It seems that everyone on the planet with blue eyes has a single, common ancestor – someone from around 6,000 to 10,000 years ago.
The original, default eye colour is brown (which is still the most dominant in most parts of the world) but a genetic mutation way back when “turned off” the ability to produce brown eyes.
Variations in eye colour from brown to green can all be explained by the amount of melanin in the iris, which is governed by a particular gene. Mutations to this gene can reduce the production of melanin, effectively ‘diluting’ brown eyes to blue.
However, studies of blue-eyed people from such diverse populations as those in Jordan, Denmark and Turkey have found that they have very little variation in the amounts of melanin in their eyes. This suggests they are all linked to one ancestor and have all inherited the ‘switch’ that turns off melanin production at the same spot in their DNA.
Scientists have been trying for decades to work out how carbon behaves deep below the Earth’s surface, in fluids 100 miles below the surface and at temperatures of up to 2,100 degrees F
Now it has been revealed that, along with carbon dioxide and methane, Deep Earth also contains a rich variety of organic carbon species that could be responsible for forming diamonds and perhaps even providing food for microbial life.
The theory, called the Deep Earth Water model, suggests that these deep fluids, expelled from descending tectonic plates, may be responsible for transporting building blocks for life up into the shallow Earth.
They may also play a role in the creation of diamonds as scientists have believed for a long time that diamonds form due to chemical reactions involving either carbon dioxide or methane.
On a good day, our computers are so fast they seen almost instantaneous and this is about as fast as silicon can go….
However this silicon-imposed speed and size limitation of computer processors and memory could be overcome if we used “phase-change materials” (PCMs) instead.
These are materials that can switch between two structural phases with different electrical states – one crystalline and conducting and the other glassy and insulating – in billionths of a second.
The smallest silicon-based logic and memory devices are about 20 nanometres in size – around 4,000 times thinner than a human hair- but PCM devices can function down to about 2 nanometres.
The particular PCM researchers have been experimenting with is a chalcogenide glass, which can be melted and recrystallised in half a nanosecond (which is a billionth of a second) using voltage pulses.
In these PCM devices, logic operations and memory are located together rather than separately, as they are in silicon-based computers, and processing speeds could be 500 to 1,000 times faster than the average laptop we use today.
All this – and using less energy than current computers. All of which is great, but since the internet is already creaking at the seams I think it’s a bit like creating cars that can travel at 250 miles an hour when the road network is designed (on a good day) for 70 miles an hour and, in the busiest places, leaves your crawling along at 20……..
Massive galaxies have stopped making their own stars and instead are snacking on their smaller neighbours, according to Australian scientists.
They looked at more than 22,000 galaxies and found that smaller galaxies are very efficient at making stars from gas, but more massive ones produce hardly any stars themselves and instead grow by eating other galaxies.
Our own galaxy, the Milky Way, is at this tipping point and is likely to continue to grow by eating rather than collecting gas. It hasn’t merged with another galaxy for a very long time but scientists can see the remnants of the old galaxies we have cannibalised. The next two galaxies on our menu – in about four billion years – are the Large and Small Magellanic Clouds.
However, we will get a taste of our own medicine a billion years later when we are due to merge with the Andromeda Galaxy which, being the bigger of the two, will consume the Milky Way.
Most of us have heard of Archaeopteryx – the so-called first bird..the missing link if you like, between the dinosaurs that we know from the fossil record and the modern feathered creatures we love to see in our gardens…..
Well – it turns out that dinosaurs were covered in feathers long before they tried to get off the ground.
Modern birds are descendants of a particular branch of medium-sized predatory dinosaurs called therapods. If you think you don’t know what a therapod looked like, think again because Tyrannosaurus Rex was one of these two-legged meat eaters, as was the smaller velociraptor, made famous by the film Jurassic Park.
Just like their descendants, these dinosaurs were warm-blooded and they evolved feathers rather than fur to keep warm because – current thinking says – of their acute colour vision.
Mammals generally have rather poor colour vision because they tended to be nocturnal during the early stages of their evolution, but reptiles and birds have extremely good vision.
Not only did dinosaurs have the three colour receptors for red, green and blue that humans have, but they probably also had (like their closest living relatives today – crocodiles and birds) the ability to see extremely short-wave and ultra-violet light.
Before dinosaurs evolved feathers, they had hairs similar to a mammal’s fur and these hairs gradually turned into feathers which are much better for optical signalling. The broad, flat surface area of feathers allowed for the constant refraction of light which is absolutely essential to produce blues and greens as well as the metallic shimmering we find so attractive about birds’ plumage.
By developing feathers, dinosaurs were able to show off across the colour spectrum and be warm-blooded animals at the same time, which is something mammals have never (yet) managed…
Water is present throughout our solar system – not only is the earth awash with it, but it is found on icy comets, on the moon and in the permanently shadowed basins of Mercury and Mars.
So – where did it come from? And why does it matter?
