Sunday, July 20, 2014

Interesting stuff about light

This conversation happened on Facebook and there is no point in adding to it, as communication has broken down. However, the last addition* is like an itch I can't scratch, and so instead of adding stuff there, I thought I'd write about light.

A pro baseball player can throw a baseball at around 90 miles per hour (mph). If he were to do the same throw whilst standing on top of a vehicle moving at 60 mph, then the ball would be traveling at 150 mph. Now, if the baseball player where to stand still and use a torch, the light would leave the torch at 299,792,458 metres per second (m/s). If he then was on a vehicle moving at 542 m/s, and shone his torch, the light would not leave the torch at 299,793,000 m/s. It would leave at 299,792,458 m/s.

299,792,458 m/s is the speed of light. Actually, it's the speed of light through a vacuum, light travels slightly slower through the air (and slower again through water, this explains the rainbow. The red end of the spectrum slows down more than the blue end of the spectrum when light enters water, and so this is why we can see rainbows).

299,792,458 m/s is also the fastest anything can move in the universe. To achieve this speed, you must have no mass. The faster you want to throw a ball, the more effort (and therefore energy) you must put into throwing it. To move something with mass at the speed of light would require infinite energy. So far the photon (a particle of light) is the only known massless particle, though others are theorised such as the graviton.

This all might sound theoretical at the moment, but it is used practically as well. Without our knowledge of the above, Sat Navs would not work. If you were to go and drive with a Sat Nav for an hour, the satellites that work  out where you are would actually experience less than an hour. This is pretty counter intuitive.

The best way that helped me understand it is like this: Imagine you're in a car going at 60 mph. If a car drove past you at 70 mph, from your point of view in the car it would like it was moving past you at 10 mph. Likewise, if you were level with another car travelling at 60 mph, from your point of view, they would look still (and this effect is used in action movies for our heroes or villains to jump from one vehicle to another whilst they move at high speed). If you then accelerated to 70 mph, it would like the car that was next to you was now moving behind you at 10 mph.

Now if we think back to the second paragraph, light always travels at the speed of light. In all the cases above, whichever of the cars you are in, you will always see light travelling at the same speed. Speed is distance traveled over a period of time. If light always travels the same distance over a period of time, no matter how much distance you are travelling in that time, something has got to give, and this is relativity, as described by Einstein. It's called relativity because time is relative. The faster you move, the slower time passes for you relative to an external observer who is moving slower than you (or not moving at all).

This effect is called Time Dilation, and was used in the plot for the original Planet of the Apes films - Charlton Heston et al travelled on a ship going at close to the speed of light, and were on it for 18 months, however, as the ship crashes onto an unknown planet, it's noted that the year is 3978 - a full 2006 years after the crew left Earth. The satellited servicing our Sat Navs also experience time dilation, and this must be taken into account when they calculate where exactly it is we are.

Now, it's true that our understanding of relativity is incomplete, as it doesn't (yet) tie in with our understanding of gravity. But this does not mean that it is wrong. Newton's Laws of Motion do not take into account relativity (which was why they caused a headache when trying to predict the orbits of the planets), but they were not wrong when described objects moving on Earth. Working out the flight path of a plane, or the airspeed velocity of an unladen swallow, Newtonian mechanics are just fine. We know that Einstein's Special and General Theories of Relativity are good approximations of the truth, because without them, things like Sat Navs wouldn't work, and it also explains a great deal more about what we observe in the universe.

If you've found this interesting, then I'd encourage you to check out the following books, as they go into great detail about the evidence for the above, and more besides:

Big Bang by Simon Singh < Especially this one, which I think is the most accessible
The Particle at the End of the Universe by Sean Carroll
Why does E = mc2? by Brian Cox and Jeff Forshaw

*The last post in the conversation said "Particles are still physical, so in theory, like waving your hand through the air, you would push those particles away from the point of origin faster than their original speed"

Wednesday, June 18, 2014

Stay classy Deepak

So Deepak Chopra has issued (an insult laden, hence the title of this post) challenge, which he sees as a parallel to James Randi's Million Dollar Challenge. As Jerry Coyne has pointed out, it is not in parallel, as he is asking for an explanation of quite a complex problem (the Hard Problem of consciousness), whereas all Randi asks for is a demonstration with no explanation required (someone backing up their claim to paranormal abilities in a controlled environment). However, I thought I'd add it to the blog, as it gives me an excuse to highlight some pretty cool things.

