Lunar Eclipse, the Moon’s Interior, and the Holy GRAIL

By Sami Asmar

Earth's moon

In addition to the awesome views they offer, lunar eclipses have always provided scientific clues about the moon’s shape, location and even surface composition. Although there will continue to be opportunities for observers to examine and reflect on fundamental concepts about the moon, such as its origin and interior structure, more modern tools are aiding these observations.

When it comes to understanding what a moon or a planet is made of remotely — short of touching it or placing seismometers on its surface or probes below the surface — classical physics comes to the rescue. By measuring the magnetic and gravitational forces that are generated on the inside and manifested on the outside of a planet or moon, we can learn volumes about the structure of its interior.

A spacecraft in the proximity of the moon can detect these forces. In the case of gravity, the mass of the moon will pull on the spacecraft due to gravitational attraction. If the spacecraft is transmitting a stable radio signal at the time, its frequency will shift by an amount exactly proportional to the forces pulling on the spacecraft.

This is how we weigh the moon and go further by measuring the detailed distribution of the densities of mountains and valleys as well as features below the moon’s surface. This collection of information is called the gravity field.

In the past, this has lead to the discovery mascons on the moon, or hidden, sub-surface concentrations of mass not obvious in images or topography. If not accounted for, mascons can complicate the navigation of future landed missions. A mission, human or robotic, attempting to land on the moon would need to have a detailed knowledge of the gravity field in order to navigate the landing process safely. If a spacecraft sensed gravitational pull higher than planned, it could jeopardize the mission.

GRAIL spacecraft

The Gravity Recovery and Interior Laboratory (GRAIL) mission, scheduled to launch in September, is comprised of twin spacecraft flying in formation with radio links between them to measure the moon’s gravity field globally. This is because a single spacecraft with a link to Earth would be obstructed when the spacecraft goes behind the moon, leaving us with no measurement for nearly half of the moon, since the moon’s far side never faces the Earth. The GRAIL technique may also reveal if the Moon has a core with a fluid layer.

So as you go out to watch the lunar eclipse on the night of Dec. 20, think about how much we’ve learned about the moon so far and what more we can learn through missions like GRAIL. Even at a close distance from Earth, the moon remains a mystery waiting be uncovered.

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    3 Responses to “Lunar Eclipse, the Moon’s Interior, and the Holy GRAIL”

  1. Richardo Brown A.A A,S Says:
    December 20th, 2010 at 9:41 am

    I’am Richardo Brown A.A. A.S. And I’ am a Planetary Society volunteer who is waiting for the opportunity to Send a Message in Space on the C.D. Rom of the Grail satellite next September I have a NASA / Planetary Society send a message certificate on the LRO.
    I love my research paper on the Moon, it is a world I would request for geological sediments and metaphoric rocks from its continental crust and mantle, I would station radio telescopes in a X,Y field range for deep space observation (perfect for the moons far side), I wohld assemble a doomed scientific astronomical laboratory of space research for all the sciences found to experiment and research with.

    Research Paper

    The Moon: Exploring This World

    Richardo Brown: Signature installed and instrimented on the Lunar Reconnanse Orbiter

    Craters dot the moon’s surface. Materials thrown from impacts that made them centers radial patterns of bright ejecta with scars left over by objects that smashed the earth in our early solar system of the star: Sun. The largest are the impact basins, enormous craters raning up to around (1,553mi) across. Lava flooded the basin floor sometime after titanic collisions formed them, creating the smooth, dark surfaces that the eye grography maps as Marias or Seas. Blocks of rock hurled formed with impacts gathering nd becoming larger made what is called the satelite of planet Earth.

    Fissures, domed hills and wrinkling ridges all fissioned togther with ancient volcanic lava and weak gravity formed geological igeious basalt and metamorhic anothosite. The lunar surface is sheathed in regolith, a fine dusty tikite,creared by constant bombardment of astroids, comets, and meteoroids. The geology of the moon was brought back to planet Earth by six crews of Apollo astronants from 1969 to 1972. The rocks and dust were copmpletely dry discovering the moon has no water of itas own. The moon is sometimes bombarded by icy – water rick comets. Most of the cometary water evaporizates into space, but some of it may be trapped as ice in the bottoms of shadowing craters near the lunar polars until a few years ago today the temperature on the moons at it coldest point was -274 degrees.

    The highlands of the moon are packed together indicating that these ancient areaswere hit repeatedly by astroids and comets and planetoids, in the violent days of our solar system.

    My naming of a few mares (seas ) on the satelitte Moon:

    Near side to the planet Earth:

    Oceanus Procellarum

    Mares: Frigorius, Serenitatis, Imbrium, Tranquilitatis, Crisium, Fecunditatis, Humorum, Nubrium, Nectaris, orientale, Cognitum.

