I am very aware of the preciousness of time. I was given two to three years to live. I faced a life unable to properly communicate. Fortunately my mind was unaffected.

While all around me people have passed the day deep in conversation, I have often been transported afar, lost inside my own thoughts, trying to fathom how the universe works.

I have spent my life traveling across the universe inside my mind. Through theoretical physics I have sought to answer some of the great questions.

But there are other challenges, other big questions which must be answered and these will also need a new generation who are interested, engaged, and with an understanding of science.

How will we feed an ever growing population, provide clean water, generate renewable energy, prevent and cure disease, and slow down global climate change?

One of the great revelations of the Space Age has been the perspective it has given humanity on ourselves. When we see the Earth from space, we see ourselves as a whole. We see the unity and not the divisions. It is such a simple image with a compelling message. One planet. One Human race.

We are here together and we need to live together with tolerance and respect. We must become global citizens. We are all time travelers, journeying together into the future. But let us work together to make that future a place we want to visit.

Be brave, be determined, overcome the odds. It can be done. Seize the moment. Act now.