Chopra says:  "If I ask you to imagine a sunset on the ocean right now, and we have the experience somewhere then explain to me where that picture is, and don't just give me a neural correlate or NCC as it's called. Neural Correlates of Consciousness are well known. They are not a good enough explanation for how we experience the world, how we experience colour, taste, sound, form, any perception."

Well, NCCs may not offer the actual solution for the Hard Problem of consciousness, but they certainly seem to point in the right direction. Consider this:

"So do imagery and vision share space in the brain? The neuropsychologists Edoardo Bisiach and Claudio Luzzatti studied two Milanese patients with damage to their right parietal lobes that left them with visual neglect syndrome. Their eyes register the whole visual field, but they attend only to the right half: they ignore the cutlery to the left of the plate, draw a face with no left eye or nostril, and when describing a room, ignore large details - like a piano - on their left. Bisiach and Luzzatti asked the patients to imagine standing in the Piazza del Duomo in Milan facing the cathedral and to name the buildings in the piazza. The patients named only the buildings that would be visible on the right - neglecting the left half of imaginary space! Then the patients were asked to mentally walk across the square and stand on the cathedral steps facing the piazza and describe what was in it. They mentioned the buildings that they had left out the first time, and left out the buildings that they had mentioned. Each mental image depicted the scene from one vantage point, and the patients' lopsided window f attention examined the image exactly as it examined real visual inputs."
Pinker, S (1997). How the Mind Works. St Ives: Penguin Books. p288 - 289.

Chopra asked where an imaginary picture sits, and it must obviously be within the brain. When certain neurons are damaged, even our mental imagery gets affected! So whilst we can't explain how the image got there, we can at least conclude it is in the brain.

Chopra's followed up his challenge with a second video, in which he explains his idea of consciousness: that instead of consciousness being produced by the matter of the brain, it is instead top down, with consciousness being fundamental, and it is this that creates the material world we see.

This idea is the same kind of problem that comes about when discussing the soul - why is it that consciousness is so tied to the brain if it is fundamental? If it is consciousness itself that produces qualia in our brains, why do some of these get affected after brain damage, as we have just seen?

In his second video Chopra also says that we (as skeptics): "Do not understand that we do not have access to reality but only to our perceptions, that whatever we experience as reality is the contents of our mind". We clearly do, and this also links into his comments about colour perception in the first video. Optical illusions demonstrate this:

I've posted this optical illusion before:




The blue and green are the same colour. If you look closely, what does change is the lines in between the "blue" and "green", which are either pink or orange. Our perception of the colour is influenced by the colours around it. We cannot escape it, much like another favourite illusion:



The square labelled A is the same colour as the square labelled B.

We may not have sussed how qualia arise, but we do know what causes these illusions (the world map is explained here, and the here, the checker board illusion). All these optical illusions happened because they exploit short cuts our brains take as they have evolved to work out what the world around them is like.

On top of that, colour is an illusion any way. Consider this from the Oatmeal (and do go and read the whole strip, really do, I'll not be offended if you don't bother reading the rest of this post. Go):



We may be able to wax philosophical about whether my blue is the same as your blue, but the mantis shrimp can see the world in a glorious technicolour that we can't hope to imagine.

The exploration of how we, and other organisms, perceive the world is still ongoing. The fact that science hasn't explained it all is not a problem!

When Chopra said "[How we perceive] ..any perception. You can't explain it. Texture, solidity. You can't explain that." I was reminded of these two things:

Bill O'Reilly's infamous "Tide goes in, tide goes out, you can't explain that" and also the Insane Clown Posse's lyric - "f***ing magents, how do they work?" (you can see this wonderful Veritasium and MinutePhysics collaboration if you're curious). Now it's true that in Chopra's case he's picked up on something that, as yet, has not been fully explained. But this is a strength for science - saying "I don't know" is a perfectly respectable answer, especially when it's followed by "Let's try and find out".

This challenge is just fluff (though it would be interesting to see how seriously Chopra takes it, is it possible to see his bank statements proving the money's there for example?). Whilst he may not have ring fenced this money, it is a shame that he has amassed so much from his pseudoscience and platitudes that he himself does not always follow. However, as Haldane said "Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose", and quantum mechanics of the real sort do seem to back him up.

It's ok that science hasn't explained "the normal" yet because scientists, and those like me that enjoying reading about the fruits of their labour, get a thrill from the sentiment of this not-actually-Carl-Sagan quote  "Somewhere, something incredible is waiting to be known".


