Saturday, 25 December 2010

An Aetheist's Message At Christmas / Diwali / Hanukkah

If you believe in a god, any kind or any number, then good for you.

Not believing takes just as much faith, trust me.  And placing even a modicum of trust in Science is utterly terrifying...that's why science as a rule is basically paranoia, trying to prove ourselves wrong.

But the one thing I can say is that whatever you believe, whether it's a world created in six days six and a half thousand years ago, or a whole Universe created by a god, or just a very exotic mathematical possibility....well it's pretty darned cool.

The world around us is amazing.  Birds fly more elegantly than anything we've ever seen, waves give us artistic expression from a plank of wood, we're aware of our place spinning through space in the suburbs of a hundred billion galaxies, maybe more.

Yes, we can argue about who, if anyone, made it.  But on a day when that argument is all too divisive, can we not at the very least take a good long look around us?  Even if there's no god, it's still mind-blowingly impressive...

The video repeats a bit, but you get the idea.  We're the only planet with life in the Universe as far as we know.  Hell of a responsibility people/apes/ants/bacteria.  And I make no apology for the music.  Queen rock.  Deal with it.

Merry thingy.

Monday, 20 December 2010

The Multiverse According To Izzard And Tegmark

You've got to believe you can be a stand-up before you can be a stand-up.  You've got to believe you can act before you can act.  You've got to believe you can be an astronaut before you can be an astronaut.  But you've got to believe.  
Eddie Izzard

Multiverse theory is a funny old thing.  It's one of those theories that might solve a bunch of problems, like the way our Universe seems to be incredibly finely tuned to allow complex life to develop, or some of the oddities of quantum theory like particles being in two different places at once.  It's a theory that has been developed and delved into by some of the most eminent physicists ever to have lived...and it's not even science.

I'm not suggesting, of course, that Martin "Astronomer Royal" Rees, Stephen Hawking, Max Tegmark and their colleagues are cheating in any sense, or wasting their time researching the subject, because it's possible that they're laying the groundwork for a game-changing new theory.  It's still not really science though...yet.

Suggesting that there is such a thing as "a Multiverse theory" is a little over simplistic and disingenuous.  There are a great many Multiverse theories.  Tegmark's work alone suggests there are at least four different possible "layers" of Multiverse, any combination of which could be correct.

There's the simplest kind, level one, which suggests that our normal, everyday  Universe is in fact infinite, or at least far, far bigger than we presently observe.  If you're sat in a boat on a calm sea with your eyes around two metres from the surface of the water then you can only see about five kilometres in any direction...the Earth curves away, limiting how far you can see.  We have the same horizon problem with the Universe, except it curves away in time.
The CMB: The furthest we can see.
The best we can do is see around 45 billion light years.  There might well be more beyond this horizon, we just can't see it.  The picture on the left is the Cosmic Microwave Background, or CMB, the echo of the Big Bang.  In even simpler terms, it's a picture of our three dimensional horizon, and the tiny, tiny ripples in it.  There have been some suggestions recently that small anomalies in the CMB are the result of more "stuff" beyond our cosmic horizon.  If our Universe does, in fact, go on for ever then the chances of there being another version of the Earth somewhere out there become almost certain.  In fact it's relatively easy to work out how far away the other version is likely to's somewhere in the region of ten to the ten to the twenty nine metres away.  That's a ten with 100,000,000,000,000,000,000,000,000,000  zeroes after it.  Quite a long way.  There's an entire alternate Universe almost identical to ours, complete with the same constellations and galaxies and large scale structures a bit further away, ten to the ten to the one hundred and fifteen metres.  I'm not even going to try typing an estimate to that, it's a big number.
  But the horizon problem still exists.  Currently we have no way whatsoever of exchanging information with bits of the Universe beyond our cosmic horizon, other than (possibly) very short range glitches in the CMB.  The main feature of a level one multiverse is that it's all part of the same Big Bang - everything is based on the same laws of physics as our little "local" bit.

The second level is where things start getting a bit weird.  It suggests there are other "post-inflation bubbles".  In essence, other Big Bangs which took place somewhere else.  The laws of physics are the same as ours, but the physical constants will be different.  Gravity might be stronger, probably resulting in a rather spectacular, short lived universe full of black holes.  Or weaker, meaning few, if any, stars and very little other than Hydrogen and Helium.  Atoms themselves may behave differently, or never form at all.  A level two Multiverse is an attractive idea because it naturally solves the fine tuning problem.  There are around forty constants in physics, numbers that are the same everywhere we look.  The charge on an electron is the same anywhere in our Universe, but there's no good reason why it has the charge it does.  If it was different then the laws of physics would still mesh together perfectly well, the Universe would still exist, it would just be different.  Life as we know it almost certainly wouldn't exist, but that doesn't really matter.  In fact, change any of the forty-odd constants by just a little bit and the chances are that any kind of complex structure, including life, couldn't exist. So why is our Universe so delicately balanced?  So subtly "designed"?
  The level two Multiverse solves this problem.  If there are an enormous number of universes, each with its own set of physical constants, then there's bound to be a few that by sheer fluke hit the right combination for life.  Life eventually evolves in this small subset of universes and sits there wondering why its universe is so well designed...

