Earth from Space, which aired in June 2013, was a NOVA program that really impacted me. It describes how satellites both give us a view of earth from space and enable us to “see” life-sustaining processes normally invisible to the naked eye. This is made possible by either reading or emitting waves that are outside of the visible spectrum of light. Viewers are able to visualize how the earth’s temperature is regulated by ocean currents, how the Sahara Desert nourishes the Amazon half a world away, how annual ice fluctuations in the arctic create an underwater brine “waterfall,” and the scale of earth’s magnetic field. As this was my first exposure to such knowledge, I was blown away by how our technology has improved our vision and understanding of how our planet supports diverse life in diverse environments.
Here’s an excerpt from the script:
NARRATOR: As a major engine, driving the world’s ocean currents, Antarctica helps protect Earth’s climate from wild swings in temperature. The constant, dependable circulation of the oceans around the globe and the relatively stable temperatures it produces, have made Earth a hospitable planet. Long-term stability provided time for life to flourish and complex animals and plants to evolve. And this is how a process that began with Antarctic ice continues to sustain our world.
Remember learning about the electromagnetic spectrum in high school? Waves of various lengths are arranged from long (radio waves) to short (gamma rays) and visible light is represented by a very small segment of this line. Visualizing the spectrum’s entire length from LA to NY, this visible section would be the size of a dime. There is so much information that our eyes have not adapted to see, but luckily, we have adapted large brains which innovate the technology to read this information in indirect ways.
For example, satellites can help us “see” the inner structure of a hurricane by bouncing microwaves off of raindrops. How neat is that?
On the lower end of the electromagnetic spectrum, just below the visible color red, infrared images detect heat and can measure water vapor rising off the oceans surface, a process marking the beginning of a tropical storm.
Microwaves emitted by satellites can penetrate through clouds to detect ice year-round. This kind of information is quite valuable for studying climate change over the years.
But the coolest part of the program to me was the precision of measurement some of our technology is capable of, and what it reveals. Using a piece of equipment called Jason, a satellite dedicated to oceanographic data collection, we are able to bounce radar off the surface of the ocean to measure it’s height within millimeters, revealing shape of sea floor. This kind of information reveals processes we never could have imagined, such as a super-colossal underwater “waterfall.” This occurs when water freezes around the South Pole; the salt is ejected because it doesn't freeze, then sinks to the sea floor as it is denser than the surrounding water.
Here is another excerpt from the script:
NARRATOR: Combining data from satellites and undersea instruments, scientists can reconstruct what is happening, hidden beneath the ice. What they learn is astounding. One trillion gallons of salty brine plunge down through the Weddell Sea every hour—a torrent equivalent to the volume of 500 Niagara Falls. The brine spreads out towards the edge of the Antarctic continental shelf and then falls into the chasm revealed by Jason. A vast submarine waterfall plummets downward. The cold, dense brine falls slowly, silently, into the abyss, two miles down to the ocean floor below. It will not resurface for hundreds of years.
Did you catch the number trillion (1,000,000,000,000)? A million is hard to imagine, let alone a billion. Well, a trillion is equal to a million millions, or a thousand billions. So, one trillion gallons of brine tumbling into the chasm per hour. We still don’t know where it goes when it falls, but we are a big step closer to understanding our planet. And this is just one of the many discoveries satellites have made! I cannot do the program justice in a short blog post... please, go watch it yourself! For me at least, there is little more thrilling or breathtaking than getting a glimpse at what is happening just beyond the horizon of our understanding.
It's about 2 hours, but worth the watch.
