2000-Year-Old Meteors to Rain Down on August 31, 2007

Peter Jenniskens, Ph.D.Meteor Astronomer, Carl Sagan Center, SETI InstituteSPACE.comThu Aug 23, 10:30 AM ET The meteors that are about to rain down in the early morning of September 1 date from around 4 A.D., the latest calculations show. It is not often that we can tell when a shooting star was first released from a comet into space, to travel as a meteoroid in an orbit around the Sun, and finally collide with Earth's atmosphere to shine as a meteor for our enjoyment. Most meteors that sporadically flash across the sky on a dark moonless night date from anonymous times. Only in recent years have we learned to trace young meteor showers, just a few revolutions old, to their date of origin. The oldest such shower, but only one revolution old, is due in the early morning of September 1, 2007. Our calculations indicate Earth is about to cross the dust trail of comet Kiess, a comet that takes some 2000 years to complete one orbit around the Sun. The trail is very narrow, so Earth will be hosed by meteoroids for only about an hour and a half. The meteoroids will approach from the direction of the constellation Auriga, the charioteer, in the north-eastern part of the sky, causing a meteor shower called the "Aurigids." If you spot one of those meteors, you may be only the fourth person alive who is known to have seen this meteor shower. In recent times, the shower was spotted in 1994 by two observers and in 1986 by one observer. If you are lucky enough to catch a picture of an Aurigid meteor using your digital camera, you will be the very first to do so. Tips on how to observe meteors and where to report the results can be found at: http://aurigid.seti.org/ The shower is visible from only part of the world. If you live in the western parts of the USA, Canada and Mexico, including Hawaii and Alaska, you might spot an Aurigid meteor. Plan to step out around 4 A.M. PDT in the early morning, warmly dressed with a blanket wrapped around your shoulders, away from city smog, with the Moon behind an obstruction, and with a wide view on the sky. Gaze up at the sky, waiting, and you may spot one of these elusive bits of matter that Comet Kiess lost 2000 years ago. This is your only chance to see this shower; the dust trail is not going to hit again in our lifetime. It is also our best chance yet to test meteor shower prediction models and look for evidence of the crust that a comet is suspected to build up during the time it spends in the Oort cloud. Comets in shorter orbits have long lost this pristine crust. Jon Giorgini of JPL/Caltech has identified observations of Comet Kiess when it returned in 1911. The orbit is now better determined than before and calculating backwards in time puts the comet near Earth's orbit in 4 A.D., give or take 40 years. It was at that time that the dust was released that we now see as meteors. The dust was ejected in wider orbits than the comet and took somewhat longer to return. Jeremie Vaubaillon of Caltech calculated where the dust would end up at Earth's orbit on September 1, 2007, if it was ejected in 4 A.D. and he found that, indeed, the dust trail will be in Earth's path. The peak is expected at 11:33 UT, or 4:33 a.m. PDT, give or take 20 minutes. From past Aurigid showers, we anticipate a shower of mostly -2 to +3 magnitude meteors with a peak Zenith Hourly Rate about 200 per hour during a 10-minute interval, with rates above 100 per hour for only 25 minutes. With a bright Moon in the sky, only 4 days past full, that translates to several tens of chances to make a wish on a meteor from around 4 A.D. To increase our chances of catching these rare meteors, we will be observing the shower from two Gulfstream GV aircraft (flying at 45,000 ft) on a parallel flight path from Wisconsin, over the Bay Area in California, and on to the Pacific in the early morning of September 1. An international team of 24 researchers will have 21 windows to aim their cameras through. The cameras are of different types, some similar to your own digital camera and camcorder, others using technologies more familiar to cameras used on astronomical telescopes or those in night vision goggles. Near the horizon, we hope to see many more meteors than will be visible from the ground, but each of us will be glad if the shower actually shows. You can participate in this research by making an effort to photograph or film the Aurigid meteors. Chances are that one of you, not us, will catch the brightest Aurigid out there. Even simple cameras can provide information about how the meteoroids break apart, as each image is composed of three different images: one in blue light, another in green, and one in red. Each color traces different aspects of the meteor's light. More information at our Aurigid Multi-Instrument Aircraft Campaign mission website: http://aurigid.seti.orgAll About Meteors Gallery: 2006 Perseid Meteor Shower Gallery: Best of the Leonid Meteor Shower Original Story: 2000-Year-Old Meteors to Rain Down on August 31, 2007

