HOW TO SEEM INTELLIGENT 101
It is simple! Just use the words
"Mmm-hmm," "Uh-huh" and "Yeah" when a person is talking to you. And then occasionally say the
last few words from what they have just said. Then say "Sounds cool." Simple! See?
Simple. Sounds cool."
Named for the Roman messenger god, who flew
from Olympus on winged heels, this little planet flits back and forth from morning sky to evening sky several times a year.
Unfortunately, it never strays far from the Sun in our sky, so it's tough to find in the glare. From the northern hemisphere,
the best times to see it in the morning this year come in early September and late December, when it looks like a moderately
bright star low in the southeast shortly before dawn. In the evening, Mercury is best seen around the end of March.
Venus, the dazzling morning or evening star, outshines all the other stars and planets in the night sky. It's
the brilliant "evening star" from the beginning of the year until early June. It then disappears in the Sun's glare
for a few days, but emerges by mid-month as the "morning star." It flirts with Mars in April and early May, then
stages a spectacular pairing with Jupiter in the morning sky in early November.
After last year's spectacular
appearance in the summer and autumn sky, Mars is a much less commanding presence this year. As 2004 begins, it appears high
overhead at nightfall, and looks like a bright yellow-orange star. It drops lower in the sky during the winter and spring,
losing a bit of brightness as it does so, then passes behind the Sun in September. It reemerges in the pre-dawn sky by around
Halloween. It stages a beautiful encounter with Venus in the western evening sky in April and early May, and passes just a
couple of degrees from Saturn in late May.
The largest planet in our solar system is a commanding
presence in the night sky for much of the year. It looks like an intensely bright cream-colored star, shining brighter than
anything else in the night sky except the Moon and Venus. It's at "opposition" in early March, when it appears brightest
for the year, and remains visible all night. It will disappear "behind" the Sun in September, then return to view
before dawn by the middle of October. Jupiter and Venus pair up in the early morning sky the first few days of November.
Saturn looks like a golden star. It spends the entire year in Gemini, although it flirts with the border
to Cancer in the fall before reversing direction and moving back toward the center of Gemini. It's brightest at the beginning
and end of the year, when it's closest to us.
Although it's the third-largest planet in the solar
system, it's so far from the Sun that you need binoculars to see it. It spends the year in the constellation Aquarius. It
stages its best appearance in August.
The fourth-largest planet in the solar system is so far away
that you need a telescope to find it. Neptune appears in the constellation Capricornus, and stages its best appearance in
The solar system's smallest and most distant planet is never visible without the aid of a good-sized
telescope. It's in the constellation Ophiuchus.
How big is the solar system?
The farthest known object
orbiting our Sun is a ball of ice and rock unofficially called Sedna, which lies about 10 billion miles away right now, although
its highly elliptical orbit will carry it up to 84 billion miles from the Sun. Early measurements made from California's Palomar
Observatory show that the object is probably 800 to 1,100 miles in diameter.
Another hop, skip, and a jump takes
us to the heliopause, where the stream of particles emitted by the Sun collides with the galactic gases of interstellar space,
forming a so-called "bow shock." The boundary between the Sun's influence and interstellar space may lie as much
as 15 billion miles ahead of the Sun's path through the galaxy, and more than 30 billion miles behind it.
still is the Oort Cloud, believed to be the source of extremely long-period comets (Hale-Bopp, for instance). This dark, incredibly
cold region awaits interstellar travelers nearly six trillion miles away -- almost a quarter of the distance to the nearest
"Why should I become
angry? Will anger change a problem?"
WITH CAT GODDESS
"Imediate assumption can close many doors."
A BILLION YEARS AGO
A billion years ago, the Moon was much closer to Earth than it will be
tonight. Its tighter orbit meant it needed just 20 days to go around us, to make a lunar month. Other things were noticeably
different, too. A day on Earth back then was only 18 hours long. People were probably wishing, "If only I had 24 hours
in a day…"
Okay, there were no people then, but the critters of the time eventually got their wish.
In the intervening eons, the Moon has been drifting away. Each year, it moves about 1.6 inches (4 centimeters) farther into
It is a coincidence of orbital and species evolution that we humans are on this planet during an era when
we can work 24/7, should that be demanded.
