[ FirstLight Astronomy Club ] The Skies Above

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There's a Whole Lot of Space in Space

The Galaxy >

How close is the nearest star? Do you know? I have to fess up that this is kind of a trick question. If you are reading this during the day, it's a gimme. Just look outside and up; that big bright blinding ball in the sky is your answer. The sun is the nearest star to our planet.

Some of us who have taken an interest in astronomy may have assumed I was asking about the nearest star outside the solar system. Those astrophiles may have answered alpha Centauri, the brightest star in the constellation of Centaurus, shining brilliantly at a distant 4.4 light years.

That would have been almost correct. Actually alpha Centauri has a wee companion called proxima Centauri which is just a tad closer at about 4.3 light years. There's a free bonus fact for you.

But the point here and for the rest of this column today is that the nearest stars outside of our system are not just a stone's throw away; they are at very, very great distances --- light years, in fact!

A light year is about 6 trillion miles, the distance light can travel in a year. Once we humans hear numbers that huge, though, it gets pretty difficult to imagine. And this is the time when we nerdy science types try to think up some analogy to make it a little more real for all of us. Here goes ...

If you could fly a jet at 500 miles per hour it would take well over a million years to get to proxima Centauri, which would require nearly 4 million inflight meals. Yikes! Not a pretty thought. And that is just the one-way ticket!

But four light years is close compared to the average distance between stars. In our part of the galaxy, in our "neighborhood," the average distance between stars is about 7 light years. We need another model here to picture this.

If our sun were the size of a grapefruit, the next nearest grapefruit star wouldn't be in the same room, or even in California. It wouldn't be in Arizona, it wouldn't be in the Mississippi. The next nearest grapefruit star would be across the nation in Washington D.C.!

There is a whole lot of space in space!

Is this great distance between stars good or bad? Here's a hint: Next time Thanksgiving rolls around you'll have one more giant thing to be thankful for.

These great distances in stars are a great thing. We don't want them closer. To paraphrase another great star, "Vee vant to be alone."

More nearby stars would have disrupted the Solar System Building Project early on by inhibiting the development of unborn planets.

If the sun had gotten together with another star even after we were born, the other star would have severely interfered with our nearly perfect circular life-giving orbit. Worst Case Scenario has us being gravitationally slingshot out of that solar system altogether!

Moreover, if a nearby neighbor were a giant star, the lethal radiation from the explosive destruction of that short-lived monster would sterilize this planet in a flash.

On the other hand, a place in the galaxy with stars fewer and farther between is not good, either. We need those occasional big bad stars --- properly spaced --- to blow their guts out into space to provide the very material we need for planets, and for life.

These incomprehensible distances between stars are not too great, not too short --- they're just right.

Questions or suggestions? Write Mark Ritter here.

Posted by Administrator at 2002.10.26 02:23 PM | Comments (0)

More to Light Than Meets the Eye

Science >

You have probably seen a rainbow of light splash on a wall as the sun shines through a piece of cut glass or crystal. What is that light? What is it revealing about our sun, or even about our universe?

A curious girl with the curious name of Annie Jump Cannon asked those questions over a century ago. Her marvel about light and her fascination with the stars led her to become one of the premier women of astronomy of the entire 20th century.

Light from a source can be passed through a prism and spread out into its spectrum. We see the sun's light dispersed like this when we marvel at the rainbow. With the proper equipment one can see thin dark lines in the spectrum, telltale lines which reveal the presence of different elements at the light source. Thus, and amazingly, the composition of a star hundreds of trillions of miles away can be determined merely by examining its light.

In the late 1800's taking the spectra of stars was becoming the thing to do. But it was tedious and in great need of being organized.

One such lab that was willing to take on that daunting task was Harvard College Observatory. There, Edward Pickering worked for decades to give the world the classic Henry Draper Catalog with hundreds of thousands of stellar spectra. But that's only part of the story.