Sunday, June 1, 2014

Why cats are better than dogs

Over at Why Evolution is True, Jerry Coyne is looking for people to answer the following:

"1. For those who love cats and dogs: what is it about cats that make them especially appealing or endearing to you?
2. For those (like me) who favor cats over dogs? Why do you prefer the moggies over the doggies?"

So, with tongue slightly in cheek...

Cats are better than dogs. This is not a subjective opinion (though the subjective parts of my argument will come first), but an objective fact.

I have been fortunate enough to have had pet cats around me all my life until I fled the nest, and the reason I have none now is that my landlord doesn't allow pets, and, I am not in a position to afford one (seriously, if you can't afford veterinary fees and such, don't get a pet). Would my personal preference have been different had I grown up with cats? Well, who knows, but this is probably a causative factor in my subjective preference to cats.

I find cats more aesthetically pleasing. Sure, dogs can be cute, or handsome, or beautiful etc, but cats are more so. They look more graceful when they move, they look more elegant when they sleep, and basically are much more pleasing to my eyes. Whilst I'm not sure it's true that "The dog may be wonderful prose, but only the cat is poetry" is a French proverb (my only source is a fridge magnet I saw), the sentiment certainly is.

Also, cats are just the right size, and feel more comfortable curled up on my lap than dogs have done. Dogs can be a bit too big, or a bit too small. Cats are just right.

Wet cats: don't really smell. Wet dogs: a bad smell, so much so, it's used an expression of derision.

Dogs are coprophages. I know we need things to break feces down, but from my perspective as a human being eating poop is yucky, especially when said dog also likes to lick you.

Purring - I love the sound of it, I love resting my hand on a purring cat and feeling it, and I find it very relaxing. There's a lot of nonsense online that purring can heal bones and similar dubious claims (hence why this is in the subjective part - if I found decent links to the benefits of purring it would be another objective claim, as only cats purr).

In Star Trek, Data could have chosen any pet in the *entire* known universe, and opted for a cat.

I like that cats are more independent - dogs are pack animals and behave as such, cats are their own boss.

Despite all this subjectivity, a look at the evidence clearly shows that cats are best, objectively. So what about objective facts?

Well, firstly let's start with a heavy hitter: Dogs kill more people than cats.

Using google, I couldn't find anything on fatalities caused by pet cats. However, there were 256 fatalities caused by dog bites in the USA between 2000 - 2009. Indeed a google search for "pet dog kills" gives 69,200,000 results, but "pet cat kills" yields only 11,500,000 results. Wikipedia's "Deaths due to animals" doesn't even include cats. Given the scarcity of decent data on cat related deaths, but the wealth of decent (and poorer) sources for data on dog deaths, it seems safe to conclude that dogs kill more people than cats. And of course, I hope you've all seen "Hero Cat" saving a child from an otherwise potentially fatal dog attack.

Now, some may point to cats indirectly affecting health through Toxoplasmosis (after all, isn't that what killed that guy in Trainspotting?). Well yes, coming into contact with cat feces is a vector for Toxoplasmosis, but then coming into contact with dog (and cat and fox) feces is a vector for toxocariasis. In both cases however, hand washing etc can avoid such things, as can providing a litter tray for your cat, and cleaning up after your dog. We are talking about the animals themselves, not the personal hygiene habits of their owners.

Whilst we talk about hygiene - dogs and cats will both lick you, but I'd much rather be licked by a cat. There's considerably less slobber, and you can also be sure that a cat hasn't just eaten some feces. Cats of course lick you, as they are actually trying to do you a favour and groom you, much like they groom themselves. Because cats are cleaner than dogs in that regard.

Owning a dog or a cat has benefits to the owner's health. Of course, owning a dog has potentially more benefits, as they need to be taken for walks (indeed, obesity in dogs is unsurprisingly associated with obesity in their owners). Now some might argue that these walks confer extra health advantages (over and above those from cats) to their owners, and this makes dogs better. They are half right. The walking is indeed a good health bonus for the dog owner, but cats are obviously better as they can exercise themselves. This also means that cat owners that want to exercise can do more than walk or run as dog owners are forced to do - like swimming perhaps. You might argue that dogs mean that their owners have to go out and exercise, and this too is true. But if a cat owner chooses not to exercise, the fault sits with them. We're talking about cats being better, not humans. But whilst we're on the subject of humans, surely the cat owner that regularly exercises for health is better at taking care of themselves than the dog owner who does it because they are forced to for the needs of their dog (much like those who do good things because they are good being more ethical than those who do good things because they will be rewarded, or to avoid punishment, but I digress...).

