The 20 big questions in science | Science | The Observer

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From the nature of the universe (that's if there is only one) to the purpose of dreams, there are lots of things we still don't know – but we might do soon. A new book seeks some answers



1 What is the universe made of?

Astronomers face an embarrassing conundrum: they don't know what 95% of the universe is made of. Atoms, which form everything we see around us, only account for a measly 5%. Over the past 80 years it has become clear that the substantial remainder is comprised of two shadowy entities – dark matter and dark energy. The former, first discovered in 1933, acts as an invisible glue, binding galaxies and galaxy clusters together. Unveiled in 1998, the latter is pushing the universe's expansion to ever greater speeds. Astronomers are closing in on the true identities of these unseen interlopers.

2 How did life begin?

Four billion years ago, something started stirring in the primordial soup. A few simple chemicals got together and made biology – the first molecules capable of replicating themselves appeared. We humans are linked by evolution to those early biological molecules. But how did the basic chemicals present on early Earth spontaneously arrange themselves into something resembling life? How did we get DNA? What did the first cells look like? More than half a century after the chemist Stanley Miller proposed his "primordial soup" theory, we still can't agree about what happened. Some say life began in hot pools near volcanoes, others that it was kick-started by meteorites hitting the sea.

Written By: Hayley Birch, Colin Stuart and Mun Keat Looi
continue to source article at theguardian.com

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  1. I like how the caption on that depiction of a black hole says “photograph”. Hmm…

    Still, an interesting, if unoriginal, article. Many of the questions seem to be merely semantic or philosophical (rather than purely or truly scientific) problems.

  2. Astronomers face an embarrassing conundrum: they don’t know what 95% of the universe is made of.

    Why does everyone always pretend the mass percentage is the measure of ignorance? The universe has three ingredients, and our understanding of one is almost perfect (right down to predicting the Higgs discovery nearly 5 decades in advance), and there are good ideas about what the other one is, based in work on completely separate physics problems. Dark energy is much harder to understand, but the fact that it’s “70 %” doesn’t correspond to how much we know.

    The former, first discovered in 1933, acts as an invisible glue, binding galaxies and galaxy clusters together.

    Glue? Its mass gravitates; that’s all! In fact, that’s how we conclude what % mass it is.

    What makes us human?

    A bunch of things; just not what we wanted to. It’s true we’re the smartest species; it’s also true we’re the best runners (but no-one seems to care), and our males have the largest penises among the primates. And, if we knew every detail of every species, we could rank humans among all of them. Or we could just rattle off our statistical properties now, e.g. the average eye diameter. But that’s not what we really want, is it? We want the question “What makes us human?” to have an answer that is nothing like the answer to “What makes aardvarks what they are?” The trouble is there’s no reason to expect it exists. Indeed, almost every “this is unique to us” claim has already been debunked.

    Just looking at your DNA won’t tell you – the human genome is 99% identical to a chimpanzee’s

    So look at the differences, then!

    Scientists think that cooking and our mastery of fire may have helped us gain big brains. But it’s possible that our capacity for co-operation and skills trade is what really makes this a planet of humans and not apes.

    Oh; was the question meant to be “why did humans get so smart?”, or possibly “why did humans get so powerful?” If we weren’t so powerful, nor would primates be collectively.

    What is consciousness?

    I’ve never understood why our ignorance on the details of this is considered such a big deal. The answer will be something to do with information theory and neural electrochemistry, and yet people often act as if consciousness is some extra magic material, the next dark matter.

    Our best theories suggest that the big bang created equal amounts of the two, meaning all matter should have since encountered its antimatter counterpart, scuppering them both and leaving the universe awash with only energy. Clearly nature has a subtle bias for matter

    The Standard Model has had a matter-antimatter asymmetry for decades. The interesting question is whether, empirically, the universe is even more asymmetric than the Standard Model can explain, and if so why.

    Our universe is a very unlikely place.

