A zero-gravity flight is a first step toward space travel.

While physics and mathematics may tell us how the universe began, they are not much use in predicting human behavior because there are far too many equations to solve. I'm no better than anyone else at understanding what makes people tick, particularly women.

It was Einstein's dream to discover the grand design of the universe, a single theory that explains everything. However, physicists in Einstein's day hadn't made enough progress in understanding the forces of nature for that to be a realistic goal.

I would like nuclear fusion to become a practical power source. It would provide an inexhaustible supply of energy, without pollution or global warming.

The radiation left over from the Big Bang is the same as that in your microwave oven but very much less powerful. It would heat your pizza only to minus 271.3*C - not much good for defrosting the pizza, let alone cooking it.

To my mathematical brain, the numbers alone make thinking about aliens perfectly rational. The real challenge is to work out what aliens might actually be like.

It's time to commit to finding the answer, to search for life beyond Earth. Mankind has a deep need to explore, to learn, to know. We also happen to be sociable creatures. It is important for us to know if we are alone in the dark.

Life would be tragic if it weren't funny.

I think we have a good chance of surviving long enough to colonize the solar system.

Work gives you meaning and purpose and life is empty without it.

A few years ago, the city council of Monza, Italy, barred pet owners from keeping goldfish in curved bowls... saying that it is cruel to keep a fish in a bowl with curved sides because, gazing out, the fish would have a distorted view of reality. But how do we know we have the true, undistorted picture of reality?

Among physicists, I'm respected I hope.

We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.

I don't think the human race will survive the next thousand years, unless we spread into space.

Perhaps one day I will go into space.

Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities... space and time not only affect but are also affected by everything that happens in the universe.

Time can behave like another direction in space under extreme conditions.

I have wanted to fly into space for many years, but never imagined it would really be feasible.

Keeping an active mind has been vital to my survival, as has been maintaining a sense of humor.

However difficult life may seem, there is always something you can do and succeed at.

I became famous, I think, really because of the interpretation of other people's songs, way back when, and that's what I enjoy the most. And I'm a lazy bugger.

There is this power that comes with being famous.

My father, being a Scotsman, taught me to look after finances. I'm shrewd. Some people may call me tight.

Well, there's not a day goes by when I don't get up and say thank you to somebody.

You can be with one of the most beautiful women in the world and still be unhappy.

I'm proud to be a railway modeler. It means more to me to be on the cover of Model Railroader than to be on the cover of a music magazine.

I suppose I miss the British cynicism and the humor.

You go through life wondering what is it all about but at the end of the day it's all about family.

I can definitely say the older I've got the better I've become at being a dad and a husband.

You find out who your real friends are when you're involved in a scandal.

I fell off my pink cloud with a thud.

My mother says I didn't open my eyes for eight days after I was born, but when I did, the first thing I saw was an engagement ring. I was hooked.

I've been through it all, baby, I'm mother courage.

It is strange that the years teach us patience; that the shorter our time, the greater our capacity for waiting.

Marriage is a great institution.

It's not the having, it's the getting.

Everything makes me nervous - except making films.

There are people out there who hate me and who say I'm arrogant, vain, and whatever. That's all part of my success. I am made to be the best.

There's no point in making predictions. It's not worth speculating because nothing is set in stone and things change all the time in football. Today there are opportunities that no one knows if they will come round again in the future.

My father always taught me that when you help other people, then God will give you double. And that's what has really happened to me. When I have helped other people who are in need, God has helped me more.

At United, there are great traditions, which you can't buy in one or two years. They are created by victories. You need to prove again and again that you are better than the others. Manchester United have always done this, and are still doing it, so they are the best.

I was ironing my own clothes when I was 11 years old. My mental strength goes back to those days.

In football, I don't have a lot of friends. The people who I really trust, there are not many... Most of the time, I'm alone.

I don't like being alone.

I have two Golden Boot awards at home. It would be nice to win another, but I wouldn't mind it if I didn't.

When you lose a person you love so much, surviving the loss is difficult.

Without football, my life is worth nothing.

Success isn't always about greatness. It's about consistency. Consistent hard work leads to success. Greatness will come.

I'm always asked, 'What's the secret to success?' But there are no secrets. Be humble. Be hungry. And always be the hardest worker in the room.

Check your ego at the door. The ego can be the great success inhibitor. It can kill opportunities, and it can kill success.