Asteroidi,komete,meteori

5

Asteroidi,komete,meteori

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Drago mi je da je uspjelo, ipak tuzno bi bilo da za neku godinu ili njih desetina neka kamencina krene na zemlju, pa da se branimo sa iskustvom zasnovanom na experimenatima i simulacijom ... Samo da im se uspjeh ne osladi ... pocece da gadjaju sve sto se krece oko Sunca Laughing Bebee Dol Laughing



Registruj se da bi učestvovao u diskusiji. Registrovanim korisnicima se NE prikazuju reklame unutar poruka.
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NASA celebrates July 4 with fireworks in space
Posted on : Tue, 05 Jul 2005 21:32:00 GMT | Author : Ravi Chopra
News Category : Space

Two hundred years of scientific research had another moment of glory when a projectile deployed by a NASA-launched spacecraft successfully collided with comet Tempel 1 at 5.52 a.m. yesterday.

Scientists and students alike in countries around the world exhilarated with boyish joy as the precision-coordinated outer-space maneuver ended exactly as was intended: in a cloud of stellar debris from the comet and the consequent crater photographed by mothership Deep Impact.

Scientists hope the expelled primordial material, comprising ice, dust and organic chemicals, will help unravel some secrets of our solar system. The collision took place 24 hours after the copper projectile - the size of a washing machine, was launched in the path of the comet.

The out-gassing (expulsion of gases from the impacted crater) is obscuring the view of one end currently and expected to continue for hours; it may even go on for weeks. However it has provided enough scientific information to keep NASA scientists busy for the next few months.

The $333m mission culminated with the impact 134 million kilometers from Earth. The copper ‘impactor’ was armed with camera and radio to take images of the comet. The last image is a close-up taken just three seconds before the impact and the projectile’s destruction. Collision speeds had reached 23,000mph, enough to vaporize any object. The comet was half the size of Manhattan Island so the impact by the projectile did little to reduce its speed. The blast was equivalent to exploding 5 tons of TNT.

Dalje

Comet Show Leaves NASA Speechless

By Thomas H. Maugh II Times Staff Writer
Tue Jul 5, 7:55 AM ET

The collision of a probe from
NASA's Deep Impact spacecraft with comet Tempel 1 blew a plume of debris thousands of miles into space and provided a spectacular first glimpse of the insides of a comet — ancient bodies that may hold the key to the origins of the solar system — scientists said Monday.

The collision — a carefully orchestrated dance at more than 20,000 mph intended to expose the comet's interior — was much larger than anyone had expected, said researchers at the Jet Propulsion Laboratory in La Cañada Flintridge.

Telescopes on Earth showed that the light from the comet increased fivefold in the aftermath of the collision at 10:52 p.m. PDT Sunday before slowly fading over several hours.

"I was trying to think how to describe this, but I am just plain speechless," said Andrew Dantzler, the director of NASA's solar system program.

The eruption of debris from the impact was so large that principal investigator Michael A'Hearn of the University of Maryland said it could take scientists a week or more to tease out a reliable image of the impact crater from behind the smokescreen of dust and gas that obscured the comet's surface.
Dalje

Afterglow: NASA Lauds Deep Impact's Comet Crash

Tariq Malik
And Anthony Duignan-Cabrera
SPACE.com
Tue Jul 5,12:05 PM ET

PASADENA -- Deep Impact scientists and engineers are lauding their mission's successful collision with Comet Tempel 1 and are already drawing some conclusions about the icy wanderer.

ADVERTISEMENT


Based on images taken by Deep Impact's Flyby mothership, which tracked the mission's collision with Tempel 1, astronomers believe the comet's surface was covered in a soft material.

"This was probably a soft surface, a dusty surface," explained said Deep Impact co-investigator Peter Schultz during a press conference today at
NASA's Jet Propulsion Laboratory (JPL). "I've made a living playing in a sandbox, and now I can say I've played with a comet."

Dalje



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Ej Leggy, gledam malo tvoju sliku,... pa sam se upitao da nisi slučajno bio na kometi u trenutku kada ga je sonda pogodila Mr. Green

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@MRKY

Jes offtopic, ali toliko se smejem, da, za sada, necu da brisem Laughing

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As Nasa controllers whooped and cheered in California at news of Deep Impact's success, their efforts were being watched intently by scientists in far-off London.

Through a live link to a news conference in London, UK space scientists were sharing in some of the delight and fascination of Deep Impact's American team.

