看了这个你就明白了。以前我也不明白。胡乱质疑会犯常识性错误。

The speed of light, (or the speed of a photon) in a near-perfect vacuum is exactly 186,282 miles per second. We perceive photons (light) traveling at this speed because they are massless, or have no ‘weight’ (but they do have kinetic energy, more on that in a bit).

Every particle in our universe (including photons) move or ‘swim’ through what scientists call “the Higgs field”. As a result of this interaction, particles acquire their mass. Different particles interact with the Higgs field with different strengths, which is why some particles are heavier (have more mass) than others. Photons move through, but do not interact at all with the Higgs field.

1. Why Can't Anything Go Faster Than The Speed Of...

   http://zidbits.com/2011/05/why-cant-anything-go-faster-than-the-speed-of-light/

   May 18, 2011 ... So to sum up, nothing can travel faster than light because the speed of lightcan be thought of as infinite speed. To match or exceed it would be ...

2. Why can't anything travel faster than light? |...

   cosmosmagazine.com/physical-sciences/why-can%E2%80%99t-anything-travel-faster-light

   Jan 5, 2015 ... Roger Rassool looks at how we first began trying to measure the speed of light, and why it is finite. Listen to this article ...

3. Why you can't travel at the speed of light |...

   www.theguardian.com/science/2014/jan/12/einstein-theory-of-relativity-speed-of-light

   Jan 12, 2014 ... This explains why nothing can travel faster than light – at or near light speed, any extra energy you put into an object does not make it move ...

1. What's the fundamental reason why the speed of...

   www.quora.com/Whats-the-fundamental-reason-why-the-speed-of-light-cannot-be-broken

   Why does the universe want to preserve the upper barrier on speed of light so much so that it readily ..... (Why can't light travel faster than the speed of light?).

2. Probing Question: Can anything travel faster than...

   http://phys.org/news/2006-03-probing-faster.html

   Mar 23, 2006 ... According to Einstein's theory of special relativity, published in 1905, nothing can exceed the speed of light. That speed, explained Einstein, is a ...

3. Faster-than-light travel: Are we there yet? |...

   http://earthsky.org/space/faster-than-light-travel-are-we-there-yet

   May 11, 2015 ... There's a cosmic speed limit that unfortunately means we won't be firing up warp drive ... Why can't we really exceed the speed of light? After all ...

4. Why nothing can travel faster than the speed of...

   www.youtube.com/watch?v=4sIA0fepnKA

   Jan 18, 2012 ... Why nothing can travel faster than the speed of light. .... The vid says "youcan't be more horizontal than horizontal," but that doesn't explain ...

5. Why can't anything travel faster than the speed of...

   http://lightm14.imascientist.org.uk/2014/03/12/why-cant-anything-travel-faster-than-the-speed-of-light/

   Mar 12, 2014 ... But you can't make any massive particle move at the speed of light. ... 186,282 miles per second, and in theory nothing can travel faster than it.

6. Faster-than-light travel: are we there yet? - The...

   http://theconversation.com/faster-than-light-travel-are-we-there-yet-41112

   May 8, 2015 ... There's a cosmic speed limit that unfortunately means you aren't going to be firing up warp ... Why can't we really exceed the speed of light?