Astronomers Say they've Found The Oldest Galaxy So Far

From Nature.com:

Astronomers say they've found oldest galaxy so far

.


. AP – In the center of this Jan. 5, 2010 NASA handout image, taken by the Hubble Space Telescope, is a hard-to-see …

By SETH BORENSTEIN, AP Science Writer Seth Borenstein, Ap Science Writer – Wed Oct 20, 5:17 pm ET

WASHINGTON – Astronomers believe they've found the oldest thing they've ever seen in the universe: It's a galaxy far, far away from a time long, long ago.



Hidden in a Hubble Space Telescope photo released earlier this year is a small smudge of light that European astronomers now calculate is a galaxy from 13.1 billion years ago. That's a time when the universe was very young, just shy of 600 million years old. That would make it the earliest and most distant galaxy seen so far.



By now the galaxy is so ancient it probably doesn't exist in its earlier form and has already merged into bigger neighbors, said Matthew Lehnert of the Paris Observatory, lead author of the study published online Wednesday in the journal Nature.



"We're looking at the universe when it was a 20th of its current age," said California Institute of Technology astronomy professor Richard Ellis, who wasn't part of the discovery team. "In human terms, we're looking at a 4-year-old boy in the life span of an adult."



While Ellis finds the basis for the study "pretty good," there have been other claims about the age of distant space objects that have not held up to scrutiny. And some experts have questions about this one. But even the skeptics praised the study as important and interesting.



The European astronomers calculated the age after 16 hours of observations from a telescope in Chile that looked at light signatures of cooling hydrogen gas.



Earlier this year, astronomers had made a general estimate of 600 to 800 million years after the Big Bang for the most distant fuzzy points of light in the Hubble photograph, which was presented at an astronomy meeting back in January.



In the new study, researchers focused on a single galaxy in their analysis of hydrogen's light signature, further pinpointing the age. Garth Illingworth of the University of California, Santa Cruz, who was the scientist behind the Hubble image, said it provides confirmation for the age using a different method, something he called amazing "for such faint objects."



The new galaxy doesn't have a name — just a series of letters and numbers. So Lehnert said he and colleagues have called it "the high red-shift blob. "Because it takes so long for the light to travel such a vast time and distance, astronomers are seeing what the galaxy looked like 13.1 billion years ago at a time when it was quite young — maybe even as young as 100 million years old — Lehnert said. It has very little of the carbon or metal that we see in more mature stars and is full of young, blue massive stars, he said.



What's most interesting to astronomers is that this finding fits with theories about when the first stars and galaxies were born. This galaxy would have formed not too soon after them.



"We're looking almost to the edge, almost within 100 million years of seeing the very first objects," Ellis said. "One hundred million years to a human seems an awful long time, but in astronomical time periods, that's nothing compared to the life of the stars."





Ask America: Learn. Listen. Be heard.

Ask America



Election forum



The Fast Fix



Map snapshot

___



Online:



Nature: www.nature.com/nature



___



Online:



http://www.nature.com/nature

Moonlight Meteor Shower Spawned By Halley's Comet

From Space.com and Yahoo News:

Moonlight Meteor Shower Spawned By Halley's Comet

SPACE.com joe Rao

space.com Skywatching Columnist

space.com – Sat Oct 16, 8:15 am ET

A junior version of the famous Perseid meteor shower thought to have originated from the remains of Halley's Comet will hit its peak over the next week, but the light of the moon may intrude on the sky show.



This upcoming meteor display is known as the Orionids because the meteors seem to fan out from a region to the north of the Orion constellation's second brightest star, ruddy Betelgeuse.



The annual event peaks before sunrise on Thursday (Oct. 21) but several viewing opportunities arise before then for skywatchers in North America. [Where to look to see the Orionids]



The shooting stars are created by small bits of space dust — most no larger than sand grains — thought to be left over from the famed Halley's Comet, which orbits the sun once every 76 years.



Currently, Orion appears ahead of us in our journey around the sun, and has not completely risen above the eastern horizon until after 11 p.m. local daylight time.