Pickering hired women to be used as "computers" to catalog the flood of spectra coming into the observatory. Although most of the women toiled for a while, then left in obscurity, some of them toughed it out and tried to make sense of all the colorful information flowing their way.

One of his computers was Annie Jump Cannon.

Blessed with a father who felt it was important for his daughter to get an education, Annie Cannon graduated from Wellesley in 1884, then shortly after joined Pickering and his computers at Harvard. And there she stayed --- for 42 years.

In those decades of patience and persistence she personally managed to catalog over 400,000 spectra! And in doing so helped give us the Henry Draper Catalog that astronomers use to this day.

But what most all astronomy students know her for is her classification system. In examining all those spectra she managed to see repeating characteristics of spectra which helped turn a then convoluted and confusing classification system into the modern one.

She gave us the famous sequence --- OBAFGKM. The hottest, meanest, bluest, biggest stars are the O's. As we proceed through the letters we get stars that are cooler, smaller, less energetic. Our own star is a G star. The cool red ones are the K's and M's. Even today astronomy students memorize the sequence with the mnemonic, Oh Be A Fine Girl (Guy), Kiss Me!

Her work and the work of her fellow computers helped us to see the big picture of stars and star formation. And all this was accomplished before the advent of modern computers.

Amazingly, although she was internationally recognized for her efforts, her name did not appear in the Harvard catalog, and she was not even officially acknowledged by Harvard until she was 75 years old, three years before her death.

Wrote Miss Cannon, "Classifying the stars has helped materially in all studies of the structure of the universe. No greater problem is presented to the human mind. Teaching man his relatively small sphere in the creation, it also encourages him by its lessons of the unity of Nature and shows him that his power of comprehension allies him with the great intelligence over-reaching all."

Questions or suggestions? Write Mark Ritter here.

Posted by Administrator at 2002.10.12 02:25 PM | Comments (0)

More About Quaoar

The Solar System >

There's a newfound fuzzy object way out in our solar system that's just made things a little bit clearer.
Last week planetary scientists Mike Brown and Chad Trujillo of Caltech announced their discovery of Quaoar, the largest solar system body found since the discovery of Pluto way back in 1930.

Using the old 48-inch Oschin Telescope on Palomar Mountain fitted with new imaging equipment, they noticed last June a new, extremely faint object in the sky just northeast of the constellation Scorpio.

Searching back through archives at Palomar, Brown and Trujillo dug up several more faint images previously taken of this rocky body dating all the way back to 1982. It had been overlooked! But, how?

Quaoar is one small rock, half the size of Pluto, and on average farther from Pluto, so very little light reaches it. Moreover, the organic material on the surface has most likely been degraded to a fare-thee-well by 4 billion years of ultraviolet bombardment from the distant sun, probably resulting in tar-like substances on some of the surface. That would make it even dimmer.

So that it managed to disappear amongst the background stars for so long is not surprising. That Brown and Trujillo actually found this tiny slow-moving dark rock is a reflection of their equipment and the tenacity of the astronomers.

"The discovery," says Steven Pravdo of NASA, "is another feather in the cap of the venerable Oschin Telescope and the modern Near-Earth Asteroid Tracking camera system."

E. C. Krupp, Director of Griffith Observatory, adds, "The real charm of this discovery is the detection of the object at all. I am delighted with and impressed by the perseverance and diligence of the astronomers who spotted it. Their quiet, painstaking work showcases mindful observation of nature."

The odd thing for most laymen is the reaction from astronomers --- they aren't surprised by this discovery at all. Michael Seeds, astronomer at Franklin and Marshall College sums it up, "If we looked and looked and looked and did not find these objects, the solar system would have to produce a note from its Mama explaining how it lost them."

So what is Quaoar and why is its discovery no surprise to the people who know the skies well? We'll have to go back in time a bit.

