I think the most important thing

that I have learned

is that there's more to learn

that we should, that we.

That we should all be hungry

for a lifetime.

I mean, for example,my next birthday, I'll be 68.

All the great scientific discoveries made

by all the great geniuses were largelymade when they were in their 20s and 30s.

And yet

I became about two years agoobsessed with particle physics,

and I was determinedto understand it before I died.

I could not have done that if I hadn'tlearned to read when I was young,

if I hadn't had the opportunity tostudy science courses in my high school.

And I lived in the second poorest state

in the United States, which most peoplemy age in my state did not have.

I happened to go to a biggerhigh school with people who.

Understood, we had to get good science

and math teachers there,and if I hadn't gone to,

in my case, Georgetown University,which was a Jesuit university

and I hadn't been subjectto the kind of rigors

that the Jesuits imposed,which made me realize that however much I

thought I knew and how smart I was,I didn't know very much.

And I wasn't very smart.

I had a lot to learn.

So that's the mostimportant thing I learned.

Your brain is a gift,and we now know that people well

into their late 60s and 70s can form newneural networks

so that even though your brain beginsto shrink in your 30s and does throughout

your life, it's none of us ever useeven close to half of our brain power.

We got a lot left

and we will, in our light on our lastday on Earth, will have a lot left.

So the idea that we now know

as a scientific measure,because of all the brain scanning

technology,that we can form these networks

and that we form them best,we're most likely to form new neural

networks later in lifeby learning something new.

So if I said I was interested in particlephysics and also in astrophysics and I'm

trying to figure out what it means thatwe've located 20 planets outside our solar

system in the last five years that seemto have enough density and be far enough

away from their sons that theymight be able to support life.

That may be the answerto the Russia Ukraine problem.

An attack from out, an attack from outerspace will immediately unite us all.

Members of Congress in the US will

immediately start hugging eachother and singing Kumbaya.

But anyway,

I can form new neural networks doing

that because I don't knowanything about it or I did.

And when I started,a theoretical physicist would do better

going to Suzuki piano lessonswith his grandchild or her grandchild

and just playing if youknew nothing about music.

But this is an incredible thingthat the most important thing I learned

is that it's important to keep on learningthat you should stay hungry and that

the greatest gift can be evenas your body begins to fail.

If your mind's still working,you need to use it.