190: Juno

Naming the space probe to Jupiter after the wife of the proverbial god seems quite appropriate. Then you realize that all the moons of the planet are named after his mistresses and the joke sinks in: Juno is coming to spy on her husband.

High flying nerd humor aside, this week has been a big week for science. After a five-year journey of 2.8 billion kilometers, Juno settled into orbit around Jupiter on July 4. The distance it covered is the equivalent of circling the earth 70,000 times. Starting its journey on a big rocket from earth, reaching a target that far away — granting that it is the largest planet in the solar system — is quite a feat.

The route that Juno took is a fascinating lesson in orbital mechanics. Juno didn’t actually take the direct route to Jupiter. That would take far too much energy to be practical. Instead, Juno followed a path that put it in orbit around the sun. The orbit would take two years. At its end, Juno passed close to the earth and used the earth’s gravity to pick up enough speed to propel it to its destination.

As it approached Jupiter it received another boost in speed owing to the planet’s gravity. By then it was traveling at 266,000 kph. Juno then turned around and fired its rockets for 35 minutes in order to decelerate and fall into Jupiter’s orbit. It will circle Jupiter for the next two years, taking photos, measuring magnetic fields, and mapping the planet. At the end of that, it will deliberately crash into Jupiter, taking measurements and sending them back to earth all the while.

Why is this project so important? Jupiter is still a mysterious planet. We don’t know what’s beneath those fast swirling clouds that cover its entire surface. Is there a solid core underneath or is it purely gas and dust? What’s the composition and mix of the elements in its atmosphere? Answering these questions can give us some ideas of how the solar system and the earth formed.

Up until the end of its mission, Juno will really be mostly data gathering. Then the real work starts as scientists sift through and analyze the data, refining old theories and forming new ones. That will likely take years more.

And then what? Someday we’ll muster the courage and the will to leave this chunk of rock that is the earth, when we ourselves will travel the same route that Juno and all her predecessors took, then all these lessons will hold in good stead.

The poem for tonight is Lament of the Border Guards by Alfredo O. Cuenca, Jr. That is all.

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Dom Cimafranca

Teacher, writer, project manager, and all-around nice guy.