A windshield wiper at work on a rainy day (Basheer Tome via Flickr/Creative Commons)

German scientists plan to use moving vehicles to measure precipitation on rainy days, after noticing that drivers control the speed of their windshield wipers according to the intensity of rainfall—faster for heavy rain and slower for light rain or drizzle.

Writing in Hydrology and Earth System Sciences, the University of Hanover scientists say they will use cars equipped with GPS systems as mobile rain measuring devices.

The amount of rainfall can vary quite a bit within even small parts of a region. The scientists said that while standard rain gauges can provide accurate measurements, some parts of the world may have very few of these gauges in place and those they do have are spread out over a large area.

As a result, the measurements made by the rain gauges aren’t able provide the detailed information that would reflect that variation, information that could be vital to help predict and prevent flooding.

“If moving cars could be used to measure rainfall the network density could be improved dramatically,” said Uwe Haberlandt, project leader for the RainCars project, an initiative that was conceived after a brainstorming session between the scientists.

To test the idea, the researchers went to work in a laboratory equipped with a rain simulator that mimicked both light and heavy rainfall. They placed cars equipped with different types of windshield wiper systems, into their rain simulator to determine the relationship between wiper speed and rainfall intensity.

For their first experiment, they placed a person inside each of the cars to manually adjust the speed of the wipers for the best windshield visibility.

“The experiments have shown that the front visibility is a good indicator for rainfall intensity,” says Ehsan Rabiei, the paper’s lead author.

But the researchers also found that measurements made with this method might not be dependable since they would rely on the visibility perception of the individual making the manual wiper speed adjustments.

Moving on to their next rain simulator experiment, the researchers tested optical sensors used by some new wiper systems that allow the systems to operate automatically. These sensors use infrared laser beams that can detect rain drops collecting on the device’s surface. Each sensor reading, according to the researchers, corresponds to a specific amount of water – in other words, the more readings made by the sensors, the more intense the rainfall.

“The optical sensors measure the rain on the windshield in a more direct and continuous manner so, currently, they would be the better choice for rain sensors in cars,” said Haberlandt.

The researchers also found that speed isn’t the only factor that can impact rain measurements.

Here’s a car that’s being tested under the research group’s rain simulator (www.ikg.uni-hannover.de, Daniel Fitzner)

“Our experiments so far were carried out in an ideal and controlled environment. In nature there are external effects like wind, spray from other cars or shielding trees that can affect the readings, and rainfall characteristics are different from the rain simulator,” said Rabiei.

The research team’s goal isn’t so much about a higher accuracy of measuring rainfall, as it is about being able to increase the number of available measurement points.

A study published in 2010 by two members of the team showed that a system using a higher number of gauges that perhaps weren’t so accurate still provided more reliable rainfall readings than one that used a smaller number of much more accurate gauges.

The researchers said that they are already back at work conducting field experiments that use cars to measure the amount of real rainfall in and around their home city of Hanover.

They’re conducting these experiments with the help of volunteers, a taxi company and a car company, and say that they would like to see more people involved in this work.

A gamma-ray pulsar is a compact neutron star that accelerates charged particles to speeds that are described only by the theory of relativity in a strong magnetic field. The process produces gamma radiation seen in violet. (NASA/Cruz de Wilde)

A network of 40,000 volunteer researchers, along with 200,000 personal computers worldwide, has helped scientists from the Max Planck Institutes for Gravitational Physics and Radio Astronomy – the Albert Einstein Institute (AEI) discover four gamma-ray pulsars.

Pulsars are compact and rapidly rotating neutron stars which are the remains of stars that have exploded.

The discoveries made by this unique collaboration were made possible by an online computing project called Einstein@Home, which was launched back in 2005 as a joint program from the Center for Gravitation and Cosmology at the University of Wisconsin-Milwaukee and the AEI in Hannover, Germany.

The volunteers were from countries such as Australia, Canada, France, Germany, Japan and the USA, and used data from NASA’s Fermi Gamma-Ray Space Telescope, according to the AEI.

“Our innovative solution for the compute intensive search for gamma-ray pulsars is the combination of particularly efficient methods along with the distributed computing power of Einstein@Home,” said AEI’s Holger Pletsch, who’s also the lead author of the study. “The volunteers from around the world enable us to deal with the huge computational challenge posed by the Fermi data analysis. In this way, they provide an invaluable service to astronomy.”

