Five Things We’ve Learned From Science

Five Things We’ve Learned From Science

Because there’s not been much progress in the fundamentals of physics – the Standard Model is still essentially the same as it was 30 years ago – it can sometimes feel that we’ve not learned that much new recently. Sure, we have a lot of exciting technology, particular computers and smart phones, but these are all operationalistions of existing basic science rather than based on anything new.

I think this is a classic example of the current time paradox, where we see what’s happening now as unexceptional and don’t notice all the things that are actually transformative. So in celebration of science marching on, here are five new things we’ve learned that we simply didn’t know when I was a child.

Extrasolar planets. For me this is the biggest and most exciting. When I was young, we literally had no idea as to whether there were planets round other stars. Now we’ve detected hundreds; we know that planets are actually pretty common and even have some idea of what they look like (their size, at least). I’ve sure this is behind the recent upsurge in slower-than-light science fiction: the universe has just become a little bit smaller.

Genetics is more complicated than we thought. I remember the human genome project and how we thought at the time that this would unlock the whole of human biology. Well, that was an impressive project – and now we’ve mapped thousands of genomes of different species – but even more interesting is the way we’ve discovered how complicated the whole thing is, going far beyond ‘this section of DNA codes for a protein and that’s it’. Overlapping genes, ‘junk’ DNA being less junk than we’d thought, the whole fields of proteomics and epigenetics – a whole new vista has opened since the ’90s.

Neutrinos have mass. I don’t know what implications this has, mainly because we’ve still not discovered how to do a whole lot with neutrinos, but it feels pretty fundamental. This was discovered in 1998, so I can really remember books going from ‘we don’t really know if neutrinos have mass’ to actually learning how they acquire mass in third year physics.

AI. You could put this down as a technology – and it is – but there’s a real element of discovery, too. People used to claim that once a computer wouldn’t be able to beat humans at chess until we had real AI – well, they’ve beaten us at Go now, and we’re still clearly not there. It’s a fascinating field: we’ve made huge strides in computer’s abilities, from IBM’s Watson to self-driving cars, but also learned a lot about what broad-spectrum intelligence means, and how sophisticated it is.

Bose-Einstein concentrates. We’ve discovered a huge amount about super-cooled states and condensed matter. The new state of matter that is a Bose-Einstein concentrate (essentially a macroscopic state that shows quantum properties), the slowing and halting of light in 2001 and more – these seem to be pushing at the edges of knowledge in a way the nuclear physicists were in the mid-20th century.

10 thoughts on “Five Things We’ve Learned From Science

  1. Did we really think it was plausible that planets were a one-off fluke? I know we’ve only recently been able to actually identify (to some degree) what stars have what sort/size of planets but I was never aware of the concept that planets simply didn’t exist beyond the solar system.

    On AI the thing that stuns me is that we have now been beaten at Go and chess by computers not specifically designed to play those games: by general systems that learn the game and how to win. They’re not relying on piggybacking on millenia of human tactical and analytical development, but rediscovering and bettering it from scratch.

    1. I don’t think people thought there were no other planets anywhere, but there were definite debates over whether they were rare (e.g. 1 in a 1000). It’s one of the terms in the Drake Equation and classic Anthropic principle: we can’t use our solar system to deduce anything about the likelihood of others. And there were real difficulties in getting mathematical models that explained how the solar system (the fact that other solar systems mainly look nothing like ours, blowing most of our formation theories out of the water, does show we were right to be dubious that we knew what was going on).

      Agree on AI, though interestingly it utterly bombed when used on a Eurogame, so still some way to go.

    2. We didn’t think that extrasolar planets would not exist – indeed the concept of there being planets beyond our own Solar System is several centuries old (see e.g. Giordano Bruno in the late 16th Century). There was, however, an attitude in the 1980s that astronomers looking for exoplanets were on a dead-end career, because the likelihood of detecting them was deemed to be so remote. (The first confirmed detection of a planet outside the Solar System was a pair of planets orbiting a pulsar, in 1992, made possible because the timings of the pulses was so regular that time wobbles/shifts were detectable.)

      What wasn’t appreciated, however, was that planetary systems would be so diverse (planets around binary stars, planets in 4-star systems, planets with giant planets very close to their star etc.). Indeed, the first detection of a planet around a sun-like star (51 Pegasi b, in 1995) was almost missed – they were searching their data for orbital periods somewhere around a year, not the 4 day period that they originally found.

      Once the detections were made, however, things moved very quickly. At time of writing the exoplanet catalogue (http://exoplanet.eu/catalog/) contains 3781 confirmed planets, in 2829 planetary systems.

      It reminds me a little of the discovery/confirmation that galaxies were beyond our own. There were debates for nearly 2 centuries about whether the “spiral nebulae” were within our galaxy or beyond it – they were certainly too far to measure by the methods at the time (parallax measurements), but the size of the Milky Way itself was unknown to within an order of magnitude or two (tens to hundreds of thousands of light years). This culminated in the Shapley-Curtis Debate in 1920. In 1925, when Hubble published the distance to the Andromeda Galaxy (née Nebula) as around 1 million light years (he was wrong by a factor of 2 or so – it’s 2.5 Mly away!) the matter was essentially settled.

