100 million and still surviving

In the Cambridge University Botanical Gardens stands a Giant Redwood tree call the “Dawn Redwood.”  It stands more than 70 feet tall – the height of an eight-story building.

But its height is not what makes it special.  It’s special because its ancestry can be traced back 100 million years to when the dinosaurs still reigned, and when it flourished in what is now Great Britain.  Until 1941 scientists only knew of it through fossils and thought it had been extinct for at least 5 million years.

It was rediscovered in 1941 in a village in Szechuan, China.  Its journey back to Britain was interrupted by war.  Butin 1948, a seed reached Cambridge, where it was nurtured and flourished.

The Dawn redwood can now be seen through Great Britain.  Unfortunately, it is seriously endangered in China.

The birth, the life, and the death of a star

I’m not sure which I find more astonishing – that we can actually describe the life of our sun, both past and to come, or the fact that anybody in the world who has access to the internet can watch a six-minute U-tube video of the life cycle of a star similar to our sun.

Our own sun is the source of all our energy on earth, so when it finally burns out, life – at least life resembling anything we have thus far remotely  imagined – will disappear completely.  

That may be something to worry about, but one can take some consolation in the fact that the sun still has another two billion years to run.

In the meantime, here’s a preview of what it will be like:

 http://www.youtube.com/watch?v=qd1kBjJPPlU

Gift on deposit

In the middle of the 17th century, the people of Cheshire, southeast of Liverpool in northern England, were envious of neighbouring towns that were getting rich mining the coal that lay beneath their feet.  So they began to dig too.  But they didn’t find coal.

Under the town of Cheshire lies an almost incomprehensibly huge deposit of salt.  

It was left behind 220 million years ago in the Triassic period when the dinosaurs were king.  England lay beneath a tropical sea then, and over millions of years as it evaporated, the salt, mixed with sand blown in from eastern deserts, was left behind.

People have been using the brine that bubbled to the surface in Cheshire since at least 600 BC.  By the industrial period, though, this method produced paltry results next to the riches delivered by digging up coal.  So they started to dig, and opened the first salt mine in 1690.  Today the salt is mined by huge machines that can take a single bite and spit out a chunk 16 feet wide and 20 feet deep.  It works 24/7, pulverizing 20,000 tonnes a day, enough to fill and re-fill 2000 gritters day in and day out.  50 million tonnes have been taken out in the last 50 years.

Despite this, the salt is no where near being depleted.  Huge caverns created by the excavated materials are now used for storage, some for government records going back as far as the 16th century, some for toxic waste.  25 truckloads arrive each day, 100,000 tonnes  annually.  They don’t expect all the room ever to be filled.  The rooms where waste will be stored for the next 100 years have already been assigned for the purpose.  

The mine itself is already so big that there are street lights and maps to guide workers around the what is the size of a town.

The dinosaurs would, no doubt, be amazed.

2008 was longer than usual. Really

Welcoming in the new year for 2009 was just a little more complicated than usual.  And actually, the “usual” is already a good deal more complicated than most of us realize as we toast the new year at the stroke of midnight.

Because there is more than one way to measure when the old year ends and a new one begins.

For starters, different cultures start the new year at different times.  The Chinese new year begins with the Year of the Ox on January 26.  The Jewish new year doesn’t begin until September 18, and the Muslim new year – which is 1430 – began December 28.

The date most of us consider the standard as the new year is based on the Gregorian calendar established in 1582 which is based on the time it takes the earth to orbit the sun.  Sort of…

Most of us know that the extra day in leap year every four years is to adjust for the fact that it takes just a little longer for the earth to circumnavigate the sun than a year.  Actually, the leap year doesn’t solve the entire problem because it takes 365.2422 days for the earth to circle the sun, and eventually, leap years would have our time getting ahead of solar time.   So leap years are omitted at the turn of the century of the year is not divisible by 400.  Which is why there wasn’t a leap year is 1900, but there was in the year 2000.

It gets worse.

It doesn’t take the earth exactly 24 hours – which is what we call a day -to spin on its axis.  It actually takes 23 hours 56 minutes and 4 seconds.  But because the earth is moving around the sun at the same time as it is spinning, it does take 24 hours for the sun to get back to the same position relative to earth.  

BUT…

The speed at which the earth is spinning is slowing down ever so slightly.  So every once in a while, an extra leap second has to be added to the end of the year to keep our “human” time in sync with the earth and sun.

This is not the only way to do it.  The Islamic calendar is based on the cycles of the moon, and the Jewish and Chinese calendars are based on both the movement of the moon around earth, and the earth around the sun.

And then there’s the atomic clock…

Not only strange…

The Hubble Telescope has been sending us photographs from almost as far away as it is possible to go.  Space and what’s out there is not only “deeply strange,” but also almost “impossibly beautiful.”

If you haven’t seen them already, here are a few worth marvelling at.  In fact, they are marvellous even if you’ve seen them a dozen times already.

Hubble telescope’s top ten greatest space photographs

The Sombrero Galaxy – 28 million light years from Earth – was voted best picture taken by the Hubble telescope. The dimensions of the galaxy, officially called M104, are as spectacular as its appearance. It has 800 billion suns and is 50,000 light years across.

The Ant Nebula, a cloud of dust and gas whose technical name is Mz3, resembles an ant when observed using ground-based telescopes. The nebula lies within our galaxy between 3,000 and 6,000 light years from Earth.

