Science News

Coronal Hole Seen Over Sun’s North Pole By SOHO Spacecraft.

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A space telescope aimed at the sun has spotted a gigantic hole in the solar atmosphere — a dark spot that covers nearly a quarter of our closest star, spewing solar material and gas into space.

The so-called coronal hole over the sun’s north pole came into view between July 13 and 18 and was observed by the Solar and Heliospheric Observatory, or SOHO. NASA released a video of the sun hole as seen by the SOHO spacecraft, showing the region as a vast dark spot surrounded by solar activity.

 

Coronal holes are darker, cooler regions of the sun’s atmosphere, or corona, containing little solar material. In these gaps, magnetic field lines whip out into the solar wind rather than looping back to the sun’s surface. Coronal holes can affect space weather, as they send solar particles streaming off the sun about three times faster than the slower wind unleashed elsewhere from the sun’s atmosphere, according to a description from NASA.

“While it’s unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, failing to loop back down to the surface, as they do elsewhere,” NASA’s Karen Fox at the agency’s Goddard Space Flight Center in Greenbelt, Md., explained in an image description.

These holes are not uncommon, but their frequency changes with the solar activity cycle. The sun is currently reaching its 11-year peak in activity, known as the solar maximum. Around the time of this peak, the sun’s poles switch their magnetism. The number of coronal holes typically decreases leading up to the switch.

After the reversal, new coronal holes appear near the poles. Then as the sun approaches the solar minimum again, the holes creep closer to the equator, growing in both size and number, according to NASA.

The $1.27-billion (1 billion euros)SOHO satellite was launched in 1995 and is flying a joint mission between NASA and the European Space Agency (ESA). It watches solar activity from an orbit about the Lagrange Point 1, a gravitationally stable spot between Earth and the sun that is about 932,000 miles (1.5 million kilometers) from our planet.

Source: http://www.huffingtonpost.com

Spiders’ Electrostatic Charge Helps Them Trap Prey In Their Webs, New Study Shows.

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Spiders may trap unsuspecting prey by sucking them in using electrostatic attraction, new research suggests.

The new study, published in the journal Scientific Reports, found that the spiderweb of the common cross spider (or garden spider) is attracted to electrically charged objects, with the sticky threads of spider silk arcing toward each other in response to a charged object.

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Stroke of inspiration

Some flying insects, as they flap their wings, for instance, generate an electric charge. As such the new results suggest that charged bugs such as honeybees could be sucked into, and then trapped by, a spider’s sticky web as they fly by. [Ewww! Photos of Bat-Eating Spiders]

“Charged insects can produce a deformation of a spiderweb,” said study co-author Victor Ortega-Jimenez, a biologist at the University of California, Berkeley. “Any insect that is flying very close to the spiderweb can be trapped by the electrostatic effect.”

Ortega-Jimenez noticed this phenomenon while playing with a simple toy with his daughter: an electrostatically charged “magic wand” that can cause objects such as paper to levitate. While doing so, they decided to charge up a few insects and even brought it near a spiderweb that was nearby, which deformed in response to the magic wand

He also knew that honeybees generate an electric charge of up to 200 volts as they flap their wings, which may help them pick up pollen from negatively charged flowers. Several studies have revealed that spiderwebs can dramatically deform in response to prey. So he wondered whether spiderwebs could use electrostatic attraction to lure prey.

Charging webs

To find out, Ortega-Jimenez and his colleague Robert Dudley gathered spiderwebs of the cross spider (Araneus diadematus) from around the UC Berkeley campus. Back at the lab, they studied how the spiderwebs responded to electrically charged objects.

They found that the web and positively charged objects were attracted to one another. What’s more, the silk threads of the spiderweb curved toward each other underneath a charged honeybee that was falling toward it, making it likelier that the hapless insect would get entangled in the deadly web. The deformation was nearly half the length of the insects, a fairly big change.

“This is quite intriguing,” said Markus Buehler, a materials scientist who studies spider silk at the Massachusetts Institute of Technology, who was not involved in the study. “This attraction pulls the insect to the web and enhances the likelihood that it is being caught in the web.”

But it’s not clear how often this strange effect plays out in nature. Cross spiders mostly dine on flies, not bees, and so far, no one has tested whether flies have an electric charge. The bigger question, Buehler said, is how many insects are electrically charged.

Source: huffingtonpost.com


 

 

Meteors Don’t Strike Twice.

