Polar Stratospheric Clouds at Night

Feb. 14, 2017: Arctic nights are usually colored by the aurora borealis. Last night was different. The colors came from polar stratospheric clouds (PSCs). Lars Lehnert photographed the display from Abisko, Sweden:

“We saw these clouds all day long,” says Lenart, “and they continued into the night. I’ve never seen anything quite like it.”

In Kiruna, Sweden, longtime PSC photographer Mia Stålnacke saw them, too: “This was a first for me!” she says. “The polar stratospheric clouds which lit up the Arctic skies in daylight are still here. Now they are beautifully lit up by the Moon instead!”

This is a remarkable episode of PSCs–the best in many years according to some longtime residents of northern Sweden. Arctic sky watchers should remain alert for more, both day and night, as this unusual winter continues.

Realtime PSC Photo Gallery

Evolution of a Coronal Hole

Dec. 26, 2016: Christmas 2016 was special for sky watchers around the Arctic Circle.  The skies filled with some of the best Northern Lights of the year, including rare outbursts of white and pink. The source of the display: A giant “coronal hole” in the sun’s atmosphere sprayed our planet with solar wind. The hole opened up in July 2016 and it has been strobing Earth with solar wind every ~28 days ever since as the hole pirouettes with the slowly rotating sun.

Spaceweather.com reader Stuart Green has prepared a plot showing the evolution of the coronal hole and the effect it has had on the magnetic field at his private observatory in Preston, England.  Click on the image to inspect the full 6 months:

Inset images come from NASA’s Solar Dynamics Observatory. The coronal hole is the giant dark region, starting small in July, then growing and shape-shifting as the year unfolds.

The background strip chart recording shows the instability of the magnetic field around Green’s private observatory. When the coronal hole is facing Earth, big changes are measured.

“I’ve been recording geomagnetic activity over the past three years using a home built/ home designed magnetometer,” says Green. “The sensor is buried in my garden about 0.5m below the surface in an East/West orientation to allow very sensitive (sub nanotesla) measurements of magnetic declination during geomagnetic storms. The plots show the change in magnetic flux density in nanotesla occurring between readings every 2.5 minutes.”

Green’s presentation suggests that this yawning hole is a long-lived feature on the sun, and it will probably be back as potent as ever 28 days from now.  Stay tuned for magnetic unrest–and more Arctic auroras–in January.

Noctilucent Clouds Appear over Antarctica

Nov. 24, 2016: This just in from NASA’s AIM spacecraft: The sky above Antarctica is glowing electric blue. A ring of bright noctilucent clouds (NLCs) has formed around the South Pole, shown here in a Nov. 24th image taken by the spacecraft’s Cloud Imaging and Particle Size (CIPS) Instrument:

“This season started on Nov. 17th, and is tied with 2013 for the earliest southern hemisphere season in the CIPS data record,” says Cora Randall, a member of the AIM science team at the University of Colorado.

NLCs are Earth’s highest clouds. They form more than 80 km above Earth’s surface. Indeed, they are a mixture of Earth and space:  Wisps of summertime water vapor rising from the planet below wrap themselves around meteoroids, forming tiny crystals of ice. Emphasis on summertime; NLCs appear on the eve of summer in both hemispheres.

There is growing evidence that noctilucent clouds are boosted by climate change.  In recent years they have been sighted at lower latitudes than ever before, and they often get started in earlier months as well.

“The early start of the 2016 season was not at all a surprise,” says Randall. “The southern hemisphere polar stratospheric winds switched to their summer-like state quite early this year.”

Readers, you can monitor developments over Antarctica right here on Spaceweather.com. “Daily daisies” from NASA’s AIM spacecraft are automatically posted every 24 hours, showing the dance of electric-blue around the frozen continent.

Realtime Noctilucent Cloud Photo Gallery

The Heliophysics Summer School: 10 Years and Counting

Some institutions of cutting-edge learning are very old.  Harvard: 380 years.  Princeton: 270 years. Caltech: 125 years.

Others are a little younger.

This year, academicians around the world are celebrating the 10th anniversary of the “Heliophysics Summer School,” a fresh-faced academy that introduces the next generation of scientists to a field of study that, arguably, didn’t even exist when the new millennium began.

“Heliophysics is something new and exciting,” says Lika Guhathakurta of NASA Headquarters.

“It’s a leap across scientific boundaries,” says Karel Schrijver, formerly of the Lockheed Martin Solar & Astrophysics Laboratory.

“It is a blueprint for the Universe,” says Amitava Bhattacharjee, Professor of Astrophysical Sciences at Princeton University.

It begins with Helios, our sun. Of all the objects in the cosmos, the sun affects our planet most. It is the 900lb gorilla of the Solar System, shaping climate, weather, even life itself.

