Tim Coulson
speaker
53 appearances
1 recordings
1 series
first heard May 2025
last heard May 2025
Tim Coulson’s voice in public audio — every appearance, attributed to the second.
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Science has made astonishing progress in working out why it is we exist. With each passing year, we have a better understanding of all the remarkable things that had to happen from the beginning of the universe 13.8 billion years ago until now.
It's a pleasure to be on.
So I think so. I think over the last, say, 50 to 100 years, science has made astonishing progress in working out why it is we exist. In particular, all the things that had to happen for us to be here. I don't want to kid anyone that it has all the answers. There's still quite a lot to find out. But yeah, with each passing year, we're finding out a little bit more.
and we have a better understanding of all the remarkable things that had to happen from the beginning of the universe 13.8 billion years ago until now.
So it's true that lots of things had to happen. And so without going through them all, but the universe first of all had to form, and it did so as a pinprick of intense energy. And some of that energy then converted into matter. So things called quarks and electrons. And over time they formed atoms and then molecules and we had stars and then the earth formed and life had to form.
And then there were various steps that had to occur for us to come about. And if one or two of those things hadn't happened, it's entirely possible we wouldn't be here. However, the universe is also so incalculably vast that if we look across the whole universe, it seems probable that intelligent life evolved at least once, or we know it evolved once, but it may have evolved many times.
And I think what science is starting to be able to tell us is some of the likelihoods of some of these events occurring on the grand scale of the entire universe.
We don't have any, the only intelligent life, and in fact, the only life we have found so far is on Earth. However, we have only looked in a very tiny corner of our neighborhood, very small part of the universe for evidence of life coming from elsewhere. So there are trillions and trillions of planets in the bit of the universe we can see, that's called the observable universe.
Yet we've only pointed our telescopes at about 6,000 planets. And the ones that we've pointed the telescopes at tend to be gas giants. So planets a little bit like Jupiter or Saturn that, as far as we can tell, don't have liquid water. And we think that liquid water is necessary for life.
So although we haven't found any evidence of intelligent life elsewhere, we haven't looked very far or very hard at all.
I think it's the latter. And so one of the challenges is we don't know how long intelligent life lives in civilizations where they're capable of sending out signals for other intelligent life to detect and then respond to.
So all of the civilizations that have appeared on Earth before, so the ancient Greeks, the ancient Egyptians, the Aztecs, et cetera, they've only survived for a few hundred, possibly a few thousand years. Our current civilization is a few hundred years old, a couple of thousand tops, and we don't know how long it lasts for.
Now, if you think about it, the universe is 13.8 billion years, so a couple of thousand years is but a blink of an eye. And so the likelihood of two intelligent civilizations being close enough to gather, close enough to one another in the vastness of the universe to communicate, is actually quite a small probability.
But despite that, we are going to keep listening out and we're going to keep listening to see whether there's any evidence of intelligent life. But what we might find is evidence of simpler life, say bacteria, living on other planets.
And there is even some space probes that have gone out to the moons of Jupiter and Saturn to look for evidence of bacterial lives on those moons, because what we do know is liquid water does exist on those moons.
So I think the way that I would answer that question is probably in a couple of parts. And so we understand what had to happen for life to get started. And there are sort of three things that need to happen. Life is just very complicated chemistry and it's chemistry that can replicate. So it's chemistry that can make copies of itself.
And there are actually quite simple reactions that can make copies of themselves. They're called autocatalytic reactions. And so we think that life started off as an autocatalytic reaction that became more and more complicated. And we have some ideas why that might happen. The second thing that life needs to get going is energy.
And the very first life on Earth was almost certainly driven by volcanic energy. It's known as chemosynthesis. So it would have relied on highly reactive molecules that were created by volcanoes. And it used that to power its replication. And then the third thing it needs are membranes to sort of keep it all together, to keep the replicating molecules together.
And those are quite easy to form as well. So given that, we think that simple life probably gets going quite frequently within the universe. There are probably not every planet by any stretch of the imagination. But I think a lot of biologists and a lot of chemists now suspect that life gets going reasonably easily. And it got going quite quickly on Earth once conditions became suitable.
We had liquid water for that to happen. So we don't think the early Earth was so unusual that life would have got started only on this planet. We suspect it's quite commonplace. Now, if that's the case, the next question is, how long does it need to become complicated? And life has been evolving on Earth for about 4 billion years.
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