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Three Things to be Thankful For

A Perfect Balance >

Thanksgiving is here again. Perhaps you still observe Big Dinner With The Relatives. You may even follow the ancient but healthy ritual of having everyone at the dinner table express something he or she is thankful for.

Want to impress the relatives this year?

Following are several real astro-centric Thanksgiving responses. You may want to cut one out and hide it in your lap, so when The Question inevitably comes your way, you'll be armed and ready. Ready?

Response #1: This big, hot, steamy turkey here reminds me that I'm thankful for the rate of supernovae in our part of the galaxy!

A star's whole life is spent making enough heat energy to push out against the gravity pushing in. When the big stars finally run out of fuel their cores collapse under the oppressive force of gravity and --- ka-BLAM! --- the outer shells of the stars spew out into space in one of the most violent explosions known, the supernova, drenching everything for tens of light-years around with lethal radiation.

If this happened more frequently around us, Earth would be constantly sterilized. There would be no Thanksgiving.

But the supernovae also blow the stuffing out of the dead star, spewing out all the new-formed elements of the periodic table, things like carbon and oxygen and silicon and iron and so on --- all the stuff you and I and the poor turkey and this whole planet are made of.

So they have to happen frequently enough to provide material for planets and life. It appears their rate is just perfect.

Response #2: Why, the thin delicate crusts on these biscuits remind me that I'm thankful for the collision that pulverized our planet and created the Moon!

Very early on in the life of Earth, we got hit real well by a passing rogue planet about the size of Mars. We didn't get hit head on --- it was a glancing blow. But that blow knocked a whole load of our light --- then thicker --- crust into space.

The beauty of all this is many-fold. Earth got extra radioactive guts for its innards, allowing it to retain a hotter interior for longer. This heat drives the amazing plate tectonics that are responsible for nearly every landform on the planet.

Moreover, our new crust was thinner and more able to experience the newly fueled plate tectonics, the benefits of which could fill a book.

But a huge bonus from this collision is that it also gave us our Moon. Yes, that big bright ball of rocky material was once part of this planet. But its newfound place in space steadies our orbit, lengthened our day, and keeps us from wobbling uncontrollably. Yippee!

Response #3: The steam rising from these light, fluffy mashed potatoes reminds me to be thankful for the fine-tuned but oft ignored water cycle that planet Earth has!

Our planet is at just the right distance from the sun for water to exist in all three states --- solid, liquid, and gas. Farther, it all freezes. Closer, it all evaporates away. Here we can enjoy literal oceans of water that can evaporate in one place and fall as rain or snow sometimes thousands of miles away.

This keeps a pretty constant supply of life-giving water going all over Earth, like a giant sprinkler system. And the water making its way back to the oceans helps to erode away raised landforms to assist in the production of fertile topsoils. Go water!

Those are three astronomical reasons to be full of thanks. Go and impress, and have a great Thanksgiving!

Questions or suggestions? Write Mark Ritter here.

Posted by Administrator at 2002.11.23 02:17 PM | Comments (0)

Walking Blindly into Heavy Traffic

Comets >

It's that time again; time to walk blindly into heavy traffic.

The Leonids meteors will be streaking through the atmosphere early Tuesday morning for what could possibly be the last meteor storm for decades or more. Please, if you get the chance, take a glorious peek at these visitors from outer space. It will be an awesome experience, and one that the whole family can experience --- if you remember to set your alarm clock!

Regular readers here will recall that a normal meteor shower involves the collisions of two things --- a stream of debris and planet Earth.

The stream of debris comes from comets making their merry way through the solar system in their orbit around the sun. As they get closer to the sun and warm up a bit, they slough off tr-billions of teensy tiny rocky bits, usually no bigger than a grain of sand.

This train of dust follows approximately the same elliptical orbit as mother comet. If that comet's orbit happens to cross Earth's orbit, worlds collide.

When Earth ploughs through the debris train --- kaboom zaloom! --- the little particles hit our atmosphere at fiery speeds of up to 70 km/s and disintegrate in a flash of light we call a meteor.

Around November 18 each year, our orbit goes through the debris train of Comet Tempel-Tuttle, which itself came through the neighborhood just several years ago. Normally it's a nice little meteor show, with maybe a couple dozen meteors per hour.

But every third of a century or so we get a heapin' helpin' of dirt thrown right into our upper atmosphere and our skies light up in an aerial attack called a meteor storm. Why only then?