Earth and the sun are deeply and intricately connected, not only by simple rays of light and heat, but also by a complex web of electricity, magnetism, solar wind and extreme ultraviolet radiation.  Lines of electrical current and magnetic force can sometimes be traced, without interruption, all the way from the ground beneath our feet to the base of seething sunspots 93 million miles away.  Our planet and our star are, in a sense, one.

“Back in the early 2000s, NASA had a division called the ‘Sun-Earth connection,’ which recognized this link,” recalls Guhathakurta.  ”When Mike Griffin became the NASA administrator in April of 2005, he asked us to come up with a one-word description of our division that captured both the holistic simplicity and the vast scope of the sun-Earth system. Ultimately it is Sun-Earth connection division director Dick Fisher who is credited with inventing the word ‘heliophysics’.”

Re-naming the “Sun-Earth connection” wasn’t just a marketing ploy, it signaled an authentic shift in thinking about stars and their relationships to planets, moons, asteroids and comets.

“Heliophysics is a unique science,” says George Siscoe of Boston University. “You can see this by realizing that all matter in the universe is organized macroscopically by two long-range forces: gravity and magnetism. As the saying goes, gravity sucks, hence the origin of dense objects like planets, stars, galaxies, etc. But magnetism repels, hence magnetospheres, solar storms, geomagnetic storms, and all large-scale magnetically organized structures in the universe. A very important part of heliophysics is made up of the structures that result when the pull of gravity and the push of magnetism compete.”

Once upon a time, the study of gravity and magnetism were separated by high academic walls.  They had their own textbooks, their own course numbers, and their own professors who rarely talked shop together. Heliophysics breaks down these barriers—and many others.

“In a sense,” says Shrijver, “heliophysics is the equivalent of what ecology is to the life sciences: a discipline that brings awareness of the processes that couple a vast network of conditions into the whole. In order to make heliophysics work as the equivalent of ecology, a sense of community needs to exist: heliophysics is thus also the activity of teaching across traditional discipline boundaries to stimulate the curiosity of one discipline to reach out to the expertise of another.”

Heliophysics plays out on scales ranging from the fusion of subatomic particles taking place in the heart of the sun to the grand sweep of magnetic storms that can engulf entire planets.  It stitches together aspects of weather, climate, plasma physics, Earth science, astronomy, and even biology.  A true heliophysicist is at home discussing all topics, all scales.

Enter the Heliophysics Summer School:

“A new science needs new scientists,” says Guhathakurta, “and 10 years ago we set out to create them. The Heliophysics Summer School was established for this purpose.”

Funded by NASA and managed by UCAR, the first Heliophysics Summer School was convened in July 2007.  The Deans were George Siscoe and Karel Schrijver. During an intense, immersive two-week session, 35 young scientists were instructed by 23 experts in topics ranging from practical techniques in supercomputer modeling to the fundamental physics of magnetic explosions.  Lab sections tested the exhausted but excited students’ mastery of concepts that, heretofore, were rarely discussed in the same room, much less the same lab activity.

Since then hundreds of students from dozens of countries have attended the summer school.  Graduates with extraordinary promise compete for and receive Jack Eddy Fellowships, named after John A “Jack” Eddy, a pioneering researcher in solar physics who shaped thinking about the Sun-Earth connection in the 20th century. These fellowships provide the support they need to continue their studies as heliophysics post-docs at leading Universities.  Later, some Jack Eddy Fellows return to the Heliophysics Summer School as instructors.

“We’ve created a whole heliophysics life cycle,” says Guhathakurta.  “Caterpillars enter the cocoon of the Summer School and emerge as beautiful Heliophysics butterflies.  Jack Eddy Fellows are the Monarchs.”

Not bad for a school that’s only 10 years old…

Stay tuned for the next article in this series: The Heliophysics Textbooks.

Earth’s Inconstant Magnetic Field

by Dr. Tony Phillips (Spaceweather.com)

Every few years, scientist Larry Newitt of the Geological Survey of Canada goes hunting. He grabs his gloves, parka, a fancy compass, hops on a plane and flies out over the Canadian arctic. Not much stirs among the scattered islands and sea ice, but Newitt’s prey is there–always moving, shifting, elusive.

His quarry is Earth’s north magnetic pole.

At the moment it’s located in northern Canada, about 600 km from the nearest town: Resolute Bay, population 300, where a popular T-shirt reads “Resolute Bay isn’t the end of the world, but you can see it from here.” Newitt stops there for snacks and supplies–and refuge when the weather gets bad. “Which is often,” he says.

Scientists have long known that the magnetic pole moves. James Ross located the pole for the first time in 1831 after an exhausting arctic journey during which his ship got stuck in the ice for four years. No one returned until the next century. In 1904, Roald Amundsen found the pole again and discovered that it had moved–at least 50 km since the days of Ross.

The pole kept going during the 20th century, north at an average speed of 10 km per year, lately accelerating “to 40 km per year,” says Newitt. At this rate it will exit North America and reach Siberia in a few decades.

