Wednesday, June 28, 2017


Growing up in the '50s, I remember reading about the great promise of atomic energy. Nuclear reactors, we were told, would produce so much energy so efficiently that electricity would essentially be free--"too cheap to meter," as Lewis Strauss, Chairman of the United States Atomic Energy Commission, said in 1954.

As we know, reality didn't turn out to be quite so rosy. Between cost overruns and delays, opposition supercharged by the 1979 Three Mile Island meltdown, reliability issues, and the still-unsolved problem of what to do with nuclear waste, nuclear power came to be seen as far more problematic than promising. Currently, nuclear plants generate just 20 percent of all electric power in the US, and their share is gradually falling.

Solar power plant
License: CCO Public Domain

In the meantime, clean, renewable sources of energy--especially wind and solar--have been burgeoning. With renewables surging and nuclear flagging, it was inevitable that renewables would eventually win out. The only question was when.

That question has now been answered. According to the US Energy Information Administration, in March and April of this year renewable energy sources produced more energy for the US than nuclear plants--21.6 vs 20.34 percent in March and 22.98 vs 19.19 percent in April.

"Renewable energy is now surpassing nuclear power, a major milestone in the transformation of the US energy sector," says Tim Judson, Executive Director of the Nuclear Information and Resource Service.

And with solar energy growing by 38 percent and wind energy by 14 percent in the last year alone, this extremely positive trend has nowhere to go but up. I, for one, will be delighted when the only signs of out nuclear power misadventure are the silent silos of decommissioned plants.

Signpost memorializing the nuclear accident at Three Mile Island
Credit: The Baltimore Sun
With the cancellation of two planned reactors in South Carolina, just two new nuclear power plants are in the works in the US.  Nuclear energy can no longer compete with wind and solar. The end is in sight.

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Friday, June 23, 2017


A five-year study of 260,000 men and women in the UK found that bicycling to work every day reduced their risk of dying by more than 40 percent compared to commuters who drove or used public transport. In addition, the risk of developing cancer fell by 45 percent, and of being diagnosed with heart disease by 46 percent.

"This is really clear evidence that people who commute in an active way, particularly by cycling, were at lower risk," says Jason Gill, a physician-researcher at the University of Glasgow and corresponding author of the study.

New Yorkers bicycling to work
Credit: Streetfilms
Walking to work had a similar but smaller protective effect, probably because people who used bicycles for their commute exercised longer and more intensely than walkers. 

The powerful protective effect of active rather than passive commuting held up even when the researchers controlled for known risk factors such as smoking, weight and diet.

One benefit of bicycling to work, the researchers point out, is that unlike going to the gym or planned workouts, commuting becomes a no-willpower-needed habit. "You need to get to work every day, so if you build cycling into the day it essentially takes willpower out of the equation," says Gill.


You can read the original article, in BMJ, the British Medical Journal, here.

Sunday, June 18, 2017


Here's a quick quiz for you--match the names of the seven richest people in the world with their currrent net worth:

Jeff Bezos                                                      $89.3 billion

Warren Buffett                                               $84.1 billion

Larry Ellison                                                  $83.5 billion

Bill Gates                                                        $76.6 billion

Carlos Slim Helu                                             $64.8 billion

Amancio Ortega                                               $62.9 billion

Mark Zuckerberg                                              $55.5 billion

(Correct answer at bottom of this post)
Now, let's add up their net worth:                  $516.7 billion

What's interesting about that? It's considerably more than is owned by the least wealthy 50 percent of the people in the world, around 3.8 billion people.

World wealth distribution (2012)

It's hard for me to come up with a good reason why seven men should have more wealth (and the power that comes with it) than 3.8 billion people. Can you?


Current order from the top: Gates, Bezos, Ortega, Buffett, Helu Zuckerberg, Ellison.


Friday, June 16, 2017


Despite the best efforts of President Trump and EPA Administrator Scott Pruitt, the US continues to make progress in renewable energy generation. The national Energy Information Administration (EIA) reports that in March of this year 10 percent of all electricity generated in the US came from wind and solar--a first for the US.