    Grography on the United States and European Space Agencies landings on the Moon:

    Apollo 11 – Tranquility Base, Ranger 8 – Mare Tranquilitatis, Sureyor 5, Ranger 6, Apollo 16 - Mare Serenitatis, Luna 21,

    Mare Crisium: Luna 15, Luna 23, Luna 24. Mare Fecunditatis: Luna 26, Luna 18 Luna 20. Mare Imbrium: Luna 17, Luna 2. Mare Imbrium and Palus Putredinus. Sinus Aestuum: Suveyor 8. Senus Medii: Suveyor 6, Suveyor 4. Oceanus Procellarium: Luna 8, Luna 9, Luna 7, Suveyor 1. Mare Cognitum: Luna 5, Apollo 12, Suveyor 3, Ranger 7. Alphonsus (crater) Ranger 9. Hipporchus and Thophilus 6800 (craters) Tycho : Surveyor 7

    Far Side in the dark sideof the Moon: Ioffe( crater) Ranger 4. Apollo, Mendel, Lyman, Von Karman, Mare Korolev, paschen, Mendeleev, Hertzsprung, Keepler, Mach, Michelson, Campbell, Mare Moscovense, Compton Birkoff, Pasteur, D. Alembert, Blanchard.

    Richardo Brown

    The Moon: Satellite of Planet Earth

    The Moon is 2,160 miles (3,476 kilometers) in diameter, one quarter the diameter of earth. The moons mass is 1/81 the mass of earth. Its density is 3.3 times the density of water. Hydrogen, helium, neon and argon atoms make up its atmosphere. It’s made of solid rock, rills, and craters and dried up lava mares. There is no liquid water to crode the surface and no active volcanism. The moon crusted and cooled down about 4.6.b.y.a. with its rocks at most 4.5 billion years old, so moon rocks are bone dry. The moon is made of material blasted out of Earth by a huge object up to three tomes the mass of Mars that struck a glancing blow to the young Earth. The Giant Impact (GP) knocked all this material up in onto space as a vapor of hot rock. Like huge stone material snowflakes it condensed and solidified, knocking together in powerful impacts of accumulated rock in big pieces, and then melted by lava from the impacts forming “The Moon” the impact of craters from planetubles, asteroids and comets dating 3.b.y.a.

    The Moon: Explore

    Richardo Brown: Signature installed and instrumented on the Lunar Reconnaissance Orbiter

    Craters dot the moon’s surface. Materials thrown from impacts that made them centers radial patterns of bright ejecta with scars left over by objects that smashed the earth in our early solar system of the star: Sun. The largest are the impact basins, enormous craters ranging up to around (1,553mi) across. Lava flooded the basin floor sometime after titanic collisions formed them, creating the smooth, dark surfaces that the eye geography maps as Marias or Seas. Blocks of rock hurled formed with impacts gathering and becoming larger made what is called the satellite of planet Earth.

    Fissures, domed hills and wrinkling ridges all fissioned together with ancient volcanic lava and weak gravity formed geological igneous basalt and metamorphic anothosite. The lunar surface is sheathed in regolith, a fine dusty titkite, cleared by constant bombardment of asteroids, comets, and meteoroids. The geology of the moon was brought back to planet Earth by six crews of Apollo astronauts from 1969 to 1972. The rocks and dust were completely dry discovering the moon has no water of its own. The moon is sometimes bombarded by icy – water tailed comets. Most of the cometary’s water evaporizates into space, but some of it may be trapped as ice in the bottoms of shadowing craters near the lunar polar areas. Until a few years ago today the temperature on the moons at it coldest point was -274 degrees.

    The highlands of the moon are packed together indicating that these ancient areas were hit repeatedly by asteroids and comets and planetoids, in the violent days of our solar system.

    My naming of a few mares (seas) on the satellite Moon:

    Near side to the planet Earth:

    Oceanus Procellarum

    Mares: Frigorius, Serenitatis, Imbrium, Tranquilitatis, Crisium, Fecunditatis, Humorum, Nubrium, Nectaris, orientale, Cognitum.

    Grography on the United States and European Space Agencies landings on the Moon:

    Apollo 11 – Tranquility Base, Ranger 8 – Mare Tranquilitatis, Sureyor 5, Ranger 6, Apollo 16 - Mare Serenitatis, Luna 21,

    Mare Crisium: Luna 15, Luna 23, Luna 24. Mare Fecunditatis: Luna 26, Luna 18 Luna 20. Mare Imbrium: Luna 17, Luna 2. Mare Imbrium and Palus Putredinus. Sinus Aestuum: Suveyor 8. Senus Medii: Suveyor 6, Suveyor 4. Oceanus Procellarium: Luna 8, Luna 9, Luna 7, Suveyor 1. Mare Cognitum: Luna 5, Apollo 12, Suveyor 3, Ranger 7. Alphonsus (crater) Ranger 9. Hipporchus and Thophilus 6800 (craters) Tycho : Surveyor 7

    Far Side in the dark sideof the Moon: Ioffe( crater) Ranger 4. Apollo, Mendel, Lyman, Von Karman, Mare Korolev, Paschen, Mendeleev, Hertzsprung, Keepler, Mach, Michelson, Campbell, Mare Moscovense, Compton Birkoff, Pasteur, D. Alembert, Blanchard.

    Richardo Brown

    L.R.O. Moon Mission

    Planetary Society Millenninum Edition 2000/ Membership Directory 1999

    Mars 2013 (Astronomy Textbook 2015c.e.)

  2. bce-online.com Says:
    June 21st, 2011 at 7:36 am

    everything you wrote its correct !

  3. Florida Bright Futures Says:
    October 2nd, 2011 at 11:36 pm

    Bright Futures…

    [...]Blog - NASA Jet Propulsion Laboratory » Blog Archive » Lunar Eclipse, the Moon’s Interior, and the Holy GRAIL[...]…

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