As I sit in my office, typing at the computer, I do not feel like I am moving. However, this is only a perception based on looking at the world around me. In fact, I am actually moving very, very fast or not at all.
In the time it took you to read that paragraph, you have travelled around 4,000 kilometres or sat perfectly still. It is all a matter of perspective. Let me explain.
The Earth rotates once on its axis every 24 hours if we use the sun as a reference point. With respect to the constellations or the rest of the universe, the Earth completes one rotation every 23 hours and 56 minutes. This is called a "sidereal day." The difference is subtle but it is important in astronomy. However, for our purposes, a 24 hour day will do.
Prince George is located at about 54 degrees north which, given that the radius of the Earth is 6,393 km, means that the circumference of the Earth at this latitude is 32,500 km. That is, if you were to travel due east or west and never changed your latitude, it would take you 32,500 km to get back home. This is less than the circumference of the Earth at the equator (about 40,000 km) due to trigonometry and the curvature of the Earth.
What this means is that every 24 hours we travel 32,500 km around the axis of the Earth requiring an average speed of 1,358 km/h. And that is not the least of it.
The planet Earth is also travelling around the sun in a yearly orbit. Roughly speaking, the radius of Earth's orbit is 150,000,000 km. This gives us a circumference of 943,700,000 km which we travel in 8,766 hours. Our average speed is 107,650 km/h. Kind of redefines the term speeding, doesn't it?
Note that this is our average speed because you have to take into consideration that the rotation of the Earth about its axis means that sometimes we are going as much as 1,358 km/h faster than this and sometimes 1,358 km/h slower. We are always speeding up or slowing down as we orbit the Sun.
Of course, that is not the last of it. The Sun and all of its planets are travelling together, past all of the other stars in our region, at a speed of 71,300 km/h towards the constellation Hercules. Further, all of the stars in our neighbourhood orbit around the centre of the Milky Way at an astounding 800,000 km/h. And the galaxy itself is travelling through space at the phenomenal rate of 2.2 million km/h in the direction - from our perspective - of the Centaurus constellation.
When all of these motions are combined, our net speed is about 1.4 million km/h in the direction of the constellation Leo. (And there are still people who insist that we are not making any progress!)
Of course, all this whizzing through space is only one way to look at the Universe.
In the early part of this century, the astronomer, Edwin P. Hubble, was studying the night sky and, in particular, galaxies.
Using the Doppler shifts observed in the light from these galaxies and, in particular, the line spectra arising from key elements, he came to a rather startling conclusion: all of the more distant galaxies are moving away from us. Furthermore, from his careful measurements, Hubble was able to postulate that the "recessional speed of a distant galaxy is proportional to its distance away."
This conclusion eventual gave rise to the "Big Bang Theory" the notion that the Universe started in a single explosion of energy and matter that has been expanding ever since. Of course, this leads to the question: where did this explosion occur? That is, where was the centre of the Big Bang?
As far as we can tell with our present capabilities, all of the matter in the Universe seems to be expanding uniformly in all directions. That is, there is no centre. Or any point in the Universe is just as likely to be the centre as any other point.
Indeed, any and every point can be declared the centre of the Universe with equal certainty.
If that is the case, then the centre of the Universe - the one spot not expanding and hence not moving relative to the rest of the Universe might as well be the spot right between your eyes. Yes, from a cosmological point of view, the Universe could be - indeed, is - revolving around you.
Of course, this is probably not something that you want to tell anyone else.