The online computer project connects 200,000 home and office computers to a global supercomputer.  Since identifying these new gamma-ray pulsars requires a lot of computing power, the combined computing ability provided by the Einstein@Home network of personal computers, along with the supercomputer, provides scientists with an efficient yet more cost effective way to conduct their research.

A neutron star is the densest object astronomers can observe directly, crushing half a million times Earth’s mass into a sphere about 20 kilometers across. This illustration compares the size of a neutron star to the area around Hanover, Germany (NASA)

“The first-time discovery of gamma-ray pulsars by Einstein@Home is a milestone – not only for us but also for our project volunteers. It shows that everyone with a computer can contribute to cutting-edge science and make astronomical discoveries,” said Bruce Allen from AEI and the principal investigator of Einstein@Home. “I’m hoping that our enthusiasm will inspire more people to help us with making further discoveries.”

Pulsars have usually been detected by the beam of electromagnetic radiation or radio waves they emit when the signal points toward Earth. But, according to AEI officials, the four pulsars discovered through this collaborative effort are only visible in gamma-rays and not radio waves.

AEI officials said special follow-up observations of all four new pulsar discoveries will be conducted with radio telescopes located at Germany’s Max Planck Institute for Radio Astronomy and the Parkes Observatory in Australia.  Scientists hope these observations will confirm that radio waves won’t be detected in the pulsars.

Data gathered by the Fermi Gamma-Ray Space Telescope, which was launched from the Cape Canaveral Air Force Base on June 11, 2008 is also credited with helping scientists to discover thousands of gamma-ray sources that they said had been previously unknown.   According to AEI those gamma-ray sources may also include hundreds of yet undiscovered pulsars.

The Sun photographed by NASA’s Solar Dynamics Observatory (SDO). (NASA/SDO (AIA))

Here at Science World, one of our favorite topics is the sun. We’ve been able to provide you with a number of informational pieces regarding events and phenomena such as the ebb and flow of the sun’s activity throughout its roughly 11 year solar cycle.

As the sun goes through this process – from when it’s least active (solar minimum) to its most active (solar maximum) and back again – it undergoes what scientists describe as a “complete makeover” when its magnetic field reverses or flips its polarity.  The sun’s magnetic north becomes its south and vice versa, causing effects that can ripple throughout our solar system.

Scientists say that our sun, which is nearing the peak of its current solar cycle, is about to flip its magnetic poles. The current solar cycle that began in 2008 or 2009 is the 24^th since scientists started tracking them back in 1755.  Compared to previous solar cycles, researchers have said that the current cycle appears to be weaker than any other before it, perhaps the weakest in 100 years.

While not much is known about the actual mechanics behind this polarity flip, solar scientists at Stanford University’s Wilcox Solar Observatory are keeping an eye on the sun’s magnetic field, monitoring and measuring it every day, as they have done since 1975.

Large field-of-view image of sunspots. The image has been colored yellow for aesthetic reasons. (Royal Swedish Academy of Sciences)

The daily monitoring efforts allow these researchers to observe and identify the magnetic polarity reversal as it actually takes place on the sun’s surface.  This upcoming shift in the Sun’s poles will be the fourth the observatory has watched.

While we laypeople tend to label the sun’s magnetic poles as north and south, Todd Hoeksema, a solar physicist and Director of the Wilcox Solar Observatory, suggests that we think of the poles as positive and negative. “It’s best not to think of it like a big bar magnet.  That works OK for Earth but not the Sun.  Think of the Sun as having a large number of smaller magnetic fields scattered over the surface,” he said.

Of course, hearing that the sun is about undergo a significant event like a pole reversal can alarm some people who may wonder if they might be in danger.  But, according to Hoeksema we have nothing to worry about.

“When it happened about eleven or twelve years ago, you probably didn’t even notice,” he said.

Hoeksema explains that the pole reversal process takes place over time throughout the solar cycle where sunspots come up at the Sun’s mid-latitudes (equator) and spread out toward its poles.  Gradually, as the magnetic flux (a measurement of the quantity of magnetism) that comes up with the sunspots moves pole-ward it erodes the existing polar fields and replaces them with magnetic fields that have the opposite polarity.

