Martin Rees said this quote

Given the scale of issues like global warming and epidemic disease, we shouldn't underestimate the importance of a can-do attitude to science rather than a can't-afford-it attitude.

~ Martin Rees

If we ever established contact with intelligent life on another world, there would be barriers to communication. First, they would be many light years away, so signals would take many years to reach them: there would be no scope for quick repartee. There might be an IQ gap.

~ Martin Rees

A monkey is unaware that atoms exist. Likewise, our brainpower may not stretch to the deepest aspects of reality. The bedrock nature of space and time, and the structure of our entire universe, may remain 'open frontiers' beyond human grasp.

~ Martin Rees

It is foolish to claim, as some do, that emigration into space offers a long-term escape from Earth's problems. Nowhere in our solar system offers an environment even as clement as the Antarctic or the top of Everest.

~ Martin Rees