Akshat Rathi

China’s exceptionally well-preserved fossils may have been the result of a volcanic eruption

February 5, 2014February 5, 2014 Akshat RathiLeave a comment

A series of fossil discoveries in the 1990s changed our understanding of the lives of early birds and mammals, as well as the dinosaurs they shared an ecosystem with. All those discoveries had one thing in common: they came from a small region in northern China that preserved what is now called the Jehol Biota.

Until now, however, no one knew why so many well-preserved fossils have been found in that region. In a new study published in Nature Communications, researchers have found that this remarkable preservation might have been the result of a Pompeii-like event, where hot ash from a volcanic eruption entombed these animals.

Dino colours

According to Sarah Gabbott at Leicester University, who wasn’t involved in the study, “unravelling the environments in which fossilisation took place, as the authors do in this paper, is very important. It places the fossils within the context of their habitat and it allows us to determine what filters and biases may have played a part.” These biases may affect which organisms get preserved.

The fossils of the Jehol Biota are from the Early Cretaceous period, about 130 million years ago, and they comprise a wide variety of animals and plants. So far, about 60 species of plants, 1000 species of invertebrates, and 140 species of vertebrates have been found in the Jehol Biota.

Photos show the typical entombing poses of the Jehol terrestrial vertebrate fossils. This boxer-like pose is typical of victims of pyroclastic density currents, resulting from postmortem tendons and muscles shortening. Baoyu Jiang

One of the most remarkable discoveries to arise from these fossils came in 2010, when Michael Benton of the University of Bristol found colour-banding preserved in dinosaur fossils. These stripes of light and dark are similar to stripes in modern birds, and provided further evidence that dinosaurs that evolved into birds. Benton also found that these fossils had intact melanosomes – organelles that make pigments. This discovery allowed paleontologists, for the first time, to tell the colours of dinosaurs’ feathers.

Rising from the ashes

Baoyu Jiang of Nanjing University, the lead researcher of the new study, has been studying fossils from Jehol Biota for more than a decade. “About two years ago, we realised that the sediments and their enclosing skeletons may provide key clues about what happened to these animals when they were killed and buried,” he said.

The fact that so many fossils were found exquisitely preserved from the same time period suggested some form of mass death. Even before Baoyu started this work, there were suggestions that volcanoes may have been responsible.

Using 14 different fossils from five locations within the deposits, Baoyu found marks of fast-moving ash and hot gas, known as pyroclastic flows, that can only result from a nearby volcanic eruption. The bones showed black streaks, which suggests charring had occurred.

Almost Pompeii

But questions remain. The area that supported the Jehol Biota is suspected to have been a wetland with many lakes. Most fossils are found in lakebeds, suggesting that either the fossils were washed into these lakes by floods or that the animals were in the lakes before fossilisation took place.

Baoyu believes that if fossils don’t separate at bone joints, it means the animals must have been in the lake before dying. But that is not a convincing argument, Gabbott said. “A freshly dead carcass, buoyed by decay gases which collect in the stomach, can be transported for tens if not hundreds of kilometres without such disarticulation (separation of bones at joints).”

No other fossil location, let alone that which produced so many well-preserved samples, has ever been suggested to have undergone a similar event. A comparison can be made to what happened in Pompeii in 79 AD, when Mount Vesuvius erupted. The ensuing destruction led to the preservation of the city’s architecture and objects but not of people or animals. The human and animal remains we see from Pompeii are plaster casts of the empty spaces their decomposed bodies left in the ash.

Still, Jehol Biota and Pompeii both show how mass tragedies at the feet of volacanoes can preserve the past for future generations to discover.

First published on The Conversation. Image credit: Chuang Zhao and Lida Xing

New laser-printed material is lighter than water, as strong as steel

February 4, 2014 Akshat RathiLeave a comment

Materials shape human progress – think stone age or bronze age. The 21st century has been referred to as the molecular age, a time when scientists are beginning to manipulate materials at the atomic level to create new substances with astounding properties.

Taking a step in that direction, Jens Bauer at the Karlsruhe Institute of Technology (KIT) and his colleagues have developed a bone-like material that is less dense than water, but as strong as some forms of steel. “This is the first experimental proof that such materials can exist,” Bauer said.

Material world

Since the Industrial Revolution our demand for new materials has outstripped supply. We want these materials to do many different things, from improving the speed of computers to withstanding the heat when entering Mars’ atmosphere. However, a key feature of most new materials still remains in their strength and stiffness – that is, how much load can they carry without bending or buckling.

All known materials can be represented quite neatly in one chart (where each line means the strength or density of the material goes up ten times):

Jens Bauer/PNAS

The line in the middle at 1000kg/m³ is the density of water – all materials to its left are lighter than water and those on the right are heavier. Few fully dense solid materials are lighter than water. Those that are tend to be porous, like wood or bone, and they exhibit exquisite structures when observed under a microscope, and they served as inspiration for Bauer’s work.

For many years, material scientists have thought that some empty areas on the compressive strength-density chart should be filled by materials that theory predicts. Computer simulations could be used to indicate an optimum microstructure that would give a material the right properties. However, nobody had tools to build materials with defined patterns at the scale of a human hair.

With recent developments in lasers and 3D printing, however, a German company called Nanoscribe started offering lasers that could do just what Bauer wanted. Nanoscribe’s system involves the use of a polymer that reacts when exposed to light and a laser that can be neatly focused on a tiny spot with the help of lenses.

