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One Giant Leap

The Calendar >

Is a leap year really necessary? Isn't it just an ancient formality we still hopelessly cling to? Well, unless you want to celebrate Christmas in shorts and sandals, or risk a snowstorm during a Fourth of July fireworks extravaganza, you'd better accept it as one of life's "good things."

The Earth, moon, sun, and stars follow the laws of nature, not the laws of man. Our planet spins around on its axis at just the right rate, it is tilted at just the right angle, and it circuits the sun in exactly the right amount of time to make life very, very comfortable on this planet. That all these don't allow a nice, neat human-made calendar is not of great concern at the cosmic scale.

We all know the typical calendar year is 365 days long --- 365 spins of the globe. That fact has been known for millennia by many people groups. The sun, from our point of view, takes that long to travel one complete circuit through the stars. Or we moderns might say that it takes that long for Earth to orbit the Sun once. But it isn't exactly 365 days; it's just a wee bit longer than that.

Actually it takes 365 days, 5 hours, 48 minutes, and 46 seconds to complete one exact trip around the sun. The immediate effect those extra hours have is unnoticeable. After one year, an uncorrected man-made calendar and the natural seasons will be off by just a quarter day. After a decade they will disagree by just over two days.

But if you don't correct for it, you'll notice after generations pass that the holidays your great-great-grandparents celebrated in the spring are now taking place in what feels more like winter, and the special days your people would traditionally celebrate as summer rituals are now taking place when the leaves are budding on the trees.

The Roman calendar, the chief influence in our modern calendar, was one unholy mess by the time Julius Caesar came to power. By the first century B.C. their uncorrected calendar was off by 3 months compared to the seasons! Caesar, with the help of an Alexandrian astronomer named Sosigenes, was determined to clean it up.

So, in 46 B.C. he boldly declared that 67 days were to be added to the end of November so that the calendar would match again with the seasonal celebrations. And each month --- from January to December --- which before his decree had a seemingly random number of days assigned to it, was given the amount of days we have now on our calendar (e.g. 31 for January, 28 for February, etc.)

But wisely he went one step further. Sosigenes knew that the year was really about 365 1/4 days. So to avoid calendrical confusion down the line, Julius decreed a leap day into February every four years to make up for the lost day and assure that the seasons and calendars would remain close. Hence the 2000-year-old tradition of leap day was born.

But the year, remember, is not exactly 365 1/4 days long and after another 16 centuries passed, even the leap days weren't keeping the calendar and seasons together. So, in 1582, the Gregorian calendar --- after Pope Gregory XIII --- was introduced which again would yank days right out of the calendar to correct it, but then add a new rule.

Every century year (e.g 1600, 1700, etc.) would not get the leap day unless it was divisible by 400. That is why the century year of 2000 got a leap day, it being divisible by 400. The year 2100 will not.

Got all that? There's more. To bring the calendar even closer to the seasons for as long as humans walk the earth, it has been recently agreed upon that the years 4000 and 8000 will also get their leap year status revoked. Make note of that if you are planning anything then.

Keeping our calendars in harmony with the seasons may be a pain, but it's a small price to pay for a planet with the perfect spin, the ideal tilt, and the just right year.

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

Posted by Administrator at 2004.02.21 12:45 PM | Comments (0)

A Noble 'QUEST'

Observing >

What do you do when that old telescope of yours has seen its day? Throw it away? Barter over it in a garage sale? Convert it into a new water heater? May it never be! You breathe into it the breath of new life and turn it into the world's largest astronomical camera.

And that's precisely what a team of astrophysicists from Caltech, Yale University, the Jet Propulsion Laboratory, and Indiana University has done with the 56-year-old Oschin Telescope on nearby Palomar Mountain.

Built at the same time as the famous 200-inch Hale Telescope, the 48-inch Samuel Oschin Telescope saw first light in 1948 and has been a sturdy workhorse for more than half a century, scanning the heavens in various sky surveys.

