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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)

Gettin' Busy with the Moon

Observing >

Get a calendar in one hand, a pencil in the other, and let's mark off some November dates of celestial interest.

Tonight you can catch a glimpse of the just-past-full Moon of November which actually had the moniker "the Frosty Moon" --- seriously. But for a couple hours Saturday night it was more like Frosty the No-Moon (no relation to Frosty the Snowman).

Yes, our nearly full Moon this evening --- technically a waning gibbous --- comes, not coincidentally, right on the heels of Saturday's lunar eclipse. You will recall that a lunar eclipse happens as the Moon slowly passes through Earth's long, fat shadow on exactly the opposite side of Earth as the sun.

The Moon goes around us once a month but doesn't always go through our shadow giving us a lunar eclipse. Nor does it pass directly in front of the Sun every month providing us a solar eclipse. Its orbit is slightly tilted so it only has a chance of "getting in the way" every six months or so, during what is called "eclipse seasons." The Moon is in such an alignment now.

Presently our orbiting friend is on his way to the other side of Earth to get between us and the Sun, to cast its shadow on us --- a celestial form of "getting even." In two weeks, on the 23rd, it will finally arrive to vengefully block out the sun's light! But alas! its very skinny shadow will dot only the icy cold southern reaches of the Great White South --- Antarctica. Scientists there, joined by some penguins and eclipse fanatics with a lot of time and money, will be freezing together in the shadow of the Moon.

On the same date, the 23rd, the Moon coincidentally will also be at its closest approach to the Earth, a point called perigee. This combination of being on the same side as the sun and being so near us at the same time will affect those of us who live near the ocean. How?

When the Moon and Sun are on the same side like this their combined gravitational forces can pull our oceans up toward them resulting in fairly high tides. Because it is so close compared to the sun, the Moon actually exerts a greater pull than the sun even though it is so tiny, which explains why it is the major influence in tides. Moreover, when the Moon is at perigee, as it will be then, its pull is even greater and the tides even higher.

On the nights of the 16th through the 19th (but peaking on the night of 17th/18th) we have the annual Leonid meteor shower. And as usual, it is hard to tell what it will be like. Will we have hundreds of meteors an hour or just a few? Will there be giant fireballs, or just barely-lit shooting stars? It's impossible to tell, but the great mystery of these events is part of the fun of it all, and is what gets the meteor mobs all fired up on these nights. Go out after midnight for your best chance of seeing them.

And finally for those who take astrology --- as opposed to astronomy --- seriously, consider the following: On Saturday the 22nd, the Sun enters the astrological sign of Sagittarius. The problem? The sun is actually still in Libra headed for Scorpius. It won't be in Sagittarius until next month. And, interestingly enough, on the 30th the Sun enters the constellation Ophiuchus. Ophiu-who?

There is no sign in Ophiuchus in astrology. Oops.

Until next time, clear skies!

Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com.

Posted by Administrator at 2003.11. 8 01:02 PM | Comments (0)



Looking for something?	« October 2003 \| Main \| December 2003 » '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) Gettin' Busy with the Moon Observing > Get a calendar in one hand, a pencil in the other, and let's mark off some November dates of celestial interest. Tonight you can catch a glimpse of the just-past-full Moon of November which actually had the moniker "the Frosty Moon" --- seriously. But for a couple hours Saturday night it was more like Frosty the No-Moon (no relation to Frosty the Snowman). Yes, our nearly full Moon this evening --- technically a waning gibbous --- comes, not coincidentally, right on the heels of Saturday's lunar eclipse. You will recall that a lunar eclipse happens as the Moon slowly passes through Earth's long, fat shadow on exactly the opposite side of Earth as the sun. The Moon goes around us once a month but doesn't always go through our shadow giving us a lunar eclipse. Nor does it pass directly in front of the Sun every month providing us a solar eclipse. Its orbit is slightly tilted so it only has a chance of "getting in the way" every six months or so, during what is called "eclipse seasons." The Moon is in such an alignment now. Presently our orbiting friend is on his way to the other side of Earth to get between us and the Sun, to cast its shadow on us --- a celestial form of "getting even." In two weeks, on the 23rd, it will finally arrive to vengefully block out the sun's light! But alas! its very skinny shadow will dot only the icy cold southern reaches of the Great White South --- Antarctica. Scientists there, joined by some penguins and eclipse fanatics with a lot of time and money, will be freezing together in the shadow of the Moon. On the same date, the 23rd, the Moon coincidentally will also be at its closest approach to the Earth, a point called perigee. This combination of being on the same side as the sun and being so near us at the same time will affect those of us who live near the ocean. How? When the Moon and Sun are on the same side like this their combined gravitational forces can pull our oceans up toward them resulting in fairly high tides. Because it is so close compared to the sun, the Moon actually exerts a greater pull than the sun even though it is so tiny, which explains why it is the major influence in tides. Moreover, when the Moon is at perigee, as it will be then, its pull is even greater and the tides even higher. On the nights of the 16th through the 19th (but peaking on the night of 17th/18th) we have the annual Leonid meteor shower. And as usual, it is hard to tell what it will be like. Will we have hundreds of meteors an hour or just a few? Will there be giant fireballs, or just barely-lit shooting stars? It's impossible to tell, but the great mystery of these events is part of the fun of it all, and is what gets the meteor mobs all fired up on these nights. Go out after midnight for your best chance of seeing them. And finally for those who take astrology --- as opposed to astronomy --- seriously, consider the following: On Saturday the 22nd, the Sun enters the astrological sign of Sagittarius. The problem? The sun is actually still in Libra headed for Scorpius. It won't be in Sagittarius until next month. And, interestingly enough, on the 30th the Sun enters the constellation Ophiuchus. Ophiu-who? There is no sign in Ophiuchus in astrology. Oops. Until next time, clear skies! Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com. Posted by Administrator at 2003.11. 8 01:02 PM \| Comments (0)
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