The constellation is at its best several hours later. At around 5 a.m. – Orion will be highest in the sky toward the south – Orionids typically produce around 20 to 30 meteors per hour under a clear, dark sky.



But skywatchers beware: You will be facing a major obstacle in your attempt to observe this year’s Orionid performance. As bad luck would have it, the moon will turn full on Oct. 23. Bright moonlight outshines fainter meteors, seriously reducing the number anyone can see.



The gradual build up to the full moon will hamper – if not outright prevent – dark-sky observing during the Orionid meteor shower's peak on Oct. 21.



The Orionids are actually already underway, having been active only in a very weak and scattered form since about Oct. 2. But a noticeable upswing in activity is expected to begin around Oct. 17, leading up to their peak night.



"Orionid meteors are normally dim and not well seen from urban locations," notes meteor expert, Robert Lunsford, adding that "it is highly suggested that you find a safe rural location to see the best Orionid activity."



Damage control for 2010



With all this as a background, perhaps the best times to look this year will be during the predawn hours several mornings before the night of full moon. That’s when the constellation Orion (from where the meteors get their name) will stand high in the northeast sky.



In fact, three "windows" of dark skies will be available between moonset and the first light of dawn on the mornings of Oct. 18, 19 and 20.



Generally speaking, there will be about 150 minutes of completely dark skies available on the morning of the 18th.This shrinks to about 100 minutes on the 19th, and to about 50 minutes by the morning of the 20th.



This skywatching table shows prime Orionid meteor shower viewing times for some select U.S. cities.



In the table, all times are a.m. and are local daylight times. "Dawn" is the time when morning (astronomical) twilight begins. A "Window" is the number of minutes between the time of moonset and the start of twilight.



For example: When will the sky be dark and moonless for Orionid viewing on the morning of Oct. 20 from Houston?



Answer: There will be a 50-minute period of dark skies beginning at moonset (5:16 a.m.) and continuing until dawn breaks (6:06 a.m.).



Perhaps up to a dozen forerunners of the main Orionid display might appear to steak by within an hour’s watch on these mornings, particularly on the 20th, the morning before the peak. It might even be worthwhile to try on Thursday morning, Oct. 21, although for most places, the moon will not set until just after the first light of dawn.



Halley's legacy



In studying the orbits of many meteor swarms, astronomers have found that they correspond closely to the orbits of known comets.



The Orionids are thought to result from the orbit of Halley's Comet, as some of the dust that has been shed by this famous object intersect earth’s orbit around the sun during October.



There are actually two points along Halley’s path, where it comes relatively near to our orbit. Another one of these points occurs in early May causing a meteor display from the constellation Aquarius, the Water Carrier.



The tiny particles that are responsible for the Orionid and Aquarid meteors are – like Halley itself – moving through space in a direction opposite to that the earth. This results in meteors that ram through our atmosphere very swiftly at 41 miles (66 km) per second. Of all the meteor displays, only the November Leonids move faster.



Orionid postmortem



After the peak, activity will begin to slowly descend, although most of the meteors will be squelched by the light of the moon. Rates drop back to around five per hour around Oct. 26. The last stragglers usually appear sometime around Nov. 7.



It is indeed unfortunate that the Moon will likely obliterate most of the Orionids in the nights following the peak, but the viewing odds will be much better before the break of dawn on those mornings leading up to the peak. Almost certainly, you should sight at least a few of these offspring of Halley's Comet as they streak across the sky.



In the absence of moonlight a single observer might see at least a couple of dozen meteors per hour on the morning of the peak, a number that sadly can not be hoped to be approached in 2010. In fact, it appears that this year, fans of the Orionids will be uttering the same lament that the old Dodger fans in Brooklyn used to: "Wait till next year!"

Is Obama Trying To De-Colonize Space?

From The Christian Science Monitor and Floyd Reports:

Opinion


Is Obama trying to 'decolonize' space?

Observers were puzzled when President Obama apparently gave the space agency NASA a new mission to reach out to the world’s Muslims. But his action makes sense when you consider the influence of anticolonial ideology.





