How did we get here?

People are everywhere. Seriously we're like a bloody ants nest, every continent, every mountain, every habitable area. We're all over it. Even in place where humans really shouldn't be able to survive like the icy depths of Siberia or the scorching dunes of the Sahara, there's always a group of humans to be found just hanging in there at the limits of survival.

But how did we get here? It's an age old question that has perplexed even the greatest minds among us, with some looking to nature, some looking to religion and some even looking to the expanse of space above us! So today I'm going to talk about how humans spread all across the world from our humble beginnings in Africa! (You weren't expecting that were you?)

One thing that most people agree on in this area is that we came from Africa. Even among deeply religious people it is often accepted purely due to the extensive fossil evidence that shows our ancestors living there 2 million years ago. So humans popped up in Africa, and by humans I mean something like Australopithecus which wasn't really human but was nearly there.

Now as anyone who has been out in the wilderness or played a video game will know, humans have a tendency to explore. Whether its because they got hungry, curious or there just wasn't enough room, these early humans began to spread out and settle all over Africa. At the same time there were a lot of potential candidates for humanity existing at the same time, three of the largest being homo erectus, homo neanderthalensis and of course, homo sapien.

Homo erectus did quite well for itself, although it was really more of a stepping stone to more advanced species. Despite the fact that its brain wasn't enormous and it was only the first species to walk on two legs, it still managed to inhabit basically all of Africa and then eventually spread to what are now Saudi Arabia and Spain. From Saudi Arabia, they spread all throughout the middle East and Southern Asia, eventually even managing to get about halfway through Indonesia which is a pretty mazing achievement. This map shows their progress:


Next up is probably the most famous other human - the Neanderthal (homo neanderthalensis). These guys were much closer to modern humans in terms of evolution, in fact their DNA is less than 0.5% different to ours and there was a lot of cross breeding between the two species. In fact they are so close to our own species that they are often classified as a subspecies of homo sapiens. Ultimately, however, the dominant genome of homo sapiens caused the Neanderthals to die out either through absorption by interbreeding or maybe violent conflict. Either way they're not about any more and nobody is certain as to why.

But how far did Neanderthals get? They left Africa through Saudi Arabia much like homo erectus, but they took a completely different direction afterwards. Instead of sticking to warmer climates around the equator, they headed for what is now central Europe and north western Asia. However there is one catch that didn't really effect our upright amigos in the equatorial regions, the Earth was in the middle of a little cold period at that time. An ice age in fact.

This ice age limited the distance that the Neanderthals could go North as even areas further south than Russia could have been completely uninhabitable due to the cold. This pushed them further West towards the popular holiday destinations of Spain, France, Portugal and the like. They did this a long time before humans were even considering it and were habiting a big section of Eurasia  This is the sort of region they ended up in:

So homo erectus did surprisingly well for such an early species and Neanderthals probably could have done better if it wasn't for the pesky glaciers all over the place, but what about homo sapiens? How did we get here and there and everywhere?

We started off just like everyone else, in Africa. And in what was probably some sort of tradition at this point, we took the route out though the middle east and Spain. However instead of going anywhere really new, we just sort of hung around with our relatives in the areas already established as habitats, south Eurasia, Africa and the Philippines.

However shock and horror, about 60000 years ago there was another cold snap, but this one was pretty big and effected everything. It is thought that this cold snap reduced the population of humanity to under 10000, meaning we were hanging by a thread. However this ended and conditions eventually began to finally improve.

Branching out from the Philippines, humans made the next big leap in migration by managing to get to Australia and Indonesia, forming colonies about 50000 years ago.

When the ice age finally began to recede, a little after 50000 years ago, settlers finally began to poise themselves to explore and settle in the cold climates of northern Europe and Asia, A feat that was previously impossible due to climates that would freeze everyone really really fast.

However, a group of Asian homo sapiens then made the next great leap about 20000 years ago where they discovered an enormous ice bridge in north East Russia. In crossing it they became the first people on Earth to reach the Americas and colonies formed either side of the Rockies, eventually stretching down through Mexico to South America as well.