Astronomers find a hole in the universe

By SETH BORENSTEIN, AP Science WriterFri Aug 24, 7:45 AM ET Astronomers have stumbled upon a tremendous hole in the universe. That's got them scratching their heads about what's just not there. The cosmic blank spot has no stray stars, no galaxies, no sucking black holes, not even mysterious dark matter. It is 1 billion light years across of nothing. That's an expanse of nearly 6 billion trillion miles of emptiness, a University of Minnesota team announced Thursday. Astronomers have known for many years that there are patches in the universe where nobody's home. In fact, one such place is practically a neighbor, a mere 2 million light years away. But what the Minnesota team discovered, using two different types of astronomical observations, is a void that's far bigger than scientists ever imagined. "This is 1,000 times the volume of what we sort of expected to see in terms of a typical void," said Minnesota astronomy professor Lawrence Rudnick, author of the paper that will be published in Astrophysical Journal. "It's not clear that we have the right word yet ... This is too much of a surprise." Rudnick was examining a sky survey from the National Radio Astronomy Observatory, which essentially takes radio pictures of a broad expanse of the universe. But one area of the universe had radio pictures indicating there was up to 45 percent less matter in that region, Rudnick said. The rest of the matter in the radio pictures can be explained as stars and other cosmic structures between here and the void, which is about 5 to 10 billion light years away. Rudnick then checked observations of cosmic microwave background radiation and found a cold spot. The only explanation, Rudnick said, is it's empty of matter. It could also be a statistical freak of nature, but that's probably less likely than a giant void, said James Condon, an astronomer at the National Radio Astronomy Observatory. He wasn't part of Rudnick's team but is following up on the research. "It looks like something to be taken seriously," said Brent Tully, a University of Hawaii astronomer who wasn't part of this research but studies the void closer to Earth. Tully said astronomers may eventually find a few cosmic structures in the void, but it would still be nearly empty. Holes in the universe probably occur when the gravity from areas with bigger mass pull matter from less dense areas, Tully said. After 13 billion years "they are losing out in the battle to where there are larger concentrations of matter," he said. Retired NASA astronomer Steve Maran said of the discovery: "This is incredibly important for something where there is nothing to it."

Lunar Eclipse Photos

All right, I promised you photos. It's hard to find them right now, I'm sure there are still many that getting posted. However, I have three spectacular photos of the moon going to total and the blood-red moon photo of the total eclipse. Ohhhhhh! This was the photo I took below, but with a 35mm... I never thought I would get one like this and of course I didn't. Maybe I'll keep this one and pretend I took it. *smiles* Blood-red! Wow! Now I know everyone thinks my shot below is better than any of these, but don't judge to harshly. These people did pretty well in my opinion.

Wow! What a show!

I got myself up and headed outside this morning to see a spectacular show. I was quickly disappointed as the moon had slipped behind the trees. Thinking quickly I got in my car and drove to my parents house a few blocks away, up the hill from me. I pulled into their driveway and saw the best site...sitting on their front porch I could see everything. The sky was clear, no trees and the best start to the total lunar eclipse. Unfortunately, I was unable to watch it finish. The moon would have set anyway before it had finished. I hope you had a great view and would love to see some pictures. This was my lame attempt for a picture. You can see the very bottom of the moon (yes that is what this picture is of...) Coming back to my computer, looking at this picture from the distance you can make out the sides of the moon too...I'm better then I thought. *smiles* I will post some pictures here of the eclipse after I find some good ones.

Tonight is the night for the total eclipse

Hope you have clear skys for the eclipse tonight. Unfortuantly I am on the east coast, but it should still be pretty spectacular. Let me know how your night went.

