The
purpose of this feature is to give scout leaders, educators and naturalists an
idea of some of the natural events coming up each month. We will try to
cover a variety of natural events ranging from sky events to calling periods of
amphibians, bird and mammal watching tips, prominent wildflowers and
anything else that comes to mind. We will also note prominent
constellations appearing over the eastern horizon at mid-evening each month for
our area for those who would like to learn the constellations. If you have
suggestions for other types of natural information you would like to see added
to this calendar, let us know!
Though we link book references to nationwide sources, we encourage you to
support your local book store whenever possible.
Notes From August 2022
Celer Crab Spider on Late Boneset, 08/30/22 iPhone image.
In "The Outermost House" Henry Beston wrote of animals; "We
need another and a wiser and perhaps more mystical concept of animals...we
patronize them for their incompleteness, for their tragic fate for having
taken form so far below ourselves. And therin do we err. For the animal
shall not be measured by man. In a world older and more complete than
ours, they move finished and complete, gifted with the extension of the
senses we have lost or never attained, living by voices we shall never
hear."
I was reminded of this passage recently when I was learning about new
studies on the phenomenon of ballooning in spiders. When ballooning, a
spider stands on tiptoes, raises its abdomen in the air and produces silk
threads that catch the wind. Many species use this technique to disperse,
including the species shown at right. You can see a study of crab spiders
ballooning here. All three
species shown are common this time of year. In my area, crab spiders can
be found on Late Boneset (also called Late-flowering Thoroughwort) and
other flowers. The Scarlet Sheetweaver is quite common even on suburban
lawns. If you get out of bed while the dew is still present, their webs
are easy to see. They hang beneath the web, usually in the center. Colors
vary from the bright red shown to orange and yellow-brown. Bowl and Doily
Spiders, named for their bowl-shaped webs and the flat web beneath (doily
is an old word for a flat circular ornamental mat), are found among
vegetation and shrubs, and sometimes amoung the branches of eastern cedars.
Scarlet Sheetweaver beneath dew-covered web, May 8th, 2015
These tiny aeronauts have been known to travel long distances.
Ballooning spiders have appeared on ships hundreds of miles from land and
have been detected on weather balloons above 16,000 feet. The phenomenon
has been known since Aristotle, and Charles Darwin encountered thousands
of ballooning spiders when he was 60 miles from the coast of Argentina
during his historic voyage on the Beagle. The sails of the ship were
covered in gossamer, the fine threads that spiders produce from the tip of their abdomen.
One thing puzzled him about the spiders. There was no wind at all, but the
spiders still launched off the ship. He wrote, "I repeatedly observed the
same kind of small spider, either when placed or having crawled on some
little eminence, elevate its abdomen, send forth a thread, and then sail
away horizontally, but with a rapidity which was quite unaccountable."
There is a famous quote by the late science fiction writer Isaac Asimov;
"The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it) but "That's funny..."
It seemed like there was some other force besides the wind that
helped enable flight. Electrical forces were suspected in the 19th
century, with some hypothesizing that the multiple silk threads
used in ballooning did not tangle because they had the same electrical
charge and repelled each other. But the first
experiment to prove the role
of the atmospheric electrical field in ballooning was conducted by the University of
Bristol in Bristol, England in 2018. The experiment was designed to see if
spiders could use the electrical field that surrounds the Earth, called
the
global atmospheric electrical circuit, to lift off and fly without the
presence of any wind. This electrical field is a voltage gradient that
increases with altitude and extends from the surface of the Earth to the
upper reaches of the atmosphere. We humans are not aware of it except when
the field is very strong, usually in dangerous situations where lightning
is about to strike. If you are hiking and feel your hair standing on end,
immediately go downslope and get flat to the ground. But spiders and some insects like bees and bumblebees can sense small
distortions in the electrical field around vegetation and structures and
make use of them. This atmospheric potential gradient could not sustain
itself without continuous recharging by thunderstorms around the world. If
you have ever wanted to delve into physicist Richard Fyneman's famous
lecture series, you can find his lecture on electricity in the atmosphere
here.
Bowl and Doily Spider beneath dew-covered web,
March 31st, 2012
In the Bristol experiment spiders were placed on a pinnacle inside a box in
which no air movement was possible. A voltage gradient similar to what is
experienced in nature was put across the box that could be switched on and
off. When it was switched on the spiders immediately assumed the
ballooning position and produced silk from their abdomens. Some of them
then floated around the box. When the voltage gradient was switched off,
the spiders descended, when it was switched back on the spiders rose. The
spiders sense the electric field via mechanosensitve hairs on their legs
called trithrobothria. These hairs are extremely sensitive.
It's fascinating to me that spiders can make use of this unseen
atmospheric field and even navigate it. Those spiders that encounter water
while ballooning
do have some means to survive it in mild conditions.
Is there anything these creatures can't do?
The best times of year to encounter ballooning in spiders is
in the spring and the fall.
Sky Events for September 2022
The Autumnal Equinox
for the Northern Hemisphere
will occur on 9:04pm EDT on September 22, signaling the
beginning of fall.
Jupiter May 8th, 2015. 20" Newtonian Reflector and ZWO ASI
120MMS camera.