But now a group of astronomers has made it even better by hooking up to it a kind of super science surveillance camera that can study the universe from our solar system all the way out to the farthest reaches of space --- over 10 billion light years away.

Called QUEST (Quasar Equatorial Survey Team), this Mother of All Digital Cameras is a masterful coordination of 112 charged-coupled devices (CCDs), the same critters capturing images inside digital cameras nowadays. But this camera is bigger --- a whole lot bigger.

But why not use Palomar's legendary 200-inch Hale telescope to do this? A 200-inch mirror can pick up a whole lot more light than one just 48 inches across. Scott Kardel, Palomar Public Affairs Director explains, "Yes, the 200-inch can see deeper, but the 48-inch can see a field of view that is more than 31 times wider, about the width of your hand at arm's length. It gives astronomers a much bigger net that they can cast to find interesting things in the universe."

Oschin's wide field of view coupled with that large array of CCDs allows astronomers to collect a massive amount of data, the very lifeblood of science. How much data? Would the equivalent of about two million books per month impress you?

But wait! There's more.

The way the whole new-fangled contraption is set up allows astronomers to put together successive images of the sky and perform a little observing magic.

"Previous sky surveys provided essentially digital snapshots of the sky," says S. George Djorgovski, professor of astronomy at Caltech. "Now we are starting to make digital movies of the universe."

The Palomar-QUEST survey, as it is officially called, is like an all-sky spy movie camera on the constant lookout for all kinds of mysterious celestial objects. The enormity of its wide field array and the ability to make what are essentially motion pictures of the night sky mean that astronomers can easily pick out suspects that move clandestinely in the heavens or vary in their brightness. What sort of perpetrators might these include?

Close to home, QUEST will be used to hunt down rogue asteroids. These give themselves away by moving slowly and dimly through the background stars. Once discovered, their orbits can be plotted to determine whether or not they might be headed this way anytime soon in a collision course with our planet. Discovering these scoundrels quickly may allow us to actually do something about them before they strike.

Other astronomers will use QUEST to look for flotsam and jetsam in a distant icy swarm of objects beyond the orbit of Pluto called the Kuiper Belt. Mike Brown and Chad Trujillo of Caltech used the pre-QUEST Oschin telescope two years ago to discover Quaoar, the largest object found in our solar system since Pluto in 1930. With the newly bedecked Oschin, Brown hopes to discover in the Belt what he believes are objects the size of Mars.

The latest bombshell from the realm of astronomy is that our universe is not just expanding; it's actually speeding up as it expands. All indications are that we live in an accelerating universe. But there are a lot of unanswered question to this bizarre scientific dilemma. Acting as a sort of "first alert" system, QUEST will quickly and accurately find normal everyday exploding stars called supernovae, which are used to measure how fast we are expanding.

The most devastating explosions in the universe, gamma ray bursts, are elusive to say the least. Possibly the results of freakishly big supernova explosions called hypernovae, they are very unpredictable and last just seconds. QUEST's quick response eyes-on-the-sky will be used to find and identify the brutes.

At the near farthest reaches of space lie terrifying monsters, young galaxies possessed by supermassive black holes at their very core. These beasts, called quasars, are also on the list of QUEST's Most Wanted. QUEST will work together with the Big Scopes to help solve riddles of what happened in the infancy of our universe, shortly after the Creation Event.

Adds Scott Kardel, "George Djorgovski has been using the QUEST data as a part of the search for high red shift (very distant) quasars. The 200-inch armed with a spectrograph, is used to confirm if the objects are indeed quasars. The Keck in Hawaii is then used to take more detailed follow-up observations."

It's an elegant and mysterious universe we live in. The new Oschin Telescope/Palomar-QUEST survey should make it a little less mysterious, and prove it even more beautifully elegant than we imagined.