--------------------------------------------------------------------------------



--------------------------------------------------------------------------------



By Dinesh D'Souza / October 13, 2010



New York

Soon after becoming president, Barack Obama evidently gave the space agency NASA a new mission of reaching out to the world’s Muslims. Observers were puzzled. Why should rocket scientists focused on outer space now worry about hearts and minds on Earth?



Skip to next paragraph

Related Stories

Opinion: Newt Gingrich is right: Obama shares anticolonial values -- American values

Newt Gingrich dissertation on Congo sheds light on his jab that Obama is 'anticolonial'

.I believe I have solved the mystery. The reason is that President Obama has adopted his father’s ideology; the son is, as his father was, an anticolonialist. And according to this worldview, NASA is a symbol of America’s effort to colonize outer space. It follows that Obama wants to “decolonize” NASA, and that means converting it from its traditional mission of American exploration into a kind of international project to recognize what Muslims and others have contributed to the development of science.



FOR ANOTHER VIEW, READ Newt Gingrich is right: Obama shares anticolonial values -- American values



A strange new mission

Several months ago, NASA chief Charles Bolden announced that Mr. Obama had given him three priorities: “He wanted me to help reinspire children to want to get into science and math. He wanted me to expand our international relationships. And third, and perhaps foremost, he wanted me to find a way to reach out to the Muslim world and engage much more with dominantly Muslim nations to help them feel good about their historic contributions to science and math and engineering.”



Mr. Bolden added that the International Space Station was a kind of model for NASA’s future, since it was not just a US operation but included the Russians and the Japanese.



For former astronauts Neil Armstrong and John Glenn, Bolden’s remarks – which the White House later tried to correct – surely added insult to the injury they felt Obama has caused with his new budget and vision for NASA, which includes shelving the ambitious Constellation program and relying on foreign and commercial spacecraft.



Even some Obama supporters expressed puzzlement. Sure, we are all for Islamic self-esteem, and 800 years ago the Muslims did make some important discoveries, but what on earth was Obama up to here?



What motivates Obama?

To answer this question, we must figure out what motivates Obama; we must know what is Obama’s dream. Fortunately we don’t have to speculate, because Obama tells us in his autobiography, “Dreams from My Father: A Story of Race and Inheritance.”



The title alone is telling, but as Obama writes in the book: “It was into my father’s image, the black man, son of Africa, that I’d packed all the attributes I sought in myself, the attributes of Martin and Malcolm, DuBois and Mandela.”



Though Obama also candidly admits to feeling mugged by reality when he learned more about his father, several figures who know him well say the ideological fire of the father still burns within the son. As his grandmother Sarah Obama told Newsweek, “I look at him and I see all the same things, he has taken everything from his father. The family is still intact, this son is realizing everything the father wanted – fighting for people, the dreams of the father are still alive in the son.”



So there it is: Obama’s dream is his father’s dream.


Anticolonial ideology


So who was Barack Obama Sr. and what was his dream? First and foremost, he was an anticolonialist. He came of age during Kenya’s struggle for independence from British rule. I know about anti-colonialism because I grew up in India in the aftermath of British rule there. Anticolonialism was the ideology of my parents and grandparents, and it shaped a whole generation of third world people during the second half of the 20th century.



Skip to next paragraph

Related Stories

Opinion: Newt Gingrich is right: Obama shares anticolonial values -- American values

Newt Gingrich dissertation on Congo sheds light on his jab that Obama is 'anticolonial'

.The basic principle of anticolonialism is that the world is divided into two parts: the colonizers and the colonized. The colonizers are the evil Americans and Europeans, and they got rich by invading and looting the nations of Asia, Africa, and South America.



Even today, this ideology holds, America continues to occupy two countries, Iraq and Afghanistan, and to use its power to dominate and subjugate the rest of the world. The solution, of course, is decolonization, and this means that America must get out and stay out and in the future play a much more modest and humble role in the world.



We know that Barack Obama Sr. was an anticolonialist because he says as much in a 1965 article he wrote in the East Africa Journal. And it seems that his son Barack Obama Jr. is following in his father’s footsteps because he is trying to get America out of both Iraq and Afghanistan and he has informed many international audiences that he seeks a more modest global role for America.



