Cosmology

Cosmology is about studying the universe.  It has been done since the earliest civilisations.  Among the earliest astronomers were the Greeks who named stars according to mythical gods and beasts.  They saw patterns in the sky, constellations, naming them after animals (e.g. Ursa (a bear)) or people (e.g. Virgo (a young woman)) many of which we still use today.

These constellations are in the Northern Sky.  Since people thought the Earth was flat, they never considered the night sky in the Southern Hemisphere.  One man sailed a ship far into the Atlantic to hear the setting Sun drop with a hiss into the sea.  He was to be disappointed.  Since people are thought to have travelled across the Atlantic, presumably others did go South, but were never heard of again.

The Southern night sky is like this:

Astrologers have always attempted to predict the future by looking at the behaviour of stars and planets.  Even today people believe in horoscopes; journalists can write any drivel they like, and someone will believe it.  (My horoscope always told me that it was a good day for financial speculation.  No-one is worse with money than me.)  Astrology has nothing whatever to offer serious scientific study of the universe.

Cosmology is still the quest to understand where we came from and where we are going.  Cosmologists and astronomers (who nowadays do much the same thing) are studying all sorts of things, including:

• Planets orbiting other stars;
• Dark matter;
• Black holes;
• The origin of the Universe;
• The fate of the Universe.

 Many of these can't be seen directly.  Even a big planet cannot be seen directly from Earth.  It's far too far away.  But very tiny movements of stars can be seen and our understanding of gravity helps us to deduce the existence of a planet.

We will be looking at how cosmologists work and the sophisticated techniques they use.