvB's Avatar
    March 2007
    12,718 Posts


    That's a pretty intense photo of Musk. (I also love the lightning)
    Elon is such a cool guy. He seems like a normal person after seeing his interviews. He's definitely up there on my list of people whose hands I need to shake before I/they die.

    Edited:

    You'll be interested to hear then that they have a launch scheduled for April 30th where they will send up their own spacecraft to dock with the ISS (arrives May 3rd).

    Edited:

    That rocket is significantly larger though:

    "HIGH REACH"
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  22. Post #342
    I honestly love physics; what could be cooler than learning how the universe works?    nothing    Problem is, I'm becoming increasingly worried about whether or not I can actually do the math it requires. I'm barely getting though Calculus II as it is, and its only going to get worse.
    God, I have no real problem with the concepts and ideas behind black holes, general relativity and all of that. But I can't mathify worth shit, I'm terrible at maths, and if I plan to work with astrophysics I need to become a lot better within that.
    My real beef doesn't come in calculus form, but the simplest of math. I can't divide more then the absolutely most basic stuff without a calculator and I can't take 7 times 3 in my head. My brain's annoyingly selective when it comes to math regarding what I know well and what I'm horrible at, which is divided ca. 50/50.
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  23. Post #343
    Gold Member
    Pelf's Avatar
    September 2007
    2,924 Posts
    Fuck yes, just found out SpaceX is giving a talk at my school next week.
    What school? Be sure to fill us in.
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  24. Post #344
    Robbi's Avatar
    March 2012
    1,001 Posts
    Fuck yes, just found out SpaceX is giving a talk at my school next week.
    Can I come over next week?
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  25. Post #345
    Gold Member
    booster's Avatar
    July 2006
    20,702 Posts
    I've had this thought ever since I saw that talk on TED concerning the asteroid Apophis, and the means they plan on using to change its course. And when he started talking about using a satellite as a sort of gravitational tether to slowly but surely alter its course, it got me thinking , what if we used this tethering so precisely that we could later direct this asteroid into our own orbit and then somehow mine it. I know it sounds very optimistic, but I wouldn't label it an impossible mission considering we have about 17 years until it is supposedly going to "arrive". So that'd mean we'd have about 15 or so years (due to planning and whatnot) to develop the technology necessary. Not only would this be a milestone in space missions, but it'd be the beginning for asteroid mining. Do you guys think there would be any chance of this actually happening in 2029, or is it just a dream that won't come true for another century?
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  26. Post #346
    Gold Member
    Pelf's Avatar
    September 2007
    2,924 Posts
    I've had this thought ever since I saw that talk on TED concerning the asteroid Apophis, and the means they plan on using to change its course. And when he started talking about using a satellite as a sort of gravitational tether to slowly but surely alter its course, it got me thinking , what if we used this tethering so precisely that we could later direct this asteroid into our own orbit and then somehow mine it. I know it sounds very optimistic, but I wouldn't label it an impossible mission considering we have about 17 years until it is supposedly going to "arrive". So that'd mean we'd have about 15 or so years (due to planning and whatnot) to develop the technology necessary. Not only would this be a milestone in space missions, but it'd be the beginning for asteroid mining. Do you guys think there would be any chance of this actually happening in 2029, or is it just a dream that won't come true for another century?
    According to Wikipedia, the average orbital speed of Apophis is 30.728 km/s. Orbital speed for LEO is about 7.8 km/s. It would have to be slowed down a lot for it to enter orbit.
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  27. Post #347
    We're made of star-stuff
    LarparNar's Avatar
    February 2009
    10,078 Posts
    According to Wikipedia, the average orbital speed of Apophis is 30.728 km/s. Orbital speed for LEO is about 7.8 km/s. It would have to be slowed down a lot for it to enter orbit.
    Pretty sure that's orbital velocity relative to the sun.

    It would most likely have to be slowed down quite a bit to stay in orbit though, I don't know what it's earth-relative velocity is, and I can't find it on Wikipedia.
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  28. Post #348
    So we observe the vacuum energy to be something like 10^-8 ergs/m^3 and QFT predicts it to be on the order of 10^112 ergs/m^3. 120 orders of magnitude: close enough!
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  29. Post #349
    Scarbo's Avatar
    January 2010
    453 Posts
    So we observe the vacuum energy to be something like 10^-8 ergs/m^3 and QFT predicts it to be on the order of 10^112 ergs/m^3. 120 orders of magnitude: close enough!
    I was wondering about vacuum energy; since it's impossible to have a complete vacuum because of quantum fluctuations, does that make the entire universe a completely infinite source of energy? Could we somehow continue to extract energy from a cubic metre of space forever?
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  30. Post #350
    I was wondering about vacuum energy; since it's impossible to have a complete vacuum because of quantum fluctuations, does that make the entire universe a completely infinite source of energy? Could we somehow continue to extract energy from a cubic metre of space forever?
    10^-8 ergs could power a 40-Watt bulb for 0.000000000000000025 seconds.

    So not exactly infinite energy.
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  31. Post #351
    Most of you have probably seen it or heard it already, but I just love this
    Sagan is such a poet.
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  32. Post #352
    Dennab
    January 2009
    1,725 Posts

    So, what do you think about that supposed monolith on Mars?
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  33. Post #353
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  34. Post #354
    Gold Member
    Pelf's Avatar
    September 2007
    2,924 Posts
    I read that it's just a roughly rectangular boulder and the low resolution (1px = 1 foot) obscures the finer details making it look like some sort of monolith.

    Edited:

    Another version:



    (click it)
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  35. Post #355
    Robbi's Avatar
    March 2012
    1,001 Posts

    So, what do you think about that supposed monolith on Mars?
    Clearly Aliens preparing to invade.
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  36. Post #356
    I think we should try and touch it, so we can evolve.
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  37. Post #357
    OvB
    Facepunch resident scientist
    OvB's Avatar
    March 2007
    12,718 Posts
    Look who I found in the campus library the other day.

    Unfortunately the real Buzz was not there to my knowledge.
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  38. Post #358
    Captain Armed Dildo, Master of Ratings
    cpt.armadillo's Avatar
    February 2011
    5,455 Posts
    I think we should try and touch it, so we can evolve.
    But think of all the space children!
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  39. Post #359
    We're made of star-stuff
    LarparNar's Avatar
    February 2009
    10,078 Posts
    Look who I found in the campus library the other day.

    Unfortunately the real Buzz was not there to my knowledge.


    A7L suit (same kind Buzz used) without the outer layer.
    Looks pretty solid.

    Those things are also incredibly expensive.


    Edit: Here I am, talking about space suits, and I manage to put an image in quote tags instead of image tags...

    Edited:

    Buzz is a boss btw:

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  40. Post #360
    Gold Member
    J Paul's Avatar
    October 2007
    2,860 Posts
    I personally like the A7LB suits modified for Skylab. They have a Gemini-like helmet, but also they have most of the features and improvements made for the later Apollo missions.

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