San Gorgonio Pass windfarm
Riverside County, California
Credit: Nandaro

While the US is by no means the leader in the proportion of energy derived from renewable sources, we are adding a great deal of solar, wind and other renewable-energy infrastructure, so we can expect both the amount and percentage of clean, green energy to grow rapidly.

The fundamental reason for this is that large-scale wind and solar energy is now cheaper than electricity from fossil fuels. This is yet another situation where the slogan "follow the money" rings true, or, to put it another way, actual economics trumps Trumponomics.


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Monday, June 12, 2017


Jupiter may have formed at the dawn of the Solar System, and protected Earth

Scientists have been able to pin down the age of our Solar System by measuring the decay products of naturally radioactive materials incorporated into meteorites when they first formed. The oldest such inclusions date back 4.5682 billion years ago--a point in time often used as a marker for the birth of the Solar System.

Since the planets are thought to have formed as solid materials condensed from the primordial gas and dust making up the solar nebula or protoplanetary disc, and then gradually clumped together, the planets must all be younger than 4.5682 billion years. Planet formation is thought to have stopped within 10 million years or so, because by then the young Sun's solar wind had blown away most of the gas and dust needed for planet building.

The question is: just when did planets start to form and how long did it take?

A clever new analysis suggests that Jupiter, the largest and most massive planet in the solar system, formed surprisingly early and surprisingly fast--within the Solar System's first one million years. That's important because that early formation of Jupiter may have kept any planets larger than Earth--so called super-Earths--from forming in or migrating into the inner solar system.

Jupiter as captured by the Hubble Space Telescope in April, 2014, with an  
overlay of the giant planet's brilliant aurora in UV (Hubble, July 24, 2016)
Credit: NASA

The creative new approach to dating Jupiter's birth taken by Thomas Kruijer and colleagues at the Institute for Planetology at the University of Muenster was inspired by their realization that there are two related but different populations of meteorites orbiting the Sun (and occasionally falling to Earth where they can be studied). Like identical twins raised apart, the meteorites show strong similarities, yet differ because of their histories.

The researchers realized that the most likely explanation for those two families of meteorites was that as Jupiter formed it created a gravitational barrier that divided a primordial reservoir of gas and dust into inner and outer zones, within which the two different populations evolved.

"Our data showed that these meteorite populations did not mix for several million years," says Kruijer. "The only plausible way to explain this observation is that a gas giant planet, most likely Jupiter, acted as a barrier separating the two reservoirs."

They researchers focused on molybdenum and tungsten isotopes in samples from 19 iron meteorites. The meteorites' radioactive decay profiles placed them into two families known as carbonaceous (CC) and non-carbonaceous (NC) meteorites, and pointed to their formation at different times within two spatially separated reservoirs of the same primordial material. The isotopic signatures show that the NC meteorites formed early and in the outer reaches of the solar nebula while the CC meteorites formed somewhat later and closer to the Sun.

"Only in the last few years has it become clear that meteorites show some kind of dichotomy in their genetic heritage," says Kuijer. "This in part reflects the advances in analytical techniques that have been made, most notably in the precision of isotope analyses."

Iron meteorite (from Barrington Crater, Arizona)
Credit: Taty2007

The two families of meteorites appear to have become isolated from one another about a million years after the solar nebula first started to condense. The most likely cause of the separation, the authors believe, was the birth and growth of Jupiter. The model that best fits their analysis is one in which Jupiter's rocky core grew to 20 times the mass of the Earth by the time the solar nebula was a million years old. That mass was sufficient to split the protoplanetary disc into inner and outer parts.

Protoplanetary disc around the star TW Hydrae
showing a gap caused by a forming planet
Credit: Hubble Space Telescope, NASA/ESA

"Our study is the first to show that Jupiter can actually be dated by establishing when these reservoirs formed and for how long they survived," says Kuijer. "Our results show how the solid interior core of Jupiter formed very rapidly, within only about one million years after the start of solar history, making it the oldest planet in the Solar System," says Kuijer.

Their models indicate that Jupiter's core continued to grow for another few million years, followed by the accretion of the giant planet's dense atmosphere. Jupiter currently weighs in at 317.8 Earths.