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Without precedent or warning, a loud boom sounding like a major piece of artillery frightens your normally quiet neighborhood. Houses shake and dishes rattle. The jolt is singular, percussive — and ominous. Later the TV news reports that the boom was heard over many miles, but nothing exploded. No supersonic aircraft flew by. Someone saw yellow light in the sky.

Residents of New York’s Rockland and Westchester Counties, not far from New York City, experienced this in March 2009. It could have been a rare, beach ball sized meteor that disintegrated before it hit the ground. Meteors are certainly supersonic and have been known to make loud sonic booms. A bounty hunter offered $10,000 for a piece of the meteorite.

But the meteor theory blew up a couple days later. Another loud boom in the same area jolted people awake at 5:15 am. Nanuet resident Keith Wallenstein said of the second boom. “The house was shaking. It sounded like someone had flown an F-16 over the house. If it was thunder, it had to be right on the house. [But] I know a bunch of people who heard it within 3 to 4 or 5 miles away.”

By now you may be thinking the military was up to something after all. They’d be mum about it, wouldn’t they?

In James Fenimore Cooper’s day there were no supersonic aircraft. As he recounted in 1850:

The ‘Lake Gun’ is a mystery. It is a sound resembling the explosion of a heavy piece of artillery, that can be accounted for by none of the known laws of nature. The report is deep, hollow, distant, and imposing. The lake seems to be speaking to the surrounding hills, which send back the echoes of its voice in accurate reply. No satisfactory theory has ever been broached to explain these noises. Conjectures have been hazarded about chasms, and the escape of compressed air by the sudden admission of water; but all this is talking at random, and has probably no foundation in truth. The most that can be said is, that such sounds are heard, though at long intervals, and that no one as yet has succeeded in ascertaining their cause.

Cooper was talking about Lake Seneca, one of the Finger Lakes in upper New York State. The Lake Gun was the name given to the booms by local settlers. The Native Americans said it was their god talking.

Moodus, Connecticut is another hot spot for loud booms, and other noises too. The Native Americans there called the area Machemodus, or Place-of-Noises, and warned the early settlers about them. The Moodus noises ceased in the 1980’s but sprang back to life in 2011. In 1979 Boston College’s Weston Observatory set up seismometers and measured Moodus quakes producing pops or bangs more than a hundred times too small for people to feel, some as low as minus 2 on the Richter scale. The geologists found that the source of the quakes is in hard bedrock only 1500 meters deep under Moodus, very shallow for an earthquake. They offered no explanation for the sound.

Quakes hundreds or thousands times more powerful occur elsewhere yet are nearly silent. More powerful quakes, ones that start to do damage do make noise, but more like rolling rumbles, not singular explosions. Why should some quakes produce percussive booms so efficiently?

The booms are not caused by an explosion nor any material object moving supersonically. Instead they are launched by the world’s largest loudspeaker: the ground or surface all around you, especially if it is hard bedrock or water (water is actually very stiff-try compressing it!).

This is apparently controversial. A website devoted to the Guns of Barisol, India, on the northern shore of the Bay of Bengal, another place of bewildering sonic booms, tries to inoculate readers against the microquake explanation of the booms: “You may read . . . that the Guns of Barisal are supposed to be caused by earth movements too feeble to be felt. Earthquakes can make noises, but not when no movements are felt….” Actually this statement is quite false: small quakes can produce loud booms.

Oddly, the surface does not need to move very far nor very fast to launch exceedingly loud sound resembling cannon fire or a sonic boom. What it does need is a lot of acceleration. But how can something have huge acceleration, yet not wind up moving very far or very fast?

The answer is the acceleration must be very brief. Suppose the ground accelerates at 1000 G’s straight up before recoiling and reversing direction, all in 1000th of a second. (The Tesla Roadster, capable of 0 to 60 in 3.2 seconds, accelerates 1000 times less at under 1 G) If the ground or water surface does that, its speed is never more than a modest 1 meter per second, and it will move less than a millimeter! But one heck of a loud boom will be launched if large surface areas do that.

Acceleration is the agent of sound production. An accelerating surface “surprises” the air next to it and launches a pressure wave moving at the speed of sound, even though the surface and the air itself never comes close to moving that fast. When your fingernail touches a desktop, you hear an audible clack. The surface of the desk clearly never moves very far, and the desktop certainly doesn’t move any faster than your fingernail was moving, but the sudden contact of desk with fingernail causes a significant (many G’s ) but short lived acceleration of the desktop, which launches the sound.

