In 1181 AD, a bright "guest star" was observed to linger in the sky for around six months. Nearly 850 years later, the likely remnants of this event were rediscovered and tentatively linked to the ...

The third known visitor from interstellar space, comet 3I/ATLAS, is putting on a show that plays out in high‑energy light instead of visible fireworks. As it barrels through the inner solar system, ...