Level three is based on the weird results of quantum theory.  One of the founding experiments is called Young's Double Slit.  I'll let Mark Everett (of rock band Eels) explain:

Why is a rock star talking about a two hundred year old physics experiment?  It's because his father, Hugh Everett III, was a physicist who suggested that this experiment shows two parallel universes overlapping.  The only difference between "our" Universe and the parallel one is that in ours the photon went through the left slit, and in the other universe it went through the right.  Because the two universes are otherwise identical there is a certain amount of leakage between the two, they are able to very subtly influence each other, resulting in the interference pattern.

Everett's "Many Worlds" interpretation was fairly roundly rejected by the rest of the physics community when he first suggested it, and you can see why.  It really does sound like something from a science fiction novel.  The idea is undergoing a little bit of a renaissance however.  The modern interpretation is that all possible moments in time, in all possible universes, actually exist, and ours Universe is simply a "most likely" path through this higher level of Multiverse.  It explains the probabilistic nature of quantum mechanics, the slightly fuzzy nature of the Universe when we take a very close look at it...we're looking at a collection of possible universes, not our Universe at all.
  Again, there's no real way to test this satisfactorily.  There is the quantum suicide experiment for example.  The experimenter stands in front of a machine gun which is connected to a device which measures the spin of a subatomic particle.  The spin can be either up or down - if it's up then the gun fires, if it's down the gun doesn't.  If Everett's idea is right, and does actually represent a Multiverse, then there will always be a universe where the experimenter survives.  If the measurement is done ten times then there will be 1023 universes where the newspaper headline is "Idiot Scientist Shot In Face" and one where the experimenter survives.  Unfortunately (for the theory, if not the experimenter), there is always exactly the same small chance of survival (even if the Multiverse idea is wrong, so you can never have a definitive answer.

Tegmark's last level, the fourth, is the most philosophical in nature.  All of the previous levels share one thing in common, the laws of mathematics.  Even if the laws of physics change, they can still be described with equations and mathematical expressions that would be recognisable to us.  Changing the universal gravitational constant, G, changes the universe.  A level four parallel universe changes the equation that G appears in.  Currently there are no known ways, even theoretically, that this idea can be physically tested or explored in any way.

Tegmark's ideas are by no means the only ones, but they are a popular basis for investigating the nature of a Multiverse if it exists.  No, none of it makes testable and new predictions at the moment, so it's not science yet.  The implications, on the other hand, are fascinating.

If an infinite Multiverse of any kind exists then we can have some fun with it.  Let's take a lottery for example.  It's intuitively obvious that you have to buy a ticket to win, but if we're in a Multiverse then that statement changes slightly...buying a ticket guarantees that you win.  Or at least one version of you, somewhere.  You're also immortal.  Whatever happens that might kill you, there's always a version that survived against the odds, and as you're able to read this, you are that immortal far at least.  The flipside is also true.  Every time you cross the road there's a version of you that is killed.  Gerry, my flatmate, has taken this principle to a humorously logical conclusion: he delights in setting small traps for me that have a tiny, miniscule, theoretical chance of killing me.  He reasons that every time he does this he gains the satisfaction of knowing he's killed me in a parallel universe, without all the drawbacks of being arrested and later murdered in prison.  He's an odd man in many ways.

So within reason anything is possible in a Multiverse.  But there's no short cut, you can't just sit back and expect to win the lottery or become an astronaut or even a stand-up comedian.  The universe where that happens is one where you bought a lottery ticket, or studied physics, or died at umpteen comedy clubs first.  You have to make sure you're in the right universe, which means you have to put the work in.

But first, you have to believe.

Monday, 6 December 2010

Just remember that you're standing on a planet that's revolving...

Just remember that you're standing on a planet that evolving,
     Revolving at 900 miles an hour.
 There's a little poetic license in Monty Python's classic, it's actually just over that, closer to 1040 miles an hour at the equator, but only six hundred-ish up here in Edinburgh.  900 works well enough though, and it scans nicely.

So yeah, we're spinning.  We all know that, like night and day.  The Earth spins, the Sun comes up, the Moon does its thing and some people even bother about the stars if they're out late enough.

Most of the time I'm worrying about the sky spinning around it's a result of some nice new guest ale in the Blind Poet, but just sometimes you get a rather literal demonstration.

This is a picture of Jupiter, plus (right to left), Europa, Ganymede and Callisto.

That's taken with a digital SLR (Nikon D100) on a telescope mount and a 270mm lens.   It's a bit out of focus, and there's either a lens flare or a galaxy to the lower right of Jupiter.  The main feature though, is the trail.  The tripod and camera were locked down, the sensor was set to delay until after the vibration had's not all my fault, honest.  It's not even a particularly long exposure, only two seconds.

