mare’s tails are wispy cirrus clouds while . . . mackerel scales are small clumpy altocumulus clouds resembling fish scales in the sky. In the days of large sailing ships, this meant a storm would be approaching soon and the sails should be lowered to protect from the accompanying high winds.
A Brocken spectre is an apparently gigantic shadow cast in fog or mist, often surrounded by an aura. According to Wikipedia:
The "spectre" appears when the sun shines from behind a climber who is looking down from a ridge or peak into mist. The light projects the climber's shadow forward through the mist, often in an odd triangular shape due to perspective. The apparent magnification of size of the shadow is an optical illusion that occurs when the observer judges his shadow on relatively nearby clouds to be at the same distance as faraway land objects seen through gaps in the clouds, or when there are no reference points at all by which to judge its size. The shadow also falls on water droplets of varying distances from the eye, confusing depth perception. The ghost can appear to move (sometimes quite suddenly) because of the movement of the cloud layer.
The Nonist has an article on Brocken spectres today, with a good collection of photos.
In considering future earthquake events, Elnashai noted that there
are two seismic mechanisms that affect the Midwest--the Wabash Valley,
with a calculated capability of a 7.1 magnitude, which will shake the
region about 900 times more violently than the West Salem earthquake in
April 2008, and the New Madrid Zone, which is capable of up to
magnitude 8, which will shake the region more than 2,700 times more
"Under such earthquakes, the ground in some critical
regions will liquefy, as it did in 1811-1812," he added. As with other
disaster scenarios, untold indirect consequences also await populations
in the region. In winter, power--and heat--will be out for weeks, as
well as water and telecommunications. Highways and bridges will be
closed along with rail lines and major metropolitan airports in
Chicago, St. Louis, and Memphis. High-rise buildings in Chicago will
lose windows and other attachments such as TV towers.
On other worlds that circle different kinds of stars, photosynthesis would grab different colored photons and produce different colored plants:
Plants on both F- and K-star planets could have colors just like
those on Earth but with subtle variations. For F stars, the flood of
energetic blue photons is so intense that plants might need to reflect
it using a screening pigment similar to anthocyanin, giving them a blue
tint. Alternatively, plants might need to harvest only the blue,
discarding the lower-quality green through red light. That would
produce a distinctive blue edge in the spectrum of reflected light,
which would stand out to telescope observers.
The range of M-star temperatures makes possible a very wide
variation in alien plant colors. A planet around a quiescent M star
would receive about half the energy that Earth receives from our sun.
Although that is plenty for living things to harvest—about 60 times
more than the minimum needed for shade-adapted Earth plants—most of the
photons are near-infrared. Evolution might favor a greater variety of
photosynthetic pigments to pick out the full range of visible and
infrared light. With little light reflected, plants might even look
black to our eyes.
From a fascinating, highly detailed and well-explained article at Scientific American by Nancy Y. Kiang.
Sundogs form as sunlight is refracted by hexagonal
plate-like ice crystals with diameters larger than 30 micrometers
and their flat faces horizontally oriented.
Sundogs are visible when the sun is
near the horizon and on the same horizontal plane
as the observer and the ice crystals.
As sunlight passes through the ice crystals, it is bent by 22 degrees
before reaching our eyes, much like what happens with 22-degree halos. This bending of light
results in the formation of a sundog.
The difference between
sundogs and halos is the preferential orientation of the
ice crystals through which the light passes before reaching our eyes.
If the hexagonal crystals are oriented with their flat faces horizontal,
a sundog is observed. If the hexagonal crystals are randomly oriented,
a halo is observed.