Fri, 17. August 2012
Cosmology questions
I consulted my GP a few weeks ago about my forthcoming hip replacement operation - and I was promptly asked to explain why transits of Venus are so rare. (It's because the orbits of Venus and Earth are tilted relative to each other. The orbital planes intersect every June and December but Venus is most often elsewhere in it's orbit so cannot align with the Sun).
Two days ago, my cousin Helen e-mailed me two great questions:
1. If a car were to travel at the speed of light, would the headlights still work? and
2. If the universe is continuously expanding, what is it expanding into?
The short answer to the first question is yes. Whoever you are, wherever you are, however fast you are travelling, you will always observe and measure light to travel at the speed of light.
The second question was more difficult because, whilst it is now known for certain that the Universe is expanding, the Universe consists of "space-time" - and neither space nor time as we know it exist outside the Universe. So, I am not even sure what "outside the Universe" actually means, especially if the Universe has no boundaries. It's best left to the Cosmologists.
I made a post on Facebook, which was just a thinly veiled dig at fundamentalist christianity:
"There is so much foolishness in this world. I think the Grand Prize for Sheer Stupidity goes to those folks who willfully discard every piece of scientific knowledge built up over recent centuries about the age of the Universe and cling to their idiotic myth that the world was created less than 10,000 years ago. It's sad that people will cling to impossibly ridiculous and disproved beliefs and are unable to accept the beauty of science and the truth it reveals."
This got a response from my Nephew Mike, promoting his belief that we live in a Multiverse. Maybe he's right but I am not sure if we will prove that in my lifetime and I am very cautious about hitching my "belief" to any theory just because I like the look of it. I am open-minded about a Multiverse, because I would not want to make the mistake of centuries past, when people thought the Earth was the centre of the Universe. Now we are not even sure if the Universe itself is the centre of the "Universe!"
That's the beauty of cosmology. It's populated by highly intelligent scientists, developing astonishing theories. Questions about the Universe are all very difficult to answer and it can be very unsatisfying when we don't yet know all the answers. There is so much we have yet to learn about the Universe - but that which we do already know can be quite astonishing.
The big problem for us is that the answers to what we don't know are bound to lie in mathematical concepts that are way beyond most of us and we will be forced to rely on the ability of cosmologists to explain their concepts in easy to understand language.
I'm looking forward to that!