That's how fast we're spinning.  Jupiter is whizzing past...or we're whizzing past Jupiter, depending on your reference frame.

The main point is that I took a photograph of Europa, the ice moon from 2001.

All these worlds are yours.  Except Europa.  Attempt no landings there.
 They didn't say anything about photos did they?

Friday, 3 December 2010

What The NASA Announcement Actually Means

The weird thing is, the message got swallowed in the argument over its importance.  But that's another post.

Here, in fairly plain language, is what it means:

They've probably found an extremophile.  Bacteria are remarkably resistant, they appear in sub-zero temperatures, high acidity, high temperatures, high salinity, all sorts of places.

Now we've found one that not only survives a high-arsenic environment, it can actually survive without phosphorus at all.

Yup, that's chemistry mumbo-jumbo to some.  In essence, phosphorus makes the backbone to DNA, it's the chemical foundation of every single living organism on the planet.  Technically, in the known universe.  Every living cell has a strand of DNA made with a strand of phosphorus.

Arsenic could do the job though.  The chemistry works.  You can, in theory, have arsenic based life, and until today it was in exactly the same category as the "silicon based life" so beloved of science fiction.  It was fiction, unsupported theory, hypothesis.  Until today.

Today a very clever scientist (with a great website) announced that she'd diluted these bacteria down until there was no phosphorus left in the system.  The bacteria were operating on an arsenic based genome.

Now, herein lies the rub: where does it come from?  No, of course it's not extraterrestrial, but is it the same as phosphorus based life?  In this case, it seems it is.  It looks like a case of normal, everyday life adapting rather spectacularly rather than a new form of life (the "shadow biosphere" that has been suggested).

Either way, NASA were absolutely right to announce this as a discovery of significance to astrobiology.  One of the following things have just been demonstrated in some style:

  • Life based on a fundamentally different chemistry is not only possible, it actually exists!

  • It might be the second spontaneous emergence of life ever observed by humans, with implications for the odds of life elsewhere.
  • It might just be normal, boring, tedious Earth life surviving in ridiculous circumstances.  Ones which are based on fundamental chemistry, suggesting that life can survive a far greater range than we previously gave it credit for, and echoing some (so far speculative) ideas about potential biochemistry for Titan, Enceladus and Europa to name a few we've already visited.

There was a lot of hype and expectation, but the fact remains, this is a highly significant breakthrough in both biochemistry and astrobiology, and has been led by the astrobiologists.  This is a big discovery for a young field which carries some important answers about the nature of life.

Wednesday, 1 December 2010

NASA Astrobiology Announcement - Wild Rumour And Conjecture

NASA issued a press release today.  Possibly something big.

There's going to be a public statement on Thursday afternoon (UK time) which will: "impact the search for evidence of extraterrestrial life.".

Now let's be very clear about two things:
  1. Astrobiology is a very young science.
  2. Astrobiologists have been a bit busy in the last couple of years.
This could be just another "Big Science Announcement" (BSA) designed to attract some publicity - and nothing wrong with that, science is cool and we should gossip about it a bit more - but it could possibly be something more.

NASA are being rather taciturn over the actual contents of the announcement, as is their right with any BSA.  However, this much is known -- the announcement involves a very special group of people.  The listed "participants" are all people with a very high level interest in astrobiology.  Interestingly, they all seem to fall in to two of three particular camps:

  • People who have suggested that we search for a "shadow biology" on Earth, to test how likely spontaneous life generation (biogenesis) is, and also to look for signs of panspermia.
  • People who have worked on the wonderfully successful Mars missions in the last couple of decades, from which geological data is the main thing we have.
  • People who have worked on desert varnish.
 Desert varnish is the clincher for me. It's odd stuff.  It's kind of a sheen that certain rocks get in very dry environments, hence the name.  It looks like it's been painted on, but in fact it's entirely natural, it just isn't biological.  It looks like lichen, it seems to grow like it, but it's not got DNA or anything like that, it's more like a mineral growth than life.

And see that first bullet point?  One of the participants in this BSA, Felisa Wolfe-Simon, published a rather influential paper last year which suggested that astrobiology should be looking for the Earth's "shadow biosphere".  The idea is that if life can develop, and if it's likely to happen, then it should have happened here on Earth more than once.  We might just not have spotted it...

Seriously, look how obsessed we are with DNA and proteins and the whole "organic" thing.  We might not spot a different kind of life if it was sat under our noses, is what Wolfe-Simon's paper suggests, and what's more, let's start looking.  And like I said, the paper was rather influential, which means people started looking.

And now some of the people who looked are standing up with her and NASA and they have something big to say.

Oh...did I mention that NASA found desert varnish on Mars years back?

So we have people looking for new life, plus something that looks a lot like life but isn't, and also exists on Mars.

Long story short?  Blogger makes wild suggestion that (possibly Silicon based) life has been found on Earth and may well also exist on Mars.

This will rock if I'm right....