# ‘Grace’ twin satellites

Gravity is usually measured in units of acceleration. In the International System of Units (abbreviated SI from French: Le Système International d’Unités) is the modern form of the metric system of units, the standard unit of acceleration is 1 meter per second squared (abbreviated as m/s2 , 1 Kg of mass multiplied by this is 1 Newton). Other units include the Gal, sometimes known as a galileo (in the centimetre–gram–second system, abbreviated CGS or cgs, in either case with symbol Gal), which equals 1 centimetre per second squared.

The force of gravity on the Earth g (gn, normalized gravity), equal to 9.80665 m/s2. The value of the gn approximately equals the acceleration due to gravity at the Earth’s surface, although the actual acceleration g varies fractionally from place to place, according to the formula:

##### The gravitational constant, approximately 6.673×10−11 N·(m/kg)2 and denoted by letter G, is an empyrical physical constant involved in the calculation(s) of gravitational force between two bodies. It usually appears in Sir Isaac Newton’s law of universal gravitation, and in Albert Einstein’s general theory of relativity. It is also known as the universal gravitational constant, Newton’s constant, and colloquially as Big G.[1] It should not be confused with “little g” (g), which is the local gravitational field (equivalent to the free-fall acceleration[2]), especially that at the Earth’s surface. (Wikipedia).

These actual gravity variations is what ‘Grace’ twin satellites, launched in March 2002 by NASA, can measure from space as a result in slight according variations in the distance between one another.

NASA ‘Grace’ twin satellites website

According to this article published in July the 30th this year (2014), which I have read this morning, water depletion in Colorado River Basin can make the heart pound.

I would like to make all of you aware of three important facts regarding water depletion.
One: Mass loss as a direct result which is what ‘Grace’ twin satellites can monitor from space because of the slight variations on gravity force measurements depending on distances and density distributions, can lead to an unbalance between forces pushing downwards, and upwards throughout the surface which is the object of these pulls. This results in earthquakes at certain points where the Earth’s crust is weaker, such as faults.
Two: It is a very common error to learn things as we are told they are, thus resulting in assuming or not assuming that things are as we were told they are, and this makes me wonder what happens with water and its magnetic properties, and changes in its behaviour related to its temperature and salinity concentration distributions. Whereas we are told in Chemistry lessons that water is sort of, a substance with which to adjust reactions’ stoichiometry, and it has not magnetic impact, I, by myself, have thought on how salty water becomes sensitive to magnetic fields; paramagnetic water, or more accurately paramagnetic watery solutions.
Three: Osmosis. It is a property which causes a gradient on flow’s circulation from lower to higher concentrations in solutions in order to balance salinities.
I have been thinking about these matters because of the Bardarbunga, Iceland seismic crisis, which is currently active and it is not the only seismic crisis taking place right now in the world, this world, the only one we all have.

## Acerca de María Cristina Alonso Cuervo

I am a teacher of English who started to write this blog in May 2014. In the column on the right I included some useful links and widgets Italian is another section of my blog which I called 'Cornice Italiana'. There are various tags and categories you can pick from. I also paint, compose, and play music, I always liked science, nature, arts, language... and other subjects which you can come across while reading my posts. Best regards.