As a comet blows by on its close approach to the sun, it sometimes dumps off an extraordinary amount of stuff. In their observations of the last several years of Leonids, astronomers have developed some pretty fancy models to explain when those blown off dust puffs blew off in the first place, where they are now, and where they are going.

With all these updated models, several teams of astronomers working on the Leonids called the peak of the storm correctly last year, not to the day or the hour, but within minutes of the actual peak.

So whereas there used to be much skepticism when the specialist called the alarm for a possible storm, now peak prognostication appears to have become a reliable science.

This year the experts predict two waves of meteors. The first wave will occur too early for us on the west coast, but the second wave should catch us in good shape.

It is "scheduled" to peak at 2:36 in the morning of the 19th. Observing the hour before and after will offer you the possibility of seeing thousands! That extraordinary speculation is the good news.

The bad news is that the moon is full. So many will be lost in the bright glare of our fully lit satellite. But that's OK. The Leonid meteors can be pretty bright, and if the night is also clear, you should be able to still see hundreds right around the peak time.

So, set the alarm clock for Tuesday morning around 2, wake the family, go outside away from the lights, back to the Moon, and look up. The longer your eyes have to adapt to the darkness, the more you will see. Then you can tell your children and your children's children that you saw the Great Leonid Storm of '02.

If the experts are correct.

Questions or suggestions? Write Mark Ritter here.

(Image obtained from the Astronomy Picture of the Day, 2001 November 4. Photo credit: Juraj Toth [Comenius U. Bratislava], Modra Observatory)

Posted by Administrator at 2002.11.16 02:19 PM | Comments (0)

The Seven Sisters and their Nebulous Grapes

The Galaxy >

There is a story among native American peoples that there are among the stars above us in the autumn night seven children. They can't find their way home and so huddle close together for safety and companionship.

That little myth is not far from the truth. Those seven children are the Pleiades and are starring in a sky near you until spring.

The Seven Sisters, as they are also known from ancient Greek mythology, are the pretty little collection of stars high up during the later evening hours this month. Often miscalled the Little Dipper, this tiny crew of toddlers gives us great insight into the life and death of stars.

As the starry story goes they are related, all born together in the same stellar nursery just a couple million years ago, a twinkling of the eye compared to the great age of the universe.

Stars are born of great clouds of gas called molecular clouds. They are called molecular clouds because along with possessing the hydrogen and helium that permeates the universe, they are cool enough to allow molecules to survive within them. But their "cloudiness" is not like the cloudiness we experience here on Earth.

Being tens of light years across --- hundreds of trillions of miles --- these giant clouds have so few atoms per volume that they out-vacuum even the best vacuums we have in labs here on the planet. But because the clouds are so genuinely enormous, the total amount of stuff they possess is immense, material enough for hundreds of stars like our sun.

It's when these happy-go-lucky clouds experience a shock --- as in a nearby supernova --- that this gas gets compressed in places and magical things begin to happen.

Little eddies of gas now begin to coalesce by their own gravity into bundles of gas, like nebulous grapes in a giant cloud cluster.

As the gas atoms fall and fall and fall towards an imaginary center of gravity, these little gas gatherings start to heat up and can actually glow. But the little balls are not yet stars.

That doesn't happen until the ball of gas --- now called a protostar --- gets small enough and dense enough and hot enough to begin a special process called fusion.

Fusion is when the tiny hydrogen nuclei, the tiniest on the whole Periodic Table if you remember your chemistry, move so fast and furiously that they actually fuse into one. When this happens in a way a little more complicated than I can explain here, helium is made and an enormous amount of energy is released.

We see a similar process in hydrogen bombs and, of course, our own sun.

The Pleiades, all forming from the same molecular cloud, can show us how star conception and birth and life differ.

From theory in the lab and observation of space, we see that the big babies, the stars with the most material, are born quickly, burn furiously, and die explosively.

Stars like our sun spend a little longer getting ready and, once born, live rather boring lives.

The lower mass stars take a lot longer to get it together before they begin fusing. But their tiny size allows them to live for over 100 billion years.

And that's what we see in the Pleiades. All the bright ones you see are the big ones, sparkling and beautiful, but doomed to a short life and a fiery end. The lower mass stars are difficult to see except with a telescope. But they'll outlive their big bright siblings long after the beautiful Seven Sisters are but a memory.

Questions or suggestions? Write Mark Ritter here.

