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The Best Science Photos of the Week

The Best Science Photos of the Week

From Live Science Staff | December 19, 2015 08:43am ET

Each week we find the most interesting and informative articles we can and along the way we uncover amazing  and cool images. Here you'll discover 10 incredible photos and the stories behind them.

Too cute?

A new study shows pandas are more likely to mate when they are able to choose their own mates. While this may not be love as humans understand it, some type of attraction is present.

There's a secret to making panda babies, and it looks a little bit like love.

Pandas are more likely to produce young when they have a preference for the partner they're meant to mate with, a new study finds. If "love" is too strong a word for this preference, it's safe to say that panda lust, at least, plays a role in reproductive success.

In a new study published Tuesday (Dec. 15) in the journal Nature Communications, researchers allowed pandas to pick their own matesby letting them observe a pair of opposite-sex bears through barriers in a special enclosure. Bears showed their romantic interest by making chirping noises and scent-marking near their preferred partner.

This freedom of choice turned out to have a major effect on the likelihood of pandas reproducing. Overall, mutual attraction raised the rates of successful mating and cub-rearing from around zero percent when the two bears weren't interested in one another to 75 percent when they were both attracted.

Data broken down by gender illustrates the effect. When a female was paired for mating purposes with a male she preferred, the pair had successful sex 70 percent of the time, compared with only about 30 percent of the time when fertile females were placed with a male they weren't interested in. Females gave birth to a cub 90 percent of the time when a preferred male was the father versus 40 percent of the time when they mated with a non-preferred male. And 100 percent of pandas who copulated with a preferred male cared for their offspring, a number that dropped to 80 percent in pandas whose offspring were fathered by unappealing mates.

Male choice mattered, too — a surprising finding, given that females that do all the gestation and rearing are generally thought to be pickier than males who invest less of themselves. But panda males invest considerable time and energy in wooing females in the wild and fending off rival males, researcher Meghan Martin-Wintle of the Institute forConservation Research, San Diego Zoo Global and PDXWildlife in Portland and her colleagues wrote. Thus, they have to be choosy about which female pandas they pursue.

When males got busy with a preferred female, they completed the sex act more than 70 percent of the time, compared with only about 30 percent of the time when mating with an unappealing female. Mating resulted in cubs almost 80 percent of the time when males picked a female they liked, but only 60 percent of the time when they had to mate with a non-preferred partner. And panda moms seemed influenced by whether the male had seen them as a good match: When males mated with a preferred partner, that female reared her cub more than 90 percent of the time. When the male fathered a cub with a female he didn't prefer, the likelihood of maternal care dropped to less than 70 percent.

Overall, the researchers found, mutual attraction can improve panda reproduction. Giving pandas free reign over their mate choices, however, may be tougher than it sounds. Conservation breeders have to be careful to ensure genetic variability in endangered species like pandas, which are few in number. But if breeders were to pre-screen bears for genetic diversity and then check in on how the pandas respond to one another, that would allow for "the best of both worlds," Martin-Wintle and her colleagues wrote.

The research was conducted at the Bifengxia Chinese Conservation and Research Center for the Giant Panda in Sichuan, China. China is working to reintroduce pandas into the wild, a goal that will require breeding more pandas than in the past. To meet this goal, the researchers wrote, biologists will need a better of understanding of how pandas reproduce on their own in the wild.

Red rainbow:

New research indicates rainbows come in up to 12 different forms. Rainbows are significantly affected by the drops of water that create them as well as where the sun is when they are created; they can appear as twin, triplet or even quadruplet and change by the second.

 Why are there so many songs about rainbows?

Perhaps because there are so many different types, each with its own distinctive features, new research suggests.

There are 12 types of rainbows, distinguished by various characteristics, the study suggests. Fat droplets of water or tiny sprays of mist will affect them, along with the angle of the sun. Rainbows can even appear astwins, triplets or quadruplets, Jean Ricard, a researcher at the National Meteorological Research Center, in France, said here yesterday (Dec. 17) at the annual meeting of the American Geophysical Union.

And even a single rainbow is always changing, he said.

