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Astronomer Royal Martin Rees on aliens, parallel universes and
the biggest threats to mankind
Rees says
extraterrestrial life would either be far less advanced - or they will have
developed full electronic intelligence.
·
By Martin Rees
Updated April 3, 2017 13:48 BST
British
cosmologist and astrophysicist Martin Rees gives a lecture entitled: 'From Mars
to the Multiverse: the Post-Human Future' during the Starmus Festival on the
Spanish Canary island
of Tenerife Desiree Martin/ AFP
Martin Rees is
Emeritus Professor of Cosmology and Astrophysics, at the University of
Cambridge, the Astronomer Royal, a member of Britain's House of Lords, and a
former President of the Royal Society. The following interview was conducted at
Trinity College,
Cambridge, by
The Conversation's Matt
Warren.
Into
space
Q: How big is the
universe … and is it the only one?
Our cosmic horizons have grown enormously over
the last century, but there is a definite limit to the size of the observable
universe. It contains all the things from which light has been able to reach us
since the Big Bang, about 14 billion years ago. But the new realisation is that
the observable universe may not be all of reality. There may be more beyond the
horizon, just as there's more beyond the horizon when you're observing the
ocean from a boat.
What's more, the galaxies are likely to go on
and on beyond this horizon, but more interestingly, there is a possibility that
our Big Bang was not the only one. There may have been others, spawning other
universes, disconnected from ours and therefore not observable, and possibly
even governed by different physical laws. Physical reality on this vast scale could
therefore be much more varied and interesting than what we can observe.
Are
we alone in the universe?
The universe we can observe is governed by the
same laws everywhere. We can observe a distant galaxy and see that the atoms
emitting the light are just the same as the ones in the lab. But there may be
physical domains that are governed by completely different laws. Some may have
no gravity, or not allow for nuclear physics. Ours may not even be a typical
domain.
Even in our own universe, there are only so
many ways you can assemble the same atoms, so if it is large enough it is
possible that there is another Earth, even another avatar you. If this were the
case, however, the universe would have to be bigger than the observable one by
a number which to write down would require all the atoms in the universe. Rest
assured, if there's another you, they are a very, very long way away. They might
even be making the same mistakes.
Q: So how likely is
alien life in this vast expanse?
We know now that planets exist around many,
even most, stars. We know that in our Milky Way galaxy there are likely
millions of planets that are in many ways like the Earth, with liquid water.
The question then is whether life has developed on them – and we can't yet
answer that.
Although we know how via Darwinian selection a
complex biosphere evolved on Earth around 4 billion years ago, we don't yet
understand the actual origin of life – the transition from complex chemistry to
the first metabolising, replicating structures. The good news is that we will
have a better idea of how that happened within the next ten or 20 years and
crucially, how likely it was to happen. This will give us a better
understanding of how likely it is to happen elsewhere. In that time, we will
also have technologies that will allow us to better search for alien life.
But just because there's life elsewhere
doesn't mean that there is intelligent life. My guess is that if we do detect
an alien intelligence, it will be nothing like us. It will be some sort of
electronic entity.
If we look at our history on Earth, it has
taken about four billion years to get from the first protozoa to our current, technological
civilisation. But if we look into the future, then it's quite likely that
within a few centuries, machines will have taken over – and they will then have
billions of years ahead of them.
In other words, the period of time occupied by
organic intelligence is just a thin sliver between early life and the long era
of the machines. Because such civilisations would develop at different rates,
it's extremely unlikely that we will find intelligent life at the same stage of
development as us. More likely, that life will still be either far simpler, or
an already fully electronic intelligence.
On
intelligence
Q: Do you believe that
machines will develop intelligence?
There are many people who would bet on it. The
second question, however, is whether that necessarily implies consciousness –
or whether that is limited to the wet intelligence we have within our skulls.
Most people, however, would argue that it is an emergent property and could
develop in a machine mind.
Q: So if the universe
is populated by electronic super minds, what questions will they be pondering?
We can't conceive that any more than a chimp
can guess the things that we spend our time thinking about. I would guess,
however, that these minds aren't on planets. While we depend on a planet and an
atmosphere, these entities would be happy in zero G, floating freely in space.
This might make them even harder to detect.
Q: How would humanity
respond to the discovery of alien life?
Aliens
probably wouldn't be at the same level of advancement as humans.
It would certainly make the universe more
interesting, but it would also make us less unique. The question is whether it
would provoke in us any sense of cosmic modesty. Conversely, if all our
searches for life fail, we'd know more certainly that this small planet really
is the one special place, the single pale, blue dot where life has emerged.
That would make what happens to it not just of global significance, but an
issue of galactic importance, too.
And we are likely to be fixed to this world.
We will be able to look deeper and deeper into space, but travelling to worlds
beyond our solar system will be a post-human enterprise. The journey times are
just too great for mortal minds and bodies. If you're immortal, however, these
distances become far less daunting. That journey will be made by robots, not
us.
Q: What scientific
advances would you like to see over the coming century?
Cheap, clean energy, for one. Artificial meat
is another. But the idea is often easier than the application. I like to tell
my students the story of two beavers standing in front of a huge hydroelectric
dam. "Did you build that?" asks one. "No," says the other.