If Kruijer and his colleagues are right, Jupiter is not only the biggest and most massive planet in our solar system, it's also the first and oldest.

In addition, they think, we may owe Jove thanks for keeping conditions closer to the sun just right for a planet like Earth rather than for a much larger and probably uninhabitable super-Earth.

"If a super-Earth had formed in the inner Solar System, then the evolution of the terrestrial planet region would have looked completely differently" Kuijer says. "This would have happened long before the Earth formed. I don't think that there would be sufficient material left at Earth's current orbit to subsequently still build an Earth-like body. Possibly, ice giants like Uranus or Neptune would have made it all the way to the inner solar system. In this light, Jupiter's early formation might have been a pre-requisite for building a planet like Earth."


You can find the June 12, 2017 PNAS article, "Age of Jupiter inferred from the distinct genetics and formation times of meteorites," by Thomas Kuijer,  Christoph Burkhardt, Gerrit Budde and Thorsten Kleine, here.


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Wednesday, June 07, 2017


Although symptoms of autism don't usually appear until a child's second year, and most autistic children aren't diagnosed until they are three or older, recent research shows that the brains of 6-month-old infants who will go on to develop autism already differ from those of normal infants.

These findings may lead to earlier diagnosis and more effective treatment for children who are at risk of developing autism.

They also provide more evidence, if that's still needed, that autism is not caused by childhood vaccinations. As Robert Emerson, the study's lead author points out, "If these differences are already present at six months of age, they would represent a biological foundation for autism that is in place before several vaccines on the CDC schedule that are administered after six months of age, including the Measles, Mumps, Rubella (MMR) inoculation, which is typically given at one year."

A child showing autistic symptoms

Emerson and colleagues at the University of North Carolina at Chapel Hill used functional magnetic resonance imaging (fMRI) while children slept to track brain size, growth and connectivity in 59 infants who were at high risk for autism because they had autistic older siblings. Twenty percent of them could be expected to develop autism, compared to 1.5 percent of children without autistic siblings.

They found a variety of differences between the brains of infants who went on to develop autism and those who didn't.

In keeping with earlier research, those infants who eventually showed autistic symptoms had a faster rate of growth in brain volume and brain surface area between six months and two years of age

The researchers then used advanced artificial intelligence techniques to differentiate between the brains of those infants who did or did not develop autism. Machine-learning programs trained themselves on the brain scans, and were eventually able to identify correctly 82 percent of the children--9 of 11--who would become autistic and 100 percent of those who developed normally.

This very high rate of discrimination was based on nearly 1000 "functional correlations"--how separate regions of the brain connect and work together--that differed between infants who were on autistic versus normal developmental paths.

Schematics representing brain scan signatures at six months that predicted later autism diagnosis in infants. Red bars indicate weaker connections in autistic infant brains, blue bars stronger connections.
[Credit: R.W. Emerson et al., Science Translational Medicine (2017)]

The authors caution that these are preliminary results using state-of-the-art technology, so further research and the development of simpler and less expensive brain-scanning techniques are needed before they can be applied clinically. 

"If future studies confirm these results, detecting brain differences may enable physicians to diagnose and treat autism earlier than they do today," says Diana Bianchi, M.D., Director or the National Institute of Child Health and Development (NICHD).

According to the Centers for Disease Control (CDC), one child out of every 68 in the US will be diagnosed with autism. The earlier that those children can be correctly diagnosed and start to receive treatment--while the brain is most malleable--the better their outcomes.

You can find a summary of an earlier Nature article about this research here, and a link to the abstract of the current study, in Science Translational Medicine, at this URL.


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For the past 20 years, researchers have believed that Homo sapiens--humans like us--appeared somewhere in the heart of Africa around 200,000 years ago and gradually spread from there into Eurasia and later to the rest of the world.

New discoveries from Jebel Irhoud, a mountainous site 100 km (62 miles) west of Marrakesh, Morocco, may require a rewrite of the textbooks.

300,000-year-old Homo Sapiens from Jebel Irhoud
composite reconstruction
Credit: Philipp Gunz, MPI EVA Leipzig

An international team of paleoanthropologists uncovered and studied fossilized remains of five individuals who lived there around 300,000 years ago and whose mixture of advanced and more primitive features places them, according to lead author Jean-Jacques Hublin, ". . . at the very root of our species, the oldest members of our species ever found in Africa or anywhere."