The theory's explanatory power

Just as telling, the anticolonial assumption explains, as no other theory can, why President Obama would apparently undertake the strange task of changing the mission of NASA. Plug in our anti-colonial model and what at first seems inexplicable – converting NASA into a community outreach program for Muslims – suddenly makes complete sense. Remove the theory and it is almost impossibly difficult to account for what Obama is doing.



Recall the Moon Landing of Apollo 11 in 1969. “One small step for man,” Mr. Armstrong said. “One giant leap for mankind.” But that’s not how the rest of the world saw it. I was eight years old at the time and still living in my native India.



I remember my grandfather telling me about the great race between America and Russia to put a man on the moon. America won that race, and everybody knew it because Armstrong placed the American flag on the moon.



So it wasn’t one giant leap for mankind, but one giant leap for the United States. It was as if that flag signified, “We Americans did this. We Americans now own the moon.” I can understand how many in the third world might see the moon landing that way, because I’m from the third world and that’s the way I saw it.



If Obama shares this view, no wonder that he wants to change NASA’s focus. Even when the Muslims aren’t involved, Obama wants to make sure the Russians and the Japanese share the credit. As Bolden put it in his Al Jazeera interview: “We’re not going to go anywhere beyond low Earth orbit as a single entity. The United States can’t do it.”



Space, you see, is for human and not merely American exploration. Obama seems determined to divert NASA from being a symbol of American greatness into a more modest public relations operation that builds ties with Muslims and other peoples. For those who cherish America’s leadership role in space, it is chilling to realize that America’s own president seeks to bring that role to an end.



Dinesh D’Souza is the president of the King’s College in New York City. His new book is “The Roots of Obama’s Rage.”

Hubble Telescope Captures First Images Of Suspected Asteroid Collision

From the AP:

Hubble captures first images of suspected asteroid collision


Buzz up!3 votes Share

retweet


EmailPrint.. AFP/NASA – This image obtained from NASA shows four Hubble Space Telescope images, taken over a five-month period, …

. Play Video Space Video:Keeping the Miners Healthy FOX News .

Play Video Space Video:Soyuz delivers new crew to ISS Reuters .

Play Video Space Video:Raw Video: 2 Russians, 1 American arrive at ISS AP .

– 2 hrs 5 mins ago

WASHINGTON (AFP) – NASA's Hubble space telescope has captured what scientists believe are the first images of a collision between two asteroids, the US space agency said Wednesday.



The images, taken from January to May with Hubble's Wide Field Camera 3, show a bizarre X-shaped object, the likes of which astronomers have never seen before, at the head of a comet-like trail of material.



Scientists have dubbed the object in the Hubble images P/2010 A2. It was found cruising around the asteroid belt, a reservoir of millions of rocky bodies between the orbits of Mars and Jupiter.



The 400-foot-wide (122 meters) object in the image is thought to be a remnant of a larger body that collided at about 11,000 miles per hour (17,700 kilometers per hour) with a smaller rock that the scientists think measured 10 to 15 feet across.



The crash released an explosion with the force of a small atomic bomb and is believed by astronomer David Jewitt of the University of California, Los Angeles, to have happened in February or March 2009.



Until now, astronomers have relied on models to make predictions about the frequency of collisions in space and the amount of dust they produced.



"These observations are important because we need to know where the dust in the solar system comes from and how much of it comes from colliding asteroids as opposed to 'outgassing' comets," Jewitt said.



Asteroid crashes are relatively common -- Jewitt estimates that modest-sized asteroids smash into each other roughly once a year.



But Hubble has achieved yet another feat in its storied space-gazing life by catching this particular collision, which astronomers believe involved two asteroids that were so faint they were unknown before the crash.



The Lincoln Near-Earth Research (LINEAR) Program Sky Survey spotted the comet-like tail of P/2010 A2 in January 2010, before Hubble captured it.



But only Hubble's images discerned the X pattern, which astronomers say offers "unequivocal evidence that something stranger than a comet outgassing had occurred" but are at pains to explain.