This was due in part to the enormous amount of information scientists are certain to glean from the collision.

And British researchers have been observing the collision from telescopes around the world, including the Faulkes Telescope and United Kingdom Infra-Red Telescope (UKIRT) in Hawaii, The INT Telescope in Spain and the UK Schmidt telescope in Australia.

But many of the scientists here are also involved in a European mission called Rosetta which aims to orbit and land on a comet for the first time.

Comet chaser

Deep Impact, they told reporters, would give valuable insights into what lies in store for the European spacecraft, which was launched in February 2004 on a 10-year trek to Comet 67P/Churyumov-Gerasimenko.

"Deep Impact is beautiful preparation for Rosetta," said Dr Andrew Coates, of the Mullard Space Science Laboratory (MSSL) at University College London.


A perfect 4 July for Nasa

In pictures
Rosetta is not designed to crash into its target. Instead, it will catch up with "CG" in 2014 after flybys of Earth, Mars and the asteroids and a three-year period of deep space hibernation.

"Anything we can do to find out more about cometary surfaces is important," Dr Coates told the BBC News website.

The Rosetta flyby spacecraft drops its lander craft towards the surface of CG. The lander then fires a harpoon to anchor it to the comet's surface.

A soft landing is a particular problem given the extremely weak gravitational force exerted by the comet nucleus. The lander, which weighs 100kg on Earth, will on the comet be as light as a sheet of paper.

If there were a slight recoil, it would bounce back like a rubber ball. To prevent this, the lander's three legs are equipped with special shock-absorbers and are fitted with ice pitons which bore into the ground immediately on touchdown.

Surprise output

"One of the big unknowns [of the Rosetta mission] is the internal structure of the nucleus, how it sticks together and the strength of the material," Dr Gerhard Schwehm, Rosetta's project scientist told the BBC News website.

"These are things we hope to learn now from the science of Deep Impact. They help us pin down our scenario when putting the [Rosetta] lander on the nucleus."

Even if they wanted to, the Rosetta team would not be able to make any big changes to the landing stage of the mission. But knowing more about the surface they are landing on will allow mission scientists to check their models of the touchdown, says Dr Schwehm.

Rosetta artist's impression, Esa
Rosetta will aim to land on a comet
Rosetta's Philae lander will determine the composition of surface and subsurface materials using spectroscopy and sample analysis. It will also take high-resolution photographs, and carries a radar to determine the internal structure of the comet's nucleus.

One of the big surprises about Monday's impact was the unexpectedly large amount of material excavated by the collision between Tempel 1 and Deep Impact's projectile.

It had been thought that the impact would excavate as much material in 15 minutes as the comet usually discharges in a month.

"I would say it's more like a year," commented Professor John Zarnecki, a space scientist at the Open University in Milton Keynes.

Early interpretations

Scientists made some early interpretations. Firstly, Comet Tempel 1's crust is probably weaker than expected.

Professor Zarnecki said it also suggested the material in the comet was probably brittle, a bit like breeze block. Dr Coates likened it to compacted snow.

Dr Schwehm said he thought that a build-up of gases just beneath the surface might have contributed to the large plume.

"When it was triggered by the impactor, they just came out," he said.

But scientists allayed fears that the impact might throw the comet off course, perhaps on a collision course with Earth.

"It was like a mosquito hitting a 747. What we've found is that the mosquito didn't splat on the surface; it's actually gone through the windscreen," explained Professor Iwan Williams of Queen Mary, University of London, and a co-investigator on Rosetta.

Though Tempel 1 poses no current threat to Earth, other cometary bodies have wrought devastation on our planet in the geological past. An asteroid or comet impact is blamed for wiping out the dinosaurs at the end of the Cretaceous Period.

"Sixty-five million years ago, one of these things took out the dinosaurs," said Faulkes Telescope director Paul Roche, before the collision. Now, he said, "we're going to get our own back".

http://news.bbc.co.uk/1/hi/sci/tech/4648437.stm

Dopuna: 06 Jul 2005 20:02

Nasa's Deep Impact spacecraft may have missed its chance to see the crater made in Comet Tempel 1 because of the large plume of material kicked out.

Seeing the crater was a key objective of the mission - scientists hoped the impact depression would tell them more about the structure of the comet.

But the team can use indirect methods to estimate the crater's dimensions.