Of course there are places like Madagascar and New Zealand which we didn't colonise for a long time later until society had developed enough to invent boats, However from then on out, humans had colonies and civilisations on every continent except Antarctica. They which thrived and grew and squabbled and divided themselves with religion and politics and war and finally became this divided mess that we're living in today.

Humans used to be united, maybe not on an individual scale, but as a species, they would devote themselves to the cause of survival even managing to bounce back from being reduced to a few thousand in a cold, perilous world with nothing but their own brains to keep them alive. One day maybe we will put aside the borders and selfishness that divides out world currently and learn to live live this again but for the moment, lets just enjoy the good in this strange, broken world.

Thanks again for reading guys :) see you soon!

Why Gravitational Waves are Relativily Amazing!

Today I'm going to write about gravity. And not the ironically scientifically inaccurate film of 2013, but the enormous scientific breakthrough that was announced earlier today.

For those of you who haven't heard yet, it was announced earlier today that gravitational waves have been picked up by the LIGO detector in The United States. I was originally intending to do a post on either how we learn or why plants are green today but lets face it, I'm not just going to sit around and write about biology while my favourite science has made what is debatably the biggest discovery since the Higgs boson.

So I guess I should start by explaining what gravitational waves are and why they are so important? Okay. 100 years ago a pretty smart guy called Einstein realised why nobody could detect variations in the speed of light no matter how hard they tried, because it was a universal constant. And he postulated that that in order to keep it constant, even time and space would bend. And so, the theory of general relativity was born.

The theory that says that space and time are one thing called space-time, like the fabric of the universe and we're all like little bugs wandering around on our speck of dirt. However space-time isn't constant, as I said its like a big piece of fabric, and as a result, it is able to stretch, contract and twist. The thing that causes it to stretch and contract is mass. Yeah that's right, anything with mass, even you, warps the space around it. When it warps this space, things around it are drawn towards it and so it gives the illusion of gravity.

So what has this got to do with gravitational waves? Einstein predicted a lot of amazing things with his theory of relativity, gravitational lensing, Frame dragging, time dilation etc. And amazingly each one of these has been tested and proven experimentally one by one. Except for gravitational waves.

Gravitational waves are when an enormous amount of mass disturbs the fabric of space-time enough to cause what are effectively ripples of physical space. This can only happen however, if the object moves in an uneven way. A circular object spinning doesn't produce them, but a non uniform supernova explosion does. They are in the form of what are known as quadrupole waves, waves which oscillate in a similar way to a slinky, except its in three dimensions and instead of a string stretching, its space. So gravitational waves are like ripples in a pond, but in the universe itself.

So why can't we detect them? Even the biggest gravitational collisions caused by neutron stars merging, super massive black holes and even hypernova explosions, produce waves which only change the size of our space on Earth by a factor of 10^-21. And such extreme events are enormously rare across the universe! So in order to detect these, we need an extremely long piece of space to measure, and something to measure it against which is smaller than the fluctuation in space, as well as a really rare powerful event to happen a long time ago in a galaxy far far away (they travel at the speed of light but still might take millions of years to reach us).

How did we do it then? We're physicists so lasers are the obvious go-to answer. So physicists in America built the LIGO (Laser Interferometer Gravitational-Wave Observatory) with two detectors, one in Washington, and one in Louisiana. In each one, a singular laser beam is split into two and travel down two tunnels which are perpendicular to each other. At the end of the tunnel they are reflected off a mirror and come straight back. As the waves have travelled equal distances, they should come back together to make a wave which  exactly the same as the initial one, however if a gravitational wave passed through the system, it would mean that the space would contract in one direction more than the other and so the resulting beam would be different to the one that set off to begin with.

On September 14th 2015, a signal was measured which, looked promising, and various observatories were consulted to look for astronomical events which could have been the cause. This signal is now known to coincide with  the collision of 2 super-massive black hole which produced more than 500 times the energy of the starts in the visible universe. The statistical evidence also shows that the chance of it being a fluke are roughly 1 in 6 million. So in summary well done them!

This marks a new age for astronomy, now that we know that gravitational waves exist and can be detected, it could pave the way towards gravitational telescopes which would let us image our universe in entirely new ways! In fact the LISA project is currently looking at how to build  gravitational wave detector in space because, although the eventual goal for these devices is astronomy, they have  long way to go yet.