Scientists have wanted to know the answer to the first question because the second question is a no-brainer – it matters because it will tell them something crucial about the likelihood of life existing elsewhere.
If the water in the solar system came about as a result of chemical processes during the birth of the sun, it means other planetary systems may have much less water, which in turn would have implications for the potential emergence of life.
If, however, the water in the early solar system came primarily from ice in interstellar space – it is likely that similar ices, along with the prebiotic organic matter they contain, are abundant in every planetary system.
Without getting into the technical details, suffice it to say that scientists have found that at least some of the water in our solar system originated in interstellar space and pre-dates the birth of the sun. So – abundant, organic-rich interstellar ices can probably be found in all young planetary systems….
Which just begs the question – where did all that ice come from originally?
Burning fossil fuels is causing climate change, right? Well, yes, but….the emission of methane from cattle is also important. Methane is 25 times more powerful as a greenhouse gas than carbon dioxide and cattle generate up to 20% of the greenhouse emissions that come from agriculture.
However, not all cattle are equally windy. There are three variables that affect the methane levels – diet, genetics and the microbiology of the cow’s rumen. The good news for farmers is that cattle that produce less methane seem to be more productive, so by jiggling the breeding strains and altering the diet, cattle could become even more profitable.
Researchers believe methane production from cows could be cut by 10% in 10-15 years and the same process could be applied to other ruminants such as sheep and goats.
Turn them into solar cells of course!
Researchers at MIT have proposed a system that recycles materials from old car batteries, which are a potential source of lead pollution in land fill, into Photo-Voltaic panels.
These solar cells use a compound called perovskite, and the technology uses lead, which is a drawback when its production comes from raw ores, leaving toxic residues. However, if the manufacturing process uses recycled lead from old batteries, it turns into a win-win for the environment.
These perovskite-based PV cells have achieved power-conversion efficiency of over 19%, which is close to that of many commercial silicon-based cells.
The lead from a single car battery could produce enough solar panels to provide power for 30 households and this break-through could be happening just in time.
Battery technology is changing rapidly and the introduction of more efficient lithium-ion batteries will leave over 200 million redundant lead-acid batteries in the United States alone.
We are getting close to being able to find out…..
By studying the atmosphere of exoplanets (those outside the solar system), we can look for gases like oxygen and methane that only co-exist if replenished by biological processes – life.
Cyanobacteria (picture from world.edu)
Mind you, simple life forms like microbes would alter the atmosphere in this way – it was cyanobacteria, after, that spent millennia creating the oxygen-rich atmosphere our ecosystem depends on.
If we could find traces of pollution, that would indicated more advanced life – not advanced enough to avoid polluting their own planet, but as advanced as us anyway.
The new James Webb Space Telescope should be able to detect two kinds of CFCs, provided they are present at ten times the level found on earth. This would indicated either a very irresponsible, polluting life form, or, perhaps, one that deliberately raised CFC levels in the atmosphere of a colonised planet that would otherwise be too cold for life.
Industrial life (picture iamcarine.blogspot.com)
This search for CFCs could also detect the remnants of extinct alien civilisations, perhaps ones that destroyed themselves by polluting their atmosphere beyond repair. Some pollutants last 50,000 years in our atmosphere and others only 10 years so if we found traces of the former but not the latter, it could indicate a civilisation that killed itself off…..or, happier thought – one that got wise in time and stopped polluting themselves into extinction….
The range and variety of plants and animals in the ecosystem we are part of is estimated to be the most diverse since life began about 3.5 billion year ago. Unfortunately, instead of celebrating and preserving this amazing world, we appear to be doing our level best to destroy the complex inter-dependent ecosystem we call home.
Since 1500, over 320 terrestrial vertebrates have disappeared and populations of the remainder show, on average, a 25% decline in abundance. The situation is just as bad for invertebrates and an international team of scientists believe we may be at the start of the planet’s 6th mass biological extinction event.
Unlike all previous extinctions – this one will have our sticky fingers all over it.
Mega fauna under threat (picture from animals.nationalgeographic.com)
Mega-fauna, such as elephants, rhinos and polar bears, face the highest rates of decline and this trend repeats the process seen in previous extinction events. These creatures may only be a small percentage of the animals at risk but their loss could have trickle-down effects on other species, shaking their stability and tipping them over the edge into irreversible decline.
Experiments have shown that removing mega-fauna from an ecosystem leaves the area vulnerable to a population explosion of rodents as seeds and shelter become more available and the risk of predation drops. Rodents are carriers of ectoparasites which can then more easily spread into the wider ecosystem.
Rodents are a classic associate of humans – where there are people, there will be rodents, taking advantage of our food stores and wasteful habits. Our population has doubled over the last 35 years and in the same period the number of invertebrates – such as beetles, butterflies and worms – has fallen by an estimated 45%.
Do we want this planet, with all its astonishing diversity or one inhabited by little except rodents and scavenging invertebrates like cockroaches?