In what’s turning into a public relations headache for the solar industry, news has emerged that a recent test of the 110-megawatt Crescent Dunes Solar Energy Project in Nevada resulted in some 130 birds catching fire, when they flew into an area of highly concentrated solar energy.
As KCET’s Rewire is reporting, the incident happened last month, but the news is only emerging now. According to Rudy Evenson, Deputy Chief of Communications for Nevada Bureau of Land Management in Reno, the birds were likely drawn to a glow created by the concentrated solar energy above the project’s sole tower.
As noted by E&E reporter Phil Taylor, plants like this one are a huge problem for birds. He describes the Ivanpah Solar Electric Generating System, a similar but larger plant in California’s Mojave Desert:
The 45-story “power towers” shine with sunlight reflected by 350,000 heliostat mirrors spread across an area four times the size of New York’s Central Park. Receivers atop the towers heat to nearly 1,000 degrees Fahrenheit, boiling water to turn turbines that crank out 392 megawatts — power for more than 100,000 houses.
This intense heat would incinerate any bird that flies within the “flux field” between the mirrors and the towers.
The smaller Crescent Dunes plant includes 17,500 heliostat mirrors that collect and focus the sun’s thermal energy to heat molten salt flowing through a 54o-foot (16 meter) tower.
Rewire describes the recent incident in Nevada:
According to Evenson, workers testing the plant moved approximately a third of the project’s ten thousand mirrors to focus sunlight on a point 1,200 feet above the ground, approximately twice the height of the power tower at Crescent Dunes.
The test started at 9:00 a.m. on January 14, Evenson told Rewire. By 10:30, biologists working on the site began noticing what have become known as “streamers,” trails of smoke and water vapor caused by birds entering the field of concentrated solar energy (a.k.a. “solar flux”) and igniting.
By the time the test ended for the day at 3:00 p.m., biologists had counted 130 such “streamers.” A subsequent test on January 15 reduced the number of mirrors aimed at the focal point above the tower, said Evenson, and that apparently ended the injuries to birds.
The ensuing mitigation procedures, which include repositioning the plant’s mirrors to reduce the intensity of solar flux, has allowed the subsequent testing of the plant, and with less risk to wildlife.
Looking ahead, and given the future potential of these concentrated arrays, the solar industry is going to have to tread very carefully. Killing or maiming most bird species, whether it’s deliberate or inadvertent, is illegal under the Migratory Bird Treaty Act.
A motorist in the Netherlands captured remarkable footage of a dove as it flies alongside vehicles at speeds reaching 60 miles per hour. Incredibly, this daredevil of a bird was able to fly with highway traffic for over 12 miles.
This video of a bird flying alongside vehicles on the A2 Amsterdam-Utrecht highway seems too good to be true, but it’s scientifically plausible.
The video identifies it as a pigeon, but it’s clearly not of your city-dwelling variety. It’s probably a homing pigeon, which can reach speeds of 50 mph or more, while flying for hundreds of miles. And in fact, homing pigeons are used in competitive pigeon racing. But given that there are about 310 species of pigeons and doves (the terms are often used interchangeably), it’s hard to know exactly what kind of pigeon this really is.
Either this bird is having one hell of a thrill ride, or it’s terribly confused about who its flock really is. Or it’s on bath salts. Regardless, this winged racer is our new hero.
Chinese legend tells of a great flood, and how Emperor Yu drove back the floodwaters, founding the Xia dynasty and giving rise to Chinese civilization. Now an international scientific collaboration has discovered the first geological evidence that such a flood may actually have happened—and the founding of the Xia dynasty may have happened hundreds of years later than historians previously thought. They describe their findings in a new paper inScience.
“Great floods occupy a central place in some of the world’s oldest stories,” theUniversity of Washington geologist David Montgomery wrote in an accompanying commentary on the new findings. “Emperor Yu’s flood now stands as another such story potentially rooted in geologic events…. How many other ancient stories of intriguing disasters might just have more than a grain of truth to them?”
There are different versions of the Great Flood myth, handed down through oral tradition for hundreds of years before finally being written down around 1000 BC. But all feature the heroic Yu, who figured out how to dredge and channel all the flooded rivers and tributaries to control the floodwaters—a task that purportedly took decades to accomplish, even with the help of a dragon to dig channels and a giant turtle to haul mud. (Myths have their fanciful elements.) This led to him becoming emperor and establishing the Xia dynasty in China.
Whether or not the Great Flood actually happened has been a longstanding bone of contention among scholars. After all, the historical record may have included the story of the flood and Emperor Yu’s role in driving back the waters as propaganda to justify imperial rule. History is written by the victors.This new geological discovery is the first real evidence for such a flood taking place.
In a press conference yesterday, lead author Wu Qinglong of Peking University in Beijing described the accidental discovery of unusual sediment in the Jishi Gorge of the Yellow River. He hypothesized that it might be linked with the great flood and the founding the Xi dynasty. It was Wu who brought together the members of the collaboration, hailing from different disciplines, to find evidence to bolster that hypothesis.
