Amazing Science

A global temperature rise of 1.5℃ above pre-industrial levels could have devastating consequences for city dwellers.

Deadly heat stress is projected to affect hundreds of millions more people each year under relatively little additional climate warming. The Paris Agreement commits the international community to limit global warming to no more than 2℃ above pre-industrial (late 19th century) air temperatures, with an aspirational target of 1.5℃. In our latest research, which looked at the impact of global temperature rises on megacities, we foundthat even if 1.5℃ is achieved, large increases in the frequency of deadly heat are expected. By 2050 about 350m more people living in megacities could be exposed to deadly heat each year.

Humans become “heat stressed” when the body absorbs more heat than is tolerable. If core body temperature rises just a few degrees above 37℃, deadly heatstroke can result. By using its cooling system – sweating – the human body can maintain a safe temperature even if air temperatures rise above 37℃. This mechanism works better in a drier atmosphere (which is why steam rooms feel hotter than saunas – even at the same air temperature). The heat index is a measure that combines this humidity effect with air temperature to provide a “feels like” temperature. A heat index in excess of about 40.6℃ is considered dangerous to human health.

As global air temperatures rise, observations and experiments with climate models suggest that atmospheric moisture content also climbs. This means that the heat index (and how hot it feels) rises faster than air temperature. Also, because the amount of moisture the atmosphere can hold increases more rapidly at higher temperatures, the heat index rises faster too, a non-linear response.

This non-linear response carries over to the definition of “global heat stress burden” used in our research, which we define as the average number of days per year over land areas with a daily heat index above 40.6℃. Using a large number of climate model simulations, we found that this quantity increases faster and faster as global average air temperatures rise. This sharp rise in global heat stress burden has important consequences.

First, any increase in global heat stress from climate warming to date will be smaller than that caused by the same additional warming in the future. We have already seen a 0.8℃ rise in global temperature, another 0.8℃ of warming could be expected to lead to a greater increase in heat stress than caused by the first 0.8℃.

Long-sought features may help researchers to improve models of solar activity and predict space weather.

Huge ripples in Earth’s atmosphere called Rossby waves help to steer the planet's jet streams and weather patterns. Now, a study in Nature Astronomy offers the best evidence yet  that similar large-scale features also exist on the Sun1.

Rossby waves were  discovered in Earth’s atmosphere in the late 1930s. Driven by a planet's rotation, they’ve been seen in the atmospheres of other planets, as well as in Earth’s oceans. In theory, these waves can form in any rotating fluid, says Scott McIntosh, a solar physicist at the National Center for Atmospheric Research in Boulder, Colorado and lead study author.

Researchers have long sought evidence of Rossby waves on the Sun, he says. And an enhanced understanding of these features and their movements could help scientists to better predict the formation of sunspots and the eruption of solar flares.

In the past, astronomers have been hampered in their search for the waves by their limited view of the Sun, because only one side can be viewed from Earth. But three solar probes — part of NASA's Solar Dynamics Observatory and its Solar Terrestrial Relations Observatory (STEREO) mission — were positioned for several years to give scientists a 360° view of the Sun’s atmosphere, or corona. (Astronomers lost communication with one STEREO probe after it slid behind the Sun in mid-2014.)

The Fibonacci numbers are the sequence of numbers defined by the linear recurrence equation.

The plot above shows the first 511 terms of the Fibonacci sequence represented in binary, revealing an interesting pattern of hollow and filled triangles (Pegg 2003). A fractal-like series of white triangles appears on the bottom edge, due in part to the fact that the binary representation of ends in zeros. Many other similar properties exist.

The Fibonacci numbers give the number of pairs of rabbits months after a single pair begins breeding (and newly born bunnies are assumed to begin breeding when they are two months old), as first described by Leonardo of Pisa (also known as Fibonacci) in his book Liber Abaci. Kepler also described the Fibonacci numbers (Kepler 1966; Wells 1986, pp. 61-62 and 65). Before Fibonacci wrote his work, the Fibonacci numbers had already been discussed by Indian scholars such as Gopāla (before 1135) and Hemachandra (c. 1150) who had long been interested in rhythmic patterns that are formed from one-beat and two-beat notes or syllables. The number of such rhythms having beats altogether is , and hence these scholars both mentioned the numbers 1, 2, 3, 5, 8, 13, 21, ... explicitly (Knuth 1997, p. 80).

