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Could the speed of light be one of the slowest things in the universe?

  1. Apr 15, 2010 #1
    Speed of light – Is it possible that it could be one of the slowest things in the universe?

    While researching and viewing solar flares from our own sun, I was completely amazed by the speed the solar flares are ejected. Then I started thinking about something interesting.

    Pluto's distance from the Sun is somewhere from 4.4 to 7.4 billion kilometers. The speed of light travels at 300,000 km/sec. / 186,000 miles/sec or around 670,616,629 mph. Light, as we know it, takes around 6.8 hours to travel from the Sun to Pluto. This will be the radius of our sample. So, it would be fair to say that light would take about 13.6 hours to travel the diameter of our solar system, assuming Pluto was the last planet in this sphere.

    To me, something that takes 13.6 hours to travel from one point in our solar system to the other may seem fast to many people, but is it really?

    Let’s now go back to that solar flare example from our sun. As a comparison, if we could somehow take a grain of sand (Just a gain) and put it as close to the sun as we can without actually touching the sun (assuming it would not just melt from the massive heat of the sun -- but only as a comparison for size purposes) it would be safe to say that a solar flare from our sun could travel the diameter of that grain of sand in less time than it would take to snap your fingers. Let’s say a 1/10 of a second for this example.

    Now, I would like to step up the scale a little bit.

    Let’s take the largest star we know of Vy Canis Majoris. Vy Canis Majoris would take 11,666,192,832,000,000 earths to fill that star. In comparison, our little solar system (the one that takes light 13.6 hours to cross the diameter) would look like a grain of sand next to this giant star. It takes 7 billion of our suns to fill up Vy Canis Majoris.

    If our solar system is a grain of sand compared to the diameter of Vy Canis Majoris and we could put that grain of sand as close to Vy Canis Majoris without actually touching it, what would happen if the massive Vy Canis Majoris ejected a solar flare?

    Would it be safe to say that the solar flare from Vy Canis Majoris would cross the diameter of that grain of sand in 1/10th of a second? About the time it takes to snap your fingers? Solar flares from stars are solar flares. They eject energy based on the mass of the star.

    If this is the case, that grain of sand happens to be the diameter of our solar system.

    But wait a minute? It takes light 13.6 hours to travel the diameter of our solar system (the grain of sand) and the solar flare of Vy Canis Majoris just crossed that distance in 1/10th of a second? That is more than a trillion times faster than the speed of light, as we know it.

    Now lets take Vy Canis Majoris, the largest star we know of. What if in this vast universe we live in there is another star that would take 7 billion Vy Canis Majoris’s to fill? What if it produced a solar flare, as we call it?

    Physics, as we are thought from our point of view seems to work fine in our little solar system, however, I believe our universe does not care about human logic and I also believe that the speed of light could actually be one of the slowest things in the universe.

    I believe the speed of light is very fast but in the whole universe, could it really be one of the slowest speeds?

    Perhaps constant is not constant at all? It is only constant as we know it.


  2. jcsd
  3. Apr 15, 2010 #2


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    What did your research tell you about the speed they are ejected?
    If the "grain of sand" is our solar system, it would not be safe to say it could cross the diameter in 1/10 of a second, solar flares certainly cannot move faster than light! If that's what you're suggesting, where did you get that idea? The energy of solar flares may be based on the mass of the star but the speed doesn't double each time you double the star's mass.
  4. Apr 15, 2010 #3


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    You got at least one thing correct, assuming that you are using human logic.

    What evidence do you have that makes you think solar flares erupt at speeds greater then c?
  5. Apr 15, 2010 #4


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    Solar flares are not based on the mass of the Star, but on a rearrangement of magnetic lines of force of the star. Even if the energy released were that many times greater, the speed at which the flare travels will not scale up by the same factor, and would never exceed the speed of light. The energy needed to accelerate something to a given speed approaches infinity as that speed nears the speed of light.
  6. Apr 15, 2010 #5
    Unfortunately time scales do not usually remain independent of length scales when viewed at larger scales. Often their is a power law relation that depends on the particular dynamics your are interested in looking at. Let's assume this is linear.

    A dynamic process that crosses the dust in the snap of the fingers when scaled to the size of the solar system would take years, maybe days, to cross the solar system.

    One thing is certain. As it is a continuous acceleration of matter, a solar flair will never exceed the speed of light.
  7. Apr 16, 2010 #6


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    You are assuming things scale linearly and speed at which flares are ejected from other stars is propotional to their size. This is not a valid assumption.
  8. May 7, 2012 #7
    From what I understand, the speed that a solar flare is ejected has nothing to do with the speed of light. Electromagnetic radiation coming from the surface of the sun is moving at 299,792,458 meters per second relative to the particles emitting the electromagnetic radiation. The particles that were accelerated as part of the solar flare also emit electromagnetic radiation. Relative to the moving particles, the electromagnetic radiation is propagating at 299,792,458 meters per second. Could someone correct me if I made a big mistake?
  9. May 7, 2012 #8


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    I would like to point out that VY Canis Majoris has a radius of ~2000 solar radii (and thus, indeed ~(2000)^3=8,000,000,000 suns could fit in it). 2000 solar radii in terms of Astronomical units is ~9.4. This means that if VY Canis Majoris were put into the center of our solar system, it would extend to about 9.4 times as far as the Earth is orbiting (very large indeed!).

    However, pluto orbits the Sun at a radius of between ~30-50AU.

    One can see then, our solar system is certainly NOT a speck of dust compared to VY Canis Majoris, it is in fact larger (much larger if you include the oort cloud as well).

    I just wanted to point this out. There are obviously other flaw of logic, as pointed out by the many posts above.
  10. May 7, 2012 #9


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    I don't know anything about solar flares, but I do know that the speed of electromagnetic radiation is NOT based on, or relative to, the source. The speed is c, regardless of the speed of the source. Surely you've heard that the speed of light is a constant (c) and is independent of its source. What we call "light" is just a part of the electromagnetic spectrum.
  11. May 8, 2012 #10
    Yes, there's really no point in a grain of sand analogy, when you can actually measure and compute things.
  12. Oct 13, 2013 #11
    I just made a scale of the sizes between Sol(our Sun), Westerlund 1 BKS AS(largest star ever discovered), Vy Canis Majoris, and the Pistol Star. I had to make a bigger piece of paper just to get the scaling right because these stars are so massive. I took 4 pieces of drawing paper and taped them together at the edges to make a bigger piece of paper.

    Anyways, not only did I do the size comparisons between stars but I did the approximate diameter of the distance between our Sun and the Earth as well as the distance between our Sun and Pluto. I included both of these distances in a straight line on the same large piece of paper that I created. Even the distance between our Sun and the Earth isn't any where near the size of a grain of sand compared to Vy CM. It is much larger than a grain of sand compared to Vy actually. Not to mention that the distance between our Sun and Pluto is approximately 2.9 times longer than the diameter of Vy Canis Majoris. So with that being said..... our solar system "as a whole" is larger than Vy Canis Majoris.

    Just wanted to point that out.

    If I am wrong then please correct me.
  13. Oct 13, 2013 #12


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