In third place is Nebula NGC 2392, called Eskimo because it looks like a face surrounded by a furry hood. The hood is, in fact, a ring of comet-shaped objects flying away from a dying star. Eskimo is 5,000 light years from Earth.

At four is the Cat’s Eye Nebula

The Hourglass Nebula, 8,000 light years away, has a pinched-in-the-middle look because the winds that shape it are weaker at the centre.

In sixth place is the Cone Nebula. The part pictured here is 2.5 light years in length (the equivalent of 23 million return trips to the Moon)

The Perfect Storm, a small region in the Swan Nebula, 5,500 light years away, described as ‘a bubbly ocean of hydrogen and small amounts of oxygen, sulphur and other elements’.

Starry Night, so named because it reminded astronomers of the Van Gogh painting. It is a halo of light around a star in the Milky Way.

The glowering eyes from 114 million light years away are the swirling cores of two merging galaxies called NGC 2207 and IC 2163 in the distant Canis Major constellation.

The Trifid Nebula. A ’stellar nursery’, 9,000 light years from here, it is where new stars are being born.

Rock of the ages

The oldest rocks anywhere in the world may have been found on the shore of Hudson Bay in Canada.  They have been dated to be 4.28 billion years old, and must have been among the very first rocks formed on Earth’s crust as our planet spun into existence 4.56 billion years ago.  One of the exciting and even astonishing things about the rocks is that they may contain evidence of some early life, surviving against what we would think are all the odds in the first firey stage of the planet.

The rocks are called by the possibly non-memoral name of Nuvvuagittuq greenstone.  You wouldn’t know just by looking at them just how extraordinary they are.  http://www.nytimes.com/2008/09/26/science/26rock.html?_r=1&partner=rssnyt&emc=rss&oref=slogin

No we can’t! The celebration of Pi

Pi is the circumference of a circle divided by its diameter.  Roughly speaking, that’s always about 3.14.  In American-speak, that’s today.  So today (I’m writing this on March 14th) is Pi day.

What I like about pi is that it is an example of the absolutely insolvable.  Pi isn’t exactly 3.14.  It’s 3.14 followed by an infinite stream of numbers.  Literally infinite.  So we can’t ever know exactly what it is.  It’s a prime example of the state of human knowledge.  Probably the inevitable, inescapable state of human knowledge:  we know a lot about it and can always learn more by generating as many more numbers after .14 as we have time and energy.

But we can never know it absolutely.  We can only know it “up to a point.”  There will always be more we can learn, and we will never reach the final Absolute Perfect Truth.

Dynamic dust

It seems like another one of those amazing things scientists seem to discover as they tramp about the universe.  An international group of sciencists from Russia, Germany, and Australia have found that galactic dust can form into helixes and double helixes that can reproduce themselves in the manner of living organisms.  They’ve seen it happen in two places – a laboratory in Germany with zero-gravity conditions, and on the International Space Station above Earth.

But what is so astonishing about their observation is that the dust they observed is inorganic – that is, not made of the carbon, oxygen and hydrogen of which all living things on Earth are made.

Ever since Galileo shook Western thought to its roots with evidence that Earth was not the centre of the universe but instead revolved around the sun, science has continued to come up with evidence that we are not the centre of all things that we thought we were. 

The implications of the possibility of non-organic life whizzing around out there are not clear.  Will we have to redefine life?  Should we start looking for extra-terrestial life in quite a different guise than the one we have been expecting?  Will this lead to new explorations of the nature of disease and medicine and replacement limbs?

An ancient skull suggests a new theory of human origins

Many people think science is about facts that can be proved, and that don’t change.  But what is accepted as fact in science is changing all the time.  The one characteristic of science is that it is not a resevoir of immutable truth, but an ongoing exploration that is never going to end.

An example of a fact – or at least a semi-fact that most paleontologists accepted as a working hypothesis – has just been changed with the discovery of a skull and a jaw bone in Kenya.  Until now, most scientists thought that a species called Homo habilis living in Tanzania, Africa about three million years ago was the ancestor of a species called Homo erectus, who was the ancestor of Homo sapiens. 

This theory of human origins is now in grave doubt because the recently discovered skull belongs to H. erectus, and the jaw bone, from a hominid living at the same time, belongs to H. habilis.  It looks, as if the two Homo species lived at the same time, for about half a million years.  So H. erectus probably did not evolve from H. habilis.  

Most probably – but this is subject to change - they both have another common ancestor.  For the time being, at least, H. habilis and H. erectus are thought to be sister species living at the same time for half a million years.

And what is the cost of this snail necklace?

Trying to find out things like how long we humans have been crafting artistic objects, wearing jewellry or using money is a painstaking business for archaeologists. 

Beads made 75,000 years ago from a single kind of snail shell and decorated with red ocre were found several years ago in a seaside cave called Blombos in South Africa.  More recently, similar shells with similar decorations and unnatural perforations that would have made it possible to string the shells together have been found in northern Africa.  They are between 74,000 and 91,000 years old.  Similar beads have been found in Algeria and Israel.

Clearly the shells were fashioned into beads by human hands.  So it is safe to assume that our artistic output has been going on for at least 100,000 years.  But the beads pose two questions that have yet to be answered.

• Were they used for jewellry, or were they a form of currency used for trading?
• And perhaps even more intrigueing, how did it happen that the same species of snail decorated in essentially the same way appears over such a huge distance?  It seems highly improbable that the similarities are sheer coincidence.  But on the other hand, it is hard to imagine that a trading system spread over such a relatively large space was taking place 75,000 years ago. 

So why was everybody decorating the same species of snail shells in the same way?