The numbers of Fibonacci numbers less than 10, , , ... are 6, 11, 16, 20, 25, 30, 35, 39, 44, ... (OEIS A072353). For , 2, ..., the numbers of decimal digits in are 2, 21, 209, 2090, 20899, 208988, 2089877, 20898764, ... (OEIS A068070). As can be seen, the initial strings of digits settle down to produce the number 208987640249978733769..., which corresponds to the decimal digits of (OEIS A097348), where is the golden ratio. This follows from the fact that for any power function , the number of decimal digits for is given by .

If you’re overweight and find it challenging to exercise regularly, now there’s good news: A less strenuous form of exercise known as whole-body vibration (WBV) can mimic the muscle and bone health benefits of regular exercise — at least in mice — according to a new study published in the Endocrine Society’s journal Endocrinology.

Lack of exercise is contributing to the obesity and diabetes epidemics, according to the researchers. These disorders can also increase the risk of bone fractures. Physical activity can help to decrease this risk and reduce the negative metabolic effects of these conditions.

But the alternative, WBV, can be experienced while sitting, standing, or even lying down on a machine with a vibrating platform. When the machine vibrates, it transmits energy to your body, and your muscles contract and relax multiple times during each second.

“Our study is the first to show that whole-body vibration may be just as effective as exercise at combating some of the negative consequences of obesity and diabetes,” said the study’s first author, Meghan E. McGee-Lawrence, Ph.D., ofAugusta University in Georgia. “While WBV did not fully address the defects in bone mass of the obese mice in our study, it did increase global bone formation, suggesting longer-term treatments could hold promise for preventing bone loss as well.”

Just as effective as a treadmill

Glucose and insulin tolerance testing revealed that the genetically obese and diabetic mice showed similar metabolic benefits from both WBV and exercising on a treadmill. Obese mice gained less weight after exercise or WBV than obese mice in the sedentary group, although they remained heavier than normal mice. Exercise and WBV also enhanced muscle mass and insulin sensitivity in the genetically obese mice.

The findings suggest that WBV may be a useful supplemental therapy to combat metabolic dysfunction in individuals with morbid obesity. “These results are encouraging,” McGee-Lawrence said. “However, because our study was conducted in mice, this idea needs to be rigorously tested in humans to see if the results would be applicable to people.”

The authors included researchers at the National Institute of Health’s National Institute of Aging (NIA). Funding was provided by the American Diabetes Association, the National Institutes of Health’s National Institute of Diabetes and Digestive Kidney Diseases, and the National Institute on Aging.

If you should one day find yourself in a spacecraft circling Mars, don’t count on a good view. The Red Planet’s dusty atmosphere will probably obscure any window-seat vistas of its deep valleys and soaring mesas. “The best way to see the planet’s surface would be to take a digital image and enhance it on your computer,” says planetary geologist Alfred McEwen, principle investigator on NASA’s High Resolution Imaging Science Experiment.

He would know: In the past 12 years, the powerful HiRISE camera has snapped 50,000 spectacular, high-resolution stereo images of the Martian terrain from the planet’s orbit, creating anaglyphs that anyone can view in 3D using special glasses. The highly detailed stereograms depict the planet’s surface in remarkable detail—but 3D glasses aren’t always handy, and still images can only convey so much about Mars’ varied topography.

To fully appreciate the Martian landscape, one needs dimension and movement. In the video you see here, Finnish filmmaker Jan Fröjdman transformed HiRISE imagery into a dynamic, three-dimensional, overhead view of the Red Planet—no glasses required. For Fröjdman, creating the flyover effect was like assembling a puzzle. He began by colorizing the photographs (HiRISE captures images in grayscale). He then identified distinctive features in each of the anaglyphs—craters, canyons, mountains–and matched them between image pairs. To create the panning 3-D effect, he stitched the images together along his reference points and rendered them as frames in a video. “It was a very slow process,” he says.

Researchers at the Tokyo Institute of Technology and Nippon Telegraph and Telephone Corporation have developed a "spin-resolved oscilloscope." This device is a basic measuring instrument for plasmonics and spintronics, which are key technologies for future electronics applications. The coupling of light and electronic charges in plasmonics will pave the way for ultra-high-speed information processing, whereas spintronics will provide low-energy-consumption technology in a highly information-oriented society. The spin-resolved oscilloscope pioneers future "spin-plasmonics," where ultra-high-speed low-energy-consumption devices will be achieved.

An electron has charge and spin, and both the charge- and spin-density excitations in an electronic system can be utilized in information processing. The dynamics of charge-density waves has been investigated in plasmonics, and that of spin-density waves has been studied in the field of spintronics. However, less effort has been devoted to combining these two technologies and to developing the expected ultra-high-speed and low-energy-consumption devices. To date, a major obstacle preventing the promotion of this research field has been the lack of a measuring instrument that is sensitive to both charge and spin.