Tips on Meteor Watching

How can I best view a meteor shower? If you live near a brightly lit city, drive away from the glow of city lights and toward the constellation from which the meteors will appear to radiate. For example, drive north to view the Leonids. Driving south may lead you to darker skies, but the glow will dominate the northern horizon, where Leo rises. Perseid meteors will appear to "rain" into the atmosphere from the constellation Perseus, which rises in the northeast around 11 p.m. in mid-August. After you've escaped the city glow, find a dark, secluded spot where oncoming car headlights will not periodically ruin your sensitive night vision. Look for state or city parks or other safe, dark sites. Once you have settled at your observing spot, lay back or position yourself so the horizon appears at the edge of your peripheral vision, with the stars and sky filling your field of view. Meteors will instantly grab your attention as they streak by. How do I know the sky is dark enough to see meteors? If you can see each star of the Little Dipper, your eyes have "dark adapted," and your chosen site is probably dark enough. Under these conditions, you will see plenty of meteors. What should I pack for meteor watching? Treat meteor watching like you would the 4th of July fireworks. Pack comfortable chairs, bug spray, food and drinks, blankets, plus a red-filtered flashlight for reading maps and charts without ruining your night vision. Binoculars are not necessary. Your eyes will do just fine.

Warp speed ahead Mr. Scott...

I find myself staring at this picture in awe of the beauty and magnifigance of the cosmos around us. Wondering how many of these solar systems may hold life and feeling disappointed that I will never know. I also wonder, if there is life out there, are they staring at us like we are at them. Makes me wonder...

Mira, streaking through space at extraordinary speeds, leaves a wake 13 light-years long.

August 15, 2007 Material blowing off Mira is forming a wake 13 light-years long, or thousands of times the length of our solar system. The space-based Galaxy Evolution Explorer (GALEX) was scanning the star during its ongoing sky survey in ultraviolet light when astronomers noticed what looked like a comet with a gargantuan tail. Mira, Latin for "wonderful," has been a favorite of astronomers for about 400 years. It is a fast-moving red giant, which sheds massive amounts of surface material, but nothing like this has ever been seen before around a star. "This is an utterly new phenomenon to us, and we are still in the process of understanding the physics involved," said Mark Seibert of Carnegie Observatories in Pasadena, California. "We hope to be able to read Mira's tail like a ticker tape to learn about the star's life." Astronomers say Mira's tail offers a unique opportunity to study how stars like our sun die and ultimately seed new solar systems. As Mira hurls along, its tail drops off carbon, oxygen and other important elements needed for new stars, planets, and possibly even life to form. This tail material, visible now for the first time, has been shed over the past 30,000 years. Billions of years ago, Mira was like our Sun. Over time, it began to swell into a variable red giant — a pulsating, puffed-up star that periodically grows bright enough to see with the naked eye. Mira will eventually eject all of its remaining gas into space, forming a colorful shell, or a planetary nebula. The nebula will fade with time, leaving only the burnt-out core of the original star (a white dwarf). Compared to other red giants, Mira is traveling unusually fast, possibly due to gravitational boosts from other passing stars. It now plows along at 291,000 mph (130 kilometers per second). Racing along with Mira is a small, distant companion thought to be a white dwarf. The pair, also known as Mira A (the red giant) and Mira B, orbit slowly around each other as they travel together in the constellation Cetus, 350 light-years from Earth. In addition to Mira's tail, GALEX also discovered a bow shock, a buildup of hot gas, in front of the star, and two sinuous streams of material coming out of the star's front and back. Astronomers think hot gas in the bow shock is heating up the gas blowing off the star, causing it to fluoresce with ultraviolet light. This glowing material then swirls around behind the star, creating a turbulent, tail-like wake. The process is similar to a speeding boat leaving a choppy wake, or a steam train producing a trail of smoke. "GALEX is so exquisitely sensitive to ultraviolet light and it has such a wide field of view that it is uniquely poised to scan the sky for previously-undiscovered ultraviolet activity," said Barry F. Madore, senior research astronomer at the Carnegie Observatories. The fact that Mira's tail only glows with ultraviolet light might explain why other telescopes have missed it. "We never would have predicted a turbulent wake behind a star that glows only with ultraviolet light," said Seibert. "Survey missions like the Galaxy Evolution Explorer can provide many surprises."

