Compared to our nearest neighbours – Mars and Venus – Earth is unbelievably hospitable to life…but why?
What was so special about earth that meant it could evolve life when the planets either side of it so clearly couldn’t?
According to new research it is all down to chance and luck. It seems that Earth’s first crust, which was rich in radioactive heat-generating elements such as uranium and potassium was torn away and lost in space through bombardment by asteroids.
This led, eventually, to the formation of a very differently constituted crust, one that consisted of tectonic plates constantly sliding across the surface. This regular overturning of the surface cools the underlying mantle, maintains the earth’s strong magnetic field and stimulates volcanic activity.
The magnetic field protects the planet from deadly cosmic rays and the erupting volcanoes bring greenhouse gases from deep within the planet to the surface where they help maintain a habitable climate.
If there had been less impact erosion early on, earth could have evolved like Venus, whose catastrophic swings in seismic activity have driven billion-year-long swings in climate, offering no opportunities for life to evolve.
This is my latest book – it is available from all the usual e-retailers …..
I think the title says it all but basically it follows the development of money from the earliest days when we bartered our surpluses to the world we live in today when most of our money is never more than numbers on a computer screen.
It looks at the way societies evolved the sort of money they needed and how, in return, having that sort of money changed the society ….
It’s an easy read for the non-specialist reader, full of interesting facts (do you know why all our shops have counters? You will once you read this book)
if you go to my publications page, you will find links to the main e-retailers ….
According to scientists in Australia, fish are the key ingredients in a new recipe aimed at restoring degraded coral reef ecosystems.
Having analysed over 800 reefs worldwide, some only slightly fished and others seriously over-fished, it seems that there are key fish species which, once returned to their optimum numbers, provide a kick-start to full restoration of the reef.
Having the right fish in the right numbers also seems to give the reefs greater resilience to large-scale threats such as climate change.
At the moment it is estimated that 75% of the world’s coral reefs are threatened and more than 20% have disappeared completely since the acceleration in climate and fishing disturbances over the last 30 years.
Since only 27% of the world’s reefs lie within marine protected areas, the importance of getting (and keeping) fish stocks to the optimum level for sustainability is vital if this essential piece of the marine ecosystem is to survive.
This new research has found that the key fish species needed to bring degraded reefs back into health are, funnily enough, the very fish that browse and graze the reef, as well as planktivores.
Not that improvement would happen overnight – a moderately fished reef would take about 35 years to recover, while a very depleted ecosystem could take nearly 60 years.
A common algae that is already grown commercially to make fish food is looking like it may be far more valuable to us than that. Never mind keeping our finny friends happy, this particular type of blobby green may also be a source of both biodiesel and even jet fuel.
It’s all to do with an algael fat called alkenone, a compound consisting of long chains of carbon atoms, which researchers believe could be a potential fuel source.
Up to now, biofuel prospectors had dismissed this algae – known as Isochrysis – because its oil is a dark, sludgy solid at room temperature rather than a more useful clear fluid. However it is the sludge that makes this algae so special as it is caused by the alkenones and is the reason the algae could be a unique source of both fuels.
Researchers have now managed to separate out the alkenones from the other fats in the algae to create a free-flowing bio-fuel. They have also, thanks to inventing a Nobel Prize-winning chemical reaction, managed to break the alkenones’ 37-39 atom carbon chains into smaller pieces of between 8 and 13 carbons. Whilst 37 carbon atom chains are too big to be used as jet fuel, the smaller sections turn out to be just right.
The two hemispheres of Mars are more different from each other than is the case on any other planet in our solar system.
The northern hemisphere is made up of non-volcanic, flat lowlands, while the southern half of the planet is predominantly highlands, punctuated by countless volcanoes.
There have been numerous theories to explain this and the latest is that a celestial object at least one tenth the mass of Mars, must have smashed into the Martian south pole early in the solar system’s history. At the time, the Red Planet’s crust would have been very thin, like the crust of a crème brulée, hiding a liquid interior. The impact would have generated so much energy that a magma ocean would have covered the southern half of the planet. This molten rock eventually solidified into the mountainous highlands we see today.
It also triggered strong volcanic activity that lasted around 3 billion years. This extreme vulcanism caused the interior to cool very rapidly (in astrological terms), to the point where it could no longer maintain any vulcanism at all and the planet effectively died.
If this is right, Mars became an extremely hostile environment very early in its history and could never have supported the emergence of any form of life.