Since humans have recorded what is in the heavens, there has been an acknowledgment of the Sun, Moon, and the brighter, naked-eye planets out to Saturn. And there were the occasional strange visitors like comets, to be sure. But that was about it. The skies above were pretty clean and well managed.

Then in 1781 distant Uranus was discovered. Shortly after, Neptune was descried. The solar system was growing. And in trying to find even more planets, new, unexpected findings were made.

In 1801 came the detection of an object between Mars and Jupiter; the first minor planet, christened Ceres, was discovered. Within years, more and more of these huge rocks were seen in an area we now call the Asteroid Belt. As hundreds more were found, there was not so much new excitement as there was a quest to find out what it all meant.

Were all these asteroids potential building blocks of a wannabe planet that just couldn't get it together, or the remains of a planet that was ripped apart, perhaps by Jupiter's intense gravity?

And there was another, related mystery, one which leads us to last week's discovery --- comets. These little critters get the bejeebers blown off them every time they come by the sun. The sun's energy and winds strip a whole lot of dust and water from them giving them their beautiful tails. Sadly, the great loss of "stuff" means they will have relatively short lives.

Moreover, their orbits take them close to the sun, but then far --- I mean billions of miles far - from the sun during the rest of their orbit.

But despite their shrinking population new comets somehow keep showing up from way out there, year after year after year. How, and from where?

"The answer had to be," believes astronomer Andy Young of San Diego State, "that there was a vast supply of comets in cold storage somewhere beyond the region occupied by the planets." Occasionally one would get bumped into an orbit that would take it close to the sun.

Elsewhere in the galaxy we see monstrous, dirty, Frisbee-shaped disks of rocky material around other baby stars, disks where we believe that rocky material is being coalesced into planets. We are led to believe, then, that we probably have a lot of leftovers in our own great freezer, out there beyond Neptune. The comets are just some of those icy chunks that get nudged in toward the sun.

We call our own Frisbee of frozen leftovers the Kuiper Belt, named after Gerard Kuiper who first proposed its existence.

Young adds, "But the leftovers shouldn't be as small as the average comet; there should be some 'half-baked' planets that never really grew to planetary size. At the edge of the planetary system there ought to be a lot of solid bodies, bigger than the average comet, but smaller than the average planet."
Enter Pluto.

When Pluto was discovered in 1930, astronomers knew something was amiss. It wasn't a gas giant like all the Big Guys out there are; it was a rock smaller than our Moon. And it had a funky lopsided orbit that sometimes took it closer to the sun than Neptune! Pluto was a planetary oddball, a freak.

But maybe no more.

Maybe, as Dr Young points out, Pluto, along with the newly discovered Quaoar are "examples of these intermediate-sized objects. Maybe Pluto was the just the first-found member of that group, and not a freak."

Most astronomers now believe Pluto, with its moon Charon, are a very large "double" Kuiper Belt Object (KBO), some of the leftovers from the infancy of our solar system. There have been many other KBOs, some called Plutinos, found in the last years with the new, modern instruments.

Does that mean Pluto will be downgraded from planet to a "mere" KBO? Krupp says no. "Membership in the Kuiper Belt battalion is no reason to disqualify Pluto as a planet. Pluto's planet-status is now more historical and cultural than physical. I'm a card-carrying member of the Fair Play for Pluto Party. Pluto is the people's planet. It earned that standing through its cultural meaning, and I see no reason to rescind its status now."

So the discovery of Quaoar came as no surprise. But is it important? You bet.

Says Seeds, "The discovery of this object confirms our understanding of how the solar system formed. I'll bet my lunch money that there are even bigger objects to be found. Probably not many, but enough to win a few nice lunches, and further confirm our understanding of the history of our planetary system."

Young concludes, "What's important here is not just 'discovering' an object, but the way in which that object ties together planets, comets, and the history of the whole solar system. It's like filling a hole in a jigsaw puzzle by noticing a piece you didn't see before."

Quaoar is one more piece that fits perfectly into the Great Puzzle.

