Probing Our Neck of the Woods

Earth and MoonI’ve spent some time recently writing about very large-scale distances, speeds, masses, and things very much out and beyond not only our every day experience, but beyond even the every day experience of our little planet.

It doesn’t seem quite fair. I’m even guilty of using the pejorative “little planet” when referring to our rocky island home. So I’m going to take a slightly different tact this time, by staying at home, and first, looking at the sky.

Well, ok, fish first. They breathe water, in and out of their gills. You can watch them floating around, gasping away at it. We can’t do that. Instead, we constantly gasp away at a gas, or rather gases, that always surround us and stretch way up into the sky.

I won’t even talk about the crud we’re pumping into it. I’ll talk about our rocky Earth – the big sphere we live on, this giant rock covered almost entirely by water with a little, tiny thin film of gas surrounding it, held in place by gravity. That stuff we breathe.

Now, when we look up at the sky it seems pretty big up there, in all directions, way up high — there’s just a lot of it. But if our Earth were the size of a basketball, the atmosphere would be paper thin. It is paper thin.

If you were to drop down, falling from even higher than passenger jets fly, you’d enjoy a couple minutes of weightless and breeziness before you reached the ground.

But if somehow you managed to fall into a hole in the Earth that continued clean through, you’d keep falling for a long time – more than a day, before you’d reach the center. Hours and hours of falling – you could sleep the night through, wake up the next day, and still be falling.

Unless there was no air in that tunnel. Then you’d fall through the hole pretty fast, accelerating to over 15,000 miles per hour, taking only 21 minutes to reach the core of the Earth, and another 21 to pop out of the ocean on the other side. As you reached the center of the Earth, you would be weightless, having reached to center of mass, but you could continue to pendulum back and forth from one side of the earth to the other, emerging from your starting hole every 84 minutes, which is, interesting, about how long it would take a satellite to orbit the earth (near the surface).

But really, you wouldn’t last more than a minute or two, falling into the earth. The temperature and pressure build quite rapidly. At the core of our planet, most scientists believe molten iron churns, while a very few believe a nuclear reaction is taking place from naturally-occurring uranium (and with some good evidence).

MagnetosphereIn any event, a tremendous magnetic field is produced by something at our Earth’s core that stretches thousands of miles out into space. Our sun, continually bombarding us with high energy plasma, is thwarted in large part by this magnetic field. This is why our paper-thin atmosphere remains, and is not stripped away by the highly energized bombardment.

But other things do happen. These polarized particles bend back Earth’s magnetic field, a little like long hair in a convertible, only more frizzy and wiry. Most of the radiation is deflected around the planet, but some very little gets trapped, or through, and the movement of our magnetic lines creates electrical currents, eventually resulting in auroras, disrupted communications, power outages and irradiated stewardesses.

So, in a noble effort to save them, or, perhaps to answer the question, “which comes first, the break in current or magnetic reconnection?”, scientists and governments are launching the Themis probes today. That’s really the secret reason I’m writing this, giving myself a good excuse to dig.

Themis ProbesIt’s actually really cool. One Delta II rocket – 3-stage. And not just one probe, but 5-in-one, or 6-in-one if you count the Earth itself. The five probes are clustered together in this flower-pod-like configuration and will emerge into space, then separate out from each other, traveling to very distant positions from each other, one clear out toward the moon. They’ll let these long wire tendrils out from themselves, stretching out into the space around them, “listening” to the Earth’s magnetic field and the interactions it has with the solar winds.

There’s a nifty animation of the launch and deployment you can view, provided by Berkeley. If, for some reason, that link disappears, I’ll be saving a copy locally as well.

Each probe will be orbiting differently around the Earth yet all will work in tandem with their observations. If one of the probes fails, the one that headed out toward the moon will come back in closer to take its place.

Scientists want to know how the solar winds interact with our magnetic field. How much energy is deflected? How much comes in? Where does it go? How is it stored? How does it move into the Van Allen radiation belt? What amount of solar activity constitutes how much radiation? And yes, of course, what kicks off the aurora, the break in electrical currents that let the magnetic fields snap back, or the snapping of the magnetic fields that let loose the currents? And where, exactly, in our magnetotail is this happening?

It’s basically learning weather science as we move further into space, getting to know our neighborhood. Charting and predicting storms, and their degrees. These orbiting probes are very versatile for this purpose, as they move in their various configurations around the planet, sometimes observing and making comparisons on the “day-side” of Earth (when they’re all between us and the sun) and sometimes back on the night-side, where it seems all the fireworks originate.

Oh, and like the sun, it seems our Earth occasionally decides to flip its polarity as well, where North becomes South, and South becomes North. We can verify this by examining old rocks. Also, we have some other satellites up there measuring the strengths of the magnetic field, too. Some are saying the magnetic field is weakening. Others are saying, it’s getting ready to flip.

Some say the earth’s core is molten because our planet is still cooling from its wilder days of smashing into Mars-sized planets. Others say, once it’s cooled enough, the magnetic field will disappear, leaving our atmosphere, and ourselves, exposed to solar radiation like the atmosphere, if you can call it that now, of Mars.

Then again, Venus doesn’t have a magnetic field, except for an induced one from the solar wind’s interaction with its ionosphere, and Venus certainly does not lack for an atmosphere. Yet.

So what does it matter, burning all this fossil fuel, gaining oil profits, etc? We’re not going to be destroying the planet. And that’s true. We don’t possess nearly the expertise for such a large-scale accomplishment. So, no matter what we do, the planet will survive, as will whatever life forms in the future happen to climb out to mull about. We can only destroy ourselves.

But why not save the stewardesses? Even though they jet across the white polar regions burning their prehistoric remains and dropping black ash all over? I mean, we’re stuck down here for now and will need a good deal of time to work up the chutzpah to go elsewhere.

There has to be more to this all than just greed and self-interest, in our little corner of things. There has to be some reason Themis exists, other than saving the cost of replacing blown-out power transformers, planning military maneuvers at times when communications will be safe, and saving airlines money by saving them the hassle of diverting and grounding on their polar routes?

There is, isn’t there?