Explanation:
Today's solstice,
the astronomical beginning of summer in the north,
is at 23:09 UT when the Sun reaches the northernmost declination in
its yearly trek through planet Earth's sky.
While most in the northern hemisphere will experience the longest
day of the year,
for some the Sun won't set at all,
still standing just above the horizon at midnight as
far south as about 66.6 degrees northern latitude.
Of course, as summer comes to the north the midnight Sun comes earlier
to higher latitudes.
Recorded near midnight,
this
time series from June 6 follows the Sun
gliding above a mountainous horizon
from a latitude of 69 degrees north.
The remarkable scene looks north over the Norwegian Sea from
Sortland, Norway.
The 2012 transit of Venus
is already in progress, with Earth's
sister planet in silhouette at the upper left against the bright
disk of the midnight Sun.