Posted by: Jack | April 25, 2007

Neil DeGrasse Tyson vs. the Speed of Light

I’m currently reading and enjoying the ever-popular Death by Black Hole and Other Cosmic Quandaries by Neil DeGrasse Tyson. I’m only about half way through but I’m certain this book will end up on my list of recommended reads.

Tonight I’m posting because I believe I have found a passage stating a theory about the beginning of the universe which seems to violate the physical limit that is the speed of light. Now I’m no astrophysicist–Tyson is–so I am assuming that the mistake is actually a misunderstanding on my part. I did a search online for anyone else who may have come to the same conclusion, be it valid or not, but came up empty.

Here is the passage in question:

As the laws of thermodynamics decree, within about one second after the big bang, the expanding fireball had cooled to 10 billion degrees and ballooned from something smaller than an atom to a cosmic colossus about a thousand times the size of our solar system.

Here are some figures which are pertinent to my argument:

  • Size of the universe at the instant of the big bang…I don’t really know but for my purposes here a value of 0 meters will suffice
  • Size of our solar system – 12,000,000,000,000 meters (1.2×10^13)
  • Tyson’s proposed size of the universe one second after the big bang – 12,000,000,000,000,000 meters (1.2×10^14)
  • Speed of light – 299,792,458 meters/second
  • Proposed distance traveled by matter and energy in first second after big bang – 6,000,000,000,000,000,000 meters (6×10^14)
  • Proposed speed of matter and energy in first second after big bang – 6×10^14 meters/second

It’s likely that you’ve already spotted the dilemma. For the universe to have expanded that quickly, matter/energy would have to have traveled far faster than the speed of light. In fact they would have to have traveled 20,000,000 times the speed of light to achieve such an expansion. According the the Star Trek Episode-Writer’s Guide, the absolute limit of space travel speed is just under 200,000 times the speed of light (Warp 10). And according to just about every non-fiction source, the absolute limit is simply the speed of light.

Can anyone let me know if they see a flaw in my conclusion? I have done some more searching and found that the speed of light may not be the absolute limit Einstein spoke of. Various theories in the fields of condensed matter physics, classical physics and quantum theory have proposed the possibilities of faster-than-light velocities. Also, some astrophysicists believe the speed of light may not be constant throughout time and may have been faster in the past. However, the fastest suspected speed of light is only 60 times the current value, not even a crawl in comparison to the 6×10^14 meters/second calculated above.

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Responses

  1. […] by Black Hole and Other Cosmic Quandaries and have greatly enjoyed it thus far. I mentioned in a previous post that within this book I found a description of the beginning of universe which seemed to violate […]


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