Ask America: Learn. Listen. Be heard.

Ask America



Election forum



The Fast Fix



Map snapshot

It might suggest that the colliding asteroids were not symmetrical, meaning material that was ejected after the impact did not make an even pattern, NASA said.



Astronomers plan to observe P/2010 A2 next year using Hubble, to see how far the dust has been swept back by the Sun's radiation and how the mysterious X-shaped structure has evolved.

Small Asteroid Zips Close By Earth As Astronomers Watch

From Space.com:

Small Asteroid Zips Close By Earth as Astronomers Watch


By Tariq Malik

SPACE.com Managing Editor

posted: 12 October 2010

12:27 pm ET



A small asteroid passed close by Earth today (Oct. 12), flying within the orbit of the moon while astronomers watched to see if the encounter caused any quakes on the space rock.



The asteroid 2010 TD54 made its closest approach to Earth at 6:51 a.m. EDT (1051 GMT), when it passed within about 28,000 miles (45,000 km) of the planet. It was flying over Southeast Asia, near Singapore, at the time. [Photo of Asteroid 2010 TD54 Flyby.]



Astronomers at the Massachusetts Institute of Technology in Boston used a remote link with a NASA Infrared Telescope Facility in Hawaii to observe the small asteroid, which was up to 33 feet (10 meters) across.



Ads by GoogleWhat is Quantum Jumping?Discover Why Thousands of People are "Jumping" to Change Their Life

www.QuantumJumping.comWill You Win the Lottery?100% Free Horoscope Reveals If Luck Is In Your Future...

JoyPeaceandHappiness.comMeade Telescopes SaleHuge Meade Telescopes Selection. Low Prices, 30% Off & Free S/H!

www.Telescopes.comAsteroid 2010 TD54 zips by



There was no risk of the asteroid entering Earth's atmosphere or exploding, and it was too small to survive the fiery entry even if it did. But that did not keep astronomers from taking a close look as the space rock sailed by.



"For 2010 TD54, we want to learn its basic composition and to watch whether its close encounter with the Earth causes any changes," astronomer Richard Binzel, a professor of planetary science at MIT, told SPACE.com.



Past studies have shown that close encounters with Earth can cause quakes on nearby asteroids that move surface material around, altering space rocks' appearances.



Asteroid 2010 TD54 was discovered Oct. 9 by astronomers with the NASA-sponsored Catalina Sky Survey in Tucson, Ariz.



Asteroid flybys common



Small asteroids that are previously unknown, like 2010 TD54, often pass by Earth.



An asteroid about 16.5 feet (5 meters) across can be expected to pass Earth inside the orbit of the moon about once a day, NASA scientists said. They typically enter Earth's atmosphere once every two years or so, they added. There are an estimated 30 million unknown asteroids in our solar system.



Bigger asteroids about 460 feet (140 meters) wide can cause widespread damage around their impact sites, but for global devastation much larger space rocks would have to strike Earth.



Binzel said he and his colleagues study asteroids by observing them in visible and near-infrared wavelengths of light, which allows them to determine which minerals are present.



"The presence and strength of mineral absorption bands over these wavelengths allow us to interpret their compositions Ð and directly relate these compositions to known meteorite samples, whenever possible," he said.



NASA regularly tracks asteroids and comets that fly near Earth as part of its Near-Earth Object Observations program, which uses a network of ground and space telescopes. The program has tracked 85 percent of the largest asteroids that fly near Earth and 15 percent of asteroids in the 460-foot class, according to the latest report.



NASA also plans to send astronauts to an asteroid by 2025 under new space plan ordered by President Obama. The mission could help scientists better understand the composition of asteroids, as well as develop better methods of deflecting them before they pose a threat to Earth, space agency officials have said.

Venus' Atmosphere Proves A Real Drag, Leading To A Discovery

From Space.com:

Yahoo! Buzz


Venus' Atmosphere Proves a Real Drag, Leading to a Discovery

By Mike Wall

SPACE.com Senior Writer

posted: 07 October 2010

07:47 pm ET



A spacecraft using a bold new method to study Venus — flying directly through the planet's atmosphere — has found that the atmosphere at Venus' poles is thinner than expected.