Keeping track of the north magnetic pole is Newitt’s job. “We usually go out and check its location once every few years,” he says. “We’ll have to make more trips now that it is moving so quickly.”

Earth’s magnetic field is changing in other ways, too: Compass needles in Africa, for instance, are drifting about 1 degree per decade. And globally the magnetic field has weakened 10% since the 19th century. When this was mentioned by researchers at a recent meeting of the American Geophysical Union, many newspapers carried the story. A typical headline: “Is Earth’s magnetic field collapsing?”

Probably not. As remarkable as these changes sound, “they’re mild compared to what Earth’s magnetic field has done in the past,” says University of California professor Gary Glatzmaier.

Sometimes the field completely flips. The north and the south poles swap places. Such reversals, recorded in the magnetism of ancient rocks, are unpredictable. They come at irregular intervals averaging about 300,000 years; the last one was 780,000 years ago. Are we overdue for another? No one knows.

see captionLeft: Magnetic stripes around mid-ocean ridges reveal the history of Earth’s magnetic field for millions of years. The study of Earth’s past magnetism is called paleomagnetism. Image credit: USGS. [more]

According to Glatzmaier, the ongoing 10% decline doesn’t mean that a reversal is imminent. “The field is increasing or decreasing all the time,” he says. “We know this from studies of the paleomagnetic record.” Earth’s present-day magnetic field is, in fact, much stronger than normal. The dipole moment, a measure of the intensity of the magnetic field, is now 8 × 1022 amps × m2. That’s twice the million-year average of 4× 1022 amps × m2.

To understand what’s happening, says Glatzmaier, we have to take a trip … to the center of the Earth where the magnetic field is produced.

At the heart of our planet lies a solid iron ball, about as hot as the surface of the sun. Researchers call it “the inner core.” It’s really a world within a world. The inner core is 70% as wide as the moon. It spins at its own rate, as much as 0.2° of longitude per year faster than the Earth above it, and it has its own ocean: a very deep layer of liquid iron known as “the outer core.”

see captionRight: a schematic diagram of Earth’s interior. The outer core is the source of the geomagnetic field.

Earth’s magnetic field comes from this ocean of iron, which is an electrically conducting fluid in constant motion. Sitting atop the hot inner core, the liquid outer core seethes and roils like water in a pan on a hot stove. The outer core also has “hurricanes”–whirlpools powered by the Coriolis forces of Earth’s rotation. These complex motions generate our planet’s magnetism through a process called the dynamo effect.

Using the equations of magnetohydrodynamics, a branch of physics dealing with conducting fluids and magnetic fields, Glatzmaier and colleague Paul Roberts have created a supercomputer model of Earth’s interior. Their software heats the inner core, stirs the metallic ocean above it, then calculates the resulting magnetic field. They run their code for hundreds of thousands of simulated years and watch what happens.

What they see mimics the real Earth: The magnetic field waxes and wanes, poles drift and, occasionally, flip. Change is normal, they’ve learned. And no wonder. The source of the field, the outer core, is itself seething, swirling, turbulent. “It’s chaotic down there,” notes Glatzmaier. The changes we detect on our planet’s surface are a sign of that inner chaos.

They’ve also learned what happens during a magnetic flip. Reversals take a few thousand years to complete, and during that time–contrary to popular belief–the magnetic field does not vanish. “It just gets more complicated,” says Glatzmaier. Magnetic lines of force near Earth’s surface become twisted and tangled, and magnetic poles pop up in unaccustomed places. A south magnetic pole might emerge over Africa, for instance, or a north pole over Tahiti. Weird. But it’s still a planetary magnetic field, and it still protects us from space radiation and solar storms.

And, as a bonus, Tahiti could be a great place to see the Northern Lights. In such a time, Larry Newitt’s job would be different. Instead of shivering in Resolute Bay, he could enjoy the warm South Pacific, hopping from island to island, hunting for magnetic poles while auroras danced overhead.

Sometimes, maybe, a little change can be a good thing.


March 31, 2016: Around the USA, science fairs are underway in all 50 states. Middle-school student Sydney R. of Turlock, California, decided to do her experiment at the edge of space. On March 23rd, she flew packets of baker’s yeast to the stratosphere onboard an Earth to Sky Calculus helium balloon. The fungi reached an altitude of 116,181 feet:

At the apex of the flight, the yeast absorbed doses of cosmic radiation more than 100x Earth-normal. Meanwhile, back on Earth, control samples remained in their usual place in the kitchen cupboard. The two samples, flown vs. control, form the basis of Sydney’s experiment.

She plans to do some “space baking.” Sydney has a recipe for brownies that calls for yeast, and she is going to prepare the dessert using both kinds of leavening. Does space yeast make the same delicious brownies as terrestrial yeast? Hungry astronauts would love to know.