ARLA/CLUSTER: "Polar Mesospheric Summer Echoes" em VHF no Artico

[João Costa > CT1FBF]

Polar Mesospheric Summer Echoes

Around the Arctic Circle, VHF radio signals are starting to echo from
Earth's upper atmosphere--a phenomenon called 'Polar Mesospheric
Summer Echoes.'

This is a sign that ice is crystallizing around specks of meteor
debris, forming the first noctilucent clouds of summer. Soon, their
electric-blue tendrils may be visible to the naked eye in the night
skies of northern countries.

Visit Spaceweather.com for observing tips and more information about PMSEs