June 28, 2012 --
If you were in any doubt as to the awesome power of the sun and its impact on the planets of the solar system, you need to find the time to visit a planetarium that's showing the movie "Dynamic Earth: Exploring Earth's Climate Engine." This NASA-created fulldome, high-resolution movie describes how the sun generates a protective "bubble" around our solar system, repelling some of the nastiest interstellar high-energy cosmic rays. However, our protector has an angry side. In this still from the movie, the magnetic field of Earth is depicted, providing us with a protective "force field" that can repel the biggest solar "temper tantrums" -- coronal mass ejections and most energetic solar wind particles.
Our Planetary Force Field The movie -- created by NASA Goddard's Scientific Visualization Studio -- uses actual NASA satellite and model data to create a visually stunning roller-coaster ride of a solar storm unfolding. Solar storms can wreak havoc with our hi-tech world if we are caught unawares. But with the help of an armada of space observatories monitoring space weather conditions, we are getting better at predicting the impact of explosive solar phenomena such as coronal mass ejections (CMEs). As shown here in this excerpt from the movie, energetic CME particles slam into the Earth's invisible magnetic field. As they are electrically charged particles (ions), they are deflected. The magnetosphere therefore creates a protective bubble around the Earth, allowing our planet to retain a thick atmosphere, ultimately supporting the evolution of our biosphere.
First Line of Defense As described by the movie's narrator, the magnetosphere is just our first line of defense. Much of the sun's electromagnetic energy (e.g. visible light) is reflected back into space so the climate can be regulated. What energy penetrates deep into our atmosphere drives air currents that, in turn, drive vast global ocean currents. Our sun literally drives the processes of our dynamic planet. But say if Earth didn't have a magnetosphere? As it turns out, Earth's sister planet Venus is a prime example of "Earth gone wrong."
When CMEs Poison Planets Venus doesn't have a global magnetic field and therefore lacks the ability to deflect the sun's ionizing radiation. The result is nothing short of hellish. For Venus, when a CME hits, the energetic solar particles "strip away lighter elements in its upper atmosphere -- hydrogen, oxygen and the molecule they form, water," says the narrator. "What's left is a 'witches brew' of noxious chemicals including thick, sulfurous clouds." Like Mars, Venus' lack of a magnetic field doesn't only mean the solar wind particles can penetrate deep into the atmosphere, observations have also shown that the solar wind has the ability to blow the planets' atmospheres into space. Due to Mars' lower mass, it lacks the gravitational clout to hold onto its thin atmosphere. This is undoubtedly a factor as to why Mars' atmosphere is 100 times thinner than Earth's.
To watch an excerpt from "Dynamic Earth: Exploring Earth's Climate Engine," you can view it on the NASAexplorer YouTube channel. To see high-resolution versions of the visualizations shown here, plus a constantly updated feed of awesome space images, browse the NASA Goddard Flickr Photostream.
READ MORE ARTICLES BY IAN O'NEILL