A sudden breaking of a large piece of rock under great tension sends out a sharp compression wave moving fast in the rock — like a sound wave, only in rock. When the wave reaches the surface, the surface is very suddenly pushed up over a large area- a huge but short lived acceleration — and a boom in born.

Sharp waves traveling in rock tend to quickly round off, so the pulse and the acceleration will be reduced unless the quake is very close to the surface, as it is in Moodus, and presumably under Rockland and Westchester Counties, Seneca Lake, etc. A Richter 1 quake is plenty to launch an ear splitting boom if it occurs close to the surface, yet at Richter 1, the geologists won’t dignify the quake with a mention.

Source: http://www.huffingtonpost.com

Viruses: Nature’s Self-Packing, Nanoscale Suitcases.

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This the season, from Thanksgiving to New Year, when tens of millions of us will travel to see family and friends. As these trips draw near everyone will face the same dilemma — what to pack? After laundry, ironing and folding, the next problem is which suitcase to choose; too small, too big, just right. What none of us think about during this time is the myriad of invisible virus particles that will be making the trip with us.

These nanoscale objects (a nanometer is one millionth of a millimeter, or 10,000 times smaller than the width of your hair) cling to our bodies looking for ways to get inside our cells and make new copies of themselves. During our trip, they will readily be exchanged with viruses taking trips with other people, either by transferring on surfaces or as aerosols in the air, especially if someone forgets to cover their face when they sneeze. Despite their apparently insidious size, and their potential for causing everything from the common cold to AIDS, viruses are not actively malign. They are in fact non-living collections of proteins and nucleic acids that simply fulfill Darwinian predictions about evolution. In their case they have evolved the property of infecting cells and replicating by using the host’s molecular machinery to produce new virus particles that escape the cell looking for a new victim. Making their hosts ill, or even killing them, is just an unfortunate side effect of this process. It is, however, a side effect that results in devastating losses in crops, as well as being the cause of many serious illnesses and deaths in animals and people every year. Understanding these events in detail is a major goal of researchers who hope to find ways to deter these pesky hitchhikers.

Working with one group of viruses that contain RNA genomes, similar to those that cause the common cold or polio, Alex Borodavka, Roma Tuma and I have just made an interesting discovery about the ways that viruses pack for their trips. In the viral world the content of the suitcase is the nucleic acid that carries the instructions for making new viruses. The suitcase is made from viral coat protein molecules that clump together to form a protective shield for that nucleic acid. Just as we do when we get to our destinations, when viruses enter cells they unpack their nucleic acids from the protein shell and the process of making new virus particles can begin. The first stages of this process are making new copies of the nucleic acid instruction book and more coat proteins to make the newly required suitcases to pack them in. The RNA in our test viruses emerges from these events rather like our clothes do after a few days at our destination, crumpled in a heap and no longer neatly folded. At the end of our trips we may discover that our suitcase is a little too small after all because we have to work hard at getting everything to fit back in. Similarly new viral suitcases are pretty cramped, and something has to happen to fold their nucleic acid molecules neatly so that they will fit inside.

Using a spectroscopic technique that allows us to see viral particles one at time, we noticed the equivalent of a Harry Potter moment for virus assembly. When viral RNAs and viral proteins are mixed together the proteins leap onto the RNA and fold it up neatly. It is as if the suitcase and the contents pack themselves. Previously people assumed that the process was much more gradual than this. Interestingly, when viral coat proteins are given non-viral RNAs they leap onto those molecules too but are not able to fold them up. That means that the viral suitcases they try to build do not close properly and so their contents cannot survive the trip to a new host. These observations pose an interesting question.

Can we mess up a viral nucleic acid’s travel plans by getting their coat proteins to treat them like non-viral equivalents? If we could we would have a powerful way to treat viral infections. Something to think about the next time you are stuck waiting for your plane, train or bus.

Happy Holidays!!

Source: http://www.huffingtonpost.com

 

The Politics of Life on Mars.

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Speculation about life on Mars has been rampant this fall. Rumors that the Mars Curiosity Rover may have found evidence of life on Mars have surfaced twice in the past few weeks. The most recent rumor started when a member of the Curiosity team was quoted as saying that they had collected data that was “Earthshaking” and “one for the history books.” This led to a barrage of rumors that Curiosity may have found organic material on Mars and some people even speculated that life had been found. The reality gave no confirmation of life, but the NASA press conference on December 3, 2012 did reveal that some simple organics were found. They were not sure if they were indigenous to Mars, if they may have been residual organics from Earth, or if they had been deposited from other space objects (meteorites) impacting Mars.

