Martin Rees: Black Holes, Alien Life, Dark Matter, and the Big Bang

Understanding The Universe

• "Today, we know that the universe is far bigger and stranger than anyone suspected."
• While we are still groping for any detailed understanding of the remote parts of the universe. We have learned two things about the most beautiful or the most terrifying things lurking out there in the cosmos in the last few decades. First, we understand that the universe had an origin about 13.8 billion years ago, in a so-called Big Bang or hot, dense state, whose very beginnings are still shrouded in mystery. We have also learned more about the extreme things in his black holes, neutron stars, and explosions of various kinds.
• One of the most potentially exciting discoveries in the last 20 years, (mainly the last 10 years) has been the realisation that most of the stars in the sky are orbited by retinues of planets, just as the sun is orbited by the Earth and the other familiar planets.
• While we are certain that these planets out in the sky have masses and orbits like the planets of our solar system, we don’t know if there is life in any of them.
• We would be foolish to give any firm estimate on whether we are alone or not. Even the smallest living organism and insect is far more complicated with layers on their complexity than the most complicated star or galaxy.
• There are only limited prospects of ever being able to understand with unaided human brains, the most fundamental theories linking together all the forces of nature. But, perhaps aided by computer simulations, understand a bit more of the complexity of nature.
• Extreme Reductionists have a very misleading perception, they tend to think that, in a sense, we are all solutions as fairly as an equation.
• Every science has its only reducible concepts in which you get the best explanation.

Human Limitations and AI

• There's no particular reason why the human brain should evolve to be well matched to understanding the deepest aspects of reality... but AI can help us. For example, the string theory, the string theory involves very complicated geometry and structures in 10 dimensions... which may be complicated geometry and may be too hard for a human being to work through, but could be worked through by an AI with the advantage of huge processing power.
• There's a big gap between what a computer can print out for us at the end, and what we can grasp and think through in our heads.

Dark Matter

• We learned that galaxies and other large-scale structures, which are moving around but prevented from flying apart by gravity. They would be flying apart, if they only contain, stuff we see, if everything in them was shining. To understand how galaxies formed, and why they do remain confined at the same time, one has to infer that there's about five times as much stuff producing gravitational forces, then the total amount of stuff in the galaxies and stars than we see, and that stuff is called dark matter. The name seems misleading as it is just transparent and not dark.
• Dark Matter is a swarm of microscopic particles, which have no electric charge, and the very small cross sections were hitting each other and hitting anything else. So they swarm around, and we can detect their collective effects. And when we do computer simulations of how galaxies form and evolve, and how they emerged in the Big Bang, then we get a nice consistent picture. If we put in five times as much mass in the form of these mysterious dark particles and, for instance, it works better if you think they're non interacting particles than if you think they're a gas, which would have shock waves. So, we know something about the properties of these, but we don't know what they are; the disappointment is that particles answering this description has not yet been found. It was thought that the big accelerator, the Large Hadron Collider at CERN might have found a new class of particles, which would have been the obvious candidates, and it hasn't. However, we have only explored a small fraction of parameter space.
• A major progress in the last 50 years is that we have a outlined picture for how the universe has evolved from the time it was expanding in just a nanosecond, up to the present.
• We could do that because after nanosecond, the physics of the material is in the same range that we can test in the lab. After a nanosecond, the particles moving around like those in the Large Hadron Collider, if you wait for one second, they are like the centres of the hotter stars and the nuclear axis produce hydrogen, helium etc, which fits the data, so we can with confidence extrapolate back to when the universe was a nanosecond old and we think we can do it with as much confidence as anything a geologist can say about the history of the earth.

Vast Universe

• What happened before the Big Bang seems outside the reach of the present science and seems to be a part of speculative science.
• If we do want to understand the very early universe, then we have to realise that it may involve even more counterintuitive concepts than quantum theory does.
• One concept we might have to jettison, is the idea of three dimensions of space, and time just ticking away.
• It's a heresy to think you have to be able to test every prediction of a theory.
• The theory of Eternal inflation, by Andrei Linde, the Russian cosmologists now at Stanford predicted eternal production of new Big Bangs based on specific assumptions about the physics; but those assumptions, of course, are just hypotheses, which aren't vindicated.
• However, there are other theories, which only predict one big bang. So we should be open minded, and not dogmatic about these options, until we do understand the relevant physics.

