If you want to understand why we believe the universe is expanding at an accelerating rate, and how this is corroborated through several independent lines of study, a great start would be to take a look at "Universal" by Brian Cox and Jeff Forshaw, which I reviewed in another post:
http://www.iceinspace.com.au/forum/s...d.php?t=150183 I
This book is a very accessible account of modern cosmology, and a lot more compelling than popular press reviews of the abstracts of scientific papers, which I genuinely doubt the journalists have actually read, let alone understood!