Friday, February 10, 2012

There are some things that will never stop amazing me

And one of them, for sure, is the precision with which we can measure things, even remotely.

The tandem satellites, which are usually 137 miles apart, are sensitive to regional changes in the Earth’s mass and gravitational pull caused by the distribution of water and ice on the planet.

When the lead satellite flies over an area of increased mass, it will sense the increase in gravity and pull slightly away from the trailing satellite. Researchers can detect changes of just one micron between the two satellites …

How much is a micron? A millionth of a meter. Or put another way, the thickness of a human hair is about 100 microns.

So, we're detecting a difference of one one-hundredth the width of a human hair, on a scale of 137 miles, between two things whizzing 500 km overhead at 27,000 km/hr. (300 miles overhead at 17,000 mph, in American.)


You know what Randall would say.

In conclusion, this proves that global warming is a hoax.

(pic. source: NASA/the GRACE mission)

1 comment:

Anonymous said...

the photo legend:

Due to an uneven distribution of mass inside the Earth, the Earth's gravity field is not uniform - that is, it has "lumps". By far the largest is a flattening at the poles, called the Earth's oblateness, but in this model we've greatly exaggerated the scale so that many smaller features can be seen. The GRACE Mission will map out the precise location and size of these lumps, enabling greater understanding of the structure of the Earth. Additionally, GRACE will monitor the mass and location of water as it moves around on the surface of the Earth, cycling between the land, oceans, and polar ice caps. Credit: The University of Texas, NASA Jet Propulsion Laboratory, and the GeoForschungsZentrum Potsdam

Thanks for a very interesting post!