Morning Sky:
Venus
will continue to rise before the Sun, but it will sink lower and
lower into the morning twilight each day. On September 5th Venus
and Regulus will rise side by side about 30 minutes before
sunrise. Venus will disappear into the Sun's glare around the
middle of October. After the great morning planetary vistas of the
summer, Mars is the only other planet rising in the morning hours,
and it just barely. The red planet rises just after midnight in
Taurus. Watch for it to come closest to Aldebaran, the red eye of
Taurus the bull, on September 7th. At that time it will be about 4
and a half degrees away. Mars is steadily brightening as it comes
to opposition in December. Its apparent diameter is around 10
seconds of an arc this month, small, but allowing some details to
be seen in most telescopes.
Evening Sky:
Saturn will be low in the southeast after sunset at the beginning
of the month in Capricornus. Neptune rises about 40 minutes after
sunset in Aquarius. Jupiter rises about an hour after sunset and
should be in great viewing position this month.
The four Galilean moons cans be spotted in binoculars, as can
Jupiter's disk. Uranus rises about an hour and 45 minutes after
sunset.
Constellations:
The Andromeda Galaxy.
Nikon 300mm f2.8 Lens at f4.0.
The views below show the sky looking east at 10:45pm EDT on September 15th.
The first view shows the sky with the constellations outlined and names
depicted. Star and planet names are in green. Constellation names are in
blue. The second view shows the same scene without labels.
In Andromeda, see if you can pick out the soft glow of the Andromeda
Galaxy. It's shown on the chart below. Don't expect to see the colors and
detail that you see in the photograph at right. It's just a soft glow with
the naked eye and binoculars. But if you succeed in spotting it, you'll be
seeing an object that's about 2.5 million light-years distant, and looking
back 2.5 million years in time as well.
Small telescopes may allow you to pick out the two brightest satellite
galaxies of the Andromeda Galaxy . These are NGC 205 (visible below
the core of the Andromeda Galaxy in the image at right) and NGC 221
(visible above and to the left of the core). Your best chance to see them
will be when the galaxy is high overhead. If you are in a pristeen dark
sky, far from city lights, you may be able to spot the two satellite
galaxies in binoculars.
September 15th, 10:45pm EDT, Looking East
September 15th, 10:45pm EDT, Looking East
On Learning the
Constellations:
We advise learning a few constellations each month, and
then following them through the seasons. Once you associate a particular
constellation coming over the eastern horizon at a certain time of year, you may
start thinking about it like an old friend, looking forward to its arrival each
season. The stars in the evening scene above, for instance, will always be
in the same place relative to the horizon at the same time and date each
September.
Of course, the planets do move slowly through the constellations, but with
practice you will learn to identify them from their appearance. In
particular, learn the brightest stars for they will guide you to the fainter
stars. Once you can locate the more prominent constellations, you can
"branch out" to other constellations around them. It may take you a little
while to get a sense of scale, to translate what you see on the computer screen
or what you see on the page of a book or app to what you see in the sky. Look for
patterns, like the stars that make up the "Square of Pegasus."
The
Earth's rotation causes the constellations to appear to move across the sky just
as the Sun and the Moon appear to do. If you go outside earlier than the
time shown on the charts, the constellations will be lower to the eastern
horizon. If you observe later, they will have climbed higher.
As each season progresses, the Earth's motion around the sun
causes the constellations to appear a little farther towards the west each night
for any given time of night.
A good book to learn the constellations is
Patterns in the Sky, by Hewitt-White.
For sky watching tips, an inexpensive good guide is
Secrets of Stargazing, by Becky Ramotowski.
A good general reference book on astronomy is the Peterson
Field Guide,
A Field Guide to the Stars and Planets, by Pasachoff. The book retails for around $14.00.
The Virtual
Moon Atlas is a terrific way to learn the
surface features of the Moon. And it's free software. You can
download the Virtual Moon Atlas here.
Apps:
The Sky Safari 6 basic version is free and a great aid for
the beginning stargazer. I really love the
Sky Safari 6 Pro. Both are available for iOS and
Android operating systems. There are three versions. The Pro is
simply the best astronomy app I've ever seen.
The description of the Pro version reads, "includes over 100 million stars, 3 million galaxies
down to 18th magnitude, and 750,000 solar system objects; including every comet
and asteroid ever discovered."
You may also want to try the very beautiful app
Sky Guide.
Though not as data intensive as Sky Safari, Sky Guide goes all out
to show the sheer beauty of the night sky.
Great for locating the planets.
A
nother
great app is the Photographer's
Ephemeris. Great for finding sunrise, moonrise, sunset and
moonset times and the precise place on the horizon that the event will
occur. Invaluable not only for planning photographs, but also nice
to plan an outing to watch the full moon rise. Available for both
androids and iOS operating systems.
Amphibians:
Marbled Salamander
Frog and toad choruses start waning in September but some frogs and toads
are still calling. Spring Peepers
are also know as "Autumn Pipers" and can be heard calling from patches of
woods during the fall. Listen also for the very dry and scratchy
version of the Upland Chorus Frog's song on rainy fall evenings.
Green Frogs and Southern Leopard Frogs occasionally call.
You can locate many species that have been calling more frequently earlier
in the year by driving the back roads slowly on rainy nights.
You can sometimes find
the eggs of Marbled Salamanders in wooded wetlands in the fall.
Nature Notes Archives: Nature Notes
was a page we published in 2001 and 2002 containing our observations about
everything from the northern lights display of November 2001 to frog and
salamander egg masses.
Night scenes prepared with The
Sky Professional from Software Bisque
