NASA's Stratospheric Observatory for Infrared Astronomy, also known as SOFIA. (Photo: NASA)

The new SOFIA observatory isn't your average NASA project. Engineers took a 30-year old 747 airplane, cut a hole in the side and installed a 17-ton telescope. Most telescopes are either on the ground or somewhere in orbit, but SOFIA falls somewhere in the middle, flying around at about 40,000 feet.

I got the chance to hitch a ride on one of its recent research flights as the plane left Moffett Field at the NASA Ames Research Center. It's definitely not the kind of flight where you get a bag of peanuts and movie.

The researchers take advantage of the nighttime sky, so we left at dusk for 10-hour tour flying zigzags across the Pacific Ocean. Each leg of the journey is carefully calculated so the telescope can pinpoint a far away star. The plane interior is packed with computers and equipment. It also lacks insulation since much of it was removed to install the telescope, so it's both cold and loud inside.

At four in the morning, the astronomers are still hard at work. If they're as tired as I am, they certainly aren't showing it.

"For me, this is very exciting," says Ian McLean, a professor at the University of California-Los Angeles. He usually works on the ground. "All my career has been ground-based astronomy. So, it's only my second flight."

McLean says there's a good reason to do astronomy in the stratosphere. The atmosphere is thinner, which means it's easier for the telescope to see the stars. "It's almost as good as space," says McLean. "Not quite, but almost."

And unlike the Hubble Space Telescope, this telescope lands everyday, which means the scientists can update and fix the equipment. "By the time you get a mission into orbit, the technology you're using is relatively old. Here we can stay state of the art all the time," says McLean. NASA began developing SOFIA in 1997 and almost cancelled the project at one point. It flew its first science mission in November 2010 and now costs about $80 million a year to operate.

Searching for a "Holy Grail"

McLean says the SOFIA telescope could show astronomers something that's considered a Holy Grail in their field: seeing a star being born. It happens in huge, dusty clouds – stellar nurseries, as Mclean calls them. "The cloud is huge, light years across and it's gradually contracting to form a whole nursery of stars."

Inside NASA's SOFIA Observatory, somewhere over the Pacific Ocean.

But there's a problem. Astronomers can't see what's happening inside the clouds because, once again, they're made of dust and it's hard to see through.

"We don't mean dust bunnies, but we mean little, tiny little grains of solid material. Doesn't matter how big a telescope you have, you can't see inside it," McLean says.

That's why SOFIA looks at a special kind of light called infrared light. If you look through a telescope on the ground, you're looking at the visible light from space – the light our eyes can see. Infrared light is invisible to us, but it penetrates space dust, which means the telescope can see through the dust too.

"You get to see what you can't see with your eye. It's like a window has been opened," says McLean. They're looking for exactly how stellar nurseries give birth to young stars. McLean says catching a star as it's forming can reveal clues about how own solar system formed.

But star birth isn't the only thing these researchers want to see. They're also looking at the way stars die.

A Star on the Way Out

As the plane makes as sharp right turn, the telescope focuses on an object called NGC 7027. It's a planetary nebula – also known as a dying star. McLean and his team are capturing an infrared image of the nebula, which is about 3,000 light years away. They can also see what it's made of.

"It has a distinctive shape. It's oval. There's a hole in the middle and that's because it literally is a shell of gas that came off the star," says McLean.

7027 is dying because the star has run out of fuel – the same fate that our sun will face in about five billion years. As it dies, the star casts off its outer layers, shedding huge amounts of material to form a cloud around it. But it's not entirely a sad story.

"It won't be wasted," says McLean. "The material that was thrown off by that star in its dying phase, somewhere, millions, perhaps billions of years from now, will find its way into a new star and the planets that form around it."

From dead stars come new stars – and planets like our own. The oxygen and nitrogen in our bodies were once formed inside a star. "The cosmos is within us," as astronomer Carl Sagan once said. "We're made of star stuff."

As sky begins to lighten, we descend towards the Dryden Aircraft Operations Facility in the Mojave Desert, where the plane is based. The SOFIA telescope is now undergoing service upgrades and then will return to the skies three times a week. Astronomers from around the world are lining up to get on board.

Block Island—a half-ton meteorite found on Mars by NASA's
Opportunity rover.Image credit, NASA/MER Opportunity

Okay, dramatic desert car scene ended. That would be the Hollywood movie version of what NASA's Mars Exploration Rover Opportunity did recently, on the lonely desert highway that it's scouting on Mars.

