Scared scientists air their climate fears

Shauna Murray, Biologist, University of Technology Sydney, University of Tokyo, University of New South Wales. Her greatest fear is reaching four degrees of warming. [Credit Nick Bowers]

Shauna Murray, Biologist, University of Technology Sydney, University of Tokyo, University of New South Wales. Her greatest fear is reaching four degrees of warming. [Credit Nick Bowers]

Australian photographer Nick Bowers has recorded the fear leading scientists feel for the future as climate change changes the way we live in Scared Scientists, a project that combines portraiture and a call to action.

Bowers used university directories and webpages like the Climate Council to track down the top minds in the fields of biology, ecology, oceanography, earth science, and weather research.

Each sat for their portrait and explained their predictions and deepest fears for the state of our planet.

Bowers work is austere, and manages to get across the anxiety that the scientists' research has given rise to.

Sarah Perkins, an extreme weather researcher at the University of New South Wales, says that she is afraid that by the time we realise we need to make changes and start to put these changes in place, it might not be enough to balance out the range of catastrophes we will be facing. [Credit: Nick Bowers]

Sarah Perkins, an extreme weather researcher at the University of New South Wales, says that she is afraid that by the time we realise we need to make changes and start to put these changes in place, it might not be enough to balance out the range of catastrophes we will be facing. [Credit: Nick Bowers]

Time Flannery, a mammologist, palaeontologist at the University of New South Wales, Monash University and La Trobe University fears the disruption of human civilisation. [Credit: Nick Bowers]

Time Flannery, a mammologist, palaeontologist at the University of New South Wales, Monash University and La Trobe University fears the disruption of human civilisation. [Credit: Nick Bowers]

When did the megaladon vanish and what can it tell us about our oceans?

An artist's impression of carcharocles megalodon, the largest shark that ever lived. [Credit: iStock]

An artist's impression of carcharocles megalodon, the largest shark that ever lived. [Credit: iStock]

The fearsome carcharocles megalodon or monster shark grew up to 18 metres in length. It was perhaps the largest fish and most dangerous predator the world has seen. The shark was found all around the planet and then became extinct.

The giant shark left an abundant fossil record from the middle Miocene (15.9 to 11.6 million years ago) to the Pliocene (5.3 to 2.6 million years ago) and its triangular fossilised teeth were once thought to be the tongues of dragons. 

Until now, scientists have been unable to pinpoint exactly when the monster disappeared from the oceans, but recent research by biologists Catalina Pimiento from the University of Florida and Christopher Clements from the University of Zurich, have put the date at around 2.6 million years ago, at the end of the Pliocene and beginning of the Pleistocene era. It was during the Pleistocene (2.6 million to 11,700 years ago) that baleen whales – including the blue whale – reached their gigantic size. The results have been published in PLOS one.

It is understood that the disappearance of top feeders, or apex predators, can trigger profound changes throughout the marine food chain. In the present day, the number of sharks in the world's oceans is declining, so the fate of the megalodon is therefore of "significant interest", the researchers say.

The researchers used an Optimal Linear Estimation (OLE) model to arrive at the estimated time of extinction, plus their knowledge of evolutionary trends in whales.

"Despite the limitations and uncertainties of the fossil record, the study of the time of extinction of C. megalodon provides a baseline to understand the establishment of the modern structure and function of gigantic filter-feeding whales," the authors say. 

Another piece in the puzzle of modern humans and Neanderthals in Siberia

A map of ancient human remains. The latest Homo sapiens finding was in Ust-Ishim,  in western Siberia.

A map of ancient human remains. The latest Homo sapiens finding was in Ust-Ishim,  in western Siberia.

When local historian Nikolay Peristov was searching the banks of the Irtysh River in Ust-Ishim, western Siberia for the mammoth bones, which he uses to make ivory carvings, he found a modern human thigh bone instead.

Radio-carbon dating discovered the bone was around 45,000 years old, making it one of the oldest Homo sapiens fossils ever found.  

But there were more surprises when Geneticist Janet Kelso and colleagues from the Max Planck Institute for Evolutionary Anthropology analysed the Siberian's genome and found it carried a similar level of Neanderthal ancestry to present-day Eurasians.

