I didn’t do anything productive today so here is something about light.
This is a beam of light traveling through a soda bottle visualized at one trillion frames per second.
Light moves at 299,792,458 meters per second. A light year is the distance that light travels in a year; just under 10 trillion kilometers. That means when a star is X lightyears away, it took the light that many years to reach your eye. That means that what you’re seeing is not a real time image.
Learning that fact was the first time science ever blew my mind. I wish I could tell you exactly when that occurred but I don’t remember (I want to say it was sometime in middle school talking about space, but I can’t be sure it wasn’t in high school). Either way, that was the first time that a science teacher told me something and my mind jumped ahead to it’s implications. We had been talking about Orion; I remember that because of the significance to Orion’s Belt in Men In Black (which may or may not have been popular then). We were informed that Rigel is a supergiant star 800 light years away from Earth.
What that meant (to me) is that Rigel could’ve gone super nova at anytime in the last 800 years and we still didn’t know. My young mind thought about the theoretical planets and civilizations surrounding this brilliant star, and how they may have already be wiped out by the death of their sun. It was so strange to me that I could be looking at something and that it might not be there.
The speed and properties of light have fascinated me ever since. The recent news about possible faster than light neutrinos has been very exciting.
It just something that we take for granted, because at the scale we operate on here on Earth, the speed of light is irrelevant. A beam of light can travel around the Earth approximately 7 and a half times in a second at the equator. It’s still weird to know that when you’re looking in the mirror, you’re not seeing yourself as you are, but as you were fractions of seconds ago.
Bored? Think about the fact that time doesn’t exist for a photon of light, it is created instantly appears at it’s destination no matter the distance. Cooking up a great sci-fi book? Read up on time dilation. My mind was once again blown when I read the first few Ender’s Game novels and realized that time dilation isn’t just a clever way to keep characters living forever, but an actual observed effect that could be exploited in the future.
The universe is kind of nuts.