In their recent paper, published in Nature Physics, Dr. Masayuki Hashisaka at Tokyo Tech and colleagues reported a "spin-resolved oscilloscope" that enables measurement of the waveforms of both charge and spin signals in electronic devices. An oscilloscope is a basic measuring instrument used in electronics; however, conventional oscilloscopes do not facilitate both charge and spin measurement.

The "charge signal" is the total charge of the spin-up and -down electron densities. Further, the "spin signal" is the difference between the spin-up and -down electron densities. Both these signals traveling in a semiconductor device can be detected by the spin-resolved oscilloscope, which is composed of a spin filter and nanometer-scale time-resolved charge detectors. The spin filter separates the spin-up and -down electrons, while the time-resolved charge detector measures the waveforms of the charge-density waves. By combining these spintronic and plasmonic devices, the spin-resolved oscilloscope is established.

Why is the sky blue? It’s a common question asked by children, and the simple answer is that blue light is scattered by our atmosphere more than red light, hence the blue sky. That’s basically true, but then why don’t we see a violet sky?

The blue sky we observe depends upon two factors: how sunlight interacts with Earth’s atmosphere, and how our eyes perceive that light.

When light interacts with our atmosphere it can scatter, similar to the way one billiard ball can collide with another, making them go off in different directions. The main form of atmospheric scattering is known as Rayleigh scattering. If you imagine photons bouncing off molecules of air, that’s a rough approximation.

But photons and air molecules aren’t billiard balls, so there are differences. One of these is that the amount of scattering depends upon the wavelength (or color) of the light. The shorter the wavelength, the more the light scatters. Since the rainbow of colors going from red to violet corresponds with wavelengths of light going from long to short, the shorter blue wavelengths are scattered more. So our sky appears blue because of all the scattered blue light. This is also the reason why sunsets can appear red. Blue light is scattered away, leaving a reddish looking sunset.

But if that’s the case, why isn’t the sky violet? Sure, blue light is scattered more than red or green, but violet light has an even shorter wavelength, so violet should be scattered more than blue. Shouldn’t the sky appear violet, or at least a violet-blue? It turns out our sky is indeed violet, but it appears blue because of the way our eyes work.

A man who was paralysed from below the neck after crashing his bike into a truck can once again drink a cup of coffee and eat mashed potato with a fork, after a world-first procedure to allow him to control his hand with the power of thought.

Bill Kochevar, 53, has had electrical implants in the motor cortex of his brain and sensors inserted in his forearm, which allow the muscles of his arm and hand to be stimulated in response to signals from his brain, decoded by computer. After eight years, he is able to drink and feed himself without assistance.

“I think about what I want to do and the system does it for me,” Kochevar explained. “It’s not a lot of thinking about it. When I want to do something, my brain does what it does.” The experimental technology, pioneered by the Case Western Reserve University in Cleveland, Ohio, is the first in the world to restore brain-controlled reaching and grasping in a person with complete paralysis.

For now, the process is relatively slow, but the scientists behind the breakthrough say this is proof of concept and that they hope to streamline the technology until it becomes a routine treatment for people with paralysis. In the future, they say, it will also be wireless and the electrical arrays and sensors will all be implanted under the skin and invisible.

“Our research is at an early stage, but we believe that this neuroprosthesis could offer individuals with paralysis the possibility of regaining arm and hand functions to perform day-to-day activities, offering them greater independence,” said Dr Bolu Ajiboye, lead author of a paper detailing the research in the Lancet medical journal.

A team of more than 80 mathematicians from 12 countries has begun charting the terrain of rich, new mathematical worlds, and sharing their discoveries on the Web. The mathematical universe is filled with both familiar and exotic items, many of which are being made available for the first time.

The "L-functions and Modular Forms Database," abbreviated LMFDB, is an intricate catalog of mathematical objects and the connections between them. Making those relationships visible has been made possible largely by the coordinated efforts of a group of researchers developing new algorithms and performing calculations on an extensive network of computers. The project provides a new tool for several branches of mathematics, physics, and computer science.

A "periodic table" of mathematical objects

Project member John Voight, from Dartmouth College, observed that "our project is akin to the first periodic table of the elements. We have found enough of the building blocks that we can see the overall structure and begin to glimpse the underlying relationships." Similar to the elements in the periodic table, the fundamental objects in mathematics fall into categories. Those categories have names like L-function, elliptic curve, and modular form. The L-functions play a special role, acting like 'DNA' which characterizes the other objects. More than 20 million objects have been catalogued, each with its L-function that serves as a link between related items. Just as the value of genome sequencing is greatly increased when many members of a population have been sequenced, the comprehensive material in the LMFDB will be an indispensible tool for new discoveries.