Also by coincidence, we're here when the Moon's apparent size in the
sky is equal to that of the Sun, so that a total solar eclipse is possible. Furthermore, we arrived comfortably after the
pockmarked satellite began showing just one face to Earth, providing that immutable and unchanging beacon we call a full Moon,
cosmic governor of terrestrial love and a lot of loony ideas.
Or, one could argue, none of this is coincidence
at all. If not for the Moon, some say, love as we know it would never have happened and we wouldn't be here to contemplate
Earth's orbiting treasure.
The Moon has had dramatic effects on our planet and the life that inhabits it, researchers
believe. The Moon stabilizes Earth's rotation, for example, preventing otherwise dramatic movements of the poles that would
fuel climate swings that some scientists figure might have doomed any chance for life to form, let alone evolve.
And biologists speculate that tides, generated mostly by the Moon, would have been a logical place for life to originate.
Sea creatures might have then used tidal regions as experimental sites for testing the habitability of land, and therefore
as an excuse to develop lungs. Put short, your gilled ancestors might have used the Moon like a gravitational guiding light
to the first non-aquatic procreation.
In that sense, the only coincidence in all this is the fact that the Moon
ever came to exist in the first place. For there was a brief time in the early history of our planet, likely 100 million years
or less, when there was no Moon in the sky.
The Earth has recently been forged out of the detritus of star formation,
assembled from dust that became rock, then boulders that collided and grew. Other planetary hopefuls roam the solar system.
Impacts are frequent. The scene is hectic.
A large rock, about the size of Mars, is doomed. It's heading toward
Earth, destined for a slightly off-center impact that will set everything that isn't already rotating into a frenzy of spin.
Upon impact, material from the incoming object and from the new Earth is cast into space. A ring of debris orbits
the planet, and in an amazingly short amount of time -- about one day -- it begins to coalesce into a satellite. It takes
somewhere between 1 and 100 years for the Moon to gather most of the stuff into a ball.
There are other theories
for how the Moon was born, but this one is widely accepted as the most plausible.
Earth may or may not have been
rotating before the impact, but it certainly was afterward. Importantly, the orbital and rotational mechanics of this new
Earth-Moon system were then planned out for all time. The impact imparted angular moment on the system, a spin that could
never be destroyed, the laws of physics tell us. Curiously, the specific relationships would change over time -- dramatically
-- and the shifts continue today.
During the past 4.5 billion years, Earth's overwhelming gravity has slowed the
Moon's rotation down and pushed the satellite away. The cause is complex, involving tides, which we'll discuss below. One
amazing result, for now, is a readily observable set of very interesting facts: It takes the Moon 29.5 days to make one revolution
about its axis. All the while, of course, the Moon is also going around the Earth. This orbit also takes 29.5 days.
Because the Moon's orbit and rotation times are the same, the satellite always shows the same face to Earth. We see that
face because sunlight reflects off it (the Moon does not make its own light).
On the Moon, all this means that
the Sun rises every four weeks, roughly. It also means there is no "dark side" of the Moon, at least not to someone
living in any hypothetical Lunaville. The side of the Moon we cannot see from Earth gets its full share of sunshine periodically,
when the Moon is between Earth and the Sun. In this configuration, the Moon is said to be new, and it reflects no sunlight
There was a time, however, when the timing was much different.
Gravity is said to be the weakest
of all the fundamental forces. But one aspect of it is very consequential: Gravity never goes away. It weakens with distance,
but it is always at work. This fact is the primary driver of tides. The side of Earth nearest the Moon always gets tugged
more than the other side, by about 6 percent.
Hey, you might say, there are two high tides on this planet at any
given moment. True. And another far more complex set of phenomena explains this.
The Moon does not just go around
the Earth. In reality, the two objects orbit about a common gravitational midpoint, called a barycenter. The mass of each
object and the distance between them dictates that this barycenter is inside Earth, about three-fourths of the way out from
So picture this: The center of the Earth actually orbits around this barycenter, once a month. The
effect of this is very important. Think, for a second, of a spacecraft orbiting Earth. Its astronauts experience zero gravity.