The Jebel Irhoud bones are the oldest securely dated fossils of our own species, pushing the origin of our species back a full 100,000 years.

Finding full-fledged Homo sapiens living so long ago and so far north in Africa leaves the location where our species emerged up for grabs. Eastern, sub-Saharan Africa, where 200,000-year-old human fossils have been found, remains a likely possibility, but now not the only one.

Hublin and colleagues now think that the early evolution of Homo sapiens may have taken place in a widely dispersed population. They point out that there were repeated periods when what is now the Sahara desert was open savanna with scattered trees, lakes and rivers. During those wetter epochs, early human groups could have interacted, interbred and evolved. "Long before the out-of-Africa dispersal of Homo sapiens, there was dispersal within Africa," says Hublin.

"The green Sahara happened several times," Hublin says. "During those periods, there could be exchanges of innovations, and also of genes.  Any favorable mutation would spread. There was no one Garden of Eden in Africa. If there is a Garden of Eden, it's all of Africa--the Garden of Eden is the size of Africa."

Hublin and his colleagues found the Jebel Irhoud fossils along with flaked-stone tools and the remains of game animals in "a pocket of reddish sediments" preserving what once was the floor of a cave on the flank of a mountain. The bones--skulls, teeth and long bones--come from at least five individuals; three adults, an adolescent and a child of 7 or 8. According to the researchers, they show a kaleidoscopic mixture of ancient and modern features, but with enough typical Homo sapiens characteristics to make them the earliest known representatives of our species.

"They contained a surprising combination of very advanced features, especially the face and the dentition, and more archaic features such as the shape of the brain case and the brain," says Hublin. "Their faces are the faces of people you could cross in the street today."

The human fossils were found in the same layers as the bones of animals they hunted, including gazelles, zebras and wildebeest, along with charcoal, and flaked stone tools typical of the Middle Stone Age.

Shannon McPherron, an expert on ancient tool use, emphasizes these early ancestors' control and use of fire, and the craft they brought to toolmaking. "The flint they used came from 25 kilometers away," he says. "They sought out high-quality raw-material locations, collected the flint, carried it around with them, and at this site, re-tooled it for their weaponry."

Some of the 300,000-year-old flint artefacts
found at Jebel Irhoud
Credit: Richter, et al.,

It was the flint tools, many of which had been burned, that allowed accurate dating of the site using thermoluminescence dating (TL). TL allows scientists to date materials that have once been heated by measuring the amount of radiation they have been exposed to since that time. McPherron found a range from 280,000 to 350,000 years ago. "The average TL ages all point towards 300,000," he says, "so 300,000 is the best estimate for the fossils and for the middle stone age artefacts. Things are all falling together around this age."

When asked why he believes that the fossils represent true members of Homo Sapiens, given their mixture of typical and more archaic traits, Hublin explains that evolution happens trait by trait and over time. He also differentiates between our entire species, which has evolved over time, and fully modern humans, who represent just the current cohort of Homo sapiens.

"There's no reason why representatives of our species living 300,000 years ago would be just like us," he explains. "We are not saying that these are modern humans—people having our morphology.  We prefer to use the term Homo sapiens for the whole lineage leading to us, but not necessarily looking like us."

The bottom line according to Hublin and his colleagues is that our clan, Homo sapiens, has roots--albeit still in Africa--that are much deeper in time and far more widespread than anyone thought until now.


An online version of the June 8 Nature paper can be found at:

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Monday, June 05, 2017


In 1865, American author and editor Horace Greeley cribbed an earlier journalist's phrase and famously wrote, "Go West, young man . . . go West and grow up with the country."

The same advice could certainly be given today with respect not to the long-closed American Frontier, but to the worldwide, opportunity-filled frontier of renewable energy--energy from the wind, the sun, the tides and other natural, non-polluting sources.