According to co-author Darryl Granger, a geologist at Purdue University, they found that evidence by mapping and dating the distinctive sediments deposited downstream from Jishi Gorge. They also examined bones from skeletons of children who died in an earthquake, found at the archaeological site of Lajia. Radiocarbon analysis of the skeletons gave a date of around 1922 BC.
From this, the collaborators were able to reconstruct a sequence of likely events occurring around this time along the Yellow River. First, there was a devastating earthquake that caused a massive landslide. This dammed the Yellow River in the Jishi Gorge, located right at the edge of the Tibetan plateau. According to Granger, quake-caused landslides are quite common to this area. The resulting lake eventually spilled over the top of the dam of debris, weakening it until it collapsed catastrophically, sending a deluge of water downriver and flooding the lowlands.
The houses of that period would have been more like caves dug into windblown sediment, according to co-author David Cohen, an archaeologist at National Taiwan University, which collapsed when the earthquake hit, killing the people inside.
“We know [the earthquake] happened the same year [as the flood] because fissures in the ground caused by the earthquake are filled with flood sediment, as are pottery jars [at the site,” said Granger. “So the people killed in the quake and the flood are intimately related.” Had it been more than a year, the annual rains would have kicked in, filling those fissures and jars with finer sediment.
The flooding would have significant enough to devastate the region. In theBook of Documents, Yu describes the flooding:
“The inundating waters seemed to assail the heavens, and in their extent embraced the hills and overtopped the great mounds, so that the people were bewildered and overwhelmed.
That’s in line with the Chinese collaboration’s estimates based on their mapping and analysis of sediment the site. Granger estimated that the flood waters may have risen 38 meters (around 124 feet) above the usual river level—about one-third the height of the Empire State Building, per Cohen—with flow rates between 300,000 to 500,000 cubic meters (79 million to 132 million gallons) of water per second. “That’s equivalent to the largest flood registered on the Amazon River, and the largest known flood on Earth in the last 10,000 years,” he said. The pile of debris that dammed the river would have been somewhere between the height of the Three Gorges Dam that spans the Yangtze River and the Hoover Dam in the US.
This timeline also coincides with a major cultural transition, as the late Neolithic Era gave way to the Early Bronze Age, although Cohen describes this as more of an interesting parallel, with no evidence as yet for direct causation. There is evidence that the system of smaller chiefdoms in place before that time suddenly collapsed, and after a transitional period, larger cities, with more complex administrative structures, a writing system, and bronze manufacturing emerged around 1900 BC.
In that sense, “The story of Yu taming the flood is the story of a new political order emerging out of the chaos of the flood,” said Cohen.
We frequently call the HiRISE camera on board the Mars Reconnaissance Orbiter “our favorite camera” and for good reason. HiRISE, the High Resolution Imaging Science Experiment, is the largest and most powerful camera ever flown on a planetary mission, sending back incredible beautiful, high-resolution images of Mars. While previous cameras on other Mars orbiters can identify objects about the size of a school bus, HiRISE brings it to human scale, imaging objects as small as 3 feet (1 meter) across.
The HiRISE team has just released more than 1,000 new observations of Mars for the Planetary Data System archive, showing a wide range of gullies, dunes, craters, geological layering and other features on the Red Planet. Take a look at some of the highlights (click on each image for higher resolution versions and more info):
Chloride and Paleo Dunes in Terra Sirenum. Credit: NASA/JPL/University of Arizona.
MRO orbits at about 300 km above the Martian surface. The width of a HiRISE image covers about about 6 km, with a 1.2 km strip of color in the center. The length of the images can be up to 37 km. If you click on each of these images here, or go to the HiRISE website, you can see the full images in all their glory. To fully appreciate the images, you can download the special HiView application, which allows you to see the images in various formats.
Dunes Within Arkhangelsky Crater. Credit: NASA/JPL/University of Arizona
HiRISE has been nicknamed “The People’s Camera“ because the team allows the public to choose specific targets for the camera to image. Check out theHiWISH page here if you’d like a certain spot on Mars imaged.
Crater Near Hydaspis Chaos. Credit: NASA/JPL/University of Arizona.
The lead image (the link to the image on the HiRISE site is here) shows a possible recurring slope lineae (RSL), mysterious dark streaks on slopes that appeared to ebb and flow over time. They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons. One possibility is this is evidence of liquid water present on Mars today. Some scientists said it could be a salty, briny liquid water flowing down the slopes.But a recent analysis says the RSLs show no mineralogical evidence for abundant liquid water or its by-products, and so it might be mechanisms other than the flow of water — such as the freeze and thaw of carbon dioxide frost — as being the major drivers of recent RSLs.
If you could hop in a time-traveling spacecraft, go back three billion years and land any place in our solar system, where would you want to end up? Earth, with its barren continents and unbreathable atmosphere? Or Mars, a chillier version its big brother? Wait, what about Venus?
Venus has a rep for being a toxic hellscape, but three billion years ago, it may have been the best piece of real estate our solar system had to offer—or at least, a close second to Earth. This hypothesis has been around for years, but it’s gaining traction thanks to climate models developed by researchers at NASA’s Goddard Institute for Space Studies and elsewhere.
