Showing posts with label impact basins. Show all posts
Showing posts with label impact basins. Show all posts

Monday, March 23, 2009

it's Gravity, Man!

My gravitational field has been determined through tracking of radio signals emited by orbiting spacecraft. This depends on the 'Doppler effect', whereby the spacecraft acceleration in the line-of-sight direction can be detemined by means of small shifts in frequency of the radio signal, and the distance from the spacecraft to the station on your planet, Earth.


However, because of my synchronous rotation, that I mentioned earlier, it is not possible for you to track my 'farside' gravitational field. My 'farside' is thus only poorly characterised.


The major characteristic of my gravitational field that you should know about is the presence of mascons, which are large positive gravitational anomalies associated with some of the giant impact basins. There anomalies greatly influence the orbit of spacecraft about the Moon, and an accurate graviational model is necessary in the planning of both manned and unmanned missions.


Therefore you need to really learn about the difference in my gravitational field, in compairsion to the earth in order to come visit me!!


Do you want to find out how much you would weigh on the moon?


The law of gravity is like a magnet which pulls any matter or attracts any matter. Basically the force of gravity is the attraction between each piece of matter, even the smallest of particles.The Sun's force of gravity holds the planet in its orbit, the Earth's gravity keeps the moon in its orbit.The moon being a small object as compared to earth have weaker gravity. This explains why astronauts on the moon can jump high with very little effort.

Sunday, March 22, 2009

Terrae



My North Pole...


My South Pole...



The lighter-colored regions of my surface are called Terrae, or more commonly just highlands,since they are higher then most of the mare of my surface. Several prominent mountain ranges on the near side are found along the periphery
of the giant impact basins, many of which have been filled by mare basalt. These are believed to be the surviving remnants of the impact basin's outer rims In contrast to the Earth, no major lunar mountains are believed to have formed as a result of tectonic events.

From images of my terrae taken by
the Clementine mission in 1994, it appears that four mountainous regions on the rim of the 73 km-wide Peary crater at my north pole remain illuminated for the entire lunar day. These peaks of eternal light are possible because of the Moon's extremely small axial tilt to the ecliptic plane. No similar regions of eternal light were found at my south pole, although the rim of Shackleton crater illuminated for about 80% of the lunar day. Another consequence of my small axial tilt is regions that remain in permanent shadow to you on earth, at the bottoms of my polar craters.