Posted by Administrator at 2002.10. 2 02:27 PM | Comments (0)



Looking for something?	« September 2002 \| Main \| November 2002 » There's a Whole Lot of Space in Space The Galaxy > How close is the nearest star? Do you know? I have to fess up that this is kind of a trick question. If you are reading this during the day, it's a gimme. Just look outside and up; that big bright blinding ball in the sky is your answer. The sun is the nearest star to our planet. Some of us who have taken an interest in astronomy may have assumed I was asking about the nearest star outside the solar system. Those astrophiles may have answered alpha Centauri, the brightest star in the constellation of Centaurus, shining brilliantly at a distant 4.4 light years. That would have been almost correct. Actually alpha Centauri has a wee companion called proxima Centauri which is just a tad closer at about 4.3 light years. There's a free bonus fact for you. But the point here and for the rest of this column today is that the nearest stars outside of our system are not just a stone's throw away; they are at very, very great distances --- light years, in fact! A light year is about 6 trillion miles, the distance light can travel in a year. Once we humans hear numbers that huge, though, it gets pretty difficult to imagine. And this is the time when we nerdy science types try to think up some analogy to make it a little more real for all of us. Here goes ... If you could fly a jet at 500 miles per hour it would take well over a million years to get to proxima Centauri, which would require nearly 4 million inflight meals. Yikes! Not a pretty thought. And that is just the one-way ticket! But four light years is close compared to the average distance between stars. In our part of the galaxy, in our "neighborhood," the average distance between stars is about 7 light years. We need another model here to picture this. If our sun were the size of a grapefruit, the next nearest grapefruit star wouldn't be in the same room, or even in California. It wouldn't be in Arizona, it wouldn't be in the Mississippi. The next nearest grapefruit star would be across the nation in Washington D.C.! There is a whole lot of space in space! Is this great distance between stars good or bad? Here's a hint: Next time Thanksgiving rolls around you'll have one more giant thing to be thankful for. These great distances in stars are a great thing. We don't want them closer. To paraphrase another great star, "Vee vant to be alone." More nearby stars would have disrupted the Solar System Building Project early on by inhibiting the development of unborn planets. If the sun had gotten together with another star even after we were born, the other star would have severely interfered with our nearly perfect circular life-giving orbit. Worst Case Scenario has us being gravitationally slingshot out of that solar system altogether! Moreover, if a nearby neighbor were a giant star, the lethal radiation from the explosive destruction of that short-lived monster would sterilize this planet in a flash. On the other hand, a place in the galaxy with stars fewer and farther between is not good, either. We need those occasional big bad stars --- properly spaced --- to blow their guts out into space to provide the very material we need for planets, and for life. These incomprehensible distances between stars are not too great, not too short --- they're just right. Questions or suggestions? Write Mark Ritter here. Posted by Administrator at 2002.10.26 02:23 PM \| Comments (0) More to Light Than Meets the Eye Science > You have probably seen a rainbow of light splash on a wall as the sun shines through a piece of cut glass or crystal. What is that light? What is it revealing about our sun, or even about our universe? A curious girl with the curious name of Annie Jump Cannon asked those questions over a century ago. Her marvel about light and her fascination with the stars led her to become one of the premier women of astronomy of the entire 20th century. Light from a source can be passed through a prism and spread out into its spectrum. We see the sun's light dispersed like this when we marvel at the rainbow. With the proper equipment one can see thin dark lines in the spectrum, telltale lines which reveal the presence of different elements at the light source. Thus, and amazingly, the composition of a star hundreds of trillions of miles away can be determined merely by examining its light. In the late 1800's taking the spectra of stars was becoming the thing to do. But it was tedious and in great need of being organized. One such lab that was willing to take on that daunting task was Harvard College Observatory. There, Edward Pickering worked for decades to give the world the