Posted by Administrator at 2002.11. 9 02:21 PM | Comments (0)



Looking for something?	« October 2002 \| Main \| December 2002 » Three Things to be Thankful For A Perfect Balance > Thanksgiving is here again. Perhaps you still observe Big Dinner With The Relatives. You may even follow the ancient but healthy ritual of having everyone at the dinner table express something he or she is thankful for. Want to impress the relatives this year? Following are several real astro-centric Thanksgiving responses. You may want to cut one out and hide it in your lap, so when The Question inevitably comes your way, you'll be armed and ready. Ready? Response #1: This big, hot, steamy turkey here reminds me that I'm thankful for the rate of supernovae in our part of the galaxy! A star's whole life is spent making enough heat energy to push out against the gravity pushing in. When the big stars finally run out of fuel their cores collapse under the oppressive force of gravity and --- ka-BLAM! --- the outer shells of the stars spew out into space in one of the most violent explosions known, the supernova, drenching everything for tens of light-years around with lethal radiation. If this happened more frequently around us, Earth would be constantly sterilized. There would be no Thanksgiving. But the supernovae also blow the stuffing out of the dead star, spewing out all the new-formed elements of the periodic table, things like carbon and oxygen and silicon and iron and so on --- all the stuff you and I and the poor turkey and this whole planet are made of. So they have to happen frequently enough to provide material for planets and life. It appears their rate is just perfect. Response #2: Why, the thin delicate crusts on these biscuits remind me that I'm thankful for the collision that pulverized our planet and created the Moon! Very early on in the life of Earth, we got hit real well by a passing rogue planet about the size of Mars. We didn't get hit head on --- it was a glancing blow. But that blow knocked a whole load of our light --- then thicker --- crust into space. The beauty of all this is many-fold. Earth got extra radioactive guts for its innards, allowing it to retain a hotter interior for longer. This heat drives the amazing plate tectonics that are responsible for nearly every landform on the planet. Moreover, our new crust was thinner and more able to experience the newly fueled plate tectonics, the benefits of which could fill a book. But a huge bonus from this collision is that it also gave us our Moon. Yes, that big bright ball of rocky material was once part of this planet. But its newfound place in space steadies our orbit, lengthened our day, and keeps us from wobbling uncontrollably. Yippee! Response #3: The steam rising from these light, fluffy mashed potatoes reminds me to be thankful for the fine-tuned but oft ignored water cycle that planet Earth has! Our planet is at just the right distance from the sun for water to exist in all three states --- solid, liquid, and gas. Farther, it all freezes. Closer, it all evaporates away. Here we can enjoy literal oceans of water that can evaporate in one place and fall as rain or snow sometimes thousands of miles away. This keeps a pretty constant supply of life-giving water going all over Earth, like a giant sprinkler system. And the water making its way back to the oceans helps to erode away raised landforms to assist in the production of fertile topsoils. Go water! Those are three astronomical reasons to be full of thanks. Go and impress, and have a great Thanksgiving! Questions or suggestions? Write Mark Ritter here. Posted by Administrator at 2002.11.23 02:17 PM \| Comments (0) Walking Blindly into Heavy Traffic Comets > It's that time again; time to walk blindly into heavy traffic. The Leonids meteors will be streaking through the atmosphere early Tuesday morning for what could possibly be the last meteor storm for decades or more. Please, if you get the chance, take a glorious peek at these visitors from outer space. It will be an awesome experience, and one that the whole family can experience --- if you remember to set your alarm clock! Regular readers here will recall that a normal meteor shower involves the collisions of two things --- a stream of debris and planet Earth. The stream of debris comes from comets making their merry way through the solar system in their orbit around the sun. As they get closer to the sun and warm up a bit, they slough off tr-billions of teensy tiny rocky bits, usually no bigger than a grain of sand. This train of dust follows approximately the same elliptical orbit as mother comet. If that comet's orbit happens to cross Earth's orbit, worlds collide. When Earth ploughs through the debris train --- kaboom zaloom! --- the little particles hit our atmosphere at fiery speeds of up to 70 km/s and disintegrate in a flash of light we call a meteor. Around November 18 each year, our orbit goes through the debris train of Comet Tempel-Tuttle, which itself came through the neighborhood just several years ago. Normally it's a nice little meteor show, with maybe a couple dozen meteors per hour. But every third of a century or so we get a heapin' helpin' of dirt thrown right into our upper atmosphere and our skies light up in an aerial attack called a meteor storm. Why only then? As a comet blows by on its close approach to the sun, it sometimes dumps off an extraordinary