It is a true demonstration of human perseverance and intelligence that, 100 years after we predict something, we are still searching for it until we find it. Personally my favourite quote is by Isaac Newton - "If I have seen further, it is by standing on the shoulders of giants." and this has never been more evident than now. The work we do today was inspired by Albert Einstein, a Giant, like Newton and Pythagoras before him, and we can only hope that one day, maybe even we may be held in such regard.

Once again thank you all so much for reading and see you next time :)

Where are the Werewolves?

They prowl in the night and howl at the moon. They transform into the form of a bloodthirsty beast when the moonlight touches their skin. They tend to produce either completely fantastic or utterly awful TV and movies. That's right, today lets forget science for a bit and delve into the realm of monsters and magic with the topic of werewolves.

Ever since man has lived alongside wolves, there have been legends of a crossover between the two. Legends have sprung up all over the world from Norway to Mexico about men who turn into wolves, whether it's because of magic, a gift from the Gods or a disease, many different cultures around there world have their own version of this tale of human - canine combinations.

Firstly Norway - the Norse belief system was widespread across the northern regions due to the large amount of colonies in areas such as Iceland. As a result, places like Iceland and Norway both had the same legends about werewolves despite the 1500km gap between then. Northern Europe had a lot of wolves, like anywhere else, and as a result legends sprung up like wildfire. Norse mythology includes many wolf based creatures such as Fenrir, the monstrous wolf which was bound up to prevent it from becoming a threat. The respect for wolves is shown as Fenrir in fact bites off the hand of the god Týr in the process and it was said that he would kill Odin in the events of Ragnarök (the end of the world). However Norse werewolf tales stem from the tales of the Ulfhednar. In the same way that beserkers were considered to be warriors who became bears, the Ulfhednar were warriors who "became wolves". This is as close as the Norse got to werewolves - angry guys running around wearing wolf pelts, however some other culture took a more direct approach.

Native Americans (American Indians) have a hell of a lot of wolf legends because they weren't so much people - as they were a lot of smaller tribes with slightly varying belief systems and different legends in each tribe. Also there were wolves absolutely everywhere in North America. A lot of the legends involve the Gods granting humans gifts or curses brought upon people. However there is another legend which isn't specifically about wolves that has drastically contributed to the Hollywood image of werewolves. This is the legend of skin-walkers or the yee naaldlooshii. Seen as evil creatures, skin-walkers were said to be able to change into any animal that they wished at will. Sound familiar? This was generally associated with black magic and taboo, meaning that they were generally seen as evil and dark beings and were widely associated with death and fear. This legend probably arose from the culture being in constant close contact with the world of nature and the deep spiritual respect which they had for the Earth and animals around them.

Finally lets look at a completely different culture in a completely different area. Some of the oldest myths about werewolves aren't from the deep forests of native america, or the frosty north of Scandinavia, but instead from the picturesque Caribbean landscape of ancient Greece. Greek werewolf legends stem from the story of king Lycanon who, for reasons that scholars can't agree on, attempted to feed Zeus human meat, some say it was the meat of his son, some say that it was an attempt to kill Zeus. However what scholars do agree is that in the legend, Zeus discovered the attempt and turned king Lycanon and all of his offspring into wolves as punishment. The word Lycanthorpy (werewolfism) is actually thought to have come from this legend.

So there you have it, werewolf legends from across the globs. Inspired by the ferocity of nature and the begrudging respect that man had for the wolf. However some doctors have attempted to find medical explanations for possible cases of Lycanthorpy, refusing to accept that it is a figment of our imagination. 

One possible explanation, proposed by Dr Lee Illis is that historical werewolves were in fact sufferers of a type of disease known as Porphyria. Symptoms of this disease include reddish teeth, psychosis and photosensitivity which, to superstitious and religious people, could seem like and undeniable case of Lycanthorpy.

So ironically, looking to the past to find evidence, is more of a witch hunt. Originating separately in several cultures, and then twisted and romanticised by Hollywood, the story of the werewolf is one of sorcery and Gods. Nevertheless it may not exactly be science but it really is interesting.

Once again thanks so much for reading guys, see you all again soon! :)