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'What Else Should I be Thankful For?'
The Solar System >
Imagine it is Thanksgiving and you are finished with The Big Meal. Perhaps you've just seen your favorite team tossing around that oblong brown ball as your family celebrated --- or commiserated --- loudly. You are tired now and decide to take a little walk just to get away from the noise, and to justify all that food you ate.
As you walk outdoors in the cool early evening air you think, "What day is this? Oh, yes! Thanksgiving!" And for the first time in this chaotic day you contemplate what you really are thankful for.
You're alive for one thing. You have learned much this year, through trial and error and event. After you reflect on these things and more, you are at a loss. "What else should I be thankful for? Have I missed anything?"
Allow me to help open the great box and give you, on a cosmic scale, more things to give thanks for.
As you walk along feeling bloated to the core, think of our own core, the core of the Earth and be thankful. Deep down there is a solid metal-rich core surrounded by an outer liquid core. This liquid core is responsible for our magnetic field --- a great, unseen protector of our planet.
The
magnetic field emanating from the core of the Earth envelops us and diverts
the solar winds around us. This shield protects life on the surface from
many effects of the tremendous solar flares and coronal mass ejections
belching out violently from the sun in recent days.
Having a hard time catching your breath after that big dinner? Be thankful you can catch a breath. Our atmosphere, through long and intricate sequences of events over the last billions of years, has settled down to the perfect combination for life.
Currently it is about 80% nitrogen, a fairly inert gas, and about 20% oxygen, the gas of life. Counterintuitively, 20% oxygen is just perfect! More oxygen is not good for reasons that are all too real for many of our readers. For one thing, fuel and oxygen make the perfect mixture for fire. Imagine how much terrifyingly faster the recent fires would have swept through if our atmosphere were 30%, 40%, or 50% or more oxygen!
Less oxygen makes complex life like ours impossibly lethargic. And of course no oxygen in the atmosphere --- the sorry condition of all of our neighboring planets --- means no life.
As you walk, look up and see the westering crescent Moon and be full of thanks --- and not just because it is aesthetically beautiful.
The gravitational tug of our Moon maintains our tides, permitting the oceans' rich tidal life. More importantly, that gravity has kept our planet from wobbling out of control as we spin around on our axis. This steadiness assures that we have rich and efficient seasonal periods.
As the skies darken and the Moon disappears, be thankful for the array of stars sparkling in the skies. If you have seen a dark sky full of stars you know already the beauty of such a scene. But what if there were even more stars?
That would not be a good thing. We can see, naked eye, about 6000 stars all year long. Seeing tens or hundreds of thousands more stars, although fascinating, would probably spell doom for us. Those stars we see are big bad stars, nearly all destined for a quick explosive death. Surrounded by too many stars ups the chances of being eradicated in one of these star deaths.
On the other hand, too few stars might mean that there are not enough explosions spewing their guts all over the place, providing raw material for the creation of planets and you and me --- and doomed turkeys.
Have a sincerely thanks-filled Thanksgiving!
Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com.
Solar wind image courtesy of NOAA.
Posted by Administrator at 2003.11.22 01:00 PM | Comments (0)