The LMFDB provides a sophisticated web interface that allows both experts and amateurs to easily navigate its contents. Each object has a "home page" and links to related objects, or "friends." Holly Swisher, a project member from Oregon State University, commented that the friends links are one of the most valuable aspects of the project: "The LMFDB is really the only place where these interconnections are given in such clear, explicit, and navigable terms. Before our project it was difficult to find more than a handful of examples, and now we have millions."

A team of researchers at the University of Wisconsin has developed a pair of glasses that allows the wearer to have tetrachromatic vision. In their paper uploaded to the arXiv preprint sever, the group describes the inspiration for their glasses and explain how they work.

Humans have three types of cone cells in the back of the eye to differentiate color. Some react to blue, some to green and some to red. The cones do their work by responding to the difference in wavelength of the incoming light. Such vision is known as trichromatic. In this new effort, the researchers have found a way of fooling the brain into seeing as if there were a fourth type of cone, by wearing glasses with two types of filters. The result is tetrachromatic vision.

To create the glasses, the researchers fashioned two types of filters, one for each eye. The filters remove some parts of the blue light spectrum. But the filters each remove a different part. When the filters are fitted into a frame and worn like regular glasses, the wearer is able to see colors that are normally hidden—metamers. In a sense, it is rather the opposite of what occurs with people who are color blind. They might see blue and red as the same, even though there is more light information there. Adding spectrum identification to color blind eyes allows for seeing more of what is already there. With the new combined filter system, a person is able to look at what appears to be an object that is all the same color, such as purple, and see more colors in it—those normally hidden metamers.

The team notes that it should be possible to extend the idea used to create their glasses to the other two colors that cone cells process, red and green, to create glasses that offer the ability to see six basic types of colors instead of the normal three. They plan to start with green. Such glasses, the team notes, might be used to spot counterfeit money, or to see a person in the jungle wearing camouflage.

In the mathematical field of dynamical systems, an attractor is a set of numerical values toward which a system tends to evolve, for a wide variety of starting conditions of the system.[1] System values that get close enough to the attractor values remain close even if slightly disturbed.

An attractor is called strange if it has a fractal structure.[1] This is often the case when the dynamics on it are chaotic, but strange nonchaotic attractors also exist. If a strange attractor is chaotic, exhibiting sensitive dependence on initial conditions, then any two arbitrarily close alternative initial points on the attractor, after any of various numbers of iterations, will lead to points that are arbitrarily far apart (subject to the confines of the attractor), and after any of various other numbers of iterations will lead to points that are arbitrarily close together. Thus a dynamic system with a chaotic attractor is locally unstable yet globally stable: once some sequences have entered the attractor, nearby points diverge from one another but never depart from the attractor.[5]

The term strange attractor was coined by David Ruelle and Floris Takens to describe the attractor resulting from a series of bifurcations of a system describing fluid flow.[6] Strange attractors are often differentiable in a few directions, but some are like a Cantor dust, and therefore not differentiable. Strange attractors may also be found in presence of noise, where they may be shown to support invariant random probability measures of Sinai–Ruelle–Bowen type.[7]

Examples of strange attractors include the double-scroll attractor, Hénon attractor, Rössler attractor, Tamari attractor, and the Lorenz attractor.

New NASA research reveals that the giant Martian shield volcano Arsia Mons produced one new lava flow at its summit every 1 to 3 million years during the final peak of activity. The last volcanic activity there ceased about 50 million years ago—around the time of Earth's Cretaceous-Paleogene extinction, when large numbers of our planet's plant and animal species (including dinosaurs) went extinct.

Cerealia Facula, a dome-like feature located in the center of Ceres’ Occator crater, is only 4 million years old -- approximately 30 million years younger than the crater itself, according to research led by Dr. Andreas Nathues of the Max Planck Institute for Solar System Research.

Occator crater is one of the largest craters on the dwarf planet Ceres. With a diameter of 57 miles (92 km), it is larger than Tycho crater on the Moon. Its steep walls stand tall at over 1.4 miles (2 km), higher than the North face of the Eiger in the Bernese Alps.

“Occator crater is located in the northern hemisphere of Ceres. In its center a pit with a diameter of about 6.8 miles (11 km) can be found. On some parts of its edges, jagged mountains and steep slopes rise up to 2,460 feet (750 m) high,” Dr. Nathues and co-authors said. “Within the pit a bright dome formed. It is 1,312 feet (400 m) high, has a diameter of 1.9 miles (3 km), and displays prominent fractures.”

