Translator: Maria Boura Reviewer: Maria K.
Hello!
Ready for some more science, Salford?
Ready to have your brains fried?
Yeah, okay!
In 1944, an Austrian physicist by the name of Erwin Schrödinger -
some of you may have heard the name -
Schrödinger's cat, the famous paradox, the guy puts the cat in the box
and somehow the cat is both dead and alive at the same time.
I'll try and explain what this is all about.
Erwin Schrödinger in 1944 -
he was one of the pioneers of quantum mechanics,
one of the greatest and most important theories in the whole of science -
in 1944, he published a book called "What is life?"
You see, until that point,
from the late 19th century to the first half of the 20th century,
physicists ruled.
We were the top dogs in science.
And all the big discoveries -
chemists and biologists may disagree -
but back then we had the Einsteins and others,
who were revolutionizing physics.
Erwin Schrödinger was one of the pioneers of this new theory of quantum mechanics.
Physicists became so cocksure of themselves, so arrogant,
they felt they could answer all problems in science.
His book "What is life?" was somewhere
where he felt he could try and use physics to explain life itself.
Physics to explain biology.
Now, he was very ambitious in this project.
It did influence and inspire many other scientists.
In fact, Francis Crick and James Watson were inspired by his work
in their discovery of the DNA and the double helix.
In fact, Francis Crick was himself really a physicist.
Two decades later, in the early 60s, in 1963,
another physicist published a paper
which didn't really make a big splash.
His name was Per-Olov Löwdin, who was a Swedish physicist,
and he wrote a paper about biology.
He wrote a paper
in which he suggested a way that DNA might mutate.
Now, DNA has two strands of very complicated molecules
wrapped around in this double helix,
and DNA contains the blueprint of life.
We hear these days that biologists are mapping the human genome;
we've made tremendous strides in the last decade.
Well, back in 1963,
Löwdin was trying to understand what is it that goes wrong -
or actually, not wrong, we need mutations for life to evolve, to change.
How do mutations take place?
We sort of know there are lots of different mechanisms.
Sometimes it's just random copying errors,
when these two strands unravel and split,
and then they make another pair of strands and they replicate.
Sometimes just things copy wrongly.
Sometimes you get radiation from outside, cosmic radiation from outer space,
that comes through and collides with the DNA inside our cells
and causes them to break, and new patterns form.
Löwdin said there might be another way.
The two strands of DNA are held together by -
it's like a ladder, that's sort of twisted around -
those rungs of the ladder,
the glue that holds the two strands together,
are basically hydrogen atoms.
Hydrogens atoms provide the glue, they're bonds.
They bond to an atom on one strand and to an atom of the other strand,
and keep them fixed together.
Löwdin suggested that maybe
this hydrogen atom can do something rather strange,
something quantum mechanical,
something called quantum tunneling.
Basically, it might be sitting closer to one atom on one strand,
and spontaneously, for strange quantum reasons,
jump across to the other side.
Because if this happens,
the structure of the molecules of DNA would change,
a mutation could take place.
It was a mathematical model,
he had no experimental evidence that this would actually take place.
That's nearly half a century ago.
To this day, we don't know whether quantum tunneling
explains certain types of mutations.
But in his paper, in the very first paragraph,
he says,
"The fact that quantum physics might explain certain phenomena in biology
would lead me to propose a new area of science, a new field,
which I would call quantum biology."
Things sort of went quiet and nothing really happened.
In the last few years, certainly in the last three or four years,
quantum biology, as a new field, has started to gain prominence again.
Not because the quantum physicists
have got cleverer in some of their wacky ideas,
but because the molecular biologists have got very clever
in designing experiments to test the wacky ideas.
I'll give you a few examples in a moment.
But let me just say something about what quantum mechanics is.
It was discovered in the early part of the 20th century.
Once people like Ernest Rutherford -
who was the first person to look inside an atom
and saw that atoms were, actually, mostly empty space
with a tiny little nucleus and electrons buzzing around the outside,
like a miniature solar system -
they realized they needed to try and understand
the structure of these atoms.
And they realized that the normal laws of physics
that everyone understood,
going all the way back to Isaac Newton, just didn't seem to work.
Strange things were going on down at the level of atoms and below.
A new type of mechanics, not Newtonian mechanics,
but what's called quantum mechanics, had to be developed.
