In a mission to learn more about the sun's inner workings, NASA is planning to launch a specially shielded spacecraft in 2018 that will plunge into the solar atmosphere. The car-sized Solar Probe Plus will explore an area just 4 million miles from the star's surface, the last region of the solar system to be explored by humans.

NASA just announced five science experiments that will fly on the scorching probe, which will be protected by a carbon-fiber heat shield that can withstand temperatures of 2,500 degrees F.

When the probe is 4 million miles away, the solar disk will loom 23 times wider in the sky than it does on Earth.

The mission will help scientists better understand solar radiation. Improved solar storm forecasts could protect future long-distance space explorers who would not be protected by Earth's magnetic field.

The SWEAP solar wind experiment will count the electrons, protons and helium ions in the solar wind and measure their properties. It will also catch some in a special cup for analysis.

Another science mission will use a wide-field camera to take 3-D pictures of the solar wind as the spacecraft flies through it. Another will take direct measurements of the sun's magnetic fields, radio emissions and shock waves, and the one more will take an inventory of the sun's contents.

"For the very first time, we'll be able to touch, taste and smell our sun," said Lika Guhathakurta, Solar Probe Plus program scientist at NASA headquarters.

NASA's goals are to figure out why the sun's corona is several hundred times hotter than the surface and why it produces an accelerating solar wind. Scientists already have high-resolution images and data of the transition zone between the atmosphere and the surface, and the solar wind has been studied extensively - but still, no one can answer some fundamental questions about the sun's evolution. The only way to do it is to go to the source, NASA says. Here's hoping the spacecraft doesn't get burned.

[NASA]

When it comes to precision sensing, secure battlefield communications, and global positioning systems, DARPA knows what time it is. However, a lack of coordinated clocks is a hindrance on the battlefield and elsewhere. That's why DARPA has put its feelers out for technology that could lead to portable atomic clocks that are miniature, ruggedized versions of the massive devices that keep standardized time in laboratories around the world.

DARPA's Quantum Assisted Sensing and Readout (QuASAR) program aims to take high-performance atomic clocks like the National Institute of Standards and Technology's NIST-F1, the massive room-sized clock housed in a lab in Boulder, Colo. Doing so won't be any easier than many other challenges DARPA brings to the table, but the agency thinks advances in nanoelectromechanical systems (NEMS) resonators and nitrogen-vacancy (NV) centers in diamonds that exhibit single-atom-like properties could create a close analog to an atomic clock in a miniature, portable package.

Atomic clocks don't lose seconds or even fractions of seconds over time (well, that's not entirely true, but time lost is negligible; NIST-F1 will neither gain nor lose a second in 60 million years), and that opens up major possibilities for syncronisity. Such portable clocks would allow for communications systems that are far more secure less susceptible to jamming and GPS positioning that is unrivaled. DARPA also thinks they might lead to precision sensors unrivaled in resolution and sensitivity.

[Network World, FedBizOpps]

Never mind that twisty compact fluo­rescent. The new energy-efficient way to light your home is with LEDs. An upcoming crop of bulbs draw 12 watts or less, edging out a typical fluorescent, and they have a more conventional shape, contain no mercury, and last at least 25,000 hours, three times as long.

They're among the first LED bulbs as bright as a classic 60-watt incandescent (about 800 lumens), and they address past problems with LEDs, such as bluish light, overheated chips and too-concentrated beams. Launch the gallery to find out how they'll do it, all within a 130-year-old form.

Click to launch the photo gallery

Most of us keep our music on our computers and our computers are increasingly mobile, but there's a disconnect between the ability to store large amounts of music on a laptop and the portability of said laptop: laptop speakers aren't worth playing music on. But a clever engineering fix by British company NXT has changed all that, conjuring big sound out of small, portable speakers powered by nothing more than a USB outlet.

Most audio amplifiers - the kind you plug into the wall - maintain a voltage of about 32 volts. That means when the music gets loud, the amp can deliver the required punch. Laptops, which must use power sparingly to preserve their portability, don't pack nearly the wallop; a USB 2.0 port produces a maximum 5.25 volts to external devices, making it impossible to power larger, high quality speakers from a laptop.

Some engineering trickery from NXT circumvents these problems by relying on the simple premise that the USB can deliver 5.25 volts all the time, even though music is not all crescendos. During quiet passages, a pair of capacitors stores unused voltage coming from the USB. The speakers monitor the music signal a few milliseconds ahead of amplification so they can release that stored up power when the interlude is over and the heavy guitar/drum combo us unleashed.

Of course, this technology is a replacement for weaker bus-powered, desktop-style speakers; pretty much any high-quality stereo speaker has an AC adapter. And the power storage is limited; the extended version of Freebird could run the capacitors out of juice, causing the volume to fall. But NXT says they've tested the speakers on a variety of musical styles with consistent success. If they can get some consumer electronics firms to hear them, the technology could be on the market by next year.

[New Scientist]

We've heard it said that Rome wasn't built in a day. And while Popular Science isn't old enough to have witnessed the Colosseum going up, we have covered in our pages some of the 20th century's most important architectural achievements rise from nothing but a dream and a blueprint.

We've combed the archives to gather some of our most important first looks at the buildings and structures that went on to define skylines around the world.

