OT: Things that go bump in the night

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  • SlimerJSpudSlimerJSpud Posts: 1,456

    From the Casimir effect, you are led to this one, which could be the real warp drive of Zefram Cochrane:

    https://en.wikipedia.org/wiki/Alcubierre_drive

     

  • Gravitational waves, not gravity waves. They're two different things.

  • LeatherGryphonLeatherGryphon Posts: 12,251
    edited February 2016

    Gravitational waves, not gravity waves. They're two different things.

    surprise 'splain for the rest of us.

     

    Post edited by LeatherGryphon on
  • TJohnTJohn Posts: 11,352

    Gravitational waves, not gravity waves. They're two different things.

    surprise 'splain for the rest of us.

     

    http://news.discovery.com/space/gravitational-waves-vs-gravity-waves-know-the-difference-160208.htm

  • Tjohn said:

    Gravitational waves, not gravity waves. They're two different things.

    surprise 'splain for the rest of us.

     

    http://news.discovery.com/space/gravitational-waves-vs-gravity-waves-know-the-difference-160208.htm

    Oh. indecision  OK, I understand the gravity of it.

     

  • SlimerJSpudSlimerJSpud Posts: 1,456

    And while we're on the subject of "Know the difference," there's another term being conspicuously misused lately. Even in the Daz store, there's a camera and script product that purports to enable you to render and show Holograms on your smartphone. YouTube is ablaze with them. These displays are *not* Holograms. With a true Hologram, you could move around to the other side of the display and see the other side of the figure being displayed. A true Hologram usually involves lasers. These smartphone displays are a fun toy, I've made one to play with, but they are not Holograms. What these displays most resemble is a Heads Up Display (HUD) from a fighter jet, or flight sim game. Anybody who ever spent time in a flight sim knows what a HUD is. A HUD is basically a beam splitter. You can see through it, but you can also see some image projected towards your eyes by the reflective surface. The gimmick on the smartphone uses clear pieces of plastic so that the projected image appears to "float" above the surface of the phone. Neat trick, but not a Hologram. You also cut the image on the smartphone screen down to 1/4 of the full screen.

  • LeatherGryphonLeatherGryphon Posts: 12,251
    edited February 2016

    Yeah, I caught that too.  I used to pounce on it but have given up.  The word "Hologram" has become property of the masses and must now be considered in context whenever it's seen.  True holograms are wonders but are rarely seen outside of hologram museums.  There was one in Washington DC that had a marvelous hologram of a microscope complete with a holographic subject on the holographic microscope stage and you looked through a holographic eyepiece that stuck out about 8 inches from the wall toward your face.  Marvelous.

    Post edited by LeatherGryphon on
  • I thought the "holograms" sounded more like a min-Pepper's Ghost effect, a view formed from absolutely no in-depth research.

  • SpitSpit Posts: 2,342
    edited February 2016
    Tjohn said:

    Gravitational waves, not gravity waves. They're two different things.

    surprise 'splain for the rest of us.

     

    http://news.discovery.com/space/gravitational-waves-vs-gravity-waves-know-the-difference-160208.htm

    Read the comments. Luboš Motl, a physicist, appears there and says that among scientists themselves it doesn't really matter which term you use.

     

    Post edited by Spit on
  • LeatherGryphonLeatherGryphon Posts: 12,251
    edited February 2016

    I read the comments.  That is, until I started to roll my eyes.  I can see how at one time people argued about how many angels could stand on the head of a pin.  Oy crying  I'm glad nothing like that happens here. angel  My philosophy is I don't argue.   I say what I believe, I smile if someone seems to agree.  If they don't agree I'll try once or twice to clarify my wording, but failing that will stamp the dust off my feet and move on. enlightened It's no skin off my nose.  And if someone actually says something well enough that it changes my mind I'll admit it instead of dogmatically defend my honor like some wound-up puppet as many arguers tend to evolve to.

    Post edited by LeatherGryphon on
  • SpitSpit Posts: 2,342

    I read the comments.  That is, until I started to roll my eyes.  I can see how at one time people argued about how many angels could stand on the head of a pin.  Oy crying  I'm glad nothing like that happens here. angel  My philosophy is I don't argue.   I say what I believe, I smile if someone seems to agree.  If they don't agree I'll try once or twice to clarify my wording, but failing that will stamp the dust off my feet and move on. enlightened It's no skin off my nose.  And if someone actually says something well enough that it changes my mind I'll admit it instead of dogmatically defend my honor like some wound-up puppet as many arguers tend to evolve to.

    Yeah..and especially arguing which term to use seems rather silly. I mentioned it only because I know and respect Luboš on things scientific.

  • icprncssicprncss Posts: 3,694

    Gravity?  Sounds familiar.  What does it do again?

  • LeatherGryphonLeatherGryphon Posts: 12,251
    edited February 2016
    icprncss said:

    Gravity?  Sounds familiar.  What does it do again?

    Don't think about it too hard.  Just relax, you'll fall into it.

    or

    "Gravity": It's what you put on meat and potatoes.

    or

    It's the hole into which the Universe drains.

     

    Post edited by LeatherGryphon on
  • kyoto kidkyoto kid Posts: 42,159

    ...gravity sucks.

  • ps1borgps1borg Posts: 12,776
    kyoto kid said:
    Spit said:
    ...

    Currently wnen letting my brain wander in unusual directions I keep finding myself asking "WHY does light have a speed?"  Sometimes I think I've found a trustworthy explanation or reasoned it out myself, and ever so briefly I have an epiphany and it becomes obvious but the moment quickly passes.  I know there is an exciting and illuminating answer but it's like trying to understand television while blind.

