0

August 7, 2011 AT 10:44 am

Life As A Photon

Universe Today‘s Steve Nerlich has a great article today on what the universe ‘looks like’ from the photon’s point of view.

From a photon’s point of view, it is emitted and then instantaneously reabsorbed. This is true for a photon emitted in the core of the Sun, which might be reabsorbed after crossing a fraction of a millimetre’s distance. And it is equally true for a photon that, from our point of view, has travelled for over 13 billion years after being emitted from the surface of one of the universe’s first stars.

So it seems that not only does a photon not experience the passage of time, it does not experience the passage of distance either. But since you can’t move a massless consciousness at the speed of light in a vacuum, the real point of this thought experiment is to indicate that time and distance are just two apparently different aspects of the same thing.

If we attempt to achieve the speed of light, our clocks will slow relative to our point of origin and we will arrive at our destination quicker that we anticipate that we should – as though both the travel time and the distance have contracted.

Similarly, as we approach the surface of a massive object, our clocks will slow relative to a point of higher altitude – and we will arrive at the surface quicker than we might anticipate, as though time and distance contract progressively as we approach the surface.

Again, time and distance are just two aspects of the same thing, space-time, but we struggle to visualise this. We have evolved to see the world in snapshot moments, perhaps because a failure to scan the environment with every step we take might leave us open to attack by a predator.


Check out all the Circuit Playground Episodes! Our new kid’s show and subscribe!

Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Learn resistor values with Mho’s Resistance or get the best electronics calculator for engineers “Circuit Playground”Adafruit’s Apps!


Maker Business — HAX Hardware Trends 2017

Wearables — Stay put, paint!

Electronics — Clarify your supply

Biohacking — Nucleus 7 – A Native Cochlear Sound Processor for iPhone

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !



4 Comments

  1. Its also hard to conceptualize the time/distance continuum because we can sense time pass while we, from our perspective, are not moving. If we remember that we are never motionless due to the movement of the earth, the solar system, galaxy we reside in, then we can understand better perhaps why time passes when we are “not moving”.

  2. But what then of quantum physics? Perhaps the photon has not yet been emitted, is being emitted, is traveling, is being absorbed, and has been absorbed. It’s polarization might be vertical or horizontal before it passes through calcite at which point it hasn’t been absorbed but now has a declared polarization…

  3. The fun of physics.

    Relativistic adding of speeds:
    It’s interesting how speeds add up when they’re relativistic. Let’s say two objects are heading towards each other at 90% speed of light. One object will see the other object traveling at only ~.93% speed of light.

    For the lack of distance:
    As an object increases speed, the universe somewhat becomes compressed with respect to the object. At the speed of light the universe seems 2d in the direction the object’s traveling. As two ships pass each other (a near head on collision), the faster they travel the flatter they seem to each other. an individual walking down the hallway of one ship would appear to be taking smaller steps down a shorter hall way with respect to the other ship…till they pass eachother
    http://en.wikipedia.org/wiki/Length_contraction

  4. “Gravity is not real, it’s just our dumbed-down interpretation of space-time curvature.”

    This statement will keep me busy for a while…

Sorry, the comment form is closed at this time.