Welcome to 2009, the year of astronomy

Welcome to 2009, proclaimed by the United Nations as the International Year for Astronomy, with a vision to “help people rediscover their place in the universe through the sky”.

The year-long celebration of astronomy marks 400 years since the first astronomical observations through a telescope by Galileo Galilei. Up to 140 countries are expected to join in the celebrations, potentially reaching 97 per cent of the world’s population.

Astronomy is one of the oldest fundamental sciences and it continues to make a profound impact on our culture.

Huge progress has been made in the past few decades. Only 100 years ago we barely knew of the existence of our own galaxy, the Milky Way.

Today we know that many billions of galaxies make up our universe and that it originated 13.7 billion years ago.

And 100 years ago we had no means of knowing whether there were other planetary systems in the universe. Today we know of more than 200 planets around other stars in our galaxy and are moving towards an understanding of how life first appeared.

Galileo has been called the father of modern observational astronomy, as well as the father of science. His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honour) and the observation and analysis of sunspots. He also worked in applied science and technology, improving compass design.

Galileo’s championing of Copernicanism was controversial. The geocentric view, which placed the earth at the centre of the solar system, had been dominant since the time of Aristotle, and Galileo’s presentation of heliocentrism, with the sun at the centre, put him at odds with the Catholic Church.

He was forced to recant his heliocentrism and spent the last years of his life under house arrest on orders of the Roman Inquisition.