Stargazers, perhaps know it, more than others, the true scales of our lives. The real distances, the real sizes…The true meanings of vast and narrow, big and small…Their points of references and perspectives are perhaps more accurate and larger than most…and perhaps they are the ones who truly might have an idea of what shall really last…
Astronomer and Professor Michael Brown speaks to Pritha Kejriwal on how he shattered the myth of the last planet and other things under the stars…
Let me start by asking you: you’ve been called the “Pluto killer”! So, how did you manage such a feat?
What I did was not so much kill Pluto as a planet. I didn’t subtract things from the solar system, I have been adding. So for the last decade, I’ve been spending most of my time looking for and discovering things in the outer edge of the solar system, beyond Neptune, and the region where Pluto is. Since 1930, when Pluto was discovered, till about 1992, Pluto was the only thing we knew about, that existed there. There was sort of this ‘’oddball’’ at the edge of the solar system. And nobody quite knew what to do with it, so they just called it a planet and forgot about it. But since 1992 we’ve been finding thousands and thousands of new things out there beyond Neptune, in the region where Pluto is. And so instead of Pluto being this oddball, that makes no sense, it is actually a part of this new vast population of these new tiny, objects. And Pluto is part of these tiny, tiny objects and not a planet
So why was it that Pluto was proclaimed as a planet in the first place? Was it that other objects were not visible at that point in time, because of their distance to us?
It was two things that helped at the same time. One was that Pluto was one of the largest things out there, the reason it was found first. It was also, as it turns out, one of the most reflective ones, and everything you see out there is due to reflected sunlight. Nothing makes it’s own light in the solar system. Stars outside do, but the things in the solar system don’t… so Pluto is covered in a very frosty surface, so it reflects a lot of sunlight. And it’s closer than most of the other things out there. So put those 3 things together, and it’s a factor of… umm…about 8 times brighter than the 2nd brightest thing in this region out there. And it happened to have just been at the limit of the technology in 1930. The technology in 1930 was photographic plates. And photographic plates could barely just detect Pluto, and not detect the next thing. So if it had been slightly better technology they would have discovered 5 or 6 objects, if it was slightly worse they would have discovered zero. But as it was, they just discovered 1, which is exactly the worst number to discover. Because you discover one, and you think: this is a unique object. There’s something special about this object. And the answer is, there are thousands of them out there that we have now discovered.
So do you think that maybe after some years we would just suddenly find that maybe Neptune is also not a planet?
No, no, definitely not. So the difference is, we know, it’s not just that we suddenly decide to change our mind, or that we didn’t know something. So now we know the nature of Pluto, we know the real size of Pluto. When Pluto was first discovered, people speculated that it might be the size of the earth or the size of Jupiter. It’s actually two-thirds the size of the moon, it’s really tiny, which most people don’t realise. It’s really tiny. So we know it’s small, there are other small things like that out there. What we really do these days, we understand the solar system much more profoundly than we did in 1930 when Pluto was first discovered. So we really understand the solar system… the best way to think about the solar system is that there are 8 planets. And these 8 planets are the dominant, controlling things in the solar system. They’re massive, they’re on these beautiful, circular orbit’s; everything else in the solar system, Pluto and all those other thousands of things out there, asteroids that are closer to us, everything sort of flits in and out of the planets, they get kicked around by the planets, they go screaming all over. The basic differences between 8 planets and everything else is just so fundamental that there’s no way that you could ever take Neptune away and say that it’s something else. There’s always the outside possibility, we might find something to add, although I don’t think that’s a possibility.
Is that why your book is called, ‘How I killed Pluto and why it had it coming’?
That was the ‘why it had it coming’. It had it coming because it never was a planet, I mean if we knew in 1930 what we know now, about what is out there, no one would have actually called Pluto a planet. I mean, it makes no sense whatsoever. And in fact, one very funny thing that I like to think about is, that Pluto just was barely bright enough to be discovered and nothing else was, the only reason that the second brightest one wasn’t brighter is because it was on a very elongated orbit and right now it’s on the very furthest point of it’s orbit, and it takes about 580 years to go around. ‘Eris’, this is the one that’s bigger than Pluto, the one I discovered. It’s on it’s most distant point in it’s orbit, and in 290 years it’ll be around the same distance as Pluto, but it’ll be brighter than Pluto. So I often think about, if the orbit had been in a slightly different location, or if society had developed 290 years later; photographic plates; and Eris and Pluto were around equally bright, and in 1930 they were both discovered at the same time, maybe you discover the fist one and say,”Wow, this a new planet” and you discover the second one and say “oh, okay, I understand now”. There’s going to be many, many things out there, and these are just the tip of the iceberg. Now we know that that’s what it is, and that’s why Pluto, since 1930 has had it coming even though we didn’t quite know it.