classic Henry Draper Catalog with hundreds of thousands of stellar spectra. But that's only part of the story. Pickering hired women to be used as "computers" to catalog the flood of spectra coming into the observatory. Although most of the women toiled for a while, then left in obscurity, some of them toughed it out and tried to make sense of all the colorful information flowing their way. One of his computers was Annie Jump Cannon. Blessed with a father who felt it was important for his daughter to get an education, Annie Cannon graduated from Wellesley in 1884, then shortly after joined Pickering and his computers at Harvard. And there she stayed --- for 42 years. In those decades of patience and persistence she personally managed to catalog over 400,000 spectra! And in doing so helped give us the Henry Draper Catalog that astronomers use to this day. But what most all astronomy students know her for is her classification system. In examining all those spectra she managed to see repeating characteristics of spectra which helped turn a then convoluted and confusing classification system into the modern one. She gave us the famous sequence --- OBAFGKM. The hottest, meanest, bluest, biggest stars are the O's. As we proceed through the letters we get stars that are cooler, smaller, less energetic. Our own star is a G star. The cool red ones are the K's and M's. Even today astronomy students memorize the sequence with the mnemonic, Oh Be A Fine Girl (Guy), Kiss Me! Her work and the work of her fellow computers helped us to see the big picture of stars and star formation. And all this was accomplished before the advent of modern computers. Amazingly, although she was internationally recognized for her efforts, her name did not appear in the Harvard catalog, and she was not even officially acknowledged by Harvard until she was 75 years old, three years before her death. Wrote Miss Cannon, "Classifying the stars has helped materially in all studies of the structure of the universe. No greater problem is presented to the human mind. Teaching man his relatively small sphere in the creation, it also encourages him by its lessons of the unity of Nature and shows him that his power of comprehension allies him with the great intelligence over-reaching all." Questions or suggestions? Write Mark Ritter here. Posted by Administrator at 2002.10.12 02:25 PM \| Comments (0) More About Quaoar The Solar System > There's a newfound fuzzy object way out in our solar system that's just made things a little bit clearer. Last week planetary scientists Mike Brown and Chad Trujillo of Caltech announced their discovery of Quaoar, the largest solar system body found since the discovery of Pluto way back in 1930. Using the old 48-inch Oschin Telescope on Palomar Mountain fitted with new imaging equipment, they noticed last June a new, extremely faint object in the sky just northeast of the constellation Scorpio. Searching back through archives at Palomar, Brown and Trujillo dug up several more faint images previously taken of this rocky body dating all the way back to 1982. It had been overlooked! But, how? Quaoar is one small rock, half the size of Pluto, and on average farther from Pluto, so very little light reaches it. Moreover, the organic material on the surface has most likely been degraded to a fare-thee-well by 4 billion years of ultraviolet bombardment from the distant sun, probably resulting in tar-like substances on some of the surface. That would make it even dimmer. So that it managed to disappear amongst the background stars for so long is not surprising. That Brown and Trujillo actually found this tiny slow-moving dark rock is a reflection of their equipment and the tenacity of the astronomers. "The discovery," says Steven Pravdo of NASA, "is another feather in the cap of the venerable Oschin Telescope and the modern Near-Earth Asteroid Tracking camera system." E. C. Krupp, Director of Griffith Observatory, adds, "The real charm of this discovery is the detection of the object at all. I am delighted with and impressed by the perseverance and diligence of the astronomers who spotted it. Their quiet, painstaking work showcases mindful observation of nature." The odd thing for most laymen is the reaction from astronomers --- they aren't surprised by this discovery at all. Michael Seeds, astronomer at Franklin and Marshall College sums it up, "If we looked and looked and looked and did not find these objects, the solar system would have to produce a note from its Mama explaining how it lost them." So what is Quaoar and why is its discovery no surprise to the people who know the skies well? We'll have to go back in time a bit. Since humans have recorded what is in the heavens, there has been an acknowledgment of