Space, Light, The Universe and Everything in Between
(Just a side note – I am still sick (feeling ok but apparently still have a fever) and still bedroom quarantined. So, because I’m thoroughly bored, here’s what I do for fun. I exercise my brain).
I’ve been having an email conversation with a friend of mine and my dad. My dad, before he retired, was a high school science teacher, he also taught astronomy and continues to be fascinated by it. He sends me emails every now and then with heads-up about various cosmological events: A meteor shower (like we had a few days ago), the visibility of a passing space station overhead, a comet, etc. I’ve been sharing these emails with a friend of mine. The latest email was a link to a video which was absolutely amazing. You have to watch this:
My Dad originally said that perhaps the narrator was wrong in saying that the galaxies were traveling away faster than the speed of light, as anything with mass could not travel faster than the speed of light. A friend of my father’s responded that actually, the narrator is correct because it is not just the fact the galaxies are traveling away – but that the distance in between is expanding, because the universe itself is expanding. (If your brain is starting to hurt – this is how I “picture” this to try and understand it: you know in those horror movies, where the person has to run down a hallway to get away, and as they start running, the hallway strangely gets stretched out and longer… it’s kind of like that)
So this started a long thread of why can’t something (or can something) travel faster than the speed of light and why? Still need to be confirmed on my understanding, but I think it has to do with the belief that as an object’s speed increases, so does it’s mass (still don’t understand why this is) and thus the energy to maintain/increase it’s speed – as you reach the speed of light, the mass increases infinitely as does the required energy – all of which are impossible to produce. But this only deals with objects with mass – Light does not have mass – so it can travel at lightspeed. And what about other things that do not have mass… What about radio waves? Sound waves travel slower than the speed of light.
Then the question of why sound travels so slowly – and that one I think I understand to be because sound is not it’s own “thing” – sound waves are patterns in the air and air particles (or other particles of material that can continue the wave pattern). Without the air or particles (for example like in a vaccuum) – there is no sound. So “sound” is dependent on these other particles for it’s “movement”. (And this movement is just slower than light’s movement) Also, just an added piece of information – as you get further away from the sound’s source, the waves get longer. Think of a pebble being dropped in water – the ripples it forms and how it dissipates the further out it gets.
Later when I was talking to my Dad he added a brief explanation of what “red shift” is (it’s mentioned in the video). Just like sound waves get longer the further away you are (remember that pebble in the water – how the ripples get stretched out the further away you are – or think about an ambulance siren as it passes you, when it’s up close, it’s a higher pitch. As it speeds away the pitch seems to get lower) Light waves also get stretched out the further away you are. With sound, you don’t have to be very far away before it shifts like that, but with light, it is a LONG LONG distance (think millions of light years away) before that shift happens. (Red light waves on the ROYGBV – red, orange, yellow, green blue, violet – spectrum are the longest wave – like that lower pitch in the siren.) So when light shifts over distance, it shifts to the red.
Anyway, you get the idea. So my dad sent over one link which had a great explanation of how the universe is expanding. Even I understood it! LOL! I love discussions like this. I feel like my BRAIN expands. But, there’s definitely a breaking point where I reach my limit of understanding and tune the rest out. That blog looks to be full of some great information. I’ll have to read through it in small chunks so my brain doesn’t expand to exploding. LOL!
Also if your brain is hungry for more: This has some more detailed information about that video above.