How long does it take sunlight to reach the Earth?

Here's a question… how long does it take sunlight to reach Earth? This sounds like a strange question, but think about it. Sunlight travels at the speed of light. Photons emitted from the surface of the Sun need to travel ...

8th century gamma ray burst irradiated the Earth, study finds

(Phys.org)—A nearby short duration gamma-ray burst may be the cause of an intense blast of high-energy radiation that hit the Earth in the 8th century, according to new research led by astronomers Valeri Hambaryan and Ralph ...

Scientists detect dark lightning linked to visible lightning

(Phys.org)—Researchers have identified a burst of high-energy radiation known as 'dark lightning" immediately preceding a flash of ordinary lightning. The new finding provides observational evidence that the two phenomena ...

Red Crucifix sighting in 774 may have been supernova

(Phys.org) -- A supernova may have actually been the mysterious "Red Crucifix" in the sky that is cited in the Anglo Saxon Chronicle for the year 774. New correspondence between a university student and Nature carries interesting ...

Spinning black hole powers jet by magnetic flux

Black holes are at the center of almost all galaxies that have been studied so far. They have an unimaginably large mass and therefore attract matter, gas and even light. But they can also emit matter in the form of plasma ...

Blazars

(PhysOrg.com) -- A blazar is a galaxy which, like a quasar, has an intensely bright central nucleus containing a supermassive black hole. In a blazar, however, the emitted light sometimes includes extremely high energy gamma ...

Astronomers detect ultra-high energy gamma-ray source

Astronomers from the Chinese Academy of Sciences (CAS) and elsewhere report the detection of a new ultra-high energy (UHE) gamma-ray source in the Galactic plane. The newly identified source, designated LHAASO J0341+5258, ...

NASA's Swift and Fermi missions detect exceptional cosmic blast

Astronomers around the world are captivated by an unusually bright and long-lasting pulse of high-energy radiation that swept over Earth on Sunday, Oct. 9. The emission came from a gamma-ray burst (GRB)—the most powerful ...

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