Posts Tagged 'gravitation'

The gravity of Antarctic ice loss

I don’t write about climate change very often, even though it’s the most important issue facing humanity. That’s mainly because it’s not my “beat“: I’m a physics and astronomy writer, and I do best when I write about topics in my areas of expertise. (And after all, there are many good writers focusing on climate change.) However, on rare occasions climate change overlaps my beat, and I covered such a case in this week’s Daily Beast column.

OK, not this kind of beat.

In this instance, we have a combination of something really cool — the measurement of tiny fluctuations in Earth’s gravity using satellites — and the alarming decrease in ice in Antarctica. Gravity is the product of mass, so places on Earth where the crust is thicker will exert a slightly greater force. Satellites like the European Space Agency’s GOCE and NASA’s GRACE are designed to study these small variations; a recent paper described a method to combine their data to achieve enough sensitivity to measure the melting ice in Antarctica. When that ice melts, it moves mass from the land into the ocean, with a corresponding change in gravity.

[I]f we really want to know how quickly Antarctica is losing ice, we need a way of measuring that loss in terms of total mass.

In that mission, scientists are aided by gravity. As Antarctic ice melts, it shifts mass from the continent into the oceans, slightly changing Earth’s gravitational field in that part of the world. We wouldn’t notice it, but orbiting observatories like the Gravity Field and Steady State Ocean Circulation Explorer (GOCE, which is more an abbreviation than acronym) can measure small fluctuations in gravity compared with other spots on our planet. [read more…]

And yes, I included Hannibal from The A-Team and a slightly immature parenthetical joke. Sometimes we have to force ourselves to laugh; otherwise anger or despair over the damage we have done — and continue to do — would overwhelm us.

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