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luc

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Posts posted by luc

  1. I think that what you are referring to is the island of Las Palmas' date=' the third largest of the Canary Islands a few hundred miles off the north west coast of Africa in the Atlantic Ocean. The island is made up of two volcanoes with a high ridge of land running north to south between the peaks. I is believed that around a trillion tons of rock, essentially the half of the western side of the ridge could slide into the sea displacing enough water to create a tidal wave that would inundate the eastern seaboard of the USA up to 100 miles inland!

     

    Apparently, a Hawaiian volcano collapse did something similar to Australia on a much smaller scale. See this Newsmedianews report

     

    It seems something terrific, I wonder what measures can be taken against it. There's some way to stop such a mega-tsunami in its way towards the coast of the USA?. Is there any way to impede the collapse of the cliff in the Canary Islands?

    http://www.bbc.co.uk/science/horizon/2000/mega_tsunami.shtml

    "Although the volcano presents no danger while it is quiescent, scientists believe the western flank will give way completely during some future eruption on the summit of the volcano. In other words, any time in the next few thousand years a huge section of southern La Palma, weighing 500 thousand million tonnes, will fall into the Atlantic ocean.

    What will happen when the volcano on La Palma collapses? Scientists predict that it will generate a wave that will be almost inconceivably destructive, far bigger than anything ever witnessed in modern times. It will surge across the entire Atlantic in a matter of hours, engulfing the whole US east coast, sweeping away everything in its path up to 20km inland. Boston would be hit first, followed by New York, then all the way down the coast to Miami and the Caribbean."

  2. Would you prefer me to use incorrect English? This language is flawed and a crazy concoction of meaningless phrases!

    I have no use for the. If teh was to be stricken from the world i would be a happy man. However' date=' if it pleases you, i shall never use it again.[/quote']

     

    I second that. I won't use the word The anymore

     

    Down with the word The!!!!

  3. There are a large number of four vectors in SR. You list some of them' date='

    but also some that are not four vectors.

    1. The velocity four-vector is (g,g v), where g is the SR gamma and v is the usual three-vector velocity we would measure as dx/dt.

    2. Acceleration is not a four vector in SR.

    3. Force (and acceleration) are not useful variables in SR.

    A four-vector force, the so called "Minkowski force" can be defined by

    F=(g dW/dt,g dp/dt} where W is the energy and p the three-vector momentum of a particle.

    4. The energy-momentum four-vector is (W,p).

    5. The displacement four-vector is (t,x,y,z).

    6. The four-potential is usually written as (phi,A), where phi was the NR scalar potential and A the NR vector potential. A is no longer referred to as "magnetic" because it also affects the electric field.

    7. The current four-vector is (rho,j).

    8. There is a four-divergence, which is a four-vector.

    9. Taking the four-divergence of tensors lead to other four-vectors.

    10. ... and so on.[/quote']

     

    Do you mean that there're an infinite number of different kind of 4-vectors? Or a finite number? If is a finite number what number is it?

  4. I mean the 4-potential where the components are (@,Bx,By,Bz), where @ is the scalar magnetic potential, and the Bs are the components of the vector magnetic potential

  5. Ok, i'm trying to figure out how many different 4-vectors exist in SR

     

    -4-velocity

    -4-acceleration

    -4-force

    -energy-momentum 4-vector

    -displacement 4-vector

    -4-potential

     

     

    Is there some other? How many different 4-vectors exist in Special Relativity?

  6. Tom, I'm referring to the Lorentz tensor used to transform a displacement 4-vector from one frame of reference to another

     

    The equation goes this way:

     

    D=LD'

    where L is the Lorentz tensor

  7. If time slows down as object or person nears the speed of light, then wouldn't everyone in this universe be in different time (my soul is in different time than your soul. I've seen part of you that you haven't experienced yet) since everyone is moving in different speed?

     

    You should try to define what's soul. I've seen gedankenexperiments in SR in which clocks are compared, but this is the first time that I read somebody wanting to compare souls

  8. How many stress-enrgy tensors exist? i know that there's the stress energy tnesor for a perfect fluid, that is the tensor that is habitually used to represent our Universe. there's also a stress energy tensor for a void universe. But I would like to know how many there are, I'm thinking even about the possibility that there exist an infinite number of different stress-energy tensors

  9. Consider the landscape of string theory, with its bazillion of different vacua, each vacua representing an universe. Is possible to travel to another vacua? :confused: If our universe is one of these vacua, can we travel to another vacuum? Is possible? Using a Black hole? Ideas, please

  10. is it the same one as my avatar?

    Yes, it's the same. In september 2004 there appeared info about this planet, but then it was less sure that it was truly a planet.

    Anyway (even that is impossible that this message get to them), greetings to the habitants of that distant planet! Here in Earth we are a bit crazy and bad tempered sometimes, but deep in our hearts we are good people!

  11. I read here and there that massless vector bosons carrying forces (e.g., the photon carrying electromagnetic force, or (if exist) the graviton carrying gravity force) can travel faster than light. I have never read tho' if there's a limit for that velocity, so I'm interested to know that limit, what's the maximum velocity that can acquire virtual particles

     

    Bye

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