On its determined long trek from Victoria Crater to the larger Endeavour Crater (a 12-mile span that Opportunity has completed about one fifth of over the past year), the rover passed by an X-box-sized block of iron that presented the appearance of a meteorite. It snapped a picture in passing, which was eventually transmitted to Earth and examined. By this time, Opportunity had already traveled about 180 meters beyond the block (dubbed "Block Island"). This is when the rover was commanded to backtrack all the way to the find (though it's doubtful it worked up a rooster tail).

Upon returning to Block Island—quite obviously an iron-nickel meteorite by appearance alone, but whose composition was confirmed by the rover's alpha particle X-ray spectrometer instrument—Opportunity took more pictures, including extreme close-ups with its microscope camera, which revealed surface patterns similar to those found on Earth iron-nickel meteorites that have been exposed to long-term weathering by wind and sand.

As interesting as stumbling upon a half-ton meteorite on the dusty plains of Mars' Meridiani Planum is, what this particular chunk of weathered iron is telling scientists sparks the imagination. In a nutshell, given the thinness of Mars' current atmosphere, scientists wouldn't expect a meteorite of this size to survive impact intact, at the speed it would be going. One of the possible explanations for Block Island's rock-houndable state is that when it fell to Mars, Mars' atmosphere was substantially thicker than it is now.

Further examination of the meteorite may reveal clues as to how long ago it fell through Martian skies. Evidence that Mars' atmosphere was warmer and thicker in the distant past, as well as the possibility that there was liquid water on the surface, has been mounting over the years. The age of this meteorite-fall could shed more light on the history of Mars' environment. If it fell billions of years ago, Block Island would weigh in as more evidence to support our current suspicions. If, however, we find that it fell more recently, then this could indicate that the atmosphere was more substantial later in Mars' history than we thought.

Imagine, if you will, a Mars that looks even more Earthlike than it does now: seas of water with waves rolling into shorelines, great clouds sending downpours of rain and snow onto mountains and plains, streams and rivers snaking through the landscape. Maybe, maybe, even some form of life?

All that from a rock? Yes, rocks talk, if we listen.

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Here's how the idea would work: Using planes or other high-altitude transport, we'd disburse millions of tons of sulfur dioxide (or hydrogen sulfide) into the stratosphere, 13 miles above the Earth. Those gases would create tiny particles, which would reflect sunlight. This process already goes on in the stratosphere – about a third of the energy from the sun is reflected back into space thanks to this dynamic. But by adding more reflecting particles, scientists think it might be possible to cool the planet – and compensate for human-induced warming.

No one has tried this idea yet – but it's something scientists have already observed — through volcanoes. In 1991, Mount Pinatubo erupted in the Philippines, spewing 20 million tons of sulfur dioxide into the atmosphere. As a result, global temperatures temporarily dropped about one degree Fahrenheit.

That doesn't necessarily mean a scheme like this would work. As UCLA Scientist Richard Turco said, it's not easy to predict how the particles would react and disburse. "If the particles are too large, that would actually create a warming effect, a greenhouse warming. Small particles are not useful because they don't reflect much radiation."

This plan isn't just a one time deal. As Turco continued, "we would need a huge monitoring system and can't afford to make any mistakes. Once you start this process, you have to maintain it for two to three centuries."

And then there's the "get out of jail free" aspect. If the focus of climate change policy becomes geoengineering, what happens to simply cutting emissions? As Professor Alan Robock of Rutgers University acknowledged, the costs and technology of geoengineering are uncertain — and it wouldn't curb other climate change impacts, like ocean acidification. "We have to focus on mitigation and keep this in our back pocket for emergencies."

According to Professor David Keith of the University of Calagry, it's worth studying geoengineering — just in case. Our greenhouse gas emissions will continue to grow. "We're not going to stop today, and even if we stopped today, there's enormous inertia," Keith said. In the event that climate change becomes catastrophic, Keith says we may need a last resort. "Whether you like or don't like this, it can be done quickly."

For more on what's new at the AGU, check out KQED's Climate Watch blog.

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I was reading out loud as we drove down I-64 towards an ever darkening sky. My friend, Brad shushed me at one point to concentrate on driving. I looked up to see why and was stunned. A sheet of water and staccato pulses of hail and lightning were all I could see. It reminded me of the intensity of being caught in blizzard conditions while driving toward Tahoe in Northern California. But here we were, in Virginia on a very warm and balmy day and the sky had literally opened up with water. What's more, hail was falling. I turned to Brad and asked how could hail exist in such warm conditions? He was stumped and I was fascinated.

With a little detective work, I came up with an answer to the dilemma. Hail is only produced in cumulonimbi clouds (thunderclouds). They usually only occur at the front of a storm system which was what we experienced. The hail hit in the first ten minutes and then was followed by heavy rain. However, the rain was warm to the touch unlike the frozen water making up the hailstones.