Click to launch the photo gallery

Considering the extent to which suspension bridges, skyscrapers, and towering monuments have become symbols of human progression, it's hard to believe that just a hundred, even fifty years ago, our most beloved landmarks only existed as blueprints dreamed up by earnest young engineers. Mount Rushmore had no faces on it. Commuters in San Francisco still rode ferries across the Bay. So-called towering skyscrapers rose only thirty floors.

In 1927, when New York's 57-story Woolworth Building was still the world's tallest high-rise, we continued to ponder the mechanics of installing elevators for high-rises. "Forty thousand people within four walls!" we exclaimed. "Edison and others warn us against threatening chaos."

At times, the process of planning and construction did involve a lot of chaos. Hundreds of workers died while building the Hoover Dam. Even Mount Rushmore's main sculptor, Gutzon Borglum, didn't live to see his masterpiece completed.

Needless to say, finishing projects was no easy feat, so we combed our archives to see how engineers turned empty lots, untended fields, and undisturbed bedrock into the past century's most iconic man-made structures.

Launch the gallery for PopSci's first looks at the Empire State Building, the Pentagon, and more.

An unmanned aerial surveillance drone is only as good as its power source, and as such many technologies are being considered that could drastically extend the duration of drone missions - for instance, DARPA's Vulture program has helped develop a giant solar plane that, theoretically, could fly for five years straight. But Seattle-based LaserMotive thinks laser power is the answer, and to prove it they recently kept a tiny 22-gram helicopter aloft for hours by beaming power to it via a laser.

LaserMotive knows a thing or two about turning laser power into mechanical energy; last year the firm beamed energy to a robot that climbed nearly 3,000 feet up a cable suspended form a helicopter, a feat impressive enough to win $900,000 from NASA. Now LaserMotive is demonstrating that similar ground-based lasers could beam energy to either fixed-wing or hovering rotary-wing UAVs high in the sky, keeping batteries topped up with juice so that they never have to land, with flight durations limited only by the durability of the aircraft's motors.

Take the tiny laser-powered helicopter. LaserMotive kept the aircraft aloft for six hours at last week's AUVSI Unmanned Systems Conference in Denver using a 7-centimeter beam of near-infrared laser that automatically tracked the helicopter as it moved up and down. The helicopter eventually failed, but only when the motor gave out. The laser never stopped beaming energy.

Better motor tech could lead to unmanned systems that fly missions that last days or weeks, powered by ground based energy beams that keep them running indefinitely. Portable UAV systems could allow troops operating at forward operating bases to send small surveillance platforms skyward to hover overhead, giving them an eye in the sky over their temporary quarters. Troops on the move could feasibly keep drones aloft above their convoys, powered from lasers mounted on the vehicles.

Of course, we could also just use lasers to blast UAVs out of the sky.

[New Scientist]

The father of evolution apparently played God with a tropical ecosystem 160 years ago, and the results could inform future experiments to terraform Mars, botanists say.

The BBC recounts how Charles Darwin helped build an artificial forest on Ascension Island, one of his subjects of study from his trips on the HMS Beagle. Today, the island is home to species of plants that would not naturally co-exist. Darwin and his friends put them there, and nearly two centuries later, their grand experiment is living proof that we can transform natural environments.

Originally used as an outpost to keep an eye on Napoleon in exile, Ascension Island, between South America and Africa, was a busy Atlantic waystation in Darwin's day. It had meager fresh water supplies, however, so Darwin and his botanist friend, Joseph Hooker, set out to change things.

The BBC interviews Darwin biographer David Catling, a professor at the University of Washington-Seattle, who says he believes Darwin decided to build a lush "Little England" on the volcanic island after visiting it in 1836.

Darwin's friend Hooker explored Ascension a few years later, and in 1847, Darwin convinced Hooker to get his father -- director of the Kew Gardens -- to send trees, hoping they would capture rain, prevent erosion and reduce evaporation.

Beginning in 1850 and continuing each year, ships brought an assortment of plants from botanical gardens in Europe, South Africa and Argentina, the BBC says. By the late 1870s, eucalyptus, Norfolk Island pine, bamboo, and banana had taken hold.

Today, Ascension is home to a cloud forest that would have taken millions of years to evolve naturally, according to Dave Wilkinson, an ecologist at Liverpool John Moores University in the UK.

It's proof that humans can build a fully functioning ecosystem simply through trial and error, he said. As the BBC reports, the same principle could be used in future Mars colonies: "Rather than trying to improve an environment by force, the best approach might be to work with life to help it find its own way."

Intelligent design, indeed.

East Coast residents are bracing for this monster, headed their way with 125-mph winds, as a fleet of NASA satellites and airplanes monitors its evolution.

As of Wednesday morning, Hurricane Earl was a Category 3 storm, but an especially large one. Storm-force winds extend 200 miles from its eye, seen above in a photo snapped from the International Space Station.

NASA scientists are flying airplanes into this swirling mass, measuring the hurricane's wind speeds, precipitation and more. As part of NASA's GRIP program - Genesis and Rapid Intensification Processes - a NASA DC-8 flew through Earl's eye six times as the hurricane intensified from a Category 2 to a Category 4 storm.

Meanwhile, an ISS crew member used a digital camera with a 50mm lens to take the above photo, from a much safer distance.