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

Posted by Administrator at 2004.02. 7 12:48 PM | Comments (0)



Looking for something?	« January 2004 \| Main \| March 2004 » One Giant Leap The Calendar > Is a leap year really necessary? Isn't it just an ancient formality we still hopelessly cling to? Well, unless you want to celebrate Christmas in shorts and sandals, or risk a snowstorm during a Fourth of July fireworks extravaganza, you'd better accept it as one of life's "good things." The Earth, moon, sun, and stars follow the laws of nature, not the laws of man. Our planet spins around on its axis at just the right rate, it is tilted at just the right angle, and it circuits the sun in exactly the right amount of time to make life very, very comfortable on this planet. That all these don't allow a nice, neat human-made calendar is not of great concern at the cosmic scale. We all know the typical calendar year is 365 days long --- 365 spins of the globe. That fact has been known for millennia by many people groups. The sun, from our point of view, takes that long to travel one complete circuit through the stars. Or we moderns might say that it takes that long for Earth to orbit the Sun once. But it isn't exactly 365 days; it's just a wee bit longer than that. Actually it takes 365 days, 5 hours, 48 minutes, and 46 seconds to complete one exact trip around the sun. The immediate effect those extra hours have is unnoticeable. After one year, an uncorrected man-made calendar and the natural seasons will be off by just a quarter day. After a decade they will disagree by just over two days. But if you don't correct for it, you'll notice after generations pass that the holidays your great-great-grandparents celebrated in the spring are now taking place in what feels more like winter, and the special days your people would traditionally celebrate as summer rituals are now taking place when the leaves are budding on the trees. The Roman calendar, the chief influence in our modern calendar, was one unholy mess by the time Julius Caesar came to power. By the first century B.C. their uncorrected calendar was off by 3 months compared to the seasons! Caesar, with the help of an Alexandrian astronomer named Sosigenes, was determined to clean it up. So, in 46 B.C. he boldly declared that 67 days were to be added to the end of November so that the calendar would match again with the seasonal celebrations. And each month --- from January to December --- which before his decree had a seemingly random number of days assigned to it, was given the amount of days we have now on our calendar (e.g. 31 for January, 28 for February, etc.) But wisely he went one step further. Sosigenes knew that the year was really about 365 1/4 days. So to avoid calendrical confusion down the line, Julius decreed a leap day into February every four years to make up for the lost day and assure that the seasons and calendars would remain close. Hence the 2000-year-old tradition of leap day was born. But the year, remember, is not exactly 365 1/4 days long and after another 16 centuries passed, even the leap days weren't keeping the calendar and seasons together. So, in 1582, the Gregorian calendar --- after Pope Gregory XIII --- was introduced which again would yank days right out of the calendar to correct it, but then add a new rule. Every century year (e.g 1600, 1700, etc.) would not get the leap day unless it was divisible by 400. That is why the century year of 2000 got a leap day, it being divisible by 400. The year 2100 will not. Got all that? There's more. To bring the calendar even closer to the seasons for as long as humans walk the earth, it has been recently agreed upon that the years 4000 and 8000 will also get their leap year status revoked. Make note of that if you are planning anything then. Keeping our calendars in harmony with the seasons may be a pain, but it's a small price to pay for a planet with the perfect spin, the ideal tilt, and the just right year. Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com. Posted by Administrator at 2004.02.21 12:45 PM \| Comments (0) A Noble 'QUEST' Observing > What do you do when that old telescope of yours has seen its day? Throw it away? Barter over it in a garage sale? Convert it into a new water heater? May it never be! You breathe into it the breath of new life and turn it into the world's largest astronomical camera. And that's precisely what a team of astrophysicists from Caltech, Yale University, the Jet Propulsion Laboratory, and Indiana University has done with the 56-year-old Oschin Telescope on nearby Palomar Mountain. Built at the same time as the famous 200-inch Hale Telescope, the 48-inch Samuel Oschin Telescope saw first light in 1948 and has been a sturdy