Alien Life

• As far as life is concerned, we don't understand how life began here on Earth, although we know Darwinian evolution of simple life to complex life; however, we don't understand what caused the transition between complex chemistry and the first replicating metabolizing entity we call life. So, we therefore can't say the existence of life was a rare fluke, which would not have happened anywhere else.
• Some biologist like Stephen Jay Gould, thought that if you reran evolution, you'd end up with something quite different, and maybe loving, intelligent species.
• Within 10 or 20 years, we might with the next big telescope, be able to image some of the earth like planets around other stars. In reality, it will take 50 years to get a resolved image, however, light can be detected.
• Exoplanets are detected by their effects on the parent star, they either cause their parents star to dim slightly when they transit and get across in front of it, and so we see the dips, or their gravitational pull makes the star wobble a bit. So most of the 5000 plus planets that have been found around other stars, they've been found indirectly by their effect.
• The European ground-based telescope called unimaginativly The Extremely Large Telescope, which has a 39 metre diameter mirror (39 metres equals 800 sheets of glass) and that will collect enough light from one of these exoplanets around the nearby star, to be able to separate out its light from that star which is a million times brighter and get the spectrum of the planet and see if it's got oxygen or chlorophyll and things in it. James webb telescope may also do that to some extent.
• If aliens were looking at the solar system, they would see the sun as an ordinary star, they would see the earth as a pale blue dot lying very close in the sky to its star (our sun), and much, much fainter. But if they could observe that dots, they could learn quite a bit, get the spectre of the light and find the atmosphere they would find the shade of blue is slightly different, depending on whether the Pacific Ocean or landmass of Asia was facing them. So, they could infer the length of the day, and the two oceans and continents, and maybe something about the seasons and the climate. That is the kind of calculation and inference, we might be able to draw within the next 10 or 20 years about other exoplanets, and, evidence of some sort of biosphere on one of them would, of course, be crucial, and it will draw out the still logical possibility that life is unique.
• Another way in which this may happen in next 20 years; people think that could be something swimming under the ice of Europa and Enceladus. Probes are being sent to detect the spray coming out to see if there's evidence for organics in that. And if we found any evidence for an origin of life that happened in either of those places, that would immediately be important, because if life has originated twice, independently, in one planetary system, the solar system, that would tell us straight away, it wasn't a rare accident, and must have happened billions of times in the galaxy.
• "I chaired the committee that the Russian American investor Yuri Milner supports 'looking for Intelligent Life'".
• What we're going to have in future is no longer the slow Darwinian selection. It will be secular intelligent design, which will be humans designing their progeny, to be better adapted to where they are. However, there may be some limits to what can be done with flesh and blood, and so they may become largely electronic, download their brains and have and be electronic. If they are electronic, then that implies that they are near immortal, therefore, they won't be daunted by interstellar travel, taking a long time. So, if we looked at what would happen on the earth in the next millions of years, then there may be these electronic entities, which have been sent out and are now far away from the Earth, but still sort of burping away in some, in some fashion to be detected. In similar manner, if there was another planet like the earth, and was ahead of us, we wouldn't see a flesh and blood civilization, but we would see these electronic progeny as it were. This then raises another question, because there's a famous argument against there being lots of aliens out there, which is that they would come and invade us and eat us. However, the escape to that is these entities would have evolved by second Intelligent Design, designed by their predecessors. Whereas Darwinian selection requires two things; aggression, and intelligence. This future Intel design may favour intelligence, because that's what they were designed for and may not favour aggression. Nonetheless we can't refute their existence in the way the Fermi Paradox is supposed to refute their existence, because these would not be aggressive or expansionist.

Space Exploration

• The End of Astronauts by Donald Goldsmith and Martin Rees argues that the practical case for sending humans into space is getting weaker all the time, as robots get better and more capable and cheaper.
• Human spaceflight, should not be pursued by NASA or public funding agencies, because it has no practical purpose. It is also specially expensive because they would have to be risk averse, in launching civilians into space.
• It is a dangerous delusion to think as Elon Musk has said, that we can have mass emigration from Earth to Mars, to escape the earth problems because, it's far easier to deal with climate change on Earth, than to transform Mars to make it properly habitable for humans.
• We humans think of ourselves as individuals, but in reality, the intelligence, the things we create that are beautiful emerges from our interaction with each other, and that may be where the intelligence is, ideas, jumping from one person to another over generations. Individual humans may not be the atoms of intelligence, rather it could be the entire organism together having the collective intelligence.
• On the moon and on Mars, everything that's useful can be done by machines much more cheaply than by humans.

Future Technology

• About the extent to which we should entrust any important decision to a machine. We need to be very careful of the extent to which AI can handle loss of information actually makes the decision for our oversight. We can use them as a supplement.
• We ought to try and slow down the application of these human enhancement techniques and Cyborg techniques for humans for just that reason.