Whilst we're talking about humans though, what will it cost you to own a cat or a dog? Pet Education gives a range of $4,242 to $38,905 (with the author's cost $12,468) for a dog over 14 years, but $4,521 to $18,322 (with the author's cost $7,713) for a cat over 14 years. Cats are clearly better in terms of value for money. Those this is obviously an epiphenomenon, as without humans, this value for money would not be known,

Smart people clearly know that cats are better - Prof. Guastello of Carroll University found that cat people tended to be smarter than dog people. Of course correlation does not imply causation - but it's win win, either cats make people smarter, or it's just that smarter people choose cats.

So there we have it, cats > dogs.



Saturday, May 17, 2014

Thanks JustGiving

So, JustGiving are yet again receiving criticism for their charging of fees for their online fundraising service they provide to charities. Unfortunately, the criticism is both untrue and unfair.

When I worked for the Meningitis Trust, some people would also give similar criticism to me "Don't you feel bad taking money from the charity". My answer was "No", because much like everybody else I like to have money to buy food, pay rent, and all the rest. It would be lovely if everyone of independent means volunteered their time for the charity sector, but this isn't going to happen, and so there are expenses that need paying.

Likewise, setting up a service like JustGiving costs - you need hardware like servers; people to produce the software itself; and then a team of people to deliver this service to the various charities. JustGiving are wonderfully transparent about the fees they charge, and another good thing about them is that their surplus is put right back into improving the service it provides.

It's true that there are other, cheaper, online fundraising services, but they follow where JustGiving lead. JustGiving are the ones that invest in developing new services, like JustTextGiving, that make it better for everyone, and provide things for the other service providers to imitate.

Without JustGiving, Stephen Sutton would not have been in a position to raise the fantastic sum that he did, and gather the publicity that he did.

In my own time I've raised over £60,000 for various charities over the last 10ish years, not all of it online, but without JustGiving I wouldn't have made nearly as much. Case in point, over Easter I was in London for the Meningitis Research Foundation, shaking a bucket for loose change. JustGiving let me have a virtual bucket for those friends of mine that couldn't drop anything in to my real one, and that was an extra £161 for the charity. Charities raise more with JustGiving than they would without, and JustGiving are well worth their fees because of this.

Full disclosure: I won, with my good friend Simon, the Most Innovative Fundraiser Award at the first Justgiving Awards in 2010, and have also had donations from Justgiving made to various fundraising pages I have had over the years. This only serves to back up my arguments - not only are they deeply passionate about helping the charities they serve, but they have a vested interest in the individual fundraisers too.

*cough* http://www.justgiving.com/whatonlythree *cough*

Monday, April 28, 2014

Live Below the Line

1.2 Billion people, that's a sixth of the world population, have to get by on just £1 a day their most basic needs - food, clean water, shelter, education, health, everything.

Live Below the Line is challenging individuals and communities to eat and drink on just £1 per day for 5 days, to bring to life the experiences of the 1.2 billion people currently living in extreme poverty. Think about that figure - 1.2 BILLION - that's nearly 20 times the population of the UK - living every day in extreme poverty.
Participants chose to take the challenge and fundraise for one of our 35 charity partners whose work is vital to ending extreme poverty.  

One such participant is my lovely friend Kate, who is says:

"Last year I successfully managed to complete this challenge, but it was a challenge. This year I am eating more food, drinking more chocolate and I have less time to plan and prepare meals. I am genuinely wondering how it is going to be possible to manage on £1 a day. 

I expect to be grumpy and hungry, but at least I can make up for it at the weekend. The reason this challenge is so important to me is becuase of the huge number of people around the world and in the uk who have no choice but to watch every penny they spend. As a mother it particularly hits me that there are parents who choose to miss meals so they can feed their children, some of them within 5 miles of where I work in London.

If you aren't taking part in the challenge please think about how much money you spend over the 5 days and the luxury you have of eating foods you enjoy rather than what you can afford to survive. It would be great if you could donate some money (my chosen charity is Save the Children), but it's more important for me to raise awareness. "


Well, that's a bit more awareness raised, but long time readers will know I'm big on the old fundraising, so if you can, why not pop by her page (or one of the many others), and donate at least £1 - for 1.2 billion people, that would be all they could possibly give today.
Related Posts Plugin for WordPress, Blogger...