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Earth Science Week 2012
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The Interesting Questions
Physicist Bryan Killett has learned that the path to knowledge starts with asking questions.
October 19, 2012
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8:22 PST
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Bryan Killett
Bryan Killett is a physicist with the GRACE mission. Credit: NASA.

Before college, I answered the phone for an internet service provider. My schedule and activities were rigid: every day, I worked the same hours and did the same things.

When I graduated, I got a job at NASA's Jet Propulsion Laboratory. Now I have a lot more flexibility and many opportunities for collaboration. I set my own hours, and I am able to work on projects that I’m excited about. My boss listens to my ideas, and we work together to study the Earth. I also get paid to travel the world. For example, I wrote this post on a train to Berlin. I was in Germany to give a presentation at the Gravity Recovery And Climate Experiment (GRACE) science team meeting.

GRACE satellites measure the Earth's changing gravity field. Gravity is stronger in places with more mass, like on top of a mountain. Water also has mass, so gravity is temporarily stronger in an area after a heavy rainstorm. Each month, GRACE measures the strength of gravity at every point on Earth. These observations allow scientists to see how mass (mainly water) moves on the Earth's surface.

Right now, I'm using GRACE data to study changes in gravity due to ocean tides. I recently suggested that some Antarctic ice streams (fast-moving glaciers) are affected by ocean tides farther inland than we'd previously thought. The ocean tides are effectively shaking loose the ice streams, hastening their slide into the sea.

Greenland's ice sheet is melting so rapidly that the gravity over Greenland is getting weaker every year. GRACE also sees similar melting in the glaciers and ice sheets of West Antarctica, Patagonia, Alaska, and the Himalayas.

GRACE data reveals a loss of ice in Greenland. Credit: NASA.
GRACE data reveals a loss of ice in Greenland. Credit: NASA.

GRACE also observed the lack of rainfall in the Amazon during 2005, which was regarded as the worst drought in over a century. However, the 2010 Amazon drought might have been even worse.

Watching these tragic events unfold through GRACE has been profoundly unsettling. On the one hand, I'm glad that we have so many satellites observing climate change, because ignoring this problem won't make it go away. On the other hand, it can be very discouraging. The scientific community has been collecting data for the past two centuries that shows Earth's climate is warming, and most of the warming is very likely due to increases in CO2 emissions. However, we've sometimes failed to communicate this to the general public.

Scientists are trained to be our own worst critics. We tend to emphasize what we don't know because that's where new discoveries emerge, but this often means we sometimes do a poor job of emphasizing what we do know.

Here's my advice to anyone who's thinking about becoming a scientist. Admitting what you don't know is the first step on the path to knowledge. Ask interesting questions, and seek out answers to what puzzles you. The true test of a scientist is whether you can admit there are things you may not know yet and keep struggling in order to reach the frontiers of knowledge.

Post by Bryan Killett, physicist working on GRACE at NASA Jet Propulsion Laboratory

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Earth Science Week 2012
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