The European Space Agency's Venus Express probe made the discovery during a series of dives through the atmosphere of Venus over the past two years. Scientists measured the drag on the spacecraft during these atmospheric dips to determine Venusian air density.



"It's really a very accurate and precise method," Venus Express project scientist Hakan Svedhem said at a news briefing Wednesday (Oct. 6). Svedhem and his colleagues presented their findings at the American Astronomical Society's Division of Planetary Sciences meeting in Pasadena, Calif.



The observations will help prepare Venus Express for one final, deep dive that will alter its orbit and extend its operational life, the researchers said.



Thinner than they thought



Venus Express' atmospheric dives revealed that the planet's polar atmosphere is about 60 percent thinner than predicted, researchers said. The team is trying to figure out what accounts for this surprising result.



The spacecraft's twisting motion during its dives also registered a sharp density change from Venus' day side to its night side, scientists said.



The Venus Express team is gearing up for another dive next week, when the probe will make its deepest foray yet into Venus' atmosphere — down to about 102 miles (165 kilometers) above the planet's surface.



This is getting closer to the aerobraking altitude that would adjust the probe's orbit, which Svedhem estimated to be about 87 miles (140 km) above the surface. But the team isn't ready to make this move yet.



"The timetable is still open because a number of studies have yet to be completed," Svedhem said. "If our experiments show we can carry out these maneuvers safely, then we may be able to lower the orbit in early 2012."



Changing course



Venus Express arrived at Venus in April 2006 and has been studying the planet's atmosphere ever since. The probe currently has a highly elliptical polar orbit that loops from 155 to 41,000 miles (250 to 66,000 km) above the Venusian surface.



When Venus Express is far away from the planet, the sun's gravity pulls it slightly off course. As a result, the spacecraft's engines must be fired every 40-50 days to compensate. The fuel to do this will run out in 2015.



Mission planners want to give the probe a chance to keep operating beyond 2015. So they're considering shaking things up and bringing Venus Express much closer to the planet, reducing its orbital period from 24 hours to 12.



To do this, scientists would dip Venus Express deep into the planet's atmosphere. The resulting drag would slow the spacecraft down and change its orbit. This maneuver is delicate and potentially risky, according to researchers.



"It would be dangerous to send the spacecraft deep into the atmosphere before we understand the density," team member Pascal Rosenblatt of the Royal Observatory of Belgium said in a statement.



However, Venus Express has no instruments capable of measuring this density directly, researchers said. So mission planners have improvised. They sent the probe skimming down into the alien atmosphere on exploratory dives — at altitudes of about 110 miles (180 km) — in July-August 2008, October 2009, February 2010 and April 2010.



During these jaunts, radio tracking stations on Earth watched for the drag exerted on the spacecraft. In addition, operators turned one of Venus Express' solar wings edge-on and the other face-on so that air resistance twisted the spacecraft, researchers said.

Comet Hartley 2 To Have Close Encounter With Earth This Month

From Space.com:

Comet and Earth to Have Rare Close Encounter


By Joe Rao

SPACE.com Skywatching Columnist

posted: 01 October 2010

08:41 am ET



Typically during the course of a year about a dozen comets will come within the range of amateur telescopes. Most quietly come and go with little fanfare, but during the upcoming weeks one rather small comet will be making an unusually close approach to the Earth.



On Oct. 20, Comet Hartley 2 will pass just over 11 million miles (18 million km) from Earth. During October it should be easily visible in small telescopes, binoculars and — from sites with dark enough skies — even with the naked eye.



This video sky map shows how to spot the comet.



Ads by GoogleSatellite image of earthFree Satellite image of earth All The Time With The Maps Toolbar

Maps.alot.comYour Name Is No Accident27 Facts You Don't Know About Your Personality and Future. But Should!