That's not because there's no gravity up there. It's because the ship and its occupants are constantly falling toward Earth
while also moving sideways around the planet. This sets up a perpetual freefall, or zero-g.
Like the orbiting spaceship,
the center of the Earth is in free-fall around the barycenter of the Earth-Moon system.
Here's the kicker: On
the side of Earth opposite the Moon, the force of the Moon's gravity is less than at the center of the Earth, because of the
greater distance. It can actually be thought of as a negative force, in essence, pulling water away from the Moon and away
from Earth's surface -- a second high tide.
Our planet rotates under these constantly shifting tides, which is
why high and low tides are always moving about, rolling in and rolling out as far as observers on the shore are concerned.
The Sun, too, has a tidal effect on Earth, but because of its great distance it is responsible for only about one-third
of the range in tides. When the Earth, Moon and Sun are aligned (at full or new Moon), tides can be unusually dramatic, on
both the high and low ends. When the Moon is at a 90-degree angle to the Sun in our sky (at first quarter or last quarter)
tides tend to be mellower.
Earlier, we said tides are at the root of alterations in the entire Earth-Moon orbital
system. Here's how: Earth spins once a day, while the Moon goes around the planet at a more plodding pace, once a month. So
the planet is always trying to drag tides along, and it succeeds a bit.
The high-tide bulges are pulled just ahead
of an imaginary line connecting the centers of Earth and the Moon. It might seem rather amazing, but a terrestrial bulge of
water has enough mass to tug at the Moon from yet another angle. The effect is to constantly prod the Moon into a higher orbit,
which explains why it is moving away from us.
The Moon, meanwhile, is yanking back on the tidal bulges. So the
water, down where it meets the ocean floor, rubs against Earth. This slows the planet down, explaining why there are 24 hours
in a day instead of the mere 18 of a billion years ago.
Finally, we need to bring up another factor that helped
all these opposing dynamics reach an agreement of sorts:
More than just water is pulled up by tides. Earth's solid
self actually stretches, too. And Earth's gravity lifts tides on the Moon, raising relatively small bulges in the seemingly
solid satellite. (Similarly, Jupiter's gravity raises tides on its icy moons in the frigid outer region of the solar system,
stretching some so dramatically that the action generates enough heat to maintain liquid oceans under their frozen shells,
Back to our Moon: Continual tugging on the lunar bulges reduced the Moon's rotation rate
over time. When the rotation had slowed to the point that it equaled the time it took for the Moon to go around the Earth,
the lunar bulges lined up with our planet, and the slowdown stopped. At that moment, one face of the Moon became forever locked
in our direction.
Earth's rotation rate is still slowing down -- our days are getting longer and longer. Eventually,
our planet's tidal bulges will be assemble along that imaginary line running through the centers of both Earth and the Moon,
and our planetary rotational change will pretty much cease. Earth's day will be a month long. When this happens, billions
of years from now, the terrestrial month will be longer -- about 40 of our current days -- because during all this time the
Moon will continue moving away.
In this future picture, any lunar colonists would then henceforth see just one
face of Earth. You can imagine this setup by stretching your arm out and looking at your palm. Now twirl around. You're face
and your palm stare at each other the whole time. If the United States happens to be on the back of your head, well, just
think what people there do not see.
The upshot: One day your descendants, if they survive a swelling Sun and other
cosmic and human perils, will have at least 960 hours to work with each day. On some nights, half the world will be able to
stare up at a full Moon for what seems like days and days. Imagine the loony things they'll have time to imagine, the strange
lore they might conjure.
STUFF TO HELP LOOK INTELIGENT
The monarch butterfly can discern tastes
12,000 times more subtle than those perceived by human taste buds.
The word "horse" in horseradish has
no relation to the animal of the same name. It means "coarse" or "rough."
In the mid-sixteenth
century, the ruler of Japan ordered that all the swords in the nation be collected and melted down. The metal was then used
to build a huge statue of Buddha.
Most dinosaurs lived to be more than a hundred years old.
is the only dog that has a black tongue. The tongues of all other dogs are pink.
Socrates, one of the most famous
Greek philosophers, never wrote down a single word of his teachings. The only knowledge we have today comes from notes taken
by his great student, Plato.
(IF ALL ELSE FAILS: VALIUUM)