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Tunguska event and blackholes

  1. Oct 20, 2007 #1
    Hi there! I have not yet taken any physics courses at my high school and so am an utter neophyte to physical science but I am about to run a roleplaying game that involves superheroes, alien invasions, black holes, and weather control and I have a few questions that probably are simple to you but stump me.

    OK now to the questions!

    1)I have heard a theory that the Tunguska event (http://en.wikipedia.org/wiki/Tunguska_event) was not caused by a comet but by a mini-black hole. What would happen if this was true? How do black holes work?

    2)Now I do know at least one thing about physics; light speed isnt broken ever. So, how would aliens from millions of light years away reach earth if possible? I guess this is more of an astronomy question but still...

    3)How do different dimensions work? Are there different dimensions?

    4)Can the Earth's weather be controlled without breaking any laws of physics?

    Thanks a ton in advance!!
  2. jcsd
  3. Oct 20, 2007 #2
    1) Check blackholes on wikipedia, or continue reading my mediocre explanation of black holes. Matter attracts matter, and the bigger mass the matter has the bigger attraction it has on other matter. For example earth attracts us with an acceleration of 9,82m/s^2. If earths mass would be bigger, we would be drawn to the ground even harder. Blackholes has such a big mass, that it attracts everything around it, even light. The light can come in, but not out, since its attraction power is so huge. And since no light can reflect on it we can't see it.

    2) I would say its not possible :)
  4. Oct 20, 2007 #3


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    1. I noticed a paper on the arxiv last week on this type of topic. I don't know whether it will be any use, but it's kind of related to your question: http://arxiv.org/abs/0710.3438

    3. What do you mean by "extra dimensions"? Do you mean, say, more than the four spacetime dimensions?

    4. Yea, sure, some of it can. I don't think the methods are that advance though. See, for example, http://en.wikipedia.org/wiki/Weather_control
  5. Oct 20, 2007 #4


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    Superheroland is not limited by real physics.

    I am both an armchair physics enthusiast and an avid superhero roleplayer. When I have a moment I'll try to answer your ?'s.

    You can PM me if you want.
  6. Oct 21, 2007 #5
    2. You might zero in on the Doppler shift. Just because light has a maximum velocity here, doesn't preclude the possibility that there are regions of space or gaps between galaxies where other limits could exceed c. Now this is only speculation. But if an external light source were to enter our system it could be that the observed shift is a reflection of it adjusting to our speed limit...

    So the idea is that once you leave our galaxy, you can zip between them through a gap in time space. Anyways, this idea might work in a comic book but its not physics.
  7. Oct 21, 2007 #6


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    I don;t really know what led them to speculate about a black hole - there's no evidence that points in that direction. I suppose it's an attempt to explain the devastation despite the lack of crater or alleged lack of extraterrestrial material found at the site.

    The idea is that the black hole passed through Earth like a knife through butter and exited unseen, somewhere in the Atlantic ocean.

    Of course, if it were captured by Earth's gravity we'd be in trouble. It could orbit the Earth, punching holes in it every few months or days or hours. The orbits would likely be highly unpredictable, thus so would the disasters.

    A worse scenarios is that its orbit does not carry it outside the Earth's surface, so it orbits internally, eating away at Earth's core and growing all the while.

    You could make a plotline of a parallel orbit with Earh where the black hole might intercept Earth on a much longer time period (there are asteroids that share Earh's orbit and wander near and far over years).

    Of course, you might have to propose a mechanism whereby the BH wasn't a continuous shining beacon of radio and X-rays in our sky...


    This is a trickier one. When we talk about dimensions in Physics, we talk about dimensions that are all around us - we're used to x,y and z, some theories propose that there are more dimensions detectable at extremely small scales.

    Think about a man walking across a tightrope. The man experiences the tightrope as a one-dimensional object - it has length, and iin it, he has one degree of freedom: forward and backward. Nows think about an ant. The Ant can wlak along the rope , but alos around the rope. The ant experiences two degrees of freedom (though one of them is still quite small and wraps around rather quickly). That second dimension is always there, though it doesn't do much good the the man.

    But these are NOT the dimensions like you read about - they're not "alternate dimensions" where a point in our dimension is correlated with a point in another dimension, and you can move back and forth between them. That's just fantasy.

    Who knows. I don't see why it couldn't be done in principle.
  8. Oct 21, 2007 #7


    Staff: Mentor

    There are two basic ways that it could theoretically be done. One is to travel at speeds close to the speed of light for a couple of decades of proper time. During that time millions of years could pass for the earth while only a few decades have for the intrepid aliens. This is possible simply using special relativity.

    The other way is to use general relativity and "bend space" in such a way that their distant galaxy is millions of light years away the normal route, but much closer via some shortcut. The usuall label for that is a wormhole or a warp.
  9. Oct 21, 2007 #8
    Everybody knows the Tunguska event was caused by aliens crash landing at the site, duh.

    I'm just kidding. But actually there are eye witnesses that say they saw something cause the event, that was traveling from the sky to the site. Thus I would guess it is a meteor since you can't quite see a black hole in such an event, right?
  10. Oct 21, 2007 #9


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    Whether one can literally see a BH is moot. One sees the halo of radiation and matter that surrounds it. Effectively there's no difference.
  11. Oct 21, 2007 #10
    I like the idea of aliens traveling close to the speed of light for 10 of their years and coming to Earth and seeing "OMG there's like, 6 Billion people here now!" I think I'll use that for some plot hooks. I'll do some aliens want to (and do) conquer Earth others want to be friends, ect. :)

    I also like the idea of a BH orbiting Earth and punching random holes in it at different intervals and have the heroes try to stop that big ole mess (possibly a back-fire from the Alien Spaceships traveling so close to the speed of light?)

    I think I understand differing dimensions now, but I don't think I can use them as a plot hook.

    Thanks for your help everyone, I have a graduate student in Physics in the game so I want it to be as close to believable as possible. Not me just being me saying "It happens because I say so!!!" stuff ;).

    Weather control mad scientist with robot minions, first chapter :evil: :).
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