"They don't look alike because when we look at a rainbow, one second later, the drops which form the primary bow and the secondary bow are not the same, because they are falling," Ricard said here in a news briefing. "If you look carefully after a few minutes you will start to see some changes in each rainbow." 

Classification scheme

Scientists have understood the basics of rainbow formation since at least Descartes' time: Sunlight interacts with water droplets in the sky, and the light is both reflected and refracted as it enters and leaves the raindrop. Because different wavelengths of light — which correspond to different colors — slow down by different speeds when they hit a raindrop, the different colors get bent at different angles, separating into the rainbow's distinctive hues. (The bizarre phenomenon known as a fire rainbow is neither a fire nor a rainbow, because it occurs when light refracts through ice crystals, not raindrops.)

In the past scientists tried to classify rainbows based on the colors in the rainbows, or the size of the droplets they refracted through. But those classifications often missed certain types of rainbows.

A double rainbow appeared in the summer sky above Toulouse following an afternoon storm.
Credit: CNRM
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To capture all the myriad "flavors" of rainbows, Ricard and his colleagues tried to figure out the minimum set of characteristics that would describe all rainbows. It turns out that rainbows can have up to four characteristics . There is the primary bow, with red on top and blue-violent on the bottom. Above that, secondary reflections inside a rain droplet always form a secondary, fainter bow above the primary bow, with the colors reversed. Between the two is a dark region, called Alexander's band, where little light from the raindrops light reflects. And sometimes, there are additional bows, called supernumerary bows, which may occur when the light rays spread and cancel each other out via diffraction and interference in the atmosphere.

Types of rainbows

Based on those characteristics, they determined there are 12 different types of rainbows, with imaginative names like RB_1, RB2, etc. The rainbows vary by whether all colors are visible, whether they have a strong Alexander's band, and whether there are supernumerary bows. Some of the more striking rainbows include only red arcs, and then there are yellow-and-orange rainbows.

When Ricard and his colleagues analyzed the physics, they found that the height of the sun in the sky was the biggest single factor affecting the rainbow's appearance. For instance, when the sun is very low in the sky, such as at sunset, light is much less intense and must travel much farther to reach the eye. Only the red wavelengths are able to make it through the atmosphere at this time, he said

"At sunset or sunrise, the color of the sun and the intensity of the incoming light changes dramatically," Ricard said.

The size of the droplet also affected a rainbow's appearance, though to a lesser degree. Wider drops make for less vivid rainbows with more widely spaced hues, he said.

While rainbow research may seem more suited to daydreamers and poets, it may have practical applications, Ricard said. For instance, if scientists can spy rainbows on exoplanets, that may be a sign of atmospheric water. And where there's water, there's often life.

Cosmic lightsaber:
NASA's Hubble Space Telescope captured this image of a new star and the jets it created, reminiscent of a lightsaber from Star Wars.

A powerful lightsaber slices through the dark clouds of dust and gas that surround it. It's not a scene from the new "Star Wars" movie but an image captured by NASA's Hubble Space Telescope.

Formed by material falling onto a newborn star, the two beams of light shoot outward from their star at supersonic speeds to create the two jets that look like the double-sided lightsaber wielded by Darth Maul in "Star Wars: Episode I – The Phantom Menace."

Collapsing clouds of dust and gas create new stars as they fall inward. Cloaked by dust and gas, the protostar grows massive enough to harness its power and begin the fusion process. In some cases, the material streaming onto the young star erupts into fiery jets that burst from the stellar poles. [Video of the Celestial 'Double-Bladed Lightsaber' Seen By Hubble]

Headbanging bee:

One species of blue-banded bee from Australia uses a unique action to gather pollen: it bangs its head against the flower at up to 350 times per second.

Australia's blue-banded bee is a successful pollinator because it uses its head — literally, scientists have found.

The smallest species of penguin on Earth donned video cameras allowing researchers to capture their hunting secrets on video. The scientists wanted to understand why these penguins hunt in groups and how it affected the outcome of the trips.

Wearing video cameras, the world's smallest penguins have revealed their hunting secrets: The little blue-hued birds swim together to stalk groups of prey, but when it comes to catching and killing their meals, it's every penguin for itself.