And throughout the 1920s,
this became a full, powerful mathematical theory.
Today, quantum mechanics is really not in doubt.
Quantum mechanics tells us how the electrons fit around atoms,
in orbits.
It tells us how atoms fit together, [about] the forces between them,
to make molecules,
to make everything we see in the universe.
But quantum mechanics is down at the level of atoms.
We don't see, generally,
the effects of quantum mechanics on the everyday scale.
It happens at such tiny scales that are completely invisible to us.
And yet, we design experiments all the time in physics labs
that seem to prove, time and time again, that quantum mechanics really works.
Quantum mechanics, therefore, underpins a lot of physics,
pretty much most of, if not all of chemistry;
chemistry underpins biology;
biology at a molecular level is basically molecules,
chemical reactions going on between them, and bonds bonding together;
biology is basically organic chemistry;
organic chemistry is basically quantum mechanics.
Quantum mechanics is, I would argue, the most important,
the most powerful theory in the whole realm of science;
it beats Darwinian natural selection with one arm behind its back -
and Darwinian natural selection is one of the greatest ideas
human kind has ever come up with.
But, at its heart, quantum mechanics is strange.
So strange
that one of the founding fathers, Niels Bohr, once said,
"If you are not baffled by quantum mechanics,
then you haven't understood it."
You have to think, "How can that be?"
If you think, "Yeah, OK, I get it,"
you have a problem.
Because it really is ungettable at a sort of common sense level.
It really is strange.
Quantum mechanics really does say that an atom can be in two places
at the same time - one atom.
When you look to see which place it really is,
it'll disappear in one place and pop up in the other.
How do you know it was in two places at once?
We can design experiments that would prove
that had it not been in both places at once,
you wouldn't get the results that you see.
An electron - a tiny particle that orbits around an atom - spins,
not in the way that the Earth spins on its axis,
but in a rather stranger way.
To the extent that an electron, when we are not looking,
is spinning both clockwise and anti-clockwise at the same time.
It sounds like,
"You physicists come up with all this nonsense; how do you know?"
That's what really happens,
and without that we wouldn't have so much of modern science.
Anyone of you who uses any device -
smartphones, TVs, computers, anything with a chip -
all rely on quantum mechanics.
Without quantum mechanics
we wouldn't have understood the nature of matter.
We wouldn't have understood the nature of semiconductors;
therefore, we wouldn't have developed chips;
we wouldn't have computers.
Most of modern technology today relies on quantum mechanics.
And yet, at its heart, it's very, very strange.
Well, I've said, you know,
biology at its heart is chemistry,
and chemistry is basically quantum mechanics.
So, surely,
biology, ultimately, relies on quantum mechanics.
Well, it does rely on quantum mechanics
in the sense that quantum mechanics describes how the atoms fit together
to make the molecules of life,
but this new field, this field of quantum biology,
is really asking whether the weirder aspects of quantum mechanics
play a role in biology.
Just last week -
the week before last, now -
the Nobel prize of physics was announced.
And it was given to two physicists who led two research teams,
one in Paris and one in Boulder, Colorado.
So the two guys who won the Nobel prize were essentially the team leaders,
but really the credit goes to these two teams.
What they've done over the last decade or two is design experiments
that show that quantum weirdness really does happen.
You might have heard phrases like quantum entaglement
or quantum coherence.
In the physical world -
by physical, I mean the non-living, non-biological world -
we do see these quantum effects all the time.
Quantum tunneling, for instance, is weird.
Quantum tunneling is a bit like Harry Potter and his friends
when they run through that brick wall on Platform Nine -
is it Nine and a Half? I forget -
in King's Cross station.
Right? Magic.
In the quantum world that happens all the time;
particles run through walls.
It's like you're kicking a ball up a bump, and you got it kick it hard enough
to get it to the top and roll down the other side.
If it's a quantum ball, down at the level of atoms,
you could kick it half-way up,
it doesn't have enough energy to get to the top,
doesn't want to roll down again and decides to go the other side.
Disappears and reappears on the other side,
like a magic trick.
But that's what happens.
That's the reason we are here because that's the reason our Sun shines.
Where the Sun gets its energy
is from a process called thermal nuclear fusion,
and thermal nuclear fusion is basically atoms of hydrogen,
basically the nuclei of atoms of hydrogen, protons squeezing together.