Numerologist.comFree Space WallpapersGet Cool Space Desktop Wallpapers w Planets, Moons & Stars-Try Them Now

wallpapers.smileycentral.comComets are composed of rock, dust, water ice and frozen gases such as carbon monoxide, carbon dioxide, methane and ammonia. [Best Comet Appearances of All Time]



Because of their low mass, comet nuclei do not become spherical under their own gravity as larger bodies in space do, and thus have irregular shapes. They are often popularly described as "dirty snowballs," though recent observations have revealed dry dusty or rocky surfaces, suggesting that the ices are hidden beneath the crust.



In addition to its close pass of Earth, Comet Hartley 2 will be visited in early November by the Deep Impact spacecraft, which already had a previous encounter with Comet Tempel 1 in 2005.



Hartley's discovery



Back on March 15, 1986, astronomer Malcolm Hartley discovered a new comet on photographic images taken at the U.K. Schmidt Telescope Unit at Siding Spring, Australia.



At the time Hartley discovered it, the newfound comet was an exceedingly faint object, with just a hint of a tail; it was about 25,000 times dimmer than the faintest stars that can be seen with the naked eye. After further images were obtained over the next several days, Hartley announced his discovery to the Central Bureau for Astronomical Telegrams in Cambridge, Mass.



This was Hartley's second discovery of a comet and so was designated as Comet Hartley 2. Orbital calculations by Brian Marsden of the Smithsonian Astrophysical Observatory in Cambridge, Mass., indicated that Hartley 2 had already made its closest approach to the sun nine months earlier and that at that time it was too close to the sun's glare to have been detected.



Marsden also calculated that the comet made a close approach to Jupiter during 1982. The comet takes roughly 6 1/2 years to circle the sun and it has since been observed again in 1991, 1997 and 2004.



Rare close encounter



This fall, Comet Hartley 2 will again be passing through the inner solar system, reaching its closest point to the sun (called perihelion) on Oct. 28 at a distance of 98.4 million miles (158.4 million km).



And while en route to the sun, it will also make a very close approach to the Earth. In fact, at 3 p.m. ET on Oct. 20, the comet will be at its closest point to our planet at a distance of 11.2 million miles (18 million km).



It's quite unusual for any comet to approach this close to Earth. Such an event only happens on average perhaps three or four times a century.



If this comet were reasonably large, it would likely put on a very spectacular show around the time of its closest approach.



Halley's Comet passed a similar distance from Earth in the year 1066 and was described in ancient records as appearing "like a moon" as well as being depicted in the Bayeux Tapestry, a long embroidered piece of cloth that depicts the Norman conquest of England.



A small, faint comet



Unfortunately, Hartley 2 is a very small and intrinsically faint comet. Observations by the Spitzer Space Telescope in August 2008 showed that the comet's nucleus has a diameter of just 0.7 miles (1.1 km). Its nucleus is only about one tenth the size of Halley's Comet and perhaps only one thirtieth that of Comet Hale-Bopp.



Nonetheless, Hartley 2 will come close enough to us to become dimly visible to the unaided eye during early to mid October.



Astronomers use magnitude to define the brightness of sky objects; the lower the magnitude, the brighter the object. The brightest stars are zero or first magnitude, while the faintest stars are sixth magnitude.



Current expectation is that the comet will reach a peak magnitude of perhaps 4.4 at the time of its closest approach. However, around that time the comet will probably appear very large in overall apparent size, perhaps similar to the apparent size of the full moon.



As a result, much of the comet's brightness will be "spread out" over that area of the sky. So visually to the eye under a dark sky it will appear not as a sharp star-like image, but more like a dim, circular patch of light.



Binoculars or a small low-power telescope will provide a somewhat more pleasing view: a dim, circular, grayish-blue ball of light with a star-like condensation (the nucleus) at the center.



If the comet develops a tail of any kind, it likely will be of the gaseous variety — very thin, faint and narrow, giving the comet the appearance of what comet expert John Bortle likens to "an apple on a stick."



Where to find it



As October begins, Comet Hartley 2 will be in the constellation of Cassiopeia, which at dusk will be positioned halfway up in the northeast sky; through Oct. 5 it will be passing below and to the right of the famous "W"-shaped formation composed of five bright stars.



