Early last week I wrote an article about how new data from Voyager 1 shed light on the structure of the Sun’s heliosphere and solar wind. Just a few days after that, researchers announced evidence of Earth’s own space wind!

Scientists proposed the existence of a space wind surrounding Earth about 20 years ago, but direct detection has eluded scientists until now.

Earth is surrounded by a magnetic field that encloses our magnetosphere. The plasmasphere is the inner part of that magnetosphere, and it looks a giant donut made of electrically-charged particles called (as its name suggests) plasma.

The Sun’s magnetic activity can accelerate plasma toward Earth, which impacts our magnetosphere. During such solar storms, we have observed plumes of material transfer between the plasmasphere and the outer magnetosphere, but researchers also proposed the existence of a steady flow of plasma that occurs around the clock. After years of theoretical work, Iannis Dandouras of the Research Institute in Astrophysics and Planetology in Toulouse, France, has directly detected this wind in data from the European Space Agency’s Cluster spacecraft.

Dandouras measured the properties of charged particles in the plasmasphere to find that the forces governing plasma motion exist slightly out of balance, forming a steady wind.

“After long scrutiny of the data, there it was, a slow but steady wind, releasing about one kilogram of plasma every second into the outer magnetosphere. This corresponds to almost 90 tons every day. It was definitely one of the nicest surprises I’ve ever had!” said Dandouras.

Don’t worry, the plasmasphere won’t evaporate away: it also refills. Dandouras reassured everyone that “due to the plasmaspheric wind, supplying plasma—from the upper atmosphere below it—to refill the plasmasphere is like pouring matter into a leaky container.”

Michael Pinnock, Editor-in-Chief of Annales Geophysicae, recognizes the importance of the new result. “It is a very nice proof of the existence of the plasmaspheric wind. It’s a significant step forward in validating the theory. Models of the plasmasphere, whether for research purposes or space weather applications (e.g. GPS signal propagation) should now take this phenomenon into account.”

We can even apply our understanding of Earth’s plasmaspheric wind to other places. Why wouldn’t another planet such as Jupiter or Saturn experience the exact same phenomenon? The Solar System could be a very windy place!

Alyssa Keimach is an astronomy and astrophysics student at the University of Michigan and interns for the Morrison Planetarium.

Image: NASA

The surface temperature of the Sun is about 6,000 Kelvins, while the outer edge of the Sun’s atmosphere, called the corona, can reach millions of Kelvins. Normally, we think of things cooling down the farther they get from an energy source… So how can temperature increase with distance from the Sun’s surface?

The Interface Region Imaging Spectrograph (IRIS) spacecraft launches from the Vandenberg Air Force Base in California on June 27th, with the intention of studying how the corona gets so hot.

“I wonder if maybe we were staring too hard at the corona to understand the corona,” says IRIS scientist Charles Kankelborg, a physicist at Montana State University. “It may be that by backing out we can get some vital clues to what’s happening.”

Between the Sun’s surface and the corona lies a layer of plasma called the chromosphere. Scientists hope that studying this area of lower atmosphere will help them uncover the reason behind the Sun’s strange temperature patterns.

From Earth, we can only observe the layer in question during a total solar eclipse, when the Moon blocks the Sun, and observers can see the halo of glowing light behind the Moon. For IRIS to see this section of sun, it will take images at temperatures between 4,500 Kelvins and 65,000 Kelvins, and ultraviolet spectra between 4,5000 Kelvin and 107 Kelvin.

IRIS is specially designed to target this little understood region of the Sun’s atmosphere. The spacecraft will follow a polar orbit—always facing the Sun—to trace the flow of energy and plasma from the lower layer of the Sun’s surface through the chromosphere and into the corona. Detailed information on this process could give astronomers an archetype for other stellar atmospheres.

Dr. Alan Title, IRIS principal investigator and physicist at the ATC Solar and Astrophysics Laboratory in Palo Alto, is excited for the launch. “With IRIS, we have a unique opportunity to provide significant missing pieces in our understanding of energy transport on the Sun. The complex processes and enormous contrasts of density, temperature and magnetic field within this interface region require instrument and modeling capabilities that are now finally within our reach.”

The launch takes place on Thursday, so the newest data about our closest star are coming soon!

You can watch the launch here at 6:00pm PDT!

Alyssa Keimach is an astronomy and astrophysics student at the University of Michigan and interns for the Morrison Planetarium.

Image: NASA