    I wish people would stop claiming that. They don’t know what probability density function to use when claiming it.

    Alter some of its settings even slightly and life as we know it becomes impossible.

    Imagine the space of values the parameters could take (unless there’s a reason they couldn’t). This comment tells us you can’t move far in certain directions without leaving our habitable zone, which means it’s not wide in those directions. That says nothing about what percentage of the space as a whole is comprised of habitable zones. To answer that question, you have to simultaneously vary all the parameters by a lot. Not only are many irrelevant, but something like half the universes “work”.

    In an attempt to unravel this “fine-tuning” problem, physicists are increasingly turning to the notion of other universes.

    Increasingly? I’d love to see the percentage’s trend, but it’s a small percentage anyway. The notion of a multiverse is taken seriously not because it’d make fine-tuning easier to explain, but because there are physical reasons for it to exist anyway, though currently not empirically established ones. For example, early inflation split spacetime into causally disconnected Hubble zones, whose parameters need not be correlated. Other universes are a consequence of M-theory’s 11-dimensional spacetime, too. Those universes wouldn’t even have the same laws, because their Calabi-Yau spaces would have different topologies.

    But how do we [sequestrate C]? One idea is to bury it in old oil and gas fields. Another is to hide it away at the bottom of the sea.

    Those are places to hide it, not ways to pull it out of the atmosphere and oceans.

    [We must] start making energy in a way that doesn’t belch out even more.

    We’ve had several options for decades. The problem is politics, not technology.

    What’s so weird about prime numbers?

    Hooray; a maths question!

    The fact you can shop safely on the internet is thanks to prime numbers – those digits that can only be divided by themselves and one.

    Digits? Are numbers all 1-digit now?

    An apparent pattern within them – the Riemann hypothesis – has tantalised some of the brightest minds in mathematics for centuries.
    Oh; the Riemann hypothesis. It does have something to do with prime numbers, but I don’t think this author understands what it is. It’s not so much a hypothesised pattern in them as a predicted property of a function that can be defined with prime numbers (or without them, if you prefer).

    How do we beat bacteria?

    Well, if it comes to that, how do we beat viruses?

    Will we ever cure cancer? The short answer is no. Not a single disease, but a loose group of many hundreds of diseases

    We can cure some percentage of the types of cancer; maybe one day that percentage will reach 100. (The percentage of cases we can cure would be lower, at least initially.) But if we’re bandying around umbrella terms, we may as well wonder when we’ll cure illness.

    When can I have a robot butler?

    If it’s smart enough to do it, we’re probably looking at slavery.

    What’s at the bottom of a black hole?

    Is the bottom where r=0? Our current understanding stops at r=2m. Everything in between matters too!

    Can we live for ever? … How do we solve the population problem?

    Why do I get the feeling we can’t have both?

    Maybe we can ship everyone off to Mars or start building apartment blocks underground.

    Mars has a quarter of Earth’s surface area. If it allows our maximum population to grow by 25 %, that might buy us only a decade or two. Even if we conquer the stars, after a time T we can only conquer a volume of space cubic in T, because of the finite speed of light. It’s not a long-term solution to a problem of exponential growth in population. We need to change the fact that people over-reproduce in the first place. Maybe not right now, but eventually.

    We could even start feeding ourselves with lab-grown meat. These may sound like sci-fi solutions

    Well, not that one; that burger has already been made. Now we just need to scale it.

    Time travellers already walk among us. Thanks to Einstein’s theory of special relativity, astronauts orbiting on the International Space Station experience time ticking more slowly.

    Going for a walk does it too, to some extent.

  3. What’s at the bottom of a black hole? See question 17.

    Black holes have bottoms????

    They MAY have centres, but I’ll stick to:- What is beyond the event horizon? assuming there is enough TIME to allow anyone to look at it!
    I’m guessing “energy”!

    Photograph: Alamy

    I don’t think so! Computer model or artist’s impression – maybe!

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