The fire in the nearby Great Dismal Swamp National Wildlife Refuge and incredibly hot and humid conditions in Virginia created ideal conditions for hail. Hail is created inside a thunderstorm that has strong updrafts of warm air and downdrafts of cold air. A water droplet with an apex point is picked up by the updrafts and travels into the cooler air and freezes. The apex point known as the condensation nuclei in the water droplet was probably dust from the fire or nearby salt water during this particular hailstorm. (Both Brad and I experienced dry and stinging eyes after going into one of the storms later that weekend, much like the stinging of salt water.) Layers of ice are then accumulated around this nuclei as the droplet goes through a cycle of being caught in an updraft and then carried beyond the freezing level of the atmosphere and then thawing partially in entering the warmer air on a downdraft. This cycle repeats itself creating increasing layers of ice. Then as some point this frozen water droplet with several irregular layers falls to the ground as hail.

Some of the largest hailstones have been recorded during summer storms in humid climates because the warm updrafts and cold downdrafts along with high surface heat create an optimal cycle for large hail. Smaller hailstones can be coupled more easily with larger hailstones in these conditions.

Video of Large Hailstones

Over the course of the weekend, we had three more thunderstorms (one of which broke a car back window nearby) and we kept an eye on a thundercloud that looked like it wanted to become a tornado. I came home very thankful for the fog! NOAA the National and Atmospheric Administration has a National Weather Service. At http://www.weather.gov/ anyone can check weather reports in any given area. To issue proper warnings and forecasts regarding hail, the National Weather Service uses a network of NEXRAD doppler radars to detect it. Hail size and probability can be determined from radar data by a computer by different algorithms and compared to the local atmospheric data to determine the threat level.

It seems the storms have not cleared yet throughout the area in Virginia we visited– severe thunderstorm warnings are still posted on NOAA. So the fireworks might have passed but thunderclouds are still lighting up the sky.

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Illustration of a blast of solar wind impacting
Earth's protective magnetic field. Credit: NASA

Did you know that the Sun also has an atmosphere, and that the Earth is inside it? In fact, the Sun's envelope of gases extends well beyond the orbit of Pluto, out to the regions of the solar system where the 3-decade-old Voyager spacecraft are only now reaching.

"Space weather" refers to the conditions in space caused by the outflow of electrically charged gases (plasma) coming from the Sun—what we call the "solar wind." The term "space weather" may conjure images of cosmic tornadoes, astral lightning bursts, and some Star Trek version of a galactic hurricane– but actual space weather is nothing so Earthly and familiar.

First of all, the "air" in space is nothing like the atmosphere we draw our breath from. Earth air, at the surface, is made of nitrogen, oxygen, argon, carbon dioxide, water vapor, and other trace elements, and is relatively dense. "Space air" is mostly hydrogen– ionized hydrogen at that (meaning stripped of its electrons and so electrically charged; the separated electrons are also blowing along in the solar wind).

Second, the gases of the solar wind are extremely rarified. Despite the talk of a solar atmosphere, solar wind, and space weather, space within the solar system is still almost a complete vacuum. At Earth's distance from the Sun, the average density of the solar wind is somewhere between 6 and 9 atoms (mostly hydrogen) per cubic centimeter. If you spread out the gas contained in an ordinary party balloon to this same thinness, it would fill a volume of space over 10 miles across!

Third, the solar wind, for all its sparseness, blows fast! Depending on conditions of space weather, the flow of solar wind past the Earth can speed along anywhere from 200 to 900 kilometers per second! Earth's fastest winds slug along at only a few hundred kilometers per HOUR.

So how does space weather—the changing conditions of the solar wind—affect us on Earth? How might you, personally, have experienced, directly or indirectly, the effects of the Sun's gentle breeze?

The most familiar phenomenon caused by space weather is Earth's beautiful auroras —the northern and southern lights. Interactions between the solar wind and Earth's magnetic field and electrically charged particles trapped in it excite atoms in the upper atmosphere to emit light. And it's not just a softly glowing night light: the most powerful auroras can generate up to a trillion Watts of power!

Solar wind "storms" can not only produce more active auroras, but can cause fluctuations in Earth's magnetic field whose effects can be felt on the ground. These "geomagnetic storms" usually pass unnoticed, perhaps causing a tiny change in the direction that compass needles point– but have also been known to overload electrical power grids and cause blackouts.

In the space around Earth, solar storms have been known to damage or disable satellites, and can put unprotected astronauts at risk. Space walks on the International Space Station are scheduled for times when space weather is – so to speak -"sunny and calm."

Thinking about space weather on Earth might seem like worrying over Atlantic hurricanes here in the Bay Area—but with more and more human activity taking place beyond the confines of our atmosphere, this is a very real and vital concern, and is taken very seriously.

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.