Illustration of the sun’s magnetic field lines extending out (NASA/SVS)

“What we’re seeing recently is more activity in the (sun’s) southern hemisphere and that’s the pole that’s just about to switch or is switching right now,” said Hoeksema.

He also pointed out that the sun’s northern pole switched about a year ago in the summer of 2012.

The sun’s two hemispheres (north and south) aren’t in perfect synchronization with each other and the number of sunspots that emerge in each of the hemispheres can be different.

Because of this, according to Hoeksema, the sun’s ‘new’ polarity that moves poleward is generally different in the north and south in both timing and strength which causes one geographic pole to change its magnetic field direction before the other.

Since it is at or near its peak of activity, the sun is has been pumping out a lot of energy particles throughout the solar system via the solar wind. Because of this outpouring of sun particles, according to Hoeksema, we’re actually being shielded from the high energy particles that come at us from other parts of the galaxy.

Todd Hoeksema from Stanford University monitors the sun’s magnetic field at Stanford’s Wilcox Solar Observatory. (Photo: Linda A. Cicero /Stanford News Service)

Along with their ground-based Wilcox Solar Observatory at Stanford, Hoeksema and his fellow scientists also use some sophisticated observational tools in space, too.  One is as an instrument aboard NASA’s Solar Dynamic Observatory (SDO) called the ‘Helioseismic and Magnetic Imager’ (HMI) which allows the team to measure the sun’s magnetic field every 45 seconds.

These measurements help scientists zero in on where and what kind of solar activity is taking place on the Sun, something that Hoeksema and his colleagues hope will help scientists better predict potentially dangerous space weather.

Dr. Todd Hoeksema joins us this weekend on the radio edition of “Science World.”  To listen to our conversation either tune into the show (see right column for scheduled times) or check out the interview below.

Also check out the video below.

Solar physicist Todd Hoekserma explains sun’s magnetic reversal (Stanford University)

A rainy day in Chicago (Bernt Rostad via Flickr/Creative Commons)

A new study shows changes in precipitation are affected by human activities and can’t be explained by natural phenomena, such as El Niños and La Niñas.

Scientists from the Lawrence Livermore National Laboratory in California published the study in the Proceedings of the National Academy of Sciences.

The researchers suggest two mechanisms will probably cause changes in the distribution and intensity of precipitation worldwide because of human release of greenhouse gases that trap heat and deplete the ozone.

First, there are some thermodynamic changes, caused by the increasing global temperatures, which will likely result in already wet regions of the world getting wetter while the dry areas will become drier.

The researchers also think increased temperatures could change global atmospheric circulation patterns – movement of air at all levels of the atmosphere – which might move storm tracks and push current subtropical dry zones toward the poles.

“Both these changes are occurring simultaneously in global precipitation and this behavior cannot be explained by natural variability alone,” said Kate Marvel, the study’s lead author. “External influences such as the increase in greenhouse gases are responsible for the changes.”

To reach their conclusions, the researchers compared various climate model predictions with global observations from 1979-2012 that were provided by the Global Precipitation Climatology Project.

(Flóra Soós via Flickr/Creative Commons)

The scientists found natural climate phenomena alone couldn’t explain the ongoing changes in global precipitation patterns. They also noted that any fluctuations in climate brought on by natural causes could either intensify or shift precipitation towards the poles, but it’s very rare for both to take place together naturally.

“In combination, man-made increases in greenhouse gases and stratospheric ozone depletion are expected to lead to both an intensification and redistribution of global precipitation,” said Céline Bonfils, another co-author of the study. “The fact that we see both of these effects simultaneously in the observations is strong evidence that humans are affecting global precipitation.”

The researchers said their studies helped them identify a “fingerprint pattern” that can explain the simultaneous changes in precipitation locations and intensity brought on by external forces such as warming caused by human activities.

“We have shown that the changes observed in the satellite era are externally forced and likely to be from man,” Bonfils said.

Obdurodon tharalkooschild, a middle to late Cenozoic giant toothed platypus. Unlike today’s platypus, this ancient species had teeth (see inset). (Peter Schouten)

Australian scientists say they’ve found the fossil of a new species of  giant platypus that walked the Earth between 5 and 15 million years ago.