A drop of a honey-like polymer is placed on a glass slide and the laser is turned on. A computer-aided design is fed into the system and the slide carefully moves such that the laser’s stationary focus touches only those points where the material is to be made solid. Once complete, the extra liquid is washed away, leaving behind materials with intricate internal structures.

However, these materials on their own are not as strong as Bauer wanted. So he coats them with a thin layer of alumina (aluminium oxide) before subjecting them to stress tests. Based on the tests, he was able to improve the theoretical models he used to design the internal structure of the materials. Their results were just published in the Proceedings of the National Academy of Sciences.

Even though alumina layers increase the density of these materials, all of them remain lighter than water. Bauer’s strongest material has a specific honeycomb internal structure and is coated with a 50 nanometre-thick (billionth of a metre) layer of alumina. It beats all natural and man-made materials that are lighter than 1000kg/m³, being able to withstand a load of 280MPa (mega pascals is a unit of measuring pressure), which makes it as strong as some forms of steel.

There are limitations. Nanoscribe’s system can only make objects that are tens of micrometres in size. “One of their newer machines can make materials in the milimetre-range, but that’s about it for now”, Bauer added. But that is not enough for any real-life application.

However, there have been rapid improvements in all the areas this work relies on: 3D printing, new polymers and laser technology. That means we may soon have a suite of new, super lightweight materials for everything from skis to aircraft parts. If nothing else, Bauer’s work shows that we are definitely in the molecular age.

First published on The Conversation. Image credit: Jens Bauer.

If you are cursing Arvind Kejriwal for throwing away a golden opportunity, you are wrong

February 2, 2014February 2, 2014 Akshat RathiLeave a comment

The Aam Aadmi Party has done the impossible. One month ago, the Facebook class of India loved them for showing what Indian politics really needs. Now they hate them for doing things that we won’t expect even corrupt politicians to do.

To understand this schizophrenia that the AAP has created among the educated middle class of India, we need to look at our own expectations. The success of Kejriwal in the Delhi elections, we thought, was the result of our disgust of the current political class. We hate those politicians who go after vote banks only so that they can fill up their own pockets with bribes. We wanted someone who could clean the muck and put worthy leaders in charge. Like Obama, he was the beacon of hope in a mess that had been decaying for decades.

As soon as he took up his place as Delhi’s chief minister, we expected Kejriwal to behave like a model chief minister—honest, sober and efficient. We wanted him to get things done. But unlike Obama who crushed the American dream after being re-elected, Kejriwal’s party members seem to be on track to crush our dreams within months of being in the government.

The law minister Somnath Bharti was accused of taking law into his own hands. The resident poet Kumar Vishwas was caught on camera making racial comments. And the leader Kejriwal was blamed to act un-statesmanlike when he resorted to protesting against his state’s police—something no chief minister had ever done before .

And yet, we must realise that Kejriwal is smart to know that pandering to our desires is impossible in the few months he has before national elections. He is partly right to blame the media for creating a hate campaign, for whom he has been a bonus. With Kejriwal, the media has one more top politician to poke beyond Rahul Gandhi and Narendra Modi.

Kejriwal’s best strategy for the national elections is going to be the same strategy he had going into Delhi elections—try to get enough seats so that AAP can be a trouble-making opposition. And for achieving that goal, it would be best to stick to the principles that won him Delhi. Something that even the Congress and the BJP have admitted to learn lessons from. The principles were to provide the people an alternative to the current crop of filthy politicians.

Of course, national elections are going to be a whole different game. Delhi’s population is all urban, but India remains largely rural.

In the Delhi elections, AAP got 30% of the votes, slightly behind BJP’s 33% and slightly ahead Congress’s 25%. He won not because of the few votes from the Facebook class, but mostly because of the votes from the poor—the rickshaw drivers, the slum-dwellers and lower middle class (which can afford mobile phones but has no use for the internet).

He succeeded because he acted as he had done for many years before—like a revolutionary. While it would be foolish think that he does not enjoy the power of being a chief minister, I would like to believe him when he says that he does not want that power if he has to compromise on his ideals. The Congress can pull remove their unconditional support and he won’t be chief minister anymore.

At this point I should disclose that I do not support Kejriwal’s economic policies, at least the ones he has shown so far. But I’m willing to experiment with having a clean politician who improves the functioning of the government and exposes its predecessor’s wrongdoings, even if the immediate effect on people’s lives will not be beneficial.

Rise of the muffler man

I like Vir Sanghvi’s clarity of thoughts. That is why when he said, “Kejriwal has become no more than a media-blaming, vote-bank politician”, I entertained his well-laid arguments seriously. Sadly, the conclusion drawn is only partly right.

Yes Kejriwal blames the media, but he is no vote-bank politician. Sanghvi’s analysis fails because he is being short-sighted. He claims that giving free water and cutting electricity prices in Delhi will get Kejriwal votes at the national level.

Kejriwal got into politics to play the long game. He recognises that what few votes he can get at the national level will come from exposing the tainted politicians, offering a good alternative and listening to the vast majority of people. He is moving the debate away from pitting personalities against each other to talking about values and ideas.

Like in Delhi, there is no way that AAP can form a majority government at the national level this year. It would be lucky if it even played a small part in forming the government. Instead, the AAP is aiming for the election of 2019. In five years, the party will have matured and the country will have grown tired of Modi. That would be the time when AAP will be a serious alternative—something Indians have been wanting for decades.

Image credit: Kumar Vishwas (not original source)