The solar flare itself—an unusually bright spot on the sun—was only a "moderate" event. Space observatories in the past year recorded about 70 such solar flares, each roughly ten times weaker than "extreme" flares, of which only two have occurred since 2007.
Instead, what shocked scientists was the unusual amount of material that lofted up, expanded, and fell back down over roughly half the surface area of the sun. The event's simultaneous launch of particles into space is called a coronal mass ejection.
Image courtesy SDO/NASA
Aurora Over the Yukon
As seen through a fisheye lens, a green aurora arcs above northwestern Canada's Yukon Territory in early May.
Taken at midnight, the picture also shows stars trailing around the north celestial pole—the point in the sky around which all the stars observed from the Northern Hemisphere rotate.
Springtime at Mars's icy south pole is seen in an image released June 7 by the European Space Agency.
Most of the image, taken by the Mars Express orbiter, shows the southern polar ice cap and other scattered ice deposits. Some dark, dusty material (left) covers part of the ice cap.
Fewer than 620 miles (a thousand kilometers) from Mars's geographic south pole, the ice here is a relatively thin at 1,640 feet (500 meters) deep. By contrast, the ice at the pole can extend to more than 2.3 miles (3.7 kilometers) deep.
Visible from far-northern parts of the Europe and Asia—including areas where the sun doesn't set during this time of year—the eclipse at times turned the sun into a glowing "smile" hugging the horizon.
"We had a lot of clouds at the sky earlier in the evening, but fortunately there was a perfect sight on the sun at the time of the eclipse," photographer Thilo Bubek said in an email.
The Hubble Space Telescope captured two billowy objects—part of a nascent nebula—in an image released June 6. A nebula is a cloud of gas or dust in interstellar space.
The cosmic body, called IRAS 13208-6020, was formed from material shed by a central star. The relatively short-lived billowing phenomenon shown here gives astronomers a chance to observe the early stages of nebula development, according to the European Space Agency.
The space shuttle Endeavour docks at the International Space Station on May 29, as seen in a series of stills from a video taken from Pau, France. The shuttle is unloading its cargo, the Alpha Magnetic Spectrometer (AMS).
Photograph courtesy Thierry Legault and Emmanuel Rietsch
River in Flux
In central Louisiana's stretch of the Mississippi River, years of human engineering have led to differing water elevations. In the above picture, dark green represents the lowest elevations—around 26 feet (8 meters)—and brighter green shows the highest—around 92 feet (28 meters).
Completed in the 1960s, the region's system of levees, locks, floodgates, and canals has so far successfully kept the river from meandering westward, as it has done several times over the centuries, according to NASA's Earth Observatory website.
After a year in isolation, six men participating in the Mars500 experiment grin in a picture released by the European Space Agency on June 3.
The men have spent 365 days in a facility near Moscow that mimics nearly every aspect of a flight to Mars, an eventual goal of the ESA.
Their simulated craft is composed of four sealed interconnected cylinders. Each crew member has his own private cabin, and the team lives and works very much like the astronauts on the International Space Station.
"The dark side of this routine is that every day for the past year we woke up at the same time to do the same medical controls with the same devices: No weekend or holiday breaks for a year!" crew member Romain Charles wrote in his diary.