Black Holes

• Black holes are now accepted as one of the most remarkable predictions of Einstein's theory.
• There's compelling evidence that black holes exist as the remnants of stars or big ones that are centres of galaxies.
• LIGO is one of the most incredible engineering efforts of all time.
• Einstein's theory extended by people like Roger Penrose, tells us that black holes are in a sense of other simple things, basically, because they are solution of Einstein's equations. What was shown in the 1960s, by Roger Penrose, in particular, and by a few other people, was that a black hole when it forms and settles down, is defined just by two quantities, its mass and its spin.
• There are lots of black holes weighing about 10, or up to 50 times as much as the sun, which are the remnants of stars.
• David detected the first 50 years ago, when a black hole was orbiting around another star, and grabbing material from the other star which swirled into it and gave us X ray. So the X rays, astronomers found these objects orbiting around an ordinary star and the missing x ray radiation very intensely varying elevations which are timescale. So something very small and dense, was given that radiation. That was the first evidence of black holes. But then the other thing that happened was realising that there was a different class of monster black holes in the centres of galaxies. And these are responsible vertical quasars, which is when something in the centre of a galaxy is grabbing some fuel and outshines all the 100 billion stars or so in the rest of the galaxy, a giant beam of light.
• Quasars were discovered when astronomers found things that looked like stars and they were small enough to be a point like, not resolved by a telescope, but out shon an entire galaxy.
• Was producing far more energy than all the stars added together. And it was the energy of the black hole that was lighting up all the gas in the galaxy.
• Most galaxies have big black holes, they vary in size.
• The black hole in our galaxy weighs about as much as 4 million suns, which is less than some several billions in other galaxies.
• If a black hole is isolated, then of course it doesn't radiate. All radiates is gas swirling into it. Which is very hot, or has magnetic field.
• Our universe is sprinkled with a bunch of galaxies and giant black holes, it was like a very large number of stars, orbiting these black holes, and then planets orbiting, likely, it seems like planets orbiting almost every one of those stars.

Cosmological Threats

• On the cosmological timescale scale, we cannot predict any threat to humans.
• We are more demanding of energy and resources, therefore we are, for the first time, changing the whole planet, through climate change, loss of biodiversity and all those issues.
• The threat of misuse of technology.
• The stakes are higher, we have huge benefits from computers, but also huge downsides as well.
• The command and control system of the nuclear weapons and the submarine fleet and all that is now more automated, and could be subject to cyber attacks.
• COVID-19 revealed so many flaws in our human institutions.
• Regulating new dangerous biological experiments is not enough, enforcing it is the challenge. To achieve this all nations have to interface a big trade off between three things we value; freedom, security, and privacy.
• Nearly everyone in Africa has reason to feel embittered, because their economic development is lagging behind most of the rest of the world. And the prospects of getting out of the poverty trap is, is rather bleak, especially as the population grows. It's a manifestation of the excessive inequalities of the fact that the 2000 richest people in the world have enough money to double the income of the bottom billion.
• Now, the gap between the way the world is and the way the world could be, is far, far wider. It therefore implies that we are ethically more at fault in allowing this gap to get wider than it was in mediaeval times.
• In light of the many crisis in the world, the world is in desperate need of leaders.

Advise for Young People

• Many people don't realise the opportunities open until it's too late. They somehow think that some of the opportunities are only open to a few privileged people, and they don't even try - they could succeed.
• For young professionals, pick an area to work in, where new things are happening, where you can do something that the old guys never had a chance to think about, don't go into a field that's fairly stagnant because then nobody wants to do or you will be trying to tackle the problems that the old guys got stuck on. For instance in science, pick a subject where there are exciting new developments and also, of course, something that suits your style. So pick some subjects that suits your style, choose where things are happening fast, and be prepared to be flexible.

Mortality

• There is this emphasis on living much longer than in the so-called Altos laboratories, which have been set up by billionaires. There's one in San Francisco, I think, and one in Cambridge. These laboratories are funded by these guys who, when young wanted to be rich, and now they're rich, they want to be young again.

Final Thought

A quote from Martin Rees:
"I'd like to widen people's awareness of the tremendous time spent lying ahead for our planet and Life itself. Most educated people are aware, the worthy outcome of nearly 4 billion years of Darwinian selection. But many tend to think that humans are somehow the common nation. Our sun, however, is less than halfway through its lifespan, it will not be humans who watch the sun's demise 6 billion years from now. Any creatures that then exist will be as different from us as we are from bacteria, or amoeba."