Cosmology asks the most profound questions we humans can imagine, such as how the Universe came into existence, how it evolved to look the way it does, and how it will end. This is thinking on the grandest of scales. In this month's Focus we explore how we came to appreciate the unimaginable size of the Universe, and the birth of the big bang theory. Next we examine how the Universe looks through the lens of the General Theory of Relativity, encountering some remarkable and counter-intuitive ideas along the way. Then we explore the secrets encoded in radiation emitted shortly after the big bang, and an astonishing solution to some serious problems with the original theory.

Elsewhere we look back on the five telescopes that changed the world, and take a look at what's going to be hot in 2010 by previewing the latest astro-kit; Keith Cooper speaks to Professor Paul Davies about his new book The Eerie Silence which reviews where 50 years of SETI has taken us, and where we must go in the future; and we get to the bottom of the latest research on that well-known Martian meteorite ALH84001.

In our regular sections we launch a new series for beginners – Wonders of the Universe – where Carole Stott begins with a guided tour of cepheid variables; Jeremy Perez shows you how to sketch the winter Milky Way in Drawn to the Universe and Martin Mobberley looks at dovetail mounts in Tech Talk. Plus coverage of all the latest news and an extensive 14-page guide to the night sky.

This month's issue also includes a stunning free lunar calendar, which isn't just a diary of the lunar phases but also a detailed Moon map and a guide to dark, Moonless skies for deep sky observing.