So Pluto is perhaps the most famous of the things that you’ve worked on, so we all talk about Pluto this much but do tell us about some other fascinating things that you’ve come across, star gazing?
You know, It’s true, most people, when I talk about what I’ve done, they really want to talk about the one, that’s killing Pluto! I mean, really, I didn’t really do anything to kill Pluto, except for find more things, and Pluto kinda killed itself. These other things that I’ve discovered out there, beyond Neptune and in the same region as Pluto, have taught us a tremendous amount about the solar system and how the solar system is put together. There’s the one that’s a little bit bigger than Pluto. It’s close to the same size as Pluto but it’s more massive than Pluto: that one sort of tells us how collisions have affected things in the outer solar system.
But these are not parts of our solar system?
These are all parts of our solar system. They go around the sun and they’re not planets. There are these 8 planets, and then there’s all these other things. And these are the largest of those other things, but they’re not planets. So the largest things that aren’t planets. Which is kind of like saying, you know, you pick up a handful of sand, and there’s a largest piece of sand and it’s not that different from the smaller piece of sand and this is kinda the same way, it’s just the biggest piece of sand. But each one of them is an individual world in a sense, that tells you, it records a little bit of the history of the formation of our entire solar system.
So if I may ask you this again, what makes a planet different from these other objects?
The explanation, there’s a definition. I’m not going to tell you the definition because it’s a really stupid definition, because there shouldn’t be a definition. Astronomers in every other field don’t have definitions: astronomers work in concepts. A star, we all know what a star is. A star is something that has nuclear fusion on the inside and gives off heat and astronomers all know that. And galaxies, we all know. But you can’t go find a rulebook somewhere and read precisely what a star is: “it must be this, Check, Check”. Planets, now, unfortunately, there’s a three part, official, lawyer like definition. Once there’s a lawyer like definition, what happens is that you get lawyers involved, or people who pretend to act like lawyers, and say, “oh well, you know, look at this definition. If you look at this definition, the earth is not a planet, so HA HA HA”. Conceptually, the difference between planets and not-planets is incredibly strong. Planets are these big, dominant things in your planetary system and larger than everything else, but also dominating gravitationally everything around them. If you took any of these little things that are flying around and you try to stick them in the middle of the planets, they will get kicked around, they would not last very long: the planets are moving everything around. If you removed anyone of the 8 planets from the solar system, the solar system would be a very different place, it would re-arrange to compensate for the planet’s being gone. If you took away Pluto, the solar system would be exactly the same.
It’s all so fascinating; it’s so spectacular, almost cinematic. But I wonder why science isn’t as popular, in popular culture, as cinema is.
I think there’s some reasons for that, and first of all, I’m not sure if it’s true, I mean a lot of cinema is science fiction. And sometimes science fiction is just silly, but good science fiction, I think is the kind that is plausible science, that takes a real plausible scientific story and gets people engaged in that. So the science fiction part is really interesting. Part of the reason I think that science is not as engaging as cinema is that scientists aren’t as good storytellers, as they need to be. If you’re a scientist and you want people to be interested in science, which we all do, you have to be able to tell stories. I mean, if I came up to you and explain to you what was going on about Pluto not being a planet, and I said, “I found this object exerts more mass than Pluto and you can look at it’s orbit, it’s elongated and eccentric etc..” and you would just yawn. I mean, you have to tell stories. People inherently like stories. And so I think scientists have to learn from cinema and their stories too.
There’s this really interesting project that a magazine called Canteen did: They’re an American magazine and what they did was get the authors and writers to dress and pose in a certain way, and put them on their covers – it was called the Writers Project or something, and the idea was to make writers as pop-cultural icons. You know, why shouldn’t writers be these fascinating personalities which people want to engage with? So do you think we should do the same thing with scientists as well?
I think it’s a great idea!! You might not want to see the scientists on the cover, that’s part of the problem, but if you’re film stars or selected for having looked partially right so, they might be more attractive to look at. But I think it’s the job of the scientists, to make themselves more interesting…I don’t think it’s the fault of the people…
But the media, would they be interested?
They can! I’m gonna blame the scientists for this one. It is not that the media does not go and talk to the scientists. It’s the scientist. When the media comes and talks to the scientist, he is not necessarily engaging. I mean, I go to innumerable presentations by scientists that are for the public. You know, sometimes scientists are bad at talking. You can’t even talk to colleagues about what you’re doing, god help you when you go and try to talk to the public! It’s not always true, but it’s often true that the scientists just aren’t good storytellers. And that needs to change.