Now, protons both have positive electric charge,
and, as you surely remember from school,
like charges repel - [you] got positive and positive -
you can't push them together.
The closer you push them,
the harder they will repel each other and want to fly apart.
And yet, in the Sun, they do stick together
because hydrogen gas in the Sun is slowly being converted into helium gas,
the next element in the periodic table.
And in the process of that change from hydrogen to helium,
a lot of energy is produced, energy in the form of heat and light.
What happens is the protons are not tiny, real little balls
that are very very small;
they are like fuzzy, wavy objects that can get close enough to each other,
and they sort of want to repel each other,
but every now and again, one of them says
"Oh, I'd like to punch through that force barrier,
jump through to the other side."
Once they get close enough together, they will stick
because there's another force
that wings over their repulsive electric force.
That nuclear force is what binds the two protons together.
But without quantum mechanics we wouldn't understand
how they'd ever get close enough for that nuclear force to win.
And yet, it does happen.
So, quantum tunneling happens all the time in the world.
I'd like to tell you, very briefly, two effects in quantum biology -
one that relies on electrons spinning two ways at once,
and one that relies on quantum tunneling.
The robin is probably the most common bird in Britain;
our best loved bird.
Robins live in Britain all year round.
But the European robins,
that live in Northern Europe, in Scandinavia and Russia,
many of them migrate during the winter.
They migrate down to Southern Europe, even to the Northern tip of Africa.
Birds are able to navigate
using a wide variety of very clever tricks.
It turns out, after many years of study,
that the European robin navigates by sensing the Earth's magnetic field;
it's a very, very weak field, but it [can] sense it.
And it doesn't sense it like a compass.
It doesn't, somehow, have a built-in GPS compass system
that sort of tells him, you know, which direction it should be going.
It turns out it's sensitive to much subtler changes
in the magnetic field.
And no-one could really understand how that happens.
It turns out the most likely scenario is one based on quantum mechanics.
That inside the retina of the robin's right eye -
not left eye, they ruled that out with experiments -
inside the retina of the robin's right eye
are tiny proteins, tiny molecules called cryptochrome
that are sensitive to light -
because that's why they're in the bird's eye -
and particular, light with blue wavelength,
the sunlight has all colours of the rainbow, all wavelengths,
but particularly blue light has a particular energy,
and what that does is knock an electron from one of the atoms
inside this cryptochrome protein.
And that electron will jump far away
from its partner that it was spinning with.
Now, these electrons -
their fates are intertwined, they're entagled.
And yet, when they move far apart,
they remain, over distance, somehow,
in instantaneous communication with each other.
And it's when they move apart that that distance means,
the action of these atoms
is sensitive to the changes in the Earth's magnetic field.
And any changes will change the different chemical reactions
that these proteins will produce,
sending signals to the brain allowing the bird to know where it is
and which direction to move in.
So, even something as non-quantumy as how the European robin navigates
would appear to require quantum mechanics.
But I want to end with the idea of Löwdin
and the suggestion that DNA mutations might take place.
That's something that we're now becoming more interested in again.
We just need to find out how we can prove that quantum tunneling,
the same process that drives the energy of the Sun,
might also drive mutations and evolution in life.
Biologists are getting very clever with their experiments,
and they can isolate the DNA, and they can look at these processes.
At the moment we're at the stage
where physicists are trying to develop very sophisticated models,
organic chemists develop very sophisticated computer programs
that can model hundreds of thousands of molecules,
and how they all jiggle about and move,
and they make a prediction
that the biologists then carry out experiments to test.
If it turns out that quantum physics does play a role in mutations,
we really don't know where that will lead,
what applications it will have.
Just one hugely speculative example, for instance,
which researchers in America are interested in,
is whether we can understand those mutations responsible for cancer.
So how a cell becomes cancerous
tends to rely on several highly unlikely mutations.
And yet, cancer is everywhere,
it will affect one in three of us at some point in our lives.
If quantum mechanics is responsible for mutations,
then we might be able to control those mutations.
Now, I'm not suggesting
that quantum mechanics is going to be the cure for cancer.
But this is a new, young, speculative area of research
where physicists, chemists and biologists are coming together,
and who knows where it may lead in the future.
Thank you very much.
(Applause)