Lunar Gateway

Plugging a space station (Lunar Gateway) into orbit around the Moon makes a lot of sense if you’re going to put a permanent base on the surface. I’m sure that it will grow in time in much the same way as the International Space Station has. The timetable for this orbiting Lunar station is the late 2020’s.

Technology, experience and advances made in this effort will help to refine the first human journey to Mars and the establishment of a permanent colony.

I doubt that Communist China would be invited along for a ride.

China in Focus

Fire erupts in the southern Chinese city of Guangzhou. The blaze engulfs a 4-story factory before firefighters managed to extinguish it. It’s still unclear what sparked it.

A port city in China claims over 10 million residents all tested negative for the virus. But Taiwan’s health minister says those results are near impossible.

Failing to seek justice through the legal system, some Chinese citizens appear to be finding new ways to vent their anger toward authorities.

Beijing warned the U.S. it may detain Americans in China. That’s in response to the Justice department’s prosecution of Chinese military-affiliated scholars.

A controversial pathway to immigration has been officially closed. Chinese tycoons and communist regime officials had used it to migrate to Europe.

The Sun

Gamma radiation from the sun was thought to come from cosmic rays interacting with the sun’s magnetic field and then colliding with gas molecules near its surface. But this long-standing theory doesn’t account for the observed strength and other features of the solar gamma-ray signal. Credit: 5W Infographics for Quanta Magazine.

A decade’s worth of telescope observations of the sun have revealed a startling mystery: Gamma rays, the highest frequency waves of light, radiate from our nearest star seven times more abundantly than expected. Stranger still, despite this extreme excess of gamma rays overall, a narrow bandwidth of frequencies is curiously absent.

The surplus light, the gap in the spectrum, and other surprises about the solar gamma-ray signal potentially point to unknown features of the sun’s magnetic field, or more exotic physics.

“It’s amazing that we were so spectacularly wrong about something we should understand really well: the sun,” said Brian Fields, a particle astrophysicist at the University of Illinois, Urbana-Champaign.

The unexpected signal has emerged in data from the Fermi Gamma-ray Space Telescope, a NASA observatory that scans the sky from its outpost in low-Earth orbit. As more Fermi data have accrued, revealing the spectrum of gamma rays coming from the sun in ever-greater detail, the puzzles have only proliferated.

Not only is the gamma-ray signal far stronger than a decades-old theory predicts; it also extends to much higher frequencies than predicted, and it inexplicably varies across the face of the sun and throughout the 11-year solar cycle. Then there’s the gap, which researchers call a “dip” — a lack of gamma rays with frequencies around 10 trillion trillion hertz. “The dip just defies all logic,” said Tim Linden, a particle astrophysicist at Ohio State who helped analyze the signal.

The likely protagonists of the story are particles called cosmic rays — typically protons that have been slingshotted into the solar system by the shock waves of distant supernovas or other explosions.

Physicists do not think the sun emits any gamma rays from within. (Nuclear fusions in its core do produce them, but they scatter and downgrade to lower-energy light before leaving the sun.) However, in 1991, the physicists David Seckel, Todor Stanev and Thomas Gaisser of the University of Delaware hypothesized that the sun would nonetheless glow in gamma rays, because of cosmic rays that zip in from outer space and plunge toward it.

Based on the rate at which cosmic rays enter the solar system, the estimated strength of the sun’s magnetic field, the density of its atmosphere, and other factors, Seckel and colleagues calculated the mirroring process to be roughly 1 percent efficient. They predicted a faint glow of gamma rays.

Yet the Fermi Telescope detects, on average, seven times more gamma rays coming from the solar disk than this cosmic-ray theory predicts. And the signal becomes up to 20 times stronger than predicted for gamma rays with the highest frequencies. “We found that the process was consistent with 100 percent efficiency at high energies,” Linden said. “Every cosmic ray that comes in has to be turned around.” This is puzzling, since the most energetic cosmic rays should be the hardest to mirror.