Those models show that for two billion years, Venus could have had balmy, Earth-like temperatures and liquid water oceans, despite getting dosed with 40 percent more solar radiation than Earth is today. But it depends on whether the Venus of bygone days spun as slowly as modern Venus does.
“If Venus was spinning more rapidly, all bets are off, ” Michael Way, lead author of a new study that has been submitted for publication in Geophysical Research Letters told Gizmodo. But, under the right conditions, “you get temperatures almost like Earth. That’s remarkable.”
The habitability of Earth and Mars have changed throughout the lifetime of the solar system. Geologic evidence suggests that Mars was much wetter in the distant past, although whether the Red Planet had liquid water oceans or was frozen under a mantle of ice is still a matter of debate. Earth, meanwhile, has swung from hothouse to icehouse and back, all the while accumulating oxygen in its atmosphere and becoming a more favorable place for complex life.
But what about Venus? The past habitability of Earth’s nearest neighbor has received scant attention compared with that of Mars. Our bias may stem from the fact that modern day Venus is so forbidding, with its impenetrably thick atmosphere, toxic thunderclouds, and atmospheric pressure nearly 100 times higher than that of Earth. When a planet turns spacecraft after spacecraft into a puddle of goo within seconds, it’s only natural for people to get frustrated and turn their attention elsewhere.
Still, just because Venus is weird and awful today doesn’t mean it always was. The entire surface was reworked by volcanic activity some 700 million years ago, and we have no idea what Venus looked like before that. But measurements of the hydrogen isotope ratio in Venus’ atmosphere imply that the planet used to have much more water—maybe enough to support oceans.
Taking a first stab at the question of whether Venus was once habitable, Way and his colleagues combined a global topographic dataset collected by the Magellan spacecraft with water and solar radiation estimates for past Venus. All of this information was plugged into global climate models, similar to those used to study climate change on Earth today.
The initial results were encouraging. Despite the fact that ancient Venus would have received much more sunlight than modern Earth 2.9 billion years ago, Way’s models predict an average surface temperature of just 11 degrees Celsius (52 degrees Fahrenheit). By 715 million years ago, the surface would have only warmed up four degrees—meaning Venus could have had a temperate climate for at least 2 billion years.
There is, however, a catch: those numbers are entirely dependent on past Venus having similar topography and orbital characteristics to modern Venus. When Way re-ran his models but gave 2.9 billion year-old Venus a facelift to look like modern day Earth, surface temperatures rose considerably.
“We wanted to see what effect topography might have had on the climate state of this world,” Way said. “Sure enough, it had a big effect.” The reason, he says, probably has to do with changes in the amount of reflective surface on Venus, and shifting atmospheric dynamics.
Another fascinating twist has to do with Venus’ rotation. In his initial models of 2.9 billion year old Venus, Way stuck with a slow, modern-day rotational period of 243 Earth days. But when he spun Venus up to give it a 16 Earth-day period, the planet once again became a pressure cooker.
This has to do with the impact of Venus’ rotational rate on atmospheric circulation patterns called Hadley cells.
“Earth has many [circulation] cells because our planet rotates fast,” Way said. “But if you rotate slowly, you have one in the north and one in the south, period. That changes the atmospheric dynamics of the world by a significant amount.”
Specifically, slow-rotating Venus develops a gigantic cloud right at the sub-solar point, that is, where the sun’s rays are hitting the surface dead on. This basically turns the atmosphere of Venus into a giant solar reflector. When Venus rotates more quickly, this pattern doesn’t form.
While the study doesn’t actually confirm that Venus was once habitable, it does point to a plausible scenario in which Venus could have been. It’s worth noting that a planet’s rotation rate can change dramatically over time—Earth’s rotation is gradually slowing down because of the Moon—and some researchers suspect that Venus spun more quickly in the past. But there’s no easy way for us to find out. We could get indirect evidence by doing population studies on small, rocky exoplanets in Venus-like orbits.
And, if Venus was a balmy paradise for billions of years, one has to wonder what sort of apocalypse led to the present-day situation.
“We really need more data before we can say much more,” Way said. But, he added, the study does indicate that worlds in Venus-like orbits should not immediately be deemed uninhabitable.
“In plots of the habitable zone, you typically see Venus on the outside,” he said. “And for modern day Venus, that’s certainly true. But, if you have a Venus-like world around a solar-type star with a slow rotation, it could be quite a reasonable place for life to exist, especially in the oceans.”
A past-habitable Venus also opens up new possibilities about the origin of life on Earth. From meteorites, we know that Earth and Mars were swapping material in the distant past, prompting astrobiologists to wonder whether the Red Planet could have seeded our world with life. But if life was just as likely to emerge on Venus, that’s one more planet to add to mix. Incredibly, we don’t know whether there are any meteorites from Venus here on Earth, because we’ve never been able to analyze a rock on Venus for comparison.
Until then, we can’t deny the possibility that our distant ancestors were actually born on that torrid acid bath next door. “It could be that life got started on Venus, and then seeded Earth,” Way said. “Or vice-versa.”