amount of stuff. In their observations of the last several years of Leonids, astronomers have developed some pretty fancy models to explain when those blown off dust puffs blew off in the first place, where they are now, and where they are going. With all these updated models, several teams of astronomers working on the Leonids called the peak of the storm correctly last year, not to the day or the hour, but within minutes of the actual peak. So whereas there used to be much skepticism when the specialist called the alarm for a possible storm, now peak prognostication appears to have become a reliable science. This year the experts predict two waves of meteors. The first wave will occur too early for us on the west coast, but the second wave should catch us in good shape. It is "scheduled" to peak at 2:36 in the morning of the 19th. Observing the hour before and after will offer you the possibility of seeing thousands! That extraordinary speculation is the good news. The bad news is that the moon is full. So many will be lost in the bright glare of our fully lit satellite. But that's OK. The Leonid meteors can be pretty bright, and if the night is also clear, you should be able to still see hundreds right around the peak time. So, set the alarm clock for Tuesday morning around 2, wake the family, go outside away from the lights, back to the Moon, and look up. The longer your eyes have to adapt to the darkness, the more you will see. Then you can tell your children and your children's children that you saw the Great Leonid Storm of '02. If the experts are correct. Questions or suggestions? Write Mark Ritter here. (Image obtained from the Astronomy Picture of the Day, 2001 November 4. Photo credit: Juraj Toth [Comenius U. Bratislava], Modra Observatory) Posted by Administrator at 2002.11.16 02:19 PM \| Comments (0) The Seven Sisters and their Nebulous Grapes The Galaxy > There is a story among native American peoples that there are among the stars above us in the autumn night seven children. They can't find their way home and so huddle close together for safety and companionship. That little myth is not far from the truth. Those seven children are the Pleiades and are starring in a sky near you until spring. The Seven Sisters, as they are also known from ancient Greek mythology, are the pretty little collection of stars high up during the later evening hours this month. Often miscalled the Little Dipper, this tiny crew of toddlers gives us great insight into the life and death of stars. As the starry story goes they are related, all born together in the same stellar nursery just a couple million years ago, a twinkling of the eye compared to the great age of the universe. Stars are born of great clouds of gas called molecular clouds. They are called molecular clouds because along with possessing the hydrogen and helium that permeates the universe, they are cool enough to allow molecules to survive within them. But their "cloudiness" is not like the cloudiness we experience here on Earth. Being tens of light years across --- hundreds of trillions of miles --- these giant clouds have so few atoms per volume that they out-vacuum even the best vacuums we have in labs here on the planet. But because the clouds are so genuinely enormous, the total amount of stuff they possess is immense, material enough for hundreds of stars like our sun. It's when these happy-go-lucky clouds experience a shock --- as in a nearby supernova --- that this gas gets compressed in places and magical things begin to happen. Little eddies of gas now begin to coalesce by their own gravity into bundles of gas, like nebulous grapes in a giant cloud cluster. As the gas atoms fall and fall and fall towards an imaginary center of gravity, these little gas gatherings start to heat up and can actually glow. But the little balls are not yet stars. That doesn't happen until the ball of gas --- now called a protostar --- gets small enough and dense enough and hot enough to begin a special process called fusion. Fusion is when the tiny hydrogen nuclei, the tiniest on the whole Periodic Table if you remember your chemistry, move so fast and furiously that they actually fuse into one. When this happens in a way a little more complicated than I can explain here, helium is made and an enormous amount of energy is released. We see a similar process in hydrogen bombs and, of course, our own sun. The Pleiades, all forming from the same molecular cloud, can show us how star conception and birth and life differ. From theory in the lab and observation of space, we see that the big babies, the stars with the most material, are born quickly, burn furiously, and die explosively. Stars like our sun spend a little longer getting ready and, once born, live rather boring lives. The lower mass stars take a lot longer to get it together before they begin fusing. But their tiny size allows them to live for over 100 billion years. And that's what we see in the Pleiades. All the bright ones you see are the big ones, sparkling and beautiful, but doomed to a short life and a fiery end. The lower mass stars are difficult to see except with a telescope. But they'll outlive their big bright siblings long after the beautiful Seven Sisters are but a memory. Questions or suggestions? Write Mark Ritter here. Posted by Administrator at 2002.11. 9 02:21 PM \| Comments (0)
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