A 370kg "impactor" released into Tempel 1's path by the flyby spacecraft crashed into the comet on Monday.

"They can calculate the volume of material thrown out and that gives them a basic idea of the crater volume," Dr Paul Roche, director of the UK-run Faulkes Telescope in Hawaii, told the BBC News website.


DEEP IMPACT: 4 JULY
The explosive moment of impact on Comet Tempel 1

In pictures
Using a best estimate of the hardness of Tempel 1's surface, scientists can calculate a rough depth and radius for the crater.

But, said Dr Roche, "it's not as nice as seeing and measuring the crater itself".

Comet evolution

The US space agency (Nasa) might yet be able to resolve part of the crater using image processing software, he added.

Scientists had planned to study the depression to determine the strength and structure of material on the comet's surface and immediately below.

Comet Tempel 1, Faulkes Telescope
The Faulkes Telescope North took pictures before and after collision
The type of crater formed could have helped determine whether Tempel 1 was composed of relatively porous, pristine material or stronger, processed material. This would give clues to how comets formed and evolved.

Regardless, the mission will give scientists heaps of data to trawl through.

Dr Roche's team at the Faulkes Telescope has been tracking the intensity of the comet before and since Monday's impact.

"There is still material gushing out of the crater right now; Tempel 1 is still brighter than it was before impact. If the hole is deep enough, material could keep flooding out for weeks or months," he said.

"We saw a brightening and fading within the course of an hour-and-a-half to two hours."

School children from Hawaii, Iceland and the UK have been involved in processing the images.

http://news.bbc.co.uk/1/hi/sci/tech/4656567.stm

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  • dex  Male
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A prevod?..

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dex ::A prevod?..

Vec smo pricali o ovome, prevoda nece biti... Naucite engleski, ljudi!

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X-rays show depth of Deep Impact
Comet Tempel 1 after impact, Nasa
The collision was caught on camera by the Deep Impact flyby craft
Scientists have been studying the X-ray light around Comet Tempel 1 after its collision with the Deep Impact probe - to gauge the size of crater created.

The US space agency's (Nasa) Swift satellite recorded the high-energy light, which got brighter and brighter over the weekend of 9-10 July.

The X-rays were produced by dust kicked up during the impact and thus indicate how big a hole was left in the comet.

Researchers say tens of thousands of tonnes of debris was released.


This will provide fascinating information about a comet's atmosphere
John Nousek, Penn State University
"Prior to its rendezvous with the Deep Impact probe, the comet was a rather dim X-ray source," said Paul O'Brien, of the Swift team at the University of Leicester, UK.

"How things change when you ram a comet with a copper probe travelling over 20,000 miles (32,000km) per hour.

"The X-ray light we detect now is generated by debris created by the collision combined with material naturally coming off the comet."

Solar winds

Although the actual impact occurred on 4 July, it takes several days for the dust and debris to reach the comet's upper atmosphere, or coma, where it can be illuminated by the high-energy particles, or solar wind, streaming away from the sun.


DEEP IMPACT: 4 JULY
The explosive moment of impact on Comet Tempel 1

In pictures
"For the first time, we can see how material liberated from a comet's surface migrates to the upper reaches of its atmosphere," said John Nousek, of Penn State University, US.

"This will provide fascinating information about a comet's atmosphere and how it interacts with the solar wind. This is all virgin territory."

Although analysis is still ongoing, scientists think enough dust was thrown up to leave a 10m (32ft) deep coating on a football pitch.

An artist's impression of the impact, AP
Artist's impression: The Deep Impact mission will reveal many secrets about comets
The Swift satellite is usually used for detecting distant natural explosions, called gamma-ray bursts, and creating a map of X-ray sources in the Universe.

However, following the Deep Impact mission to Tempel 1, it is providing the only simultaneous multi-wavelength observation, with a suite of instruments capable of detecting visible light, ultra-violet light, X-rays and gamma rays.

Swift scientists say that "different wavelengths reveal different secrets about the comet".

Professor Keith Mason, of University College London, UK, said: "Swift is a nearly ideal observatory for making these comet studies, as it combines both a rapidly responsive scheduling system with both X-ray and optical UV instruments in the same satellite."



http://news.bbc.co.uk/1/hi/sci/tech/4675581.stm

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Astronomers Having Used ESO Telescopes Start Analysing Unique Dataset on the Comet Following the Deep Impact Mission

ESO -- Ten days after part of the Deep Impact spacecraft plunged onto Comet Tempel 1 with the aim to create a crater and expose pristine material from beneath the surface, astronomers are back in the ESO Offices in Santiago, after more than a week of observing at the ESO La Silla Paranal Observatory. In this unprecedented observing campaign - among the most ambitious ever conducted by a single observatory - the astronomers have collected a large amount of invaluable data on this comet.