However, other researchers are adamant that, early collisions notwithstanding, Mars had a very significant volume of water for millions, if not billions, of years. Based on studies of the atmospheric water still to be found on Mars, researchers believe the planet’s early ocean must have been at least 20 million cubic kilometres. It is thought to have pooled in the northern hemisphere and would have covered a greater percentage of the planet than the Atlantic Ocean does the Earth.
Oceans are quite noisy places at the best of times, what with the weather, the movement and communication of fish and man-made noises like ships’ engines and sonar devices. However, the biggest cause of noise pollution in the whole underwater ecosystem is the air bubbles gushing from melting glaciers and their icebergs.
Fjords with melting glaciers are far and away the noisiest places in the ocean and generate sounds at all frequencies from 300 to 20,000 Hertz. Glacial calving is certainly noisy, but in a loud, short-lived sort of way. It is the consistent melting of ice from glaciers and their icebergs that is the real noise generator. The air trapped in the ice escapes as bubbles that ‘pop’ as they leave their icy prison, giving a constant, loud, background noise.
This begs the question of what difference will it make to the fjord ecosystem once climate change has reduced the glaciers to the point that they are melting on land instead?
At the moment, fjords with glaciers are foraging hotspots for all sorts of creatures as well as important breeding locations for harbour seals. It is thought they may use the underwater noise of the escaping air to help them hide from killer whales who hunt by listening to locate their prey.
As glaciers retreat on to land, the seals may lose this acoustic camouflage, which would explain why harbour seal populations are declining in fjords where glaciers no longer reach the sea.
Termite mounds can help prevent the spread of deserts into semi-arid ecosystems, according to a new study.
In the parched grasslands and savannas where termites make their home, they have a hugely beneficial effect on the surrounding ecology. Not only do their mounds store nutrients and moisture, but their extensive tunnels allow water to better penetrate the soil.
As a result, vegetation flourishes near termite mounds in ecosystems that are otherwise highly vulnerable to ‘desertification’.
The difference they make is so significant that lands with termite mounds can survive on substantially less annual rainfall than those without the little creatures.
A second advantage they unwittingly provide is to preserve seeds and plant life and this helps their immediate surroundings recover faster when it does eventually rain.
The amount of rain may be the same as in termite-less areas but, because the termite tunnels allow it to penetrate the soil better, the actual effect on plants is as if there had been more rain.
It may be that other mound-building animals such as ants, prairie dogs and gophers have a similar impact but so far there hasn’t been the research to prove it.
Vast ranges of volcanoes lie deep below the waves along the mid-ocean ridges that run like stitches where the earth’s tectonic plates meet.
It has always been assumed that these giants of vulcanism slowly oozed lava into the spaces left by plate movements at a regular, steady pace, having no influence on our world of air thousands of metres above them.
However, a new study shows that actually these undersea volcanoes flare up in regular cycles – some as often as every two weeks, others every 100,000 years or so – and that these eruptions happen almost exclusively in the first six months of every year.
These pulses in lava ejection are apparently tied to short- and long-term changes in the earth’s orbit and to sea-levels and may trigger natural climate swings.
The chains of undersea volcanoes stretch some 37,000 miles around the world’s oceans and produce possibly eight times as much lava as land volcanoes.
A couple of million years ago the heart of our galaxy, the Milky Way, was convulsed in a titanic eruption, driving gases and other materials outward at over 2 million miles an hour.
The aftermath of this mega-explosion can be seen today – billowing clouds of gas tower 30,000 light years above and below the plane of our galaxy.
This enormous structure was discovered five years ago, showing up as a gamma-ray glow in the sky, and being observed in x-rays and radio waves.
There are two possible origins for these massive bubbles of gas – perhaps there was a firestorm of star births at the galaxy’s centre, which would have produced supernovas and blown out the gas. Alternatively, a group of stars could have fallen into the super-massive black hole that lurks there, which would have blasted super-heated gas deep into space.
These bubbles of gas are short-lived in galactic terms, suggesting they are a repeating phenomenon in the Milky Way’s history. Another reason to be glad the earth is out in the backwaters of a spiral arm……
Our sense of touch is far more sensitive than most of us realise – so sensitive that if your finger was the size of the earth, it could feel the difference between houses and cars.
Swedish scientists have investigated the ‘unknown sense’ of tactile perception and found that people can detect nano-scale wrinkles on seemingly smooth surfaces.
Nano-scale? Basically this means we can feel a bump the size of a very large molecule.
These findings could lead to developments such as touch screens for the visually impaired. And as one of the scientist says ‘To make the analogy with vision, it is as if we have just revealed how we perceive colour. Now we can start using this knowledge for tactile aesthetics in the same way that colours and intensity can be combined for visual aesthetics’.