Gravity Field Mystery of the Moon Solved By NASA GRAIL Mission

Gravity Field Map of the Moon

The Gravity Recovery and Interior Laboratory (GRAIL) mission by NASA has solved one of the moon's mysteries, its ever changing gravitational field. Mass concentrations under the lunar surface changes the gravitational field in the area that can either push or pull approaching spacecraft.

The GRAIL mission has mapped the gravity field of the lunar surface (see image).

The image on the left, known as a Mercator projection (similar to Earth maps), represents the entire surface of the moon with the far side of the moon (the dark side) at the center of the map and the nearside (as seen from the Earth), on the left and right side. The red parts correspond to mass excesses which create areas of higher local gravity, and the blue parts correspond to mass deficits which create areas of lower local gravity.

NASA's GRAIL mission involves two washing machine sized satellites that are placed on the same lunar orbit. It mapped the gravity of the lunar surface as well as its interior and thermal history. It also has a set of cameras known as MoonKAM that are used for NASA's education and public outreach project.

Studying The Weight and Gravitational Behavior of Antimatter

Weighing Antimatter

Physicists at the University of California, Berkeley are studying the difference between matter and antimatter in relation to how it interacts with gravity.

Particles that have the same mass but with the opposite charge and quantum spin are called antimatter. Antimatter was predicted to exist in 1928 through equations by Paul Dirac. The next year, it was first observed by two physicists but considered it an anomaly and was not studied further.

Three years later, in 1932, Carl D. Anderson also observed the same thing in his experiments but instead of treating it as an error, studied it further. Bt using gamma rays, he created an anti-particle; a positively charged electron. Electrons are negatively charged and his discovery proved Dirac was right and antimatter does exist.

Anderson was awarded the Nobel Prize for Physics in 1936 for this discovery.

All particles has its antiparticle counterpart. The antiparticle of the electron is the positron. It carries a positive charge rather than a negative one. The proton's version is the anti-proton and it carries a positive charge. Despite the neutron having a neutral charge, there is an antineutron which is made up of antiquarks (the antiparticle of the quark).

Exposure To Outer Space Environment Causes Brain and Eye Abnormalities in Astronauts

Weightlessness in outer space is often called zero gravity. Technically, the term should be microgravity. Microgravity is more or less a synonym of weightlessness and zero-G, but indicates that g-forces are not quite zero, just very small. Astronauts experience microgravity once they leave the Earth's atmosphere, they are no longer affected by Earth's gravity and enter a micro-g environment. This is the environment commonly experienced in the International Space Station (ISS) and the Space Shuttle.

Magnetic resonance imaging (MRI) of the eyes and brains of 27 astronauts who have spent prolonged periods of time in space revealed optical abnormalities similar to those that can occur in intracranial hypertension of unknown cause, a potentially serious condition in which pressure builds within the skull. A retrospective analysis of the MRI data appears online in the journal Radiology.

A team of researchers performed MRIs and analyzed the data on the 27 astronauts, each of whom were exposed to microgravity, or zero gravity, for an average of 108 days while on space shuttle missions and/or the International Space Station (ISS), a habitable research facility that has been orbiting the earth since 1998. Eight of the 27 astronauts underwent a second MRI exam after a second space mission that lasted an average of 39 days.

"The MRI findings revealed various combinations of abnormalities following both short- and long-term cumulative exposure to microgravity also seen with idiopathic intracranial hypertension," said Larry A. Kramer, M.D., professor of diagnostic and interventional imaging at The University of Texas Medical School at Houston. "These changes that occur during exposure to microgravity may help scientists to better understand the mechanisms responsible for intracranial hypertension in non-space traveling patients."