13 unsolved scientific puzzles. Kinda.
The Times has a rather odd list of 13 Unsolved Scientific Puzzles. They're a bit odd, and the accompanying review is even worse. Here are a few of the 'puzzles':
1. MOST OF THE UNIVERSE IS MISSING - We can only account for 4 per cent of the cosmos
Yep, that's a big one. Dark matter + dark energy aren't understood. Here's what the other article says:
One of the great discoveries of 20th-century science was that our universe is expanding. The discovery, however, led straight to another puzzle. The puzzle is, there's nowhere near enough matter to prevent the expanding universe from blowing apart completely into a vast, sterile infinity of lifeless interstellar dust. So how come we live in a lumpy universe, one of the lumps being the planet on which we live? There must be more matter than we can see: the famous dark matter and, to go with it, something even more mysterious - dark energy.
No - what? That's nothing to do with anything, is it? This could be the still-lumpy phase of an expanding universe. The main problem is the acceleration itself: gravity should at least be slowing the expansion down, but it's actually increasing. That's dark energy, and it's an unknown. Dark matter is the discrepancy between the mass we can see and the mass we can detect by its effect on matter.
To date, however, there's not a shred of evidence for either, even though teams of scientists have been looking for years. (The UK's search “takes place 1,100m underground, in a potash mine whose tunnels reach out under the seafloor”.) The only alternative to dark matter is to tweak Newton's most fundamental laws of physics and suggest that they don't apply everywhere, all the time, in quite the same way. But physicists are a law-abiding bunch, and detest this idea.
No, there's evidence for both. We can see where dark matter is, we just don't know what it's made from. And if it's detectable, it must by nature be difficult to detect, so years of looking is probably necessary. Dark energy is more of an unknown quantity, but we see its effects, so something must be going on. And yes, scientists are unwilling to reject the laws of gravity (actually Einstein's at this kind of accuracy, but whatever), since they've made incredibly accurate predictions up to now, and the Pioneer anomaly isn't yet a clear-cut case of a violation of those laws.
2. THE PIONEER ANOMALY - Two spacecraft are flouting the laws of physics
Yes again. The Pioneer space probes aren't where they should be, and it's a bit odd.
“Nasa explicitly planned to use them as a test of Newton's law,” explains Brooks. “The law failed the test; shouldn't we be taking that failure seriously?”
The article also says "decades of analysis have failed to find a straightforward reason for it". This is what as known as taking something seriously: you try very hard to explain something unexpected, and see where that takes you. I don't see the problem here.
4. COLD FUSION - Nuclear energy without the drama
But, despite what you might have heard, “cold fusion” never really went away. Over a 10-year period from 1989, US navy labs ran more than 200 experiments to investigate whether nuclear reactions generating more energy than they consume - supposedly only possible inside stars - can occur at room temperature. Numerous researchers have since pronounced themselves believers.
Cold fusion. Right. Not really an 'unsolved scientific puzzle', as there's no evidence it exists, as far as I'm aware. And if you think the scientific establishment is deliberately ignoring a potential source of safe, clean energy that would completely transform the world, you're bonkers.
5. LIFE - Are you more than just a bag of chemicals?
Fair enough. But wtf:
In labs across the world, people are taking the raw materials of living things and trying to put them together in a way that makes them come alive. In an effort to resolve the anomalous nature of life, the idea of scientists playing God has taken a whole new turn.
It's almost like you're referencing some fiction there...can't think what. And when 'God' is just your word for 'anything I don't understand', which it clearly is, then scientists are always going to be 'playing God', and it's a silly thing to say.
6. METHANE FROM MARTIANS - NASA scientists found evidence for life on Mars. Then they changed their minds
On July 20, 1976, the Viking landers scooped up some Martian soil and mixed it with radioactive nutrients. The mission's scientists all agreed that if radioactive methane was released from the soil, something must be eating the nutrients – and there must be life on Mars. The experiment gave a positive result, but NASA denied an official detection of Martian life.
Yeah, because the results were contradictory and ambiguous. Yeesh. The atmospheric methane increases are pretty cool, though.
Ok, I need to skip a few or I'll run out of time. Arguments over sexual reproduction and death seem somewhat misprepresented, lack of free will1 is given short shrift (rejected out of hand in the accompanying article) and the placebo effect is indeed genuinely mysterious, but then at the end there's this:
13. HOMEOPATHY - It’s patently absurd, so why won’t it go away?
How the hell did this get in here? He says "there remains some slim evidence that homeopathy works" - and this is what, exactly? And what of the many, many double-blind trials that suggest otherwise? I would like to point out that people still worship Greek Gods. It's ridiculous, but why won't it go away? Maybe we should look again at Greek Gods.