Workers prepare to hoist the blades of a giant wind turbine
Credit: National Wind Technology Center/

In the first three months of 2017, a new wind turbine was commissioned every 2.4 hours somewhere in the US. Not surprisingly, that kind of growth requires lots of workers. The US wind industry employed 51,000 people in 2013 and doubled to 102,000 just three years later. Writing in Inside Climate News, journalist Paul Horn notes that just the growth in wind-industry employment in those three years equals the total employment in the US coal industry.

Solar energy is another area enjoying explosive employment growth--17 times the national employment growth rate, according to the same source. Solar energy now employs more than 260,000 people in the US, up 82 percent over the past three years.

According to the Environmental and Energy Study Institute, the US renewable energy sector as a whole employed nearly 3.4 million workers at the end of 2016. That's more than all the jobs in the entire fossil-fuel sector, and is grew an astonishing 18 percent between 2015 and 2016.

And all those jobs are producing remarkable results. The US Department of Energy reports that just under 20% of US electricity came from renewables in 2016, pretty much wiping out all predictions.

To borrow a term popularized by Newt Gingrich, it's pathetic to compare renewable energy to the moribund coal industry that President Trump promises to resuscitate. In the US, coal has shed 60,000 jobs over the last five years. (However, and kudos to Trump, it will gain 70 to 100 jobs when the Acosta Coal Mine, in Pennsylvania, opens on June 8. So revise that to minus 59,900.

Business Insider points out that the growth in clean energy in the US is part of a worldwide explosion in renewable energy, a tidal wave of change that now seems inevitable now that the cost of clean renewable energy has fallen below that of polluting, climate-threatening fossil fuels. Even with President Trump and EPA head Pruitt trying to return the US to the carboniferous era, the economics will win out.

Business Insider quotes Liz Delaney, Program Director at EDF Climate Corps, who concludes:

"Our findings would lead us to believe that the right place to invest dollars are in renewable energy rather than fossil fuels," Delaney says. "These jobs are widely geographically distributed, they're high paying, they apply to both manufacturing and professional workers, and there are a lot of them."


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Friday, June 02, 2017


Burning coal is a dirty business.  A new study makes it clear just how dirty it is, and how many lives could be saved by generating our electricity from the sun instead.

Coal-fired power plant
(CC0 Public Domain)

In research published in the peer-reviewed journal Renewable and Sustainable Energy Reviews, materials engineer Joshua Pearce and energy policy specialist Emily Prehoda quantify the number of American lives lost every year from respiratory, cardiac and other illnesses caused by pollution from burning coal. It turns out to be a shocking 52,000 lives. That's more than the number killed in car crashes (about 35,000 in recent years) and by firearms (around 12,000 per year) combined.

Pearce and Prehoda arrived at their estimate by comparing coal burning and mortality rates geographically. They found a strong correlation between rates of illness and death and proximity to coal-fired electrical plants. On average, they calculated, there's one additional death from the production of 25 million kilowatt-hours of electricity from coal. Across the US, that means that 52,000 people die every year from coal-caused air pollution.

The researchers point out that with current off-the-shelf technologies, we could generate all the electricity we need from the sun. They also examine the potential health risks from manufacturing and transporting solar panels. These turn out to be a minute fraction of the risks from coal.

It's of course true that replacing all the electricity currently generated by burning coal with solar energy would be a costly investment--about $1,000,000 for every life saved.

However, the authors point out, that doesn't count the economic value of the electricity generated. In many regions, solar energy is already cheaper than electricity from coal or other fossil fuels, and the price of solar energy is continuing to fall rapidly. (Note: wind power is even cheaper). When the monetary savings from generating our power from solar rather than coal are factored in, in most cases switching to solar saves money as well as lives.

"Unlike other public health investments, you get more than lives saved," says Pearce. "In addition to saving lives, solar is producing electricity, which has economic value."

The bottom line--the sooner and faster we make the transition from coal and other fossil fuels to solar and other renewable energy sources the better, for our health, our lives, and our pocketbooks.


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Thursday, June 01, 2017


Macron invites American scientists, engineers and entrepreneurs concerned about climate change to "come and work with us."

The youthful and forward-looking President of France, Emmanuel Macron, hit the nail on the head with his comments in response to President Trump's decision to pull the US out of the Paris Agreement on climate.