The aptly named little penguin (Eudyptula minor) is the smallest living species of penguin, growing to an average of 13 inches (33 centimeters) high and 17 inches (43 cm) long.

Previous research suggested that little penguins spent ample amounts of time swimming together when hunting food. Researchers wanted to learn more about why these birds formed groups when foraging, such as whether doing so gives them a better chance at capturing anchovies, krill, jellyfish and other prey.  

Enormous plesiosaur:

In Patagonia the skeleton of what is likely to be a new species of marine reptile was uncovered and is being cleaned and examined. With grapefruit-sized vertebra, the creature lived in the waters that covered the area 65 million years ago.

Grapefruit-size vertebra and robust rib bones come into view in irregular chunks of sandstone as paleontologist Fernando Novas uses a hammer and chisel to chip away at what may be one of the largest and most complete skeletons of a long-necked marine reptile called a plesiosaur.

The beast would've swum using enormous flippers in the waters, covering what is now Patagonia, some 65 million years ago, Novas and his colleagues have found.

Paleontologists are still carefully removing the hard sandstone surrounding the plesiosaur's skeleton, but they expect the newfound marine reptile will be a previously unknown genus and species, said project leader Novas, a paleontologist at the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires, Argentina.

Brightening up the clouds:

Recently released data indicates that reducing air pollution may actually be intensifying global warming. Events ranging from reducing sulfuremissions to naturally occurring sunspots change the amount of sunlight reaching Earth's surface, reducing the amount of warming. More pollution actually reduces sunlight by producing clouds that reflect more light back into space.

 It may seem counterintuitive, but cleaner air could actually be exacerbating global warming trends.

The soot and other particles that make up air pollution tend to scatter light back out into space. As countries around the globe have cleaned up their act, there are fewer particles to reflect light, meaning more sunlight is reaching the Earth's surface and warming it, Martin Wild, a researcher at ETH Zurich in Switzerland, said Tuesday (Dec. 15) here at the annual meeting of the American Geophysical Union.

That's not to say people can blame global warming on the clearer skies — the underlying cause of climate change is excess carbon emissions into the atmosphere. But air pollution may have counteracted some of that warming caused by excess carbon in the atmosphere, Wild said. 

Glorious Greenland:

Using historic aerial photos of the Greenland Ice Sheet, scientists have calculated ice lost over the 20th century as well as how the melt contributed to sea level rise. They hope to use the data to better calculate and plan for future sea rise.

A picture is worth a thousand words, or, in the case of the Greenland Ice Sheet, maybe a thousand scientific measurements.

A group of scientists has used a trove of historic aerial photos of the periphery of the ice sheet to estimate how much ice it lost over the course of the 20th century, before detailed satellite observations became available. From that number, they have calculated Greenland’scontribution to sea level rise over that time, which they estimate to be about 10 to 17 percent of the total global sea level rise of about 1 foot since 1900.

This picture of the ice sheet’s past behavior, presented here at the annual meeting of the American Geophysical Union and detailed in the Dec. 16 issue of the journal Nature, could help give researchers a better handle on how it might react to further future warming, improving models of ice melt and sea level rise.

Before and after in Nepal:

The Gorkha earthquake that shook Nepal in April of 2015 was surprisingly gentle, compared to the damage it could have inflicted, according to experts. Researchers believe the fault holds enough energy to rupture again and move up to 50 feet of motion; the April tremblor resulted in a shift of about 10 feet.
The terrifying magnitude-7.8 Gorkha earthquake that rattled Nepal in April is nothing compared to the temblors scientists predict could happen in the future.

The shaking observed was "unusually gentle" given the magnitude of the earthquake, leading to far fewer landslides and glacial lake overflows than could have been seen, researchers said here today (Dec. 16) at the annual meeting of the American Geophysical Union.

"The situation could have been far, far worse," said Jeffrey Kargel, who was a co-author on one of two related papers published today in the journal Science and presented at the meeting. He and other scientists aren't sure exactly why the quake didn't wreak more havoc, but another temblor, even of similar magnitude, to hit the area may not be so forgiving, the researchers said.