Curiosity’s mission should give us the answer to this eventually as it is scheduled to continue for at least another 18 months and was recently “officially” extended indefinitely. This gives Curiosity ample time to sample soil and rocks in some highly promising locations within Gale Crater on Mars. If organics exist there, Curiosity should know within the next few months.

Although Curiosity is not designed to verify life, we are left to wonder — if Curiosity did discover life on Mars, what would be the impact of that discovery to the general public and to the future of human and robotic exploration of Mars?

One thing is certain, it would have a substantial impact, but the nature of that impact could move in many different directions. A popular belief is that if we found life on Mars this would accelerate our goals of sending humans to Mars as well as our robotic efforts, and also might transform our religious and societal beliefs. This isn’t necessarily the case.

Our Place in the Universe

In fact, we have already had a test run for this hypothesis. Back in 1996, scientists announced findings that indicated that they had found fossil evidence of microbial life forms on a Martian meteorite (ALH 84001) that had been found in Antarctica a decade earlier. The story became a media sensation and President Clinton conducted a press conference to discuss the discovery. The announcement certainly did impact our robotic missions planning, but it did little to advance human space flight (we didn’t change directions in human space flight until after the Space Shuttle Columbia disintegrated in the skies over Texas.) The public enthusiasm to the announcement was also very short lived and there is little evidence that it transformed anyone’s religious or societal viewpoint. Would the confirmation of current microbial life be different? Probably not. The public would be engaged for a while (and probably enthusiastically), but the enthusiasm would be relatively short lived. It would likely take the discovery of a higher life form to ignite the type of passionate debate and emotion that was seen in the movie Contact.

Save the Microbes!

Perhaps the greatest impact would be within the mission planning community and among policy makers. Life on Mars will almost certainly make human missions to Mars far more complicated to plan. Planetary protection protocols would be very strict as we planned human missions to Mars. We would have to assure that there would be no forward, nor backward, contamination. This would become a VERY serious issue.

We should expect potential lawsuits from “Mars environmentalists” trying to block ANY human missions to Mars, claiming that we threaten the existence of indigenous Martian life. We would almost certainly hear protestors yelling slogans like “We’ve ruined our own planet, what right do we have to ruin Mars.” This process would probably be similar to the reaction in advance of the launch of the Cassini mission to Saturn back in 1997. This mission was carrying 72 pounds of plutonium dioxide (not the more dangerous plutonium 239 used in nuclear weapons) to power the mission.

The mere fact that there was a form of plutonium on board sparked fears that if the rocket exploded, plutonium would rain down on central Florida. There were numerous protests outside NASA and there even was a legal challenge in the Federal Court of Hawaii challenging the mission’s Environmental Impact Statement. Only after this challenge was rejected in Hawaii and in the Ninth Circuit Court of Appeals was the mission able to launch. Like Cassini, the legal challenges to a Mars mission would be likely to fail. Depending on when the discovery of life was made (is a human mission ten years in the future or one year in the future from the discovery), it could slow down a human mission to Mars. Discovery of life might also serve as a catalyst for various nations to propose contamination protocols in the United Nations – protocols that the US would probably not sign. Again, this would not be enough to stop a human mission to Mars.

That said, the discovery of even microbial life on Mars will be one of the most significant events in human history. And when we do send humans to Mars, we will absolutely need to take precautions and make sure we have solid protocols in place to protect Martian life and protect the crew and Earth from Martian life.

The Human Factor

Still, discovery of life on Mars should not stop a human mission to the Red Planet. On the contrary, it should be a strong case in favor of such a mission. After all, it will be far easier for us to understand the nature of this interplanetary strain of life if we have human scientists there to analyze it. There is also the strong possibility that we will not be able to provide 100 percent verification of Martian life until we send humans to Mars. At least for the foreseeable future, human explorers are the most accurate and efficient method of not only determining the nature of Martian life, but also determining long-term protocols for the protection of both indigenous life forms on other planets and for humanity.

Let’s hope that if such a discovery is made in the next few years, we are able to proceed in as rationale and productive a manner as possible.

Source:http://www.huffingtonpost.com