Astronomy question: age and size of the universe?

[mysterious 22]

Astronomers believe the universe is 13.7 billion years old, yet the diameter of the universe is 43 billion light years...how is this possible and how have astronomers got these information

It would be really helpful if someone could just give me a website where I can find the answer to this question in detail.
thnx in advance

[??????? ??????????]

http://imagine.gsfc.nasa.gov/docs/science/mysteries_l1/age.html
http://www.astro.ucla.edu/~wright/age.html
http://astronomy.nmsu.edu/astro/a110labs/labmanual/node17.html

[jxt299]

I never have seen a figure estimating the diameter of the universe. I have seen estimates of its age at up to 18 billion years--and that astronomers can see out 18 billion light years, but that more light from farther and farther away comes in every day.