The 'puzzles' are all taken from a book, which gives me pause - maybe the full text is more rigorous, and these quick generalisations are written by someone who doesn't understand the issues. But Uncertain Principles perhaps has some insight: the author worked for New Scientist, and the book apparently has the typical New Scientist attitude of glorifying fringe work, making dramatic declarations on the imminent overturning of long-held theories, and paying little attention to consensus. Seems to fit with the above.
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Dark matter detected in the lab?
I'm not really one for pubs, and I felt intimidated to the point of wanting to hide under a chair at a skeptical meetup on Saturday, but tonight's Skeptics in the Pub could be quite exciting. Phil Plait's the guest speaker, and he just posted news of something which might, just might, be a direct, laboratory detection of dark matter. Even if not, it's something new and unexplained. Coooooooool.
Keeping up with the cosmologists
If I could alter my brain and adapt to one particular profession, high on my list would be a cosmologist. It's just such a cool time to be alive, in terms of space probes confirming or disproving theories, and the universe throwing curve balls at every step. Unfortunately the maths is way beyond my capability1, but I've been roughly following the field for years and years. I find that it's important to actually keep up with developments, as things are rapidly changing. For example, the last couple of years have seen large changes in the understanding of dark matter and dark energy.
Dark matter is matter that only indicates its existence through its gravitational effect on other matter - it's not detectable in any other way. But another interpretation of this is that our understanding of gravity is wrong. This was still an option when I took an Open University cosmology course a few years back, but recent observations pretty much killed that theory.
Dark energy is the mysterious force causing the acceleration of the universe to increase, and analyses of the movements of massive-scale galaxy clusters have shown they move exactly as predicted by current theories of gravity - if dark energy were also a flaw in our understanding, it'd be detectable at those levels2.
We're figuring this all out right now. That is cool. The best I can do is stand at the sidelines and catch what I can, which is why I like Astronomy Cast so much - I can follow recent developments without great amounts of effort on my part, which suits me just fine
Today's episode caught me out - I thought I roughly understood the concept of the shape of the universe, but their recent episode on the topic caused many WTF moments. I'm a little out of date. It turns out that the WMAP probe has found the universe is likely to be totally flat - no matter how big a triangle you draw in space, the angles will always add up to 180 - but, this requires fine-tuning to an insane degree, as a difference of 1 in 447 sextillion in densities during the big bang would have created a non-flat universe. So there's got to be either a) some new physics out there or b) a bajillion big bangs, and we have to be in one of them. Wow!
Wish I could be a cosmologist. Can't, though, but I'll try to keep up - I'd hate to be alive and miss it all.
Dark matter really exists
It's long been known that with a clear view we can see only 5% of space. By looking at the movements of galaxies,as well as gravitational lensing, we can infer that they have substantially more mass than can be seen by telescopes. It was postulated that this might be taken up by dead stars, but careful surveys in our own galaxy have shown that these make up only a very small proportion. 25% of the universe seems to be dark matter, something only detectable by its gravitational effects. Dark energy makes up the other 70%, and is a different beast altogether - whatever is causing the accelerating expansion of the universe seems to be smoothly distributed, and that's pretty much all that's known. Dark matter is at least something we can get a handle on: some kind of particle we haven't detected yet, presumably.
But what if dark matter isn't caused by another particle? What if current gravitational theory is wrong for large distances, making it look like there's far more mass than really exists? This has always been a possibility. However, a new study has revealed positive evidence for the existence of dark matter, a major development for something which could only be inferred up until now. It's still possible that gravitational theory is wrong, but this seems less likely with confirmation of dark matter's existence.
Cosmologists looked at two clusters of galaxies which collided 100 million years ago - very recent in cosmological timescales. Most of the visible mass of galaxy clusters is made up of hydrogen between individual galaxies. Dark matter does not, it is thought, collide with normal matter, so it was theorized that in a collision between clusters the gases would slow each other down but leave dark matter untouched, as shown in this animation. Eventually the mass of the dark matter would re-attract the gas, but a recent collision would show a large amount of dark matter offset from the gas clouds. And so it proved. There's definitely something there.
It's very cool. Physicists and cosmologists at least know there's really something to detect, and aren't worried about a refinement of gravitational theory rendering years of searching pointless.
Cosmic Variance explain it all with much more detail.
