A cosmic explosion of gigantic proportions kept astronomers on tenterhooks in mid-October - the closest and possibly most energetic gamma-ray burst (GRB) ever observed. The GRB, designated GRB 221009A, occurred at a distance of about 2.4 billion light-years in the direction of the constellation Arrow. It was first detected on the morning of Oct. 9 by X-ray and gamma-ray space telescopes, including NASA's Fermi Gamma-ray Space Telescope, the Neil Gehrels Swift Observatory and the Wind spacecraft. As news of this discovery quickly spread, two teams of astronomers worked closely with Gemini South staff to obtain the earliest possible observations…