Many, if not most, ancient and primitive societies worshipped the Sun as a god. Sun worship continues to this day in various guises around the world. This makes a lot of sense, because the Sun has a lot of the features in common with our various cultures’ gods. We are totally dependent on the Sun It is universally known, across all cultures from the most primitive to the most enlightened and sophisticated, that the Sun is the source of all … Continue reading →
Dear Urban Astronomer, I am embarrassed to admit that although I have heard a lot about the Hubble Telescope, I’m still not actually that sure about its purpose. Does it belong to NASA or just the world in general? Is it just a telescope that sends back picures or is it looking for extra-terrestrial life? How big is it? Is it a satellite or does it just travel for eternity into space? Is it solar powered or will it eventually … Continue reading →
The Fine-Structure Constant The two fundamental assumptions about modern cosmology (the study of the origins of the universe) and astrophysics are homogeneity and universality. The first means that matter is evenly spread out through the universe (if you average out over large enough scales), while the second means that the laws of physics are the same throughout the universe. The principle of homogeneity has always seemed arbitrary to me, and unjustified; at the local level we find matter is quite clumpy, from … Continue reading →
Dark matter is the name used for the material out in the universe which we cannot see, but can detect through it’s gravitational influence. When we look at galaxies, we can see a lot of matter in the form of stars, gas and dust. We can also see how the stars within those galaxies are moving in their orbits around the galactic core. The laws of physics tell us that these orbits should be at certain speeds, depending on … Continue reading →
Brace yourself, because this question is a lot more complex than it sounds. We’re asking what the Earth’s speed is, but speed is always measured in relation to something and we usually use the Earth itself as the reference point. When we say a car is traveling at 120 km/h, we mean that it travels 120 km across the Earth in one hour and ignore the fact that the Earth itself is moving. In ordinary everyday situations, we simply assume … Continue reading →