workhorse for more than half a century, scanning the heavens in various sky surveys. But now a group of astronomers has made it even better by hooking up to it a kind of super science surveillance camera that can study the universe from our solar system all the way out to the farthest reaches of space --- over 10 billion light years away. Called QUEST (Quasar Equatorial Survey Team), this Mother of All Digital Cameras is a masterful coordination of 112 charged-coupled devices (CCDs), the same critters capturing images inside digital cameras nowadays. But this camera is bigger --- a whole lot bigger. But why not use Palomar's legendary 200-inch Hale telescope to do this? A 200-inch mirror can pick up a whole lot more light than one just 48 inches across. Scott Kardel, Palomar Public Affairs Director explains, "Yes, the 200-inch can see deeper, but the 48-inch can see a field of view that is more than 31 times wider, about the width of your hand at arm's length. It gives astronomers a much bigger net that they can cast to find interesting things in the universe." Oschin's wide field of view coupled with that large array of CCDs allows astronomers to collect a massive amount of data, the very lifeblood of science. How much data? Would the equivalent of about two million books per month impress you? But wait! There's more. The way the whole new-fangled contraption is set up allows astronomers to put together successive images of the sky and perform a little observing magic. "Previous sky surveys provided essentially digital snapshots of the sky," says S. George Djorgovski, professor of astronomy at Caltech. "Now we are starting to make digital movies of the universe." The Palomar-QUEST survey, as it is officially called, is like an all-sky spy movie camera on the constant lookout for all kinds of mysterious celestial objects. The enormity of its wide field array and the ability to make what are essentially motion pictures of the night sky mean that astronomers can easily pick out suspects that move clandestinely in the heavens or vary in their brightness. What sort of perpetrators might these include? Close to home, QUEST will be used to hunt down rogue asteroids. These give themselves away by moving slowly and dimly through the background stars. Once discovered, their orbits can be plotted to determine whether or not they might be headed this way anytime soon in a collision course with our planet. Discovering these scoundrels quickly may allow us to actually do something about them before they strike. Other astronomers will use QUEST to look for flotsam and jetsam in a distant icy swarm of objects beyond the orbit of Pluto called the Kuiper Belt. Mike Brown and Chad Trujillo of Caltech used the pre-QUEST Oschin telescope two years ago to discover Quaoar, the largest object found in our solar system since Pluto in 1930. With the newly bedecked Oschin, Brown hopes to discover in the Belt what he believes are objects the size of Mars. The latest bombshell from the realm of astronomy is that our universe is not just expanding; it's actually speeding up as it expands. All indications are that we live in an accelerating universe. But there are a lot of unanswered question to this bizarre scientific dilemma. Acting as a sort of "first alert" system, QUEST will quickly and accurately find normal everyday exploding stars called supernovae, which are used to measure how fast we are expanding. The most devastating explosions in the universe, gamma ray bursts, are elusive to say the least. Possibly the results of freakishly big supernova explosions called hypernovae, they are very unpredictable and last just seconds. QUEST's quick response eyes-on-the-sky will be used to find and identify the brutes. At the near farthest reaches of space lie terrifying monsters, young galaxies possessed by supermassive black holes at their very core. These beasts, called quasars, are also on the list of QUEST's Most Wanted. QUEST will work together with the Big Scopes to help solve riddles of what happened in the infancy of our universe, shortly after the Creation Event. Adds Scott Kardel, "George Djorgovski has been using the QUEST data as a part of the search for high red shift (very distant) quasars. The 200-inch armed with a spectrograph, is used to confirm if the objects are indeed quasars. The Keck in Hawaii is then used to take more detailed follow-up observations." It's an elegant and mysterious universe we live in. The new Oschin Telescope/Palomar-QUEST survey should make it a little less mysterious, and prove it even more beautifully elegant than we imagined. Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com. Posted by Administrator at 2004.02. 7 12:48 PM \| Comments (0)
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