      I think what’s similar between the two cases is that the evidence was so clearly in favour of one side of the argument. Contrast this with the evidence for the Big Bang (as opposed to the Steady State universe), which gradually built up over decades (galaxy redshifts, quasars, stellar nucleosynthesis, Einstein’s GR predictions etc.) but took a long time to be accepted by everyone – until the discovery of the Cosmic Microwave Background put the final nail in the coffin of the Steady State model).

      1. This is the advantage of having a professional astronomer as a regular reader! I hadn’t realised the first was discovered as early as 1992 – in my memory it was a late ’90s phenomenon, which is I guess when they started coming in droves.

        It’s also interesting that you say scientific consensus was very firmly in the ‘they’re common’ camp (and I definitely trust you to know more about this than me. Looking back, I suspect I thought it was more balanced (a) ‘rare earth’ and similar theories did exist and it can be hard to judge how strong minority theories are from reading a couple of popular science books or articles and (b) that even now, news articles about exoplanets often contain phrases such as, “at one point, some scientists thought exoplanets might be very rare,” which is technically true, but mainly serves to make the story more dramatic.

        1. I don’t think it’s necessarily true that the consensus was that they were common – though the consensus was certainly that other planets would exist. The big debate was how easy they would be to detect.

          I found one of the papers about the searches in the early 1990s (http://adsabs.harvard.edu/abs/1994Msngr..76…51K) which says:

          “The origin of the solar system is a fundamental problem in astrophysics for which many basic questions remain to be answered. Is planet formation a common or rare phenomenon? Is it a natural extension of the star formation process or is a different mechanism involved? Unlike mote stars, the SUn is not found in a binary system. Is its single status related to the face that it has a planetary system?”

          I’m not actually too sure how opinions were balanced on the frequency. I think opinion on the frequency changed with time, but there were still arguments over whether they were common or not. The existence of planets around binary stars was a big question until Kepler started finding them, for example. Frank Drake, who penned the famous “Drake Equation” to think about this problem, initially expected the fraction of stars with planets to be 0.2-0.5. By the 1990s we knew stars formed in clouds of gas and of dust, with many young stars having disks of dusty material around them (we’d seen them – e.e. “proplyds” in Orion) – though the proportion wasn’t initially clear. Given that the older stars don’t be dust disks around them, then the material has to go somewhere – possibly falling into the star, but that’s hard to arrange due to angular momentum, so the only real alternative is planets of some description.

          Is also fair to say that part of the history of science has been one of disproving every attempt to argue that the Galaxy, Sun, Earth etc. are special. The last cases for speciality are the formation of life (which is likely to be either common place, or only found here on Earth) and the evolution of intelligent life (which is still a big debate among both astrophysicists and astrobiologists).

          1. Ah, I must have misunderstood your earlier comment on the rarity – thank you for clarifying.

            On the last, one other possibility I’ve seen discussed is the likelihood that life evolves from single-cellular to multi-cellular (on the grounds that this took c. 3 billion years on earth: the time from multi-cellular to intelligence was comparably quick). So under that theory, we’d come across lots of planets covered in single celled life forms, but no higher life.

  2. On the single-cellular to multi-cellular aspect, yes, there is considerable debate about that. It appears that the evolution of mitochondria (the energy generators within cells) was a crucial development, and there are theories that this was prompted by de-oxygenation of the oceans a couple of billion years ago. I have a colleague, Annabel Cartwright, who has hypothesised [but is still looking for a way to prove the hypothesis] that Venus played a role, and that the more rapid evolution on Venus 0.5-2 billion years ago, combined with material transferred to Earth after impacts, could have effectively seeded more complex life on Earth. See https://arxiv.org/abs/1608.03074 for the paper, or http://blogs.cardiff.ac.uk/physicsoutreach/2017/07/01/pythagorean-astronomy-gravitational-waves-and-life-from-venus/ for a podcast interview.

    On the origin of single celled life itself, my understanding (as a non-astrobiologist) is that there are two main camps: 1) life originated due to random chance arrangement of chemical building blocks (e.g. amino acids, which are present in comets, meteorites etc.), and so given the number of possible combinations the chances of that happening more than once is remote.
    2) there is something that biased the chemical combinations towards those of life, or there is some other root origin of life, such that its origin is much more likely, and so life will be everywhere.

    One way to tell between the two would be to find evidence of the independent evolution of life here in our own Solar System. Sounds easy, but proving (beyond reasonable) doubt that its origin was independent of that on Earth (and there hadn’t simply bee cross-fertilisation) would be somewhat challenging. Of course, if that new life was based on something other than DNA that would be a good indicator.

    1. Certainly in the solar system, if we found something based on DNA (unless it had lots of novel base pairs or similar) my default assumption would be that this was not independent life. When you look at the number of ways to make a working eye, it seems inconceivable that RNA/DNA is the only way to convey genetic material.

  3. So what about all the things we keep learning about the brain? Those I find the most fascinating.

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