Up until now, the fossil record of the platypus indicated that only one species of the animal lived on Earth at any one time. The new study suggests this new extinct giant platypus species, called Obdurodon tharalkooschild, is a side-branch of the platypus family, rather than its direct ancestor.

The platypus is a mammal with a duck-like bill, thick fur that’s much like an otter’s, and a tail similar to a beaver’s. It has webbed feet and reproduces by laying eggs rather than giving birth like other mammals.

The animal was so odd that in 1798 when Captain John Hunter, then the governor of New South Wales, Australia, sent a pelt of a platypus along a sketch of the animal to scientists in Great Britain, the British researchers at first thought it was a joke or a hoax.

The Australian researchers were able to identify this new species of platypus from a single fossilized tooth found in the Riversleigh World Heritage Area of northwest Queensland, Australia.

“Monotremes (platypuses and echidnas) are the last remnant of an ancient radiation of mammals unique to the southern continents,” said Rebecca Pian, lead author of the study. “A new platypus species, even one that is highly incomplete, is a very important aid in developing understanding about these fascinating mammals.”

The fossilized tooth’s size leads researchers to believe this ancient platypus was about a meter in length, two times the length of today’s platypus. Today, the male platypus grows to a length of about 50 cm while females grow to about 43 cm in length.

A modern day platypus swimming underwater at the Sydney Aquarium (wehunts via Flickr/Creative Commons)

“Like other platypuses, it was probably a mostly aquatic mammal and would have lived in and around the freshwater pools in the forests that covered the Riversleigh area millions of years ago,” said Dr. Suzanne Hand of the University of New South Wales, a co-author of the study.

The ancient Obdurodon tharalkooschild was able to eat its prey with a set of well-developed teeth, unlike today’s platypus which has horny pads in its mouth instead.

The extinct platypus probably ate a varied menu that included not only crayfish and other freshwater crustaceans, but also small vertebrates such as lungfish, frogs, and small turtles.

The researchers named  the prehistoric animal Obdurodon, Greek for “lasting (obdurate) tooth,”  because its teeth are unlike today’s platypus species.  Tharalkooschild was given in honor of a story told by Indigenous Australians about the creation and origin of the platypus.

(Bill McChesney via Creative Commons @ Flickr)

The direction in which a dog wags its tail can communicate its emotional state to other canines, according to a new study published in Current Biology.

The Italian research team behind the study says dogs recognize, and respond accordingly, whether other canines wag their tails to the right or to the left.

The reason dogs understand the right versus left tail wag, according to the researchers, is because they have asymmetrically organized brains, meaning that the left and right sides of our brains are each responsible for controlling different things, much like humans.

In an earlier study, the researchers found dogs tend to wag their tails to the right when they feel positive, such as when they see their owners. Dogs wag their tails to the left when they experience negative emotions, such as feelings that might be triggered by an unfriendly dog or some other kind of danger.

The researchers say that this left and right tail wagging behavior is because of what’s taking place in the canine’s brains. A wag to the right is brought on by activation on the left side of its brain, while activity in the right side of the brain produces a wag to the left.

While this right versus left wagging behavior means something to other dogs, the researchers say that they’re probably not purposely displaying this behavior to communicate with each other.  Instead they say it’s just an automatic response due to left side or right side brain activation. But the team also points out that this behavior could serve a very helpful purpose to people like dog owners and veterinarians as another way to better understand what’s going on with the animal.

Compilation of videos shown to test dogs – left, right, no tail wagging – (Current Biology, Siniscalchi et al.)

To make their findings the researchers showed their dog subjects videos of other dogs either wagging their tails to the left or right. When the test dogs saw a video of a dog wagging its tail to the left, their heart rates increased and they appeared a bit nervous. However, when the dogs saw another animal wagging its tail to the right, they remained calm.

“The direction of tail wagging does in fact matter, and it matters in a way that matches hemispheric activation,” said Giorgio Vallortigara of the Center for Mind/Brain Sciences of the University of Trento. “In other words, a dog looking to a dog wagging with a bias to the right side—and thus showing left-hemisphere activation as if it was experiencing some sort of positive/approach response—would also produce relaxed responses. In contrast, a dog looking to a dog wagging with a bias to the left—and thus showing right-hemisphere activation as if it was experiencing some sort of negative/withdrawal response—would also produce anxious and targeting responses as well as increased cardiac frequency. That is amazing, I think.”