Noctilucent clouds are usually made of tiny ice crystals and glow in the night sky. Sunlight from below the horizon shines through the cloud causing the glow. They are common at very high latitudes and rarely seen at mid latitudes like here in the United States.
However early this morning, the Japanese launched a rocket from the Uchinoura Space Centre in Japan. It launched at just the right time, in just the right conditions so that it's trail created a huge plume of ice crystals in the high atmosphere.
The noctilucent cloud it produced was visible across a large part of Japan.