Aurorae glow when
charged atom
particles trapped in Earth's magnetosphere
cascade into the upper atmosphere (ionosphere).more
than 50 miles.(80
km).up,
producing photons as the
particles.interact
with atmospheric gases. When coronal
mass ejections from the Sun buffet our magnetosphere in a turbulent
way, a veritable
storm of protons and electrons showers down.
Midnight is the best time
to see their spectacular action. The light energy in their displays depends
upon the nature of the molecules involved. Nitrogen gases in the atmosphere
create blueish hues.
Oxygen creates greenish hues. An equal amount of both creates reddish hues.
Southern aurora can be seen in the southern hemisphere,
New Zealand, etc. Northern aurora can be seen throughout the northern hemisphere.
See also 'energy from space'.
Forecast of activity:.gi.alaska.edu/AuroraForecast
You can change
how much time you have left here.
Select a satellite to view
the Earth from: fourmilab.ch/Earthview/satellite.html
View of Earth's
lights at night. Can you spot your city or area?
X-ray.photographs
of the sky.(xrtpub.harvard.edu/);
of the Sun:.sohowww.nascom.nasa.gov/data/realtime-images.html
Got question as to the why
of things? See the WhyFiles.(whyfiles.org).
Know what
the Analemma is?
A free download
for you from John Walker.(thanks
John), co-author of AutoCAD 
.(fourmilab.ch/homeplanet/).and,
view the Earth from anywhere, the Sun, Moon, etc: (fourmilab.ch/Earthview/vplanet.html).
It's a comprehensive
astronomy / space / satellite tracking package for Microsoft Windows.
Good astronomy software
for the Mac and Windows: TheSky III by bisque.com; StarryNight Deluxe by
siennasoft.com; MegaStar Sky Atlas by willbell.com
Einstein's General
Theory of Relativity.
-Quantum
mechanics teaches us that, at the deepest level, uncertainty
rules the universe. There are things we cannot predict, even in principle.
HotBits.(fourmilab.ch/hotbits/).harnesses
this fundamental uncertainty of nature to generate truly random bits, unlike
the pseudo.random.sequences
created by an algorithm
on a computer. Along the way, you'll find a discussion of the hardware
and software used to generate the random bytes comprehensive enough to
build your own, and peek under the hood of quantum mechanics to see why
the data are genuinely random, and some of the implications of all this.
-xsunclock.(fourmilab.ch/xsunclock/):
shows you, as an icon or resizeable window, the portion of the Earth currently
day and night.
-More from John: Astronomy
and space links.(fourmilab.ch/)
-Astronomy link: planetary.org
According to
Astronomy,
January 2000, pages 28-30, Chandra.(NASA's
X-ray Observatory).images
reveal a never before seen ring of x-rays around the
pulsar
at the heart of the Crab Nebula.
"Chandra
was able to see the light
year wide ring because the space telescope's angular
resolution is 10 times sharper than any other
x-ray
observatory.
"It seems as though we are
finally seeing the glowing power conduit
that connects the Crab pulsar
and the
nebula".says
Arizona State University astronomer Jeff Hester.."The
ring is exactly in the place that it needs to be in order to be the thing
that ties the pulsar to the larger nebula.
"The Crab Nebula has a ring
surrounding its central pulsar and high speed jets shoot out from the highly
energetic pulsar in opposite directions."
-Why is light is at a constant
speed and what
produces it? The speed is just a physical measurement of the space
that occurs over time, that's why light is always at the same speed no
matter how fast you may be going. The matter through which light travels
is set.(how?).to
keep the speed of light constant and so
is gravity. This is just how the universe is set up to work as it does.
If the speed of the wave.(particles
of light).were
to fall, charge would be deposited faster than picked up, resulting in
a net creation of positive charge. If it weren't constant, then charge
conservation.(a
central tenet
of physics).would
be breached.
James B. Kaler is based
at the University of Illinois and studies and reports on a new star weekly.
James wrote Beyond the Rainbow,
Astronomy, September 2000.
His most recent book is Cosmic Clouds. On the next page, he talks
about light, from his latest book.
