BRIGHT JUPITER-MOON CONJUNCTION: When the sun goes down tonight, step outside and look south. The waxing gibbous Moon is approaching Jupiter for a beautiful conjunction alongside the red giant star Antares. At closest approach on Friday, Aug. 9th, Jupiter and the Moon will be only a few degrees apart. If you can, catch them before the evening sky fades to black. A bright conjunction framed by twilight blue is extra-beautiful. Sky map: August 9. Browse: photo gallery.
AURORA FALLS: On August 5th, a fast-moving stream of solar wind hit Earth's magnetic field. Paul Zizka was at Wapta Falls in British Columbia when the sky overhead turned green:
"This is a self-portrait taken during the fabulous display we had a few nights ago-our first significant auroras in several months here in the Canadian Rockies," says Zizka.
Another stream of solar wind is approaching Earth. Estimated time of arrival: Aug. 10-11. The incoming stream is flowing from a southern hole in the sun's atmosphere. It is not as potent as the solar wind stream of August 5th, but still could spark auroras over Canada and other high-latitude locations. Aurora alerts: SMS Text.
Realtime Aurora Photo Gallery
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A NEW SOURCE OF SPACE RADIATION: Astronauts are surrounded by danger: hard vacuum, solar flares, cosmic rays. Researchers from UCLA have just added a new item to the list. Earth itself.
“A natural particle accelerator only 40,000 miles above Earth’s surface is producing ‘killer electrons’ moving close to the speed of light,” says Terry Liu, a newly-minted PhD who studied the phenomenon as part of his thesis with UCLA Prof. Vassilis Angelopoulos.
This means that astronauts leaving Earth for Mars could be peppered by radiation coming at them from behind–from the direction of their own home planet.
NASA’s THEMIS spacecraft ran across the particles in 2008 not far from the place where the solar wind slams into Earth’s magnetic field. Researchers have long known that shock waves at that location could accelerate particles to high energies–but not this high. The particles coming out of the Earth-solar wind interface have energies up to 100,000 electron volts, ten times greater than previously expected.
How is this possible? Liu found the answer by combining THEMIS data with computer simulations of the sun-Earth interface. When the solar wind meets Earth, it forms a shock wave around Earth’s magnetic field, shaped like the bow waves that form ahead of a boat moving through water. Within this “bow shock” immense stores of energy can be abruptly released akin to the sonic boom of an airplane.
Liu found that some electrons are shocked not just once, but twice or more, undergoing mirror-like reflections within the bow shock that build energy to unexpected levels. Most of the boosted particles shoot back into space away from Earth.
Above: Dr. Terry Liu created this diagram showing the location of the natural particle accelerator and how it sprays radiation into space.
“Similar particles have been detected near Saturn, suggesting that the process is at work there as well,” says Liu. “Indeed,” adds Angelopoulos, “this type of particle acceleration could be happening throughout the cosmos–from supernovas to solar storms–wherever a supersonic wind hits a barrier.”
Meanwhile, back home, Earth-orbiting satellites and departing astronauts have a new source of radiation to contend with. It’s right over their shoulder.
Read the original research at Science Advances.
THIS GIFT IS GENIOUS: What would Einstein think!? On June 8, 2019, the students of Earth to Sky Calculus launched a cosmic ray balloon to the stratosphere. This Albert Einstein bobblehead went along for the ride:
Albert contemplated the curve of the Earth for almost 3 hours as the balloon ascended 111,222 feet above the Sierra Nevada Mountains of central California.
You can have him for $66.74--that is, 10 times the gravitational constant, G. The students are selling these bobbleheads to support their cosmic ray ballooning program. They make great novelty gifts! Each one comes with a greeting card showing the item in flight and telling the story of its journey to the edge of space.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education