"But it is based on my idea". That's the essential balance between
scientific insight and engineering development.
On
expertise
Q: Michael Gove [the
British politician who was a leader of the campaign for the UK to leave the
EU] said people have had enough of experts. Have they?
Michael
Gove Peter Nicholls/
Reuters
I wouldn't expect anything more from Mr Gove,
but there is clearly a role for experts. If we're sick, we go to a doctor, we
don't look randomly on the internet. But we must also realise that most experts
only have expertise within their own area, and if we are scientists we should
accept that. When science impacts on public policy, there will be elements of
economics, ethics and politics where we as scientists speak only as laymen. We
need to know where the demarcation line is between where we are experts and
where we are just citizens.
If you want to influence public policy as a
scientist, there are two ways to do it. You can aspire to be an adviser within
government, which can be very frustrating. Or you can try and influence policy
indirectly. Politicians are very much driven by what's in their inbox and
what's in the press, so the scientists with the greatest influence are those
who go public, and speak to everyday people. If an idea is picked up by voters,
the politicians won't ignore it.
Q: Brexit – good or
bad?
I am surprised to find myself agreeing with
Lord Heseltine [former UK Conservative government minister] and Tony Blair
[former Labour prime minister], but it is a real disaster, which we have
stumbled into. There is a lot of blame to be shared around, by Boris Johnson et
al, but also by Jeremy Corbyn [leader of the UK Labour party] for not fighting
his corner properly. I have been a member of the Labour Party for a very long
time, but I feel badly let down by Corbyn – especially as Labour voters
supported Remain two to one. He has been an ineffective leader, and also
ambivalent on this issue. A different leader, making a vocal case for Remain,
could have tilted the vote.
On the other side, Boris Johnson [now UK foreign secretary – who campaigned for Britain to
leave the EU] has been most reprehensible. At least Gove has opinions, which he
has long expressed. Boris Johnson had no strong opinions, and the honourable
thing to do if that is the case is to remain quiet. But he changed his stance
opportunistically (as in the Eton debating
society) and swung the vote.
Q: But why is it such
a disaster?
My concerns are broad geopolitical ones. In
the world as it is now, with America
becoming isolationist and an increasingly dominant Russia,
for Europe to establish itself as a united and
powerful counterweight is more important than ever. We are jeopardising
something that has held Europe together, in peace, for 60 years, and could also
break up the United Kingdom
in the process. We will be remembered for that and it is something to deplore.
One thing astronomers bring to the table is an
awareness that we have a long potential future, as well as the universe's long
past – and that this future could be jeopardised by what happens in the coming
decades.
Q: More broadly, how
much danger is the human race in?
Are
humans at risk of extinction? iStock
I have spent a lot of time considering how we
as a species can make it into the next century – and there are two main classes
of problems. First, the collective impact of humanity as its footprint on the
planet increases due to a growing population more demanding of resources.
Second, the possible misuse by error or design of ever more powerful technology
– and most worryingly, bio-tech.
There is certainly a high chance of a major
global setback this century, most likely from the second threat, which
increasingly allows individual groups to have a global impact. Added to this is
the fact that the world is increasingly connected, so anything that happens has
a global resonance. This is something new and actually makes us more vulnerable
as a species than at any time in our past.
Q: So terrorism will
pose an even greater threat in the coming century?
Yes, because of these
technologies, terrorists or fanatics will be able to have a greater impact. But
there's also the simple danger of these technologies being misused. Engineering
or changing viruses, for example, can be used in benign ways – to eradicate Zika, for example – but there's obviously a
risk that such things can get out of control.
Nuclear requires large, conspicuous and
heavily-protected facilities. But the facilities needed for bio-tech, for
example, are small-scale, widely understood, widely available and dual use. It
is going to be very hard indeed properly to regulate it.
In the short and intermediate term, this is
even more worrying than the risks posed by climate change – although in the
long term, that will be a very major problem, especially as both people and
politicians find it very difficult to focus on things further down the line.
I have been very involved in campaigns to get
all countries involved in research and development into alternative, clean
energy sources. Making them available and cheap is the only way we are going to
move towards a low carbon future. The level of money invested in this form of
research should be equivalent to the amount spent on health or defence, and
nuclear fusion and fourth generation nuclear fission should be part of that.
Q: In the medieval
world, people would start building cathedrals that only later generations would
finish. Have we lost that long-term perspective?
That's right. In fact,
one very important input behind the political discussion prior to the Paris climate agreement
was the 2015 Papal Encyclical. I'm a council member of the
Pontifical Academy of Sciences, which helped to initiate the scientific
meetings which were important in ensuring that the encyclical was a highly
respected document.
Whatever one thinks of the Catholic church,
one cannot deny its long-term vision, its global range and its concern for the
world's poor. I believe that the encyclical, six months before the Paris conference, had a big impact on the leaders and
people in South America, Africa and Asia. Religion
clearly still has a very important role to play in the world.
Q: Have you ever
encountered anything in the cosmos that has made you wonder whether a creator
was behind it?
No. Personally, I don't have any religious
beliefs. But I describe myself as a cultural Christian, in that I was brought
up in England
and the English church was an important part of that. Then again, if I had been
born in Iran,
I'd probably go to the mosque.
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