French President Emmanuel Macron
Credit: Wikimedia Commons

“To all scientists, engineers, entrepreneurs, responsible citizens who were disappointed by the decision of the president of the United States, I want to say that they will find in France a second homeland,” he said. “I call on them: come and work here with us. To work together on concrete solutions for our climate, our environment. I can assure you, France will not give up the fight.”
. . .

"We will succeed because we are fully committed," he said. "Because wherever we live, whoever we are, we all share the same responsibility. Make our planet great again!"

You can see Macron's comments on YouTube (in English) here.


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I just watched the White House Rose Garden presentation in which Trump pulled the United States out of the Paris Accord.

Trump cast the withdrawal from the long-sought and almost universally applauded international climate agreement as saving the United States, its economy and its workers from an unfair, costly, "draconian" and "onerous" compact that would give away our money, our sovereignty and our potential for economic growth to greedy foreign countries that consistently out-bargain us, exploit us and laugh at us at the same time.

"We want fair treatment," Trump declared. "We don't want other countries and their leaders laughing at us, and they won't be." 

A lot of people may be crying over the repercussions of this decision, now and far into the future. But way to go, Mr. President; nobody is laughing.*

Trump withdraws US from Paris Accord, 6/1/17
Credit: UPI

*Except perhaps Steve BannonScott Pruitt and Vladimir Putin.

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Researchers at LIGO, the Laser Interferometry Gravitational-Wave Observatory, announced today their third detection of space-time vibrations from the collision of of a pair of black holes, in this case nearly three billion light-years from Earth.

In terms of mass, this new black hole merger--which created a black hole with a mass 49 times heavier than our Sun--fell neatly between the two earlier detections, in September and December of 2015. Those two cosmic crashes resulted in black holes with 62 and 21 times the Sun's mass respectively, and took place much closer to Earth.

The current crash was between black holes with estimated masses of 31.2 and 19.4  times that of the Sun. That means that a mass equal to two Suns was converted into gravitational waves in a fraction of a second as the two black holes completed their death spiral.

Simulated black-hole merger
Credit: LIGO Lab Caltech

This third detection tells the scientists that the unique new window on the cosmos provided by gravitational-wave detectors is now wide open. With improved sensitivity of LIGO's existing laser interferometers and the addition later this year of a third detector, called Virgo, the researchers hope to be able to detect black hole mergers and other space-time-shaking events on a daily basis.

Aerial view of the Virgo interferometer near Pisa, Italy
Credit: The Virgo Consortium

Besides further proof of the existence of black holes in this mass range, the detection allowed researchers to test one of the predictions of Einstein's General Relativity--that gravitational waves travel through space at the same speed regardless of their frequency. Once again, General Relativity passed the test.

“It is remarkable that humans can put together a story, and test it, for such strange and extreme events that took place billions of years ago and billions of light-years distant from us," says MIT's David Shoemaker, LIGO's spokesperson.

The number of black holes in this mass range raises the intriguing possibility that they may at least partly explain dark matter, which is known to exist because of its gravitational effects on galaxies and galaxy clusters, but whose nature remains mysterious.

"There's this intriguing indication that with the size of black holes, 10-100 solar masses, in about the quantity that we see them or expect to see them, might account for dark matter," says LIGO researcher Mike Landry. "It's not impossible."

For the first time, researchers were able to suss out information about how the black holes were spinning before they collided. It's more likely than not that the black holes were not spinning in the same plane as their orbit. That, in turn, implies that they may have formed far apart and only later fell into each other's gravitational thrall.

As gravitational-wave astronomers detect more of these incredibly powerful cosmic events, and gain the ability to match them with observations using visible light, infrared, X-rays and gamma rays, astrophysicists, nuclear physicists and cosmologists all expect exciting new findings that will cast light on black holes, neutron stars, dark matter and the nature of space-time itself.

The new findings appear in this week's edition of Physical Review Letters.

You can view some great video simulations at LIGO's YouTube channel.

You can become a citizen scientist helping to sift actual gravitational-wave signals from the noise by participating in GravitySpy or Einstein@Home.

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