“This dome, called Cerealia Facula, contains the brightest material on Ceres.”

The researchers analyzed data from two instruments on board NASA’s Dawn spacecraft: the framing camera, and the visible and infrared spectrometer (VIR). VIR data show that Cerealia Facula is very rich in carbonate salts.

Since later impacts in this area did not expose any other material from the depth, this feature possibly consists entirely of bright material. The secondary, smaller bright areas of Occator, called Vinalia Faculae, are paler, form a thinner layer and — as VIR and camera data show — turn out to be a mixture of carbonates and dark surrounding material.

New evidence also suggests that Cerealia Facula likely rose in a process that took place over a long period of time, rather than forming in a single event. Dr. Nathues and his colleagues believe the initial trigger was the impact that dug out Occator crater. This impact happened some 34 million years ago and caused briny liquid to rise closer to the surface.

SpaceX has applied to the FCC to launch 11,943 satellites into low-Earth orbit, providing “ubiquitous high-bandwidth (up to 1Gbps per user, once fully deployed) broadband services for consumers and businesses in the U.S. and globally,” according to FCC applications. Recent meetings with the FCC suggest that the plan now looks like “an increasingly feasible reality — particularly with 5G technologies just a few years away, promising new devices and new demand for data,” Verge reports.

Such a service will be particularly useful to rural areas, which have limited access to internet bandwidth. Low-Earth orbit (at up to 2,000 kilometers, or 1,200 mi) ensures lower latency (communication delay between Earth and satellite) — making the service usable for voice communications via Skype, for example — compared to geosynchronous orbit (at 35,786 kilometers, or 22,000 miles), offered by Dish Network and other satellite ISP services.* The downside: it takes a lot more satellites to provide the coverage.

Boeing, Softbank-backed OneWeb (which hopes to “connect every school to the Internet by 2022″), Telesat, and others** have proposed similar services, possibly bringing the total number of satellites to about 20,000 in low and mid earth orbits in the 2020s, estimates Next Big Future.

Scientists are planning to capture the first ever photo of a black hole’s event horizon (the boundary of no return that light can’t event escape). The project is called the Event Horizon Telescope, and it uses a network of 9 radio telescopes found across the world that will be pointed at Sagittarius A*, the black hole 25,000 light years away at the center of our Milky Way galaxy.

Scientists say that calculations and preparations are done, and that they’re aiming to shoot the groundbreaking photo sometime early this year. “There are quite a few challenges that need to be overcome to take a picture of a black hole – it’s something that’s extremely small in the sky,” EHT scientist Feryal Ozel explains. “But what we’re hoping for is a full array observation in early 2017.”

Although our entire galaxy revolves around it, Sagittarius A* has an event horizon with a diameter of 24 million km (~14.9 million miles), or about 17 times that of our Sun. And since it’s so far away, to us it’s about the relative size of a CD on the surface of the moon, scientists say.

So what will the resulting photo look like? Scientists are predicting that it will look like a crescent of light around a black hole due to the Doppler effect making part of the ring brighter than the other. Here’s the “close up” view of a black hole that was computer generated for the movie Interstellar (created under the guidance of renowned astrophysicist Kip Thorne).

Although the invisible substance known as dark matter dominates galaxies nowadays, it was apparently only a minor ingredient of galaxies in the early universe, a new study finds.

This new finding sheds light on how galaxies and their mysterious "haloes" of dark matter have changed over time, researchers said.

Dark matter is thought to make up about 84 percent of the matter in the universe. Although dark matter is invisible, its presence can be inferred by its gravitational effects on visible matter. For instance, previous work discovered that the outer parts of galactic disks whirl faster than expected around the cores of those galaxies. These findings make sense if one assumes that "haloes" of dark matter envelop those galaxies and gravitationally pull at their outer regions. [The Search for Dark Matter in Pictures]

Now, the researchers unexpectedly find that in the early universe, dark matter played a much smaller role in galaxies than previously thought. The scientists detailed their findings in the March 16 issue of the journal Nature.

Using the European Southern Observatory's Very Large Telescope in Chile, the researchers examined six massive, star-forming galaxies from the early universe during the peak of galaxy formation 10 billion years ago. They analyzed the rotation of these galaxies to calculate how much dark matter they possessed.

When it comes to the Milky Way and other typical galaxies born in the current era of the universe, their "effective radius"—that is, the bright region that half their light comes from—is 50 to 80 percent dark matter, said study lead author Reinhard Genzel, an astrophysicist and director of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. In comparison, in half the early galaxies the researchers studied, dark matter made up 10 percent or less of the galaxies' effective radius, Genzel said.