Bertrund Russel had written this – when science ends, philosophy starts. So how do you, kind of explain the inexplicable, in your own mind? Do you philosophise after a certain point?
I don’t, I don’t! I mean, it’s actually because I kind of agree with that. Where science ends, philosophy begins. I’m a scientist, so I stop at that point. You know, the question…
So, after science, it’s more science?
NO, no, I mean, there are limits to science! I don’t know how to answer those questions! There are questions like, people will often ask me, ‘’If there was a Big Bang, what, what happened before the Big Bang?
Or, is there a God?
Yeah! Is there a god? I don’t know! Uh, and, if you have faith that there is, then to you there is…
So what is it to you? So you just stop there? You stop your thinking process, right there?
You know, actually, I don’t stop the thinking process. But I don’t tend to philosophise, I tend to be honest. Which is, if you ask me, “is there a God?”, I will answer you the best that I can, which is, ‘I don’t know.’ And if you ask me what happened before the Big Bang, I’ll say, ‘I don’t know and I can’t tell”.
So, Do you believe that whenever we do come to know, it would be only through more scientific enquiry?
No, no, I think there are limits to science, what you can learn through science. There’s a scientific limit to understanding what happened before the Big Bang.
SO is that a given, that some things will always remain inexplicable?
I think so. I do think so. For a long time, people would say that the human soul, the human psyche is inexplicable. I think we’re closing in on that… but some things would always remain just like that…unexplained…
So how does one know the limits, how do you know this is the limit, that Science cannot go beyond this?
You don’t, I guess you’re right, you don’t know the limit. But the question of God and what happened before the Big Bang, or how did the entire universe really get here? We’re part of that universe, we’re inside that universe. We have absolutely no way of stepping outside that universe and, asking questions about it as an external agent. And when you can’t do that, certain things become impossible to answer.
But, coming from you, “I don’t know how the universe came through” But there have been scientists who came up with the Big Bang theory or the oscillating two cosmos theory, whatever, there are so many theories around, I’m sure there’s been a lot of scientific thought to all of it, it’s not all jargon, surely?
No, no, the Big Bang theory, I mean, I can take you back 15 billion years and explain all, everything that happened from now, backwards 15 billion years and where, where I get stuck and I can no longer answer the questions is, is the moment that is .0000..43 zeroes and 1 seconds after the Big Bang. Between the Big Bang and that .0000 …1 seconds: Physics can’t answer that question, current physics can’t answer that question, after that, it’s all pretty understandable. Umm, but before that, we don’t even know. Was there nothing before the Big Bang? Did it oscillate? There was another universe? Were there multiple universes? These are interesting theories, but I don’t know…
And just one more quote from Bertrand Russel again, you know, because it’s so interesting, and I think about it all the time. He says that, “ If ever the history of the universe was written, man would perhaps, just be mentioned as a footnote.” Would you agree?
It has to be true..It has to be true. So I mean, if you look up at the sky at night, every one of the stars you see, has a moderately good chance of having planets around it. We don’t, we don’t know… this is one of the questions that I think science will eventually address, but we don’t, we don’t know right now. Is it easy or is it hard for life to start? We don’t know. And, it doesn’t really matter if it’s easy or hard… because the universe is effectively limitless. There are things not like us, but there are probably things, that are maybe kind of like us, maybe things you would not recognise as human, but there must be an infinite variety of beings…we’re a minor little infection on the surface of the earth. In fact, if you come back in two billion years, and write about the history, forget about the universe, write the history of the planet earth, there would be so much going on in the history of the planet, and someone would say, “Hey you know what, there was this really weird period for about a hundred thousand years when this one species came and did all these crazy things! But then they just disappeared.”!
True. But so then, being an astronomer, on a very personal note, do you really palpably feel very very small and tiny in the entire universe? And does that affect your philosophies in life? And all these questions that we socially, culturally, politically grapple with as mankind on earth, do you feel the randomness and insignificance of it all, and laugh most of it off?
No, no. In the end, we can actually feel lonely and insignificant when we look into the universe, but I actually feel a part of it. I feel, it’s our home. I look up, like, my wife pointed this out to me this one time, that every time we walk outside at night, I always look up. And I look up to see where I am, to get my bearings the same way that you might look around your neighbourhood for which house you’re by, or which mountain…I just look up, it’s just…it’s my home. The fact that my home is sort of bigger than, than what maybe a lot of people would think of as home, doesn’t make me feel like it’s not my home!
Thank you, on that note, Thank you so much for talking to us.
