A surprise observation of negative mass in exciton–polaritons has added yet another dimension of weirdness to these strange light-matter hybrid particles. Dr. Matthias Wurdack, Dr. Tinghe Yun and Dr.

Update Monday 8 p.m.: The coronal mass ejection (CME) arrived earlier and stronger than expected, around sunset on Monday. The planetary index (abbreviated Kp for it's German equivalent) initial ...