The growth of technology is such that it is not possible today for a nuclear physicist to switch into medical physics without training. The field is now much more technical. More training is needed to do the job.

I am not unhappy that my contribution was not recognized. I am sure it helped my career.

I would not encourage everyone to take up this profession. Not everyone is suited for any particular field.

It is likely that we need more radiation to improve our longevity.

We need to get across the excitement and creativity of science. That it isn't just a list of facts that have already been discovered - but a process, a creative project, that you are generating ideas, testing them and looking for evidence.

A theory not only explains the world we see, it lets us imagine other worlds, and, even more significantly, lets us act to create those worlds. Developing everyday theories, like scientific theories, has allowed human beings to change the world.

What can we gain by sailing to the moon if we are not able to cross the abyss that separates us from ourselves? This is the most important of all voyages of discovery, and without it, all the rest are not only useless, but disastrous.

So many of us have friends or family who have battled cancer, and we know how important it is to find a cure.