    Love it. I've often thought about when physicists 'see' a particle change spin, it's 'sister' across the room, so to speak, changes too. Einstein's 'spooky action at a distance'. I think they're actually looking at the same particle in a different way. Then I go off and do the dishes and don't think about it again for months.

    ...I always wondered if there was such a thing as "slow light".

    Google is your friend: http://www.gla.ac.uk/news/headline_388852_en.html

    But don't think that this means that the slowpoke photons are not travelling at the speed of light!  It all comes back to my question of "WHY does light have a speed?"

     

    If I remember right  light speed satisfies the Lorenz invariant (covariant?) for symetries in for instance quantum chromodynamics, which predict light and gravity and (I forget what else) travels at c in a vacuum (I think) 

  • icprncssicprncss Posts: 3,694

    "...they've gone to plaid..."

  • ps1borg said:
    kyoto kid said:
    Spit said:
    ...

    Currently wnen letting my brain wander in unusual directions I keep finding myself asking "WHY does light have a speed?"  Sometimes I think I've found a trustworthy explanation or reasoned it out myself, and ever so briefly I have an epiphany and it becomes obvious but the moment quickly passes.  I know there is an exciting and illuminating answer but it's like trying to understand television while blind.

    Love it. I've often thought about when physicists 'see' a particle change spin, it's 'sister' across the room, so to speak, changes too. Einstein's 'spooky action at a distance'. I think they're actually looking at the same particle in a different way. Then I go off and do the dishes and don't think about it again for months.

    ...I always wondered if there was such a thing as "slow light".

    Google is your friend: http://www.gla.ac.uk/news/headline_388852_en.html

    But don't think that this means that the slowpoke photons are not travelling at the speed of light!  It all comes back to my question of "WHY does light have a speed?"

     

    If I remember right  light speed satisfies the Lorenz invariant (covariant?) for symetries in for instance quantum chromodynamics, which predict light and gravity and (I forget what else) travels at c in a vacuum (I think) 

    Let me restate my question.  It looks like a duck and quacks like a duck, but why is there a duck?

     

  • Peter WadePeter Wade Posts: 1,682

    I read the comments.  That is, until I started to roll my eyes.  I can see how at one time people argued about how many angels could stand on the head of a pin.  Oy crying  I'm glad nothing like that happens here. angel  My philosophy is I don't argue.   I say what I believe, I smile if someone seems to agree.  If they don't agree I'll try once or twice to clarify my wording, but failing that will stamp the dust off my feet and move on. enlightened It's no skin off my nose.  And if someone actually says something well enough that it changes my mind I'll admit it instead of dogmatically defend my honor like some wound-up puppet as many arguers tend to evolve to.

    No, the arguments were about how many angels can dance on the head of a pin, not just stand there. There were vatious branches of reserch covering ballroom dancing, tap dancing, line dancing etc. But since modern dancing seems to be just standing in a warehouse and jiggling around a lot maybe the topic should be re-visited. There might be a research grant in it for someone smiley

  • SlimerJSpudSlimerJSpud Posts: 1,456

    If a man and a half can dig a hole and a half in a day and a half, how far is it from here to Chicago?

  • SlimerJSpudSlimerJSpud Posts: 1,456

    I thought the "holograms" sounded more like a min-Pepper's Ghost effect, a view formed from absolutely no in-depth research.

    Pepper's ghost is also a beam-splitter effect, but it's based on changing the light levels between the real and reflected image. It's the old girl-turns-into-gorilla trick.

  • LeatherGryphonLeatherGryphon Posts: 12,251
    edited February 2016

    I thought the "holograms" sounded more like a min-Pepper's Ghost effect, a view formed from absolutely no in-depth research.

    ...  It's the old girl-turns-into-gorilla trick.

    It's no trick.  Happens to too many women after marriage. surprise

     

    Post edited by LeatherGryphon on
  • icprncssicprncss Posts: 3,694
    ps1borg said:
    kyoto kid said:
    Spit said:
    ...

    Currently wnen letting my brain wander in unusual directions I keep finding myself asking "WHY does light have a speed?"  Sometimes I think I've found a trustworthy explanation or reasoned it out myself, and ever so briefly I have an epiphany and it becomes obvious but the moment quickly passes.  I know there is an exciting and illuminating answer but it's like trying to understand television while blind.

    Love it. I've often thought about when physicists 'see' a particle change spin, it's 'sister' across the room, so to speak, changes too. Einstein's 'spooky action at a distance'. I think they're actually looking at the same particle in a different way. Then I go off and do the dishes and don't think about it again for months.

    ...I always wondered if there was such a thing as "slow light".

    Google is your friend: http://www.gla.ac.uk/news/headline_388852_en.html

    But don't think that this means that the slowpoke photons are not travelling at the speed of light!  It all comes back to my question of "WHY does light have a speed?"

     

    If I remember right  light speed satisfies the Lorenz invariant (covariant?) for symetries in for instance quantum chromodynamics, which predict light and gravity and (I forget what else) travels at c in a vacuum (I think) 

    Let me restate my question.  It looks like a duck and quacks like a duck, but why is there a duck?

    Because they ran out of geese?

     

     

  • SlimerJSpudSlimerJSpud Posts: 1,456

    I thought the "holograms" sounded more like a min-Pepper's Ghost effect, a view formed from absolutely no in-depth research.

    ...  It's the old girl-turns-into-gorilla trick.

    It's no trick.  Happens to too many women after marriage. surprise

     

    With men, it's usually the opposite. After a few years of listening to She Who Must Be Obeyed, the hairy ape she married might be considered somewhat civilized ... except on game day!
     

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