the Sun, Moon, and the brighter, naked-eye planets out to Saturn. And there were the occasional strange visitors like comets, to be sure. But that was about it. The skies above were pretty clean and well managed. Then in 1781 distant Uranus was discovered. Shortly after, Neptune was descried. The solar system was growing. And in trying to find even more planets, new, unexpected findings were made. In 1801 came the detection of an object between Mars and Jupiter; the first minor planet, christened Ceres, was discovered. Within years, more and more of these huge rocks were seen in an area we now call the Asteroid Belt. As hundreds more were found, there was not so much new excitement as there was a quest to find out what it all meant. Were all these asteroids potential building blocks of a wannabe planet that just couldn't get it together, or the remains of a planet that was ripped apart, perhaps by Jupiter's intense gravity? And there was another, related mystery, one which leads us to last week's discovery --- comets. These little critters get the bejeebers blown off them every time they come by the sun. The sun's energy and winds strip a whole lot of dust and water from them giving them their beautiful tails. Sadly, the great loss of "stuff" means they will have relatively short lives. Moreover, their orbits take them close to the sun, but then far --- I mean billions of miles far - from the sun during the rest of their orbit. But despite their shrinking population new comets somehow keep showing up from way out there, year after year after year. How, and from where? "The answer had to be," believes astronomer Andy Young of San Diego State, "that there was a vast supply of comets in cold storage somewhere beyond the region occupied by the planets." Occasionally one would get bumped into an orbit that would take it close to the sun. Elsewhere in the galaxy we see monstrous, dirty, Frisbee-shaped disks of rocky material around other baby stars, disks where we believe that rocky material is being coalesced into planets. We are led to believe, then, that we probably have a lot of leftovers in our own great freezer, out there beyond Neptune. The comets are just some of those icy chunks that get nudged in toward the sun. We call our own Frisbee of frozen leftovers the Kuiper Belt, named after Gerard Kuiper who first proposed its existence. Young adds, "But the leftovers shouldn't be as small as the average comet; there should be some 'half-baked' planets that never really grew to planetary size. At the edge of the planetary system there ought to be a lot of solid bodies, bigger than the average comet, but smaller than the average planet." Enter Pluto. When Pluto was discovered in 1930, astronomers knew something was amiss. It wasn't a gas giant like all the Big Guys out there are; it was a rock smaller than our Moon. And it had a funky lopsided orbit that sometimes took it closer to the sun than Neptune! Pluto was a planetary oddball, a freak. But maybe no more. Maybe, as Dr Young points out, Pluto, along with the newly discovered Quaoar are "examples of these intermediate-sized objects. Maybe Pluto was the just the first-found member of that group, and not a freak." Most astronomers now believe Pluto, with its moon Charon, are a very large "double" Kuiper Belt Object (KBO), some of the leftovers from the infancy of our solar system. There have been many other KBOs, some called Plutinos, found in the last years with the new, modern instruments. Does that mean Pluto will be downgraded from planet to a "mere" KBO? Krupp says no. "Membership in the Kuiper Belt battalion is no reason to disqualify Pluto as a planet. Pluto's planet-status is now more historical and cultural than physical. I'm a card-carrying member of the Fair Play for Pluto Party. Pluto is the people's planet. It earned that standing through its cultural meaning, and I see no reason to rescind its status now." So the discovery of Quaoar came as no surprise. But is it important? You bet. Says Seeds, "The discovery of this object confirms our understanding of how the solar system formed. I'll bet my lunch money that there are even bigger objects to be found. Probably not many, but enough to win a few nice lunches, and further confirm our understanding of the history of our planetary system." Young concludes, "What's important here is not just 'discovering' an object, but the way in which that object ties together planets, comets, and the history of the whole solar system. It's like filling a hole in a jigsaw puzzle by noticing a piece you didn't see before." Quaoar is one more piece that fits perfectly into the Great Puzzle. Posted by Administrator at 2002.10. 2 02:27 PM \| Comments (0)
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