Friday, October 23, 2009

Darkside of the Moon

Pink Floyd's Darkside of the Moon album had nothing to do with the moon; however, still great music. We have all heard of the phrase 'dark side of the moon', but is there really a dark side?

Did you know... observers from earth always see the same side of the moon. How can this be? According to statistical data, the rate of rotation is equal to the rate of revolution around earth. With these two values similar, the same side of the moon always faces earth. Think about this: if the rate of rotation was equal to the rate of revolution around the sun for earth, then one side of Earth will be extremely hot and the other side will be extremely cold.

The dark side of the moon is a fictitious phrase. Think about this: when the moon is at the new moon phase, the observer from earth sees a "dark moon" the other side of the moon is all lit (as though it is a full moon). In reality, we should call that portion of the moon we do not see from earth as simply as "the other side".


Lunar Morphology



Many people think that our moon is made out of cheese. From a scientific standpoint, that is definitely false. There are many striking things we can see from earth when looking at the moon. Look at this picture, what can you see?
  • Large dark spots;
  • Mainly white colored
The moon has 1/6 of the gravitational field of earth. As such, it is easier to jump off of the surface of moon and stay afloat than on earth. Also, gases cannot be bound to the moon's surface (no gases = no atmosphere). Free celestial rock bodies (meteoroids) that are directed into the moon's orbit will eventually collide with it. When these meteorites strike the moon's surface, they produce many impact craters.

The large dark spots are called Maria. Early scientists thought the spots were lunar seas and maria is Latin for sea. These spots are iron-rich in composition as compared to the lighter areas of the moon (silicate-rich).

Another striking thing is lunar temperature. During the day when insolation from the sun is at the greatest, the temperature of the lit side of the moon can get as high as 240°C and on the other side of the moon can get as low as -240°C. The extremely low temperature is due to the lack of the sun's radiation.

Giant Impact


Since scientists were not around 4.4 to 4.5 billion years ago, scientists must think of ways as to how the moon was made and how earth may have captured it in it's gravitational field.

The successful Apollo moon landing narrowed several theories down to a single theory. Scientists analyzed moon dust and rock samples that were retrieved from the Apollo 11 mission. The samples were high in silicates, which is very similar to Earth's mantle composition.

The
Giant Impact between Earth and another planet-sized body seems to be a logical solution. I read this journal article from the Nature weekly science journals that corresponds to this data. Apparently, this planet-like celestial body collided with Earth in its molten state. As this planetesimal departed from the collision, it collected Earth's molten material, which cooled to form a silicate rich crust.

Thursday, October 1, 2009

Is it spring again?


I cannot tell you that walking past the Northport Harbor the horrendous odor you can encounter. Why does this occur? Well we experience two high and low tides per day. During low tide, sea level is at its lowest point, and during high tide, sea level is at its highest point. The differences between tides are best seen inside a harbor or along the shoreline where a significant summer or winter berm is present.

When low tide is near, villages and towns release sewage effluent into the nearby harbor or inlet. The horrendous odor that I smelled came from storm water effluent, or decaying organic matter.

Why do we experience tides? Due to the gravitational forces between earth, sun, and moon. Since the moon is a celestial body orbiting around earth, the moon and earth have a gravitational attraction. The pull of the moon slightly displaces the earth. We experience high tides where the earth is facing the moon and directly opposite of the same. The remaining two sides of the earth experience low tide (see picture).

When the sun is mixed into the equation, it enhances earth's high and low tides. When the sun, earth, and moon are aligned in a straight line, the high tides are even higher! These tides are called spring tides. When the three celestial bodies are not aligned, the tides are lower. When the moon positioned perpendicular to the sun in Earth's orbit, the tides are even lower than normal! These tides are called neap tides. This animation on tides really depict spring and neap tides. The above image demonstrates the lunar phases along with spring and neap tides.

Use this hyperlink to learn more on tides from the NOAA website:

National Oceanic and Atmospheric Administration: Tides and Currents

Friday, September 25, 2009

Total ECLIPSE of the Heart


Professor Coch at Queens College always established a few rules during my undergraduate experience. First, he stated that you should never eat yellow snow. Second, when living on Long Island, always pick up after your dog. Lastly, never stare at a solar eclipse. I guess it sounds like the Christmas Story movie, "You'll burn your eyes out kid!" Anyway, there are two types of eclipses, 1) solar and 2) lunar. During my lifetime, I only had a few chances to observe partials or annular eclipses. An eclipse occurs when a large planet-like body passes into a shadow that is created by another planet-like body.

A solar eclipse is by far the most interesting. When this type of eclipse occurs, It can be 1 p.m. in the afternoon and it can be pitch black as though it is 1 a.m. There is an infrequent location where a solar eclipse can occur. This is because the moon smaller than Earth and therefore would cast a much smaller shadow, especially when the moon is farthest from Earth in its orbit (apogee). Check out this NASA photograph of a solar eclipse from outer space just above this paragraph. When all factors are conducive to produce a total eclipse, a portion of Earth will pass in the moon's shadow called the umbra. Careful observers can see the moon moving into the sun and block all incoming solar radiation from reaching us. Careful observers who are located in the less concentrated shadow (prenumbra), can see a partial solar eclipse. Check out this picture: solar eclipse.

A spectacular site to see is a lunar eclipse. The moon has a reddish-orange-brown appearance in comparison to its grayish-white color. This occurs when incoming solar radiation is (visible light) is absorbed and the remaining light red and orange is refracted as it reaches the moon. The occurence is very similar to the solar eclipse, except now the moon passes through Earth's larger shadow, especially when the moon is closest to Earth (perigee). The words umbra and penumbra
are still used when discussing shadows from a planet-like body. Check out this picture: lunar eclipse.

Lunar Phases:
Solar: New Moon Phase
Lunar: Full Moon Phase
* See moon phases below

Eclipse Types:
Solar: Partial, Annular, Total
Lunar: Partial, Total

Schedules:
Solar
Lunar

Observing Solar Eclipse
Protection

Source: MrEclipse.com

Wednesday, September 23, 2009

Who said the Apollo moon landing was a fake?

I was brought up understanding that Buzz and Armstrong were the first humans to set foot on the moon. This was a huge accomplishment because Russia was right behind the United States in the race to the moon. I'm glad our country won that footrace. After viewing some material from Fox 5, it left me second guessing. Did Buzz and Armstrong really land on the moon, or land on a Hollywood set to depict the conditions of the moon? Well, I'll let you be the judge of that. Take a look at these 5-minute clips. It is quite disturbing...

You Tube:
Part I
Part II
Part III
Part IV
Part V