Nasa reports Total Lunar Eclipse

A total eclipse of the Moon occurs during the early morning of Tuesday, August 28, 2007. The event is widely visible from the United States and Canada as well as South America, the Pacific Ocean, western Asia and Australia. During a total lunar eclipse, the Moon's disk can take on a dramatically colorful appearance from bright orange to blood red to dark brown and (rarely) very dark gray. An eclipse of the Moon can only take place at Full Moon, and only if the Moon passes through some portion of Earth's shadow. The shadow is actually composed of two cone-shaped parts, one nested inside the other. The outer shadow or penumbra is a zone where Earth blocks some (but not all) of the Sun's rays. In contrast, the inner shadow or umbra is a region where Earth blocks all direct sunlight from reaching the Moon. If only part of the Moon passes through the umbra, a partial eclipse is seen. However, if the entire Moon passes through the umbral shadow, then a total eclipse of the Moon occurs. For more information on how, what, why, where and when of lunar eclipses, see the special web page lunar eclipses for beginners.

Definitions and explanations of Astronomy Terms

Twilight - This is the time before sunrise and after sunset where it is still light outside, but the sun is not in the sky. Civil Twilight - This is defined to be the time period when the sun is no more than 6 degrees below the horizon at either sunrise or sunset. The horizon should be clearly defined and the brightest stars should be visible under good atmospheric conditions (i.e. no moonlight, or other lights). One still should be able to carry on ordinary outdoor activities. Nautical Twilight - This is defined to be the time period when the sun is between 6 and 12 degrees below the horizon at either sunrise or sunset. The horizon is not defined and the outline of objects might be visible without artificial light. Ordinary outdoor activities are not possible at this time without extra illumination. Astronomical Twilight - This is defined to be the time period when the sun is between 12 and 18 degrees below the horizon at either sunrise or sunset. The sun does not contribute to the illumination of the sky before this time in the morning, or after this time in the evening. In the beginning of morning astronomical twilight and at the end of astronomical twilight in the evening, sky illumination is very faint, and might be undetectable. Length Of Day - This is defined to be the time of Actual Sunset minus the time of Actual Sunrise. The change in length of daylight between today and tomorrow is also listed when available. Length Of Visible Light - This is defined to be the time of Civil Sunset minus the time of Civil Sunrise. Altitude (or Elevation) - First, find your azimuth. Next, the Altitude (or elevation) is the angle between the Earth's surface (horizon) and the sun, or object in the sky. Altitudes range from -90° (straight down below the horizon, or the nadir) to +90° (straight up above the horizon or the Zenith) and 0° straight at the horizon. Azimuth - The azimuth (az) angle is the compass bearing, relative to true (geographic) north, of a point on the horizon directly beneath the sun. The horizon is defined as an imaginary circle centered on the observer. This is the 2-D, or Earth's surface, part of calculating the sun's position. As seen from above the observer, these compass bearings are measured clockwise in degrees from north. Azimuth angles can range from 0 - 359°. 0° is due geographic north, 90° due east, 180° due south, and 360 due north again. Hour Angle of the Sun - The Solar Hour Angle of the Sun for any local location on the Earth is zero° when the sun is straight overhead, at the zenith, and negative before local solar noon and positive after solar noon. In one 24-hour period, the Solar Hour Angle changes by 360 degrees (i.e. one revolution). Mean Anomaly of the Sun - The movement of the Earth around the Sun is an ellipse. However, if the movement of the Earth around the Sun were a circle, it would be easy to calculate its position. Since, the Earth moves around the sun about one degree per day, (in fact, it's 1/365.25 of the circle), we say the Mean Anomaly of the Sun is the position of the Earth along this circular path. The True Anomaly of the Sun is the position along its real elliptical path. Obliquity - Obliquity is the angle between a planet's equatorial plane and its orbital plane. Right Ascension of the Sun - The Celestial Sphere is a sphere where we project objects in the sky. We project stars, the moon, and sun, on to this imaginary sphere. The Right Ascension of the Sun is the position of the sun on our Celestial Sphere. Solar Noon (and Solar Time) - Solar Time is based on the motion of the sun around the Earth. The apparent sun's motion, and position in the sky, can vary due to a few things such as: the elliptical orbits of the Earth and Sun, the inclination of the axis of the Earth's rotation, the perturbations of the moon and other planets, and of course, your latitude and longitude of observation. Solar Noon is when the sun is at the highest in the sky, and is defined when the Hour Angle is 0°. Solar Noon is also the midpoint between Sunrise and Sunset. Sun Declination - The Declination of the sun is how many degrees North (positive) or South (negative) of the equator that the sun is when viewed from the center of the earth. The range of the declination of the sun ranges from approximately +23.5° (North) in June to -23.5° (South) in December.