The researchers concluded that Neanderthals and Homo sapiens ancestors of the Siberian man must have interbred some 7,000 to 13,000 years before he lived – previous estimates of Neanderthal and modern human couplings ranged from 37,000 to 86,000 years ago.

The Max Planck dating suggests a mating of 50,000 to 60,000 years ago – a time which coincides with the migration of modern humans into Europe and possibly into Asia.

So, thanks to the wonders of our new skills in reading ancient DNA, we have another piece in the puzzle of our inter-related history with the doomed Neanderthals that we investigated recently in Cosmos.

As Robin McKie wrote: "Not so long ago, the history of the Neanderthal seemed destined to remain as mysterious and fragmented as the occasional dusty bones dug from caves across Europe. Now Neanderthals’ DNA is not only writing the missing pages of their history, but our own."

Astronomers discover new families of comets

An artist's impression of the comets around Beta Pictoris. [Credit: European Southern Observatory]

An artist's impression of the comets around Beta Pictoris. [Credit: European Southern Observatory]

With comets in the news, from Rosetta's mission to land on one and the close fly-by of Mars by another this week, French astronomers have added to the excitement with the discovery of two new families of comets orbiting  the star Beta Pictoris, some 63 light years away.

They used the HARPS instrument at ESO’s La Silla Observatory in Chile to make the most complete census of comets around another star ever created, studying nearly 500 individual comets orbiting the star.

They can be broken down into two distinct groups – old exocomets that have made multiple passages near the star, and younger exocomets that probably came from the recent breakup of one or more larger objects.

The new results appear in the journal Nature.

Beta Pictoris and its neighbourhood. [Credit: ESO]

Beta Pictoris and its neighbourhood. [Credit: ESO]

Beta Pictoris is a young star – only about 20 million years old – and is surrounded by a huge disc of material, an active young planetary system where gas and dust are produced by the evaporation of comets and the collisions of asteroids.

Flavien Kiefer, lead author of the new study explained the significance, saying the research gives us clues to help understand what processes occur in this kind of young planetary system.

“For the first time a statistical study has determined the physics and orbits for a large number of exocomets. This work provides a remarkable look at the mechanisms that were at work in the solar system just after its formation 4.5 billion years ago," he said.

The exocomets of the first family have a variety of orbits and show a rather weak activity with low production rates of gas and dust. This suggests that these comets have exhausted their supplies of ices during their multiple passages close to Beta Pictoris.

The second family members are much more active and are also on nearly identical orbits, suggesting that they all arise from the same origin: probably the breakdown of a larger object the fragments of which are on an orbit grazing the star Beta Pictoris.

The puzzling life of Martin Gardner

Writer and poser of puzzles Martin Gardner [Credit: Elliott Erwitt/Magnum/Snapper Media] 

Writer and poser of puzzles Martin Gardner [Credit: Elliott Erwitt/Magnum/Snapper Media] 

Cosmos' resident magician Jason England reminds us that this week would've been the brilliant Martin Gardner's 100th birthday.

Gardner's 'Mathematical Games' column that ran in Scientific American from 1957 to 1986, in which he introduced obscure mathematical concepts to lay readers.

Jason recently looked back on Gardner's endless fascination with puzzles, poetry, science and magic.

Sceptics question Lockheed's fusion optimism

Superconducting magnetic coils inside Lockheed Martin's compact fusion experiment. [Credit: Lockheed Martin]

Superconducting magnetic coils inside Lockheed Martin's compact fusion experiment. [Credit: Lockheed Martin]

David Talbot at MIT Technology Review airs the doubts many scientists have expressed over Lockheed Martin's announcement that it was on track to produce a fusion reactor that would fit on the back of a pick up truck, predicting it would be up and running within a decade.

Many scientists are unconvinced. Ian Hutchinson, a professor of nuclear science and engineering at MIT and one of the principal investigators at the MIT fusion research reactor, says the type of confinement described by Lockheed had long been studied without much success.

Hutchinson says he was only able to comment on what Lockheed has released—some pictures, diagrams, and commentary, which can be found here. “Based on that, as far as I can tell, they aren’t paying attention to the basic physics of magnetic-confinement fusion energy. And so I’m highly skeptical that they have anything interesting to offer,” he says. “It seems purely speculative, as if someone has drawn a cartoon and said they are going to fly to Mars with it.”