The astronomers have now started the lengthy process of data reduction and analysis. Being all together in a single place, and in close contacts with the space mission' scientific team, they will try to assemble a clear picture of the comet and of the impact.

The ESO observations were part of a worldwide campaign to observe this unique experiment. During the campaign, ESO was connected by phone, email, and videoconference with colleagues in all major observatories worldwide, and data were freely exchanged between the different groups.

This unique collaborative spirit provides astronomers with data taken almost around the clock during several days and this, with the largest variety of instruments, making the Deep Impact observing campaign one of the most successful of its kind, and thereby, ensuring the greatest scientific outcome.

From the current analysis, it appears most likely that the impactor did not create a large new zone of activity and may have failed to liberate a large quantity of pristine material from beneath the surface.

The images obtained at the VLT show that after the impact, the morphology of Comet Tempel 1 had changed, with the appearance of a new plume-like structure, produced by matter being ejected with a speed of about 700 to 1000 km/h (see ESO PR Photo 23/05).

This structure, however, diffused away in the following days, being more and more diluted and less visible, the comet taking again the appearance it had before the impact. Further images obtained with, among others, the adaptive optics NACO instrument on the Very Large Telescope, showed the same jets that were visible prior to impact, demonstrating that the comet activity survived widely unaffected by the spacecraft crash.

The study of the gas in Comet Tempel 1 (see "Looking for Molecules"), made with UVES on Kueyen (UT2 of the VLT), reveals a small flux increase the first night following the impact. At that time, more than 17 hours after the impact, the ejected matter was fading away but still measurable thanks to the large light collecting power of the VLT.

The data accumulated during 10 nights around the impact have provided the astronomers with the best ever time series of optical spectra of a Jupiter Family comet, with a total of more than 40 hours of exposure time. This unique data set has already allowed the astronomers to characterize the normal gas activity of the comet and also to detect, to their own surprise, an active region.

This active region is not related to the impact as it was also detected in data collected in June. It shows up about every 41 hours, the rotation period of the comet nucleus determined by the Deep Impact spacecraft. Exciting measurements of the detailed chemical composition (such as the isotopic ratios) of the material released by the impact as well as the one coming from that source will be performed by the astronomers in the next weeks and months.

Further spectropolarimetric observations with FORS1 have confirmed the surface of the comet to be rather evolved - as expected - but more importantly, that the dust is not coming from beneath the surface. These data constitute another unique high-quality data set on comets.

Comet Tempel 1 may thus be back to sleep but work only starts for the astronomers.

More information

On July 4, 2005, the NASA Deep Impact spacecraft launched a 360 kg impactor onto Comet 9P/Tempel 1. This experiment is seen by many as the first opportunity to study the crust and the interior of a comet, revealing new information on the early phases of the Solar System. ESO actively participated in pre- and post-impact observations.

Apart from a long-term monitoring of the comet, for two days before and six days after, all major ESO telescopes - i.e. the four Unit Telescopes of the Very Large Telescope Array at Paranal, as well as the 3.6m, 3.5m NTT and the 2.2m ESO/MPG telescopes at La Silla - have been observing Comet 9P/Tempel 1, in a coordinated fashion and in very close collaboration with the space mission' scientific team.

The simultaneous use of all ESO telescopes with all together 10 instruments has an enormous potential, since it allows for observation of the comet at different wavelengths in the visible and infrared by imaging, spectroscopy and polarimetry. Such multiplexing capabilities of the instrumentation do not exist at any other observatory in the world.

Notes

[1]: Leading scientists of the ESO DI campaign: H. Boehnhardt (MPI, Lindau, Germany), O. Hainaut (ESO), H.U. Kaufl (ESO), H. Rauer (DLR, Germany).

