It's a full moon. I've started listening to Christmas music. I'm freeing up space on my computer. And this is my 60th blog (but technically my 59th posted blog). It seems only fitting I discuss an interesting matter that has been muddling around in the back and front and sides of my head (nooks and crannies are free of this thought).
Take a moment and consider light. Go on................ It has a velocity: 3.0 x 10^8 m/s (or verbally, three hundred million meters per second). That's pretty stinking fast you say. Duh, I know, I'm an astrophysicist (in training). Anyway. Now consider what light does for us. It illuminates things. Everything you can see with your eyes is because light is reflecting off of it. Shocking! If it were not for light bouncing off things, we would not see them, unless the object itself was a source of illumination. Now, put these two ideas together. Velocity and that things we see are because of light. We are constantly seeing the past.
Yes, we are always seeing the past. Never the now. A little meta-exi-physi-stensial for you? Well, I'm only putting it how I heard it and then thought about it. Light takes time to travel from an object to our eye. Thus, unless the object is in your eye, you are experiencing it as it was in the past (and we won't discuss neuron sensory path time). There is no now when it comes to visual stimuli. It's easy to say light from a star took 100 million years to get here because it's 100 million light-years away, but it's not something people think about when they look at a train coming at them from say....1 kilometer away. Do you know how long it took that light from the train to get to you? It's Math Time (insert intro credits to favorite TV show here).
Distance = velocity x time so t = D/v or t= (1000m)/(3 x 10^8 m/s)
t= .0000033 seconds
AHHHH! That train could have exploded and you wouldn't know it for 3.3 micro seconds!!!
So, cue a discussion if you like. Perhaps others are so adamant about the absurdity of my statement that an answer to life, the universe, and everything will come out of discusssion.
P.S. As an aside, or I guess more accurately a post script, I would like to point out the distance from the Sun to the Earth is 1.49 x 10^11 meters, which is 149 billion meters. Couple that with light speed and the Sun could explode and we wouldn't have a gorram clue for 8 minutes. Makes me chuckle just thinking about it.
4 comments:
Awesome. Thank you, Mr. Wold, for enlightening us.
But what if the sun exploded faster than light? Or, would we notice the gravitational effects before the light? How fast does gravity travel?
Indeed you raise a point Mr. Blarney. Last I knew or had heard (as in I'm not looking it up at the moment) gravity was "believed" to travel at the speed of light as well. And I believe things explode, even the Sun, with a finite, and less than light, speed.
Thank you.
My head hurts. You didn't have to steal all the brains on the way out of the womb you know and leave me with two birthmarks. Positively ungentlemanly of you sir!
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