Hutchinson adds: “Of course we’d be delighted if a real breakthrough were possible, but when someone who shows no evidence of understanding the issues makes a bald claim that they will just make a small device and therefore it will be quicker [to develop], we say, ‘Why do they think they can do that?’ And when they have no answers, we are highly skeptical.”

 

Watch a quail embryo develop in 13 seconds

The winner of the Nikon Small World in Motion competition was a 3D reconstruction of the 10-day incubation of a quail embryo by Dr. Gabriel G. Martins of the University of Lisbon.

The video is comprised of more than 1,000 separate images in a sequence of “virtual” slices through the whole embryo during its gestation in the egg. With this technique, studying the whole anatomy of large specimens like this embryo (23mm long) is possible.

You can find other entries here.

James Webb space telescope survives first test at -233ºC

A crane lifts the heart of the James Webb Space Telescope from the Goddard Thermal Vacuum Chamber where it spent weeks in a space-like environment. [Credit: NASA/Chris Gunn]

A crane lifts the heart of the James Webb Space Telescope from the Goddard Thermal Vacuum Chamber where it spent weeks in a space-like environment. [Credit: NASA/Chris Gunn]

The James Webb Space Telescope, the successor to the Hubble, has survived a gruelling 116-day test in conditions designed to mimic the vacuum and frigid temperatures it will encounter in space, 1.5 million kilometres from Earth.

The instrument was put through its paces in the thermal vacuum chamber at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The Webb will be the most powerful space telescope ever built. It is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency. The telescope is designed to take images of the first galaxies forming 13.5 billion years ago and to look through interstellar dust clouds to capture stars and planets forming in our own galaxy.

But it will have to operate in an extreme environment, with temperatures as low as  -233 degrees Celsius, or 40 degrees Kelvin. That is 127 degrees Celsius colder than any place on the Earth’s surface has ever been.

To create those conditions here, the NASA team used the massive thermal vacuum chamber, a 12-metre-tall and 8-metre-diameter cylindrical chamber that eliminates the tiniest trace of air with vacuum pumps and uses liquid nitrogen and even colder liquid helium to create the space-like temperatures.

"We complete these tests to make sure that when this telescope cools down, the four parts of the heart are still positioned meticulously so that when light enters the telescope we capture it the right way," said Paul Geithner, Webb's deputy project manger.

"The biggest stress for this telescope will be when it cools down. When the telescope structure goes from room temperature to its super cold operating temperature, it will see more stress from shrinkage than it will from violent vibration during launch."

NASA photographer Desiree Stover captured the photo of ISIM as it was lowered into the chamber for testing. The heart of the telescope weighs about as much as an elephant. Inside its black composite frame the four science instruments are tightly packed and are specially designed to capture specific information about distant light in the universe.

How Ebola shapes up against other deadly diseases

Click to expand

London-based data journalist David McCandless has come up with this graphic, comparing the deadliness of diseases and plotting them against the contagion risk. 

His contagiousness metric uses the average ‘basic reproduction number‘ – the number of additional cases generated by a single case of the disease – a statistical measure of how likely an infectious disease might spread through a population.

The graphic comes from McCandless' book Knowledge is Beautiful, the sequel to Information is Beautiful.

 

Predatory fish stocks have collapsed by two thirds

A dog-tooth tuna in water off the Maldives. Our preference for eating larger fish has caused populations to collapse. [Credit: iStock]

A dog-tooth tuna in water off the Maldives. Our preference for eating larger fish has caused populations to collapse. [Credit: iStock]

Predatory fish populations have collapsed by two thirds in the past century, thanks to our preference for eating larger species. That has encouraged fishermen to go after fish higher up the food chain, such as grouper, tuna, swordfish and sharks, a new study shows (pdf).

That is a potential disaster for the overall health of our oceans, as professor Villy Christensen, lead author of the research paper, told Scientific American.

“Predators are important for maintaining healthy ecosystems. Also, where we have had collapses of the larger fish, it has taken many decades for them to rebuild.”

Christensen and his team analysed more than 200 published food-web models from all over the world, which included more than 3,000 ocean species. Their results show that, not only had the biomass of predatory fish fallen by more than 60%, most of that decline had come since the 1970s.