Un STEVE lumineux et la Voie Lactee
Image Credit:
NASA,
Krista Trinder
What's creating these long glowing streaks in the sky?
No one is sure.
Known as
Strong Thermal Emission Velocity Enhancements (STEVEs),
these luminous light-purple sky ribbons may resemble
regular auroras,
but recent research reveals significant differences.
A STEVE's great length and unusual colors, when measured precisely,
indicate that it may be related to a
subauroral ion drift (SAID),
a supersonic river of hot atmospheric
ions thought previously to be
invisible.
Some STEVEs are
now also thought to be accompanied by
green picket fence structures, a series of
sky slats that can appear outside of the main
auroral oval that
does not involve much glowing
nitrogen.
The featured wide-angle composite
image shows a STEVE in a dark sky above
Childs Lake,
Manitoba,
Canada in 2017,
crossing in front of the central band of our
Milky Way Galaxy.