The comet then moves into the constellation of Perseus on Oct. 6 and before dawn on the morning of Oct. 8, it will be situated only 0.7 degrees below and to the right of the famous Double Star Cluster. The cluster supposedly marks the sword handle of Perseus and is often touted as one of the most impressive star clusters in the entire sky.



On the morning of Oct. 10, the comet will appear to almost touch the 4th-magnitude star, Eta Persei. On Oct. 17, it will enter the boundaries of the constellation Auriga, and on the morning of Oct. 18, Hartley 2 will be about 1.2 degrees above and to the right of the star Epsilon Aurigae and 3 degrees below and to the right of the brilliant zero-magnitude star Capella.



Between Oct. 15 and 20, within about a half hour of 4:00 a.m. local time, the comet will be passing almost directly overhead.



Moon muscles In



But one problem that will become an increasing factor during the middle of October is the waxing moon that will light up the sky during the first part of the night and will seriously interfere with observations of the comet.



The moon will set later in the night leaving the sky dark during the predawn hours, but as it approaches its full phase on Oct. 22, the amount of time between moonset and the first light of dawn will get noticeably shorter.



For example: From mid-northern latitudes on Oct. 16, moonset is at 12:56 a.m. local time and dawn breaks at 5:37 a.m., which means the sky will be dark and moonless for 4 hours and 41 minutes.



Just four mornings later, however, the nearly full moon will set at 4:51 a.m. with morning twilight beginning at 5:41 a.m., leaving just a scant 50 minutes of dark sky for comet viewing. On Oct. 21, the moon will not set until 5:51 a.m. or 9 minutes after dawn.



Coming Attractions



Even after Hartley 2 makes its closest approach to Earth, it will become part of another close approach of a different kind. On Sept. 5, more than five years after its July 4, 2005, rendezvous with Comet Tempel 1, NASA's Deep Impact spacecraft will begin beaming down the first of more than 64,000 images it's expected to take of Comet Hartley 2.



The spacecraft will continue imaging Hartley 2 during and after its closest approach on Nov. 4, when it will pass to within 430 miles (692 km) of the comet's nucleus, providing an extended look at the comet.



The flyby of Comet Hartley 2 is the second leg of the Deep Impact spacecraft's two-part extended mission known as EPOXI. During the flyby a science team from the University of Maryland will study the comet using all three of the spacecraft's instruments — two telescopes with digital color cameras and an infrared spectrometer.



Gallery: The Great Comet McNaught: Part 1, Part 2

The Best Comets of All Time

Astrophotography Telescopes for Beginners

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.





Ads by GoogleWhat is Quantum Jumping?Discover Why Thousands of People are "Jumping" to Change Their Life

www.QuantumJumping.comImage PicturesView Beautiful Picture Slide Shows Produced By Bing Travel!

www.bing.com/TravelIs Jesus Really God?Scholars Examine the Facts About Jesus' Claims to be God

www.Y-Jesus.com/JesusGodScience News and VideosWatch Science, Tech, Health Videos Learn something new today!

www.redorbit.comHubble Telescope PicturesFind Hubble Telescope pictures and more information on astronomy now!

Telescope-Pictures.best-price.comComments (2)

You must be logged in to post a comment: Log In
Register



Sort by:NewestOldestRecommendedPost a Comment





posted 01 October 2010, 11:00 am ETgordon_flash wrote:



Unfortunately the map doesn't help much. There's no cross, or dot, or anything to show the position of the comet relative to the label or to the dashed curve which, I assume, is the track of the comet in the sky (moving from right to left, according to the article).



Still, I'll doggedly have a look and see if I can spot it. Maybe it will surprise us!

.Reply
Recommend (0)
Report Abuse

Expand to View Replies (1). posted 01 October 2010, 1:16 pm ETernestborg9 wrote:

This does suck balls to be certain...such a huge failure on the part of the author. Try this link...to sky and telescope's sky map:



http://media.skyandtelescope.com/images/CometHartley2-bw.jpg

.Recommend (0)
Report Abuse.