Sunday, February 11, 2007

On Gravity

This has nothing to do with New Zealand, but... Did you see the cover story of this month's Discover? (They've stopped putting what the actual month is anywhere in the magazine so I can't tell you that, but it's got a gravity map of Earth on the cover.) The article talks about GRACE, a space mission launched in 2002 to measure the fluctuations of Earth's gravity field. They do this by investigating the minute changes of gravity over a few days, which allows you to see which regions have the greatest mass due to recent rainfall, high-density rock, or even a melting ice cap.

Of course, me being me I found this entire thing wonderfully clever. Think about it: you are using basically a souped-up version of freshman kinematics to see how the most minute changes of gravity effect your satellite flying through space, and you can do it so precisely that you can pinpoint the cause of it hundreds of miles away. Scientists even a few decades ago would have thought the entire idea was just crazed science fiction.

Anyway, the reason I'm telling you all this is because the idea of gravity fluctuating made me ponder a bit, and poetry ensued. Obviously gravity doesn't fluctuate so much that we'd normally notice, but wouldn't it be an interesting world to live in if it did?

On Gravity
by Yvette Cendes

If gravity fluctuated
As much as the weather
It would come and go
In fronts and depressions,
Pressing down like a storm
Or breathing very softly
Like the clearest winter night.

There would be days
When we would lie, helpless,
Pinned to the ground
By the rain of mass,
We wouldn't move an inch
And try very hard to breathe
Beneath the pounding weight.

But these mass-laden days
Would be not all bad,
We would always remember
The end of the storms
When we could rise up
Over mountains and cities
And fly with the birds.