And past seismological assessments suggest the fault that ruptured still has energy equaling about 33 to 50 feet (10 to 15 meters) of motion that must be released, which could lead to even bigger earthquakes. The April 25 earthquake caused the fault at the boundary of the Indian and Asian plates to shift about 10 feet (3 m), according to the U.S. Geological Survey.

Surprisingly gentle

The April 25 Gorkha earthquake uplifted low-lying regions nearby and caused the highest reaches of the Himalayas, such as Mount Everest, to shrink.

All told, the temblor triggered a total of 4,312 landslides. One of the most catastrophic of those leveled a village in the Langtang Valley, killing about 350 people.

During that landslide, huge chunks of snow and ice sitting on the steep hillsides above the valley ripped off, free-falling for about 1,640 feet (500 m) before obliterating the town of Langtang below.

"The energy involved was roughly half that of the Hiroshima nuclear explosion, or more," Kargel said in a news briefing.

The air blast alone blew away large swaths of the village, including sturdy stone hotels, he said. In an area of hillsides stretching about a 0.6 miles (1 kilometer) around the landslide, the air blast snapped trees like matchsticks.

And yet, it could have been much, much worse. That landslide was actually a relatively small one compared with those seen in other catastrophic earthquakes. While most of the landslides originated at the ridge tops, some also arose in the low-lying sediments in flat valley bottoms, which is unusual (most originate on steep slopes), and some were triggered in the weeks after the earthquake, said Dan Shugar, a geohazard researcher at the University of Washington Tacoma, who is an author on the first Science paper.

Glacial lakes held strong as well. Despite many filled-to-the-brim, precariously perched glacial lakes that seemed poised to inundate nearby villages with the slightest jolt, most did not overtop their basins, the researchers said.

It's not clear why the quake didn't cause more damage, but it could be that it shook unusually strong rocks in the region, or that its location somehow mitigated the damage, the researchers speculated.

Historic tribulations

The rocks in the region revealed that in the medieval period, multiple massive quakes reshaped the landscape in much more dramatic ways. [The 10 Biggest Earthquakes in History]

For instance, Nepal's second biggest city, Pokhara, was built on the debris from landslides after three large quakes shook the central Himalayas between A.D. 1100 and A.D. 1344. Most of the landslide rubble Pokhara was built on came from Annapurna Massif, about 9,800 feet (3,000 m) above the city, said Oliver Korup, a geohazard researcher at the University of Potsdam in Germany, who was an author on the second Science paper.

In addition, much of this massive landslide rock didn't come from the nearby mountains but instead traveled from as far as 38 miles (60 km) away — likely the result of flooded lakes that carried huge amounts of rock with the deluge, Korup said.

"The material has really buried many of these river valleys beneath tens of meters of sediments," Korup said.

For instance, the rock fill lying below Pokhara would be enough to cover downtown San Francisco in 164 feet (50 m) of sediment, he added.

Though scientists are still piecing together the confusing story told in rocks and faults in the region, the historic earthquakes were about a magnitude 8.0 or greater. By contrast, the Gorkha earthquake was a "mere" magnitude 7.8, while the largest of the aftershocks was a magnitude 7.3.

Watery art:

The Suomi NPP weather satellite caught this image of a phytoplankton bloom in the North Atlantic Ocean in September of 2015. Little is known about these fall blooms because weather in the Autumn months prevents research ships from going into the area.

It may look like a painting by Vincent van Gogh, but this mass of swirling colors is really a satellite image depicting a huge bloom of phytoplankton, or microscopic marine plant life, in the waters of the North Atlantic Ocean.

NASA acquired the image on Sept. 23 using its Suomi NPP weather satellite. The spacecraft is equipped with a special  imaging tool known as the Visible Infrared Imaging Radiometer Suite (VIIRS), which collects visible and infrared imagery.

To create this artful picture, NASA combined data from the red, green and blue infrared bands of VIIRS with additional data about the levels ofchlorophyll (green pigments found in algae and plants) present in the North Atlantic Ocean. Like terrestrial plants, phytoplankton contain light-absorbing chlorophyll and need sunlight to live and grow.

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