Members of the ESO DI observing team on site: N. Ageorges (ESO, Chile), S. Bagnulo (ESO, Chile), L. Barrera (UMCE, Chile), H. Boehnhardt (MPS, Germany), T. Bonev (Astr. Inst. Sofia, Bulgaria) , O. Hainaut (ESO, Chile), E. Jehin (ESO, Chile), H.U. Kaufl (ESO, Germany), F. Kerber (ESO, Germany), J. Manfroid (U.Liège, Belgium), O. Marco (ESO, Chile), E. Pantin (CEA, France), E. Pompei (ESO, Chile), H. Rauer (DLR, Germany), C. Sterken (Vrije Universiteit Brussel, Belgium), G.P. Tozzi (Obs. Arcetri, Italy), M. Weiler (DLR, Germany)

Members of the ESO DI observing team not on site: C. Arpigny (U.Liège, Belgium), A. Cochran (McDonald, USA), C. Delahodde (Univ. Florida, USA), Y. Fernandez (Univ. Hawaii, USA), D. Hutseme kers (U.Liège, Belgium), H. Kawakita (Gunma, Japan), J. Knollenberg (DLR, Germany), L. Kolokolova (Univ. Maryland, USA), M. Kretlow (MPS, Germany), M. Kueppers (MPS, Germany), E. Kuehrt (DLR, Germany), L. Lara (IAA, Spain), J. Licandro (IAC, Spain), C. Lisse (Univ. Maryland, USA), K . Meech (U.Hawaii, USA), R. Schulz (ESTEC, The Netherlands), G. Schwehm (ESTEC, The Netherlands), M. Sterzik (ESO, Chile), J.A. Stüwe (Leide n, The Netherlands), I. Surdej (Univ. Liège, Belgium and ESO, Garching), D. Wooden (Ames, USA), J.-M. Zucconi (Besancon, France).

[2]: This image is a of the CN (388 nm) spectrum of comet Tempel 1 observed from Paranal just before the impact (in black), the 03 of July (at UT 02:00), and the 04 of July at UT 24:00 (in red), which is the first observation after the impact. An artificial wavelength shift has been added for clarity. The post impact spectrum is clearly higher than the pre-impact one.


http://www.rednova.com/news/space/175805/comet_tem.....index.html

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NASA weighs options after Deep Impact's comet-smashing success

ALICIA CHANG

Associated Press

LOS ANGELES - NASA is considering an encore for its Deep Impact spacecraft, which made history earlier this month when it smashed a hole in a comet to study its frozen primordial core.

While the space agency has not approved a specific future mission, it did give scientists at its Jet Propulsion Laboratory in Pasadena the go-ahead to bring the spacecraft closer to Earth's orbit for a potential mission extension.

"We're trying to maintain as many options as we can," Andrew Dantzler, the director of NASA's solar system division, said Tuesday.

Deep Impact planned to fire its thrusters on Wednesday to slightly change course in a maneuver that will bring it back to Earth by 2008. Then the spacecraft will switch to safe mode to conserve energy until it receives orders for a possible second mission. If left untouched, the spacecraft will drift further away.

The original mission called for the mothership to release an 820-pound copper impactor into the path of the onrushing comet Tempel 1, record the collision from a distance and retire as space junk. But the mothership remained surprisingly healthy despite being bombarded with debris during a close flyby of Tempel 1 minutes after the collision.

Members of the Deep Impact team hope the maneuver will allow the spacecraft to steer toward 85P/Boethin, a comet that was discovered in 1975 and orbits the sun every 11 years. Since Deep Impact only carried one impactor, any future mission will not cause a cosmic smash-up. Instead, scientists hope the scientific instruments aboard Deep Impact will allow them a detailed glimpse of yet another comet.

The July 4 collision 83 million miles from Earth gave off two flashes of bright light and carved a crater in the potato-shaped comet. The collision released a larger-than-expected debris cloud extending thousands of miles into space that has prevented scientists from peering into the comet's interior. Scientists said they expect the excavated pit to be on the larger end of the scale.

The impactor vaporized as it crashed on the comet's sunlit side, but the mothership survived unharmed. It flew within 310 miles of Tempel 1 and took pictures of the receding comet as it flew away.

Comets are irregular bodies of ice and dust that orbit the sun and were born about 4.5 billion years ago - nearly the same time as the solar system itself. When a cloud of gas and dust condensed to form the sun and planets, comets formed from what was left over. Studying them could shed light on how the solar system formed.

Deep Impact blasted off in January from Florida for a 268-million-mile journey toward Tempel 1, which was discovered in 1867 and moves around the sun in an elliptical orbit between Mars and Jupiter every six or so years.

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