HOW FAST IS EARTH MOVING THROUGH SPACE?
To begin with, Earth is
rotating on its axis at the familiar rate of one revolution per day. For those of us living at Earth's midlatitudes -- including
the United States, Europe, and Japan -- the rate is almost a thousand miles an hour. The rate is higher at the equator and
lower at the poles. In addition to this daily rotation, Earth orbits the Sun at an average speed of 67,000 mph, or 18.5 miles
a second.
Perhaps that seems a bit sluggish -- after all, Mars Pathfinder journeyed to Mars at nearly 75,000 miles
per hour. Buckle your seat belts, friends. The Sun, Earth, and the entire solar system also are in motion, orbiting the center
of the Milky Way at a blazing 140 miles a second. Even at this great speed, though, our planetary neighborhood still takes
about 200 million years to make one complete orbit -- a testament to the vast size of our home galaxy.
Dizzy yet?
Well hold on. The Milky Way itself is moving through the vastness of intergalactic space. Our galaxy belongs to a cluster
of nearby galaxies, the Local Group, and together we are easing toward the center of our cluster at a leisurely 25 miles a
second.
If all this isn't enough to make you feel you deserve an intergalactic speeding ticket, consider that we,
along with our cousins in the Local Group, are hurtling at a truly astonishing 375 miles a second toward the Virgo Cluster,
an enormous collection of galaxies some 45 million light-years away.
As Vinnie said: "Don't worry about it."
WHY DO PLANETS CHANGE POSITION IN THE NIGHT SKY?
Are they catholic? No, but seriously, the planets appear to change position against the "fixed"
stars in the night sky because of the relative motion of both Earth and the planets as we all move along in our orbits around
the Sun. The swift-moving inner planets Venus and Mercury can move from morning to evening appearances and back again in as
little as a few months. The giant outer planets such as Jupiter or Saturn, with orbits taking decades to complete, appear
to move more slowly against the background of stars.
WHAT IS A RED
GIANT?
A state of stellar evolution beyond the main-sequence
life of a star. A red giant core is degenerate ionized helium, surrounded by a shell of hydrogen fusion, that expands the
outer atmosphere in response to higher core temperatures. The hydrogen fusing shell eats through the surrounding atmosphere
and deposits helium onto the shrinking core. The ballooning atmosphere cools and glows red; hence red giant. The Sun will
become a red giant the size of Earth's orbit in five to six billion years. Once the helium core reaches 100 million degrees,
it explosively begins fusing helium. The birth of the active helium core is called the helium flash. The Sun as a red giant
will fuse helium for about 2 billion years after the helium flash.
WHAT IS A BLACK HOLE?
An object with such powerful gravity that nothing can escape
from it, including light. The black hole's mass is concentrated in a point of almost infinite density called a singularity.
At the singularity itself, gravity is almost infinitely strong, so it crushes normal space-time out of existence. As the distance
from the singularity increases, its gravitational influence lessens. At a certain distance, which depends on the singularity's
mass, the speed needed to escape from the black hole equals the speed of light. This distance marks the black hole's "horizon,"
which is like its surface. Anything that passes through the horizon is trapped inside the black hole. Black holes come in
several varieties, depending on mass.
OTHER COOL QUESTIONS!
HOW DID THE CONSTELLATIONS GET THEIR NAMES?
Most
constellation names are Latin in origin, dating from the Roman empire, but their meanings often originated in the distant
past of human civilization. Scorpius, for instance, was given its name from the Latin word for scorpion, but ancient Egyptian
hieroglyphs from before 3000 B.C. refer to the star group as "Ip," the scorpion king. Orion, the hunter, bears a
Greek name, but had been seen as a hunter-hero figure since the times of ancient Babylon.
WHAT
ARE METEOR SHOWERS?
An increase in the number of meteors
at a particular time of year is called a meteor shower. Comets shed the debris that becomes most meteor showers. As comets
orbit the Sun, they shed an icy, dusty debris stream along the comet's orbit. If Earth travels through this stream, we will
see a meteor shower. Depending on where Earth and the stream meet, meteors appear to fall from a particular place in the sky,
maybe within the neighborhood of a constellation.
Meteor showers are named by the constellation from which meteors
appear to fall, a spot in the sky astronomers call the radiant. For instance, the radiant for the Leonid meteor shower is
located in the constellation Leo. The Perseid meteor shower is so named because meteors appear to fall from a point in the
constellation Perseus.
HOW CAN I BEST VIEW
A METEOR SHOWER?
If you live near a brightly lit city,
drive away from the glow of city lights and toward the constellation from which the meteors will appear to radiate.
For example, drive north to view the Leonids. Driving south may lead you to
darker skies, but the glow will dominate the northern horizon, where Leo rises. Perseid meteors will appear to "rain"
into the atmosphere from the constellation Perseus, which rises in the northeast around 11 p.m. in mid-August.
After you've escaped the city glow, find a dark, secluded spot where oncoming
car headlights will not periodically ruin your sensitive night vision. Look for state or city parks or other safe, dark sites.
Once you have settled at your observing spot, lay back or
position yourself so the horizon appears at the edge of your peripheral vision, with the stars and sky filling your field
of view. Meteors will instantly grab your attention as they streak by.
HOW DO I KNOW THE SKY IS DARK ENOUGH TO SEE METEORS?
If you can see each star of the Little Dipper, your eyes have "dark adapted," and your chosen site is probably
dark enough. Under these conditions, you will see plenty of meteors.
WHAT SHOULD I PACK FOR METEOR SHOWER WATCHING?
Treat
meteor watching like you would the 4th of July fireworks. Pack comfortable chairs, bug spray, food and drinks, blankets, plus
a red-filtered flashlight for reading maps and charts without ruining your night vision. Binoculars are not necessary. Your
eyes will do just fine.
"KEEP
LOOKING UP!"
( Rose Marie's Website www.SassieCat.com )
REMEMBER
"Imagination
is more important than knowledge. Knowledge is limited; Imagination encircles the world."
-Einstein
EXPLORE YOUR OWN SPACE/LIFE IDEAS
COSMIC ANCESTRY SPACE SCIENCE ASK AN ASTRONOMER LINEAR? WHAT'S THAT?
"Keep looking
up."
LINEAR? WHAT'S THAT??
"Nothing can be more contrary to religion and the clergy than reason and common sense."
-Francois Marie Arouet "Voltaire", French author
and playwright
www.Techno-Geeks.org
