Εμφάνιση αναρτήσεων με ετικέτα comets. Εμφάνιση όλων των αναρτήσεων
Εμφάνιση αναρτήσεων με ετικέτα comets. Εμφάνιση όλων των αναρτήσεων

Παρασκευή, Νοεμβρίου 14, 2014

Philae may not have energy to send results to Earth, says ESA

Europe's robot lab Philae may not have enough power to send to Earth the results of today's drill into the surface of its host comet, mission scientists have said.

"We are not sure there is enough energy so that we can transmit" the data, lander manager Stephan Ulamec said at a press conference webcast from European Space Agency (ESA) ground control in Germany.
Scientists are to decide whether to try a risky drilling procedure to enable an exploration probe to examine samples from the surface of a comet before its batteries run out.

The probe on Wednesday floated away from its planned landing site after harpoons designed to hold it down on the comet failed to deploy.
It is now resting precariously on two out of three legs in the shadow of a cliff on the comet.
  • The lack of light means the probe, dubbed Philae, would not draw sufficient energy to operate on its solar panels as hoped once its batteries run out.
  • The ESA team are also uncertain of its exact position, making it difficult to "hop" the probe into a better position using its landing gear.
The probe was supposed to drill into the surface of the celestial body after landing, but its unstable position and the comet's weak gravitational pull means there is a risk it could bounce off if the drill is deployed.
Despite the landing setbacks, the mission has achieved many breakthroughs, including the first time a spacecraft has followed a comet rather than just whizzing past and the first time a probe has landed on a comet.
Comets are of interest to scientists because they are remnants from the formation of our solar system, over 4.6 billion years ago.
These masses of ice and rock have preserved ancient organic molecules like a time capsule and may provide insight into how planets and life evolved.
Even if Philae is unable to drill into the surface to analyse samples, the Rosetta spacecraft will follow the comet until at least the end of 2015, even as it passes closest to the sun on its orbit.
[http://www.rte.ie]
14/11/1
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Τετάρτη, Νοεμβρίου 12, 2014

The Rosetta comet landing has made history (Space probe, Philae, reaches comet’s surface first time in history)

After 10 years of hard work and one nerve-wracking night, the Rosetta mission has made history by landing on the surface of a comet.

The lander Philae was confirmed to touch down on the surface of the comet more than 300 million miles away at 11:05 a.m. Eastern. Now, scientists expect it to send a panoramic image home and begin analyzing the comet for scientists back on Earth.

Philae is already transmitting scientific data back home, but we're still waiting to see whether the probe is in a stable position. Until we know it's anchored tight, it could roll onto its back and never get back up.

Tensions were high in the European Space Agency's German mission control center, especially as the landing window approached. Because the comet that Philae landed on is so far from Earth, there's a communications delay of 28 minutes. So as the minutes ticked by, the Rosetta team knew that Philae had already either landed or failed — and there was nothing they could do but wait for the data to reach them. Those following the video online were nearly as desperate for news, and Twitter became a sounding chamber of anticipation and excitement.

But a few minutes after 11 a.m., the stern, cautious expressions of the mission control team melted into smiles. And just like that, the world swiveled from anxiety to elation: Philae was on the surface of the comet and ready to do some science.
 [washingtonpost.com]
12/11/14
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For the first time in the history of space exploration a research probe has reached the surface of a comet.
The robotic lander Philae of the European Space Agency separated from the spacecraft Rosetta and landed on the comet 67P/Churyumov-Gerasimenko 500 million kilometers away from the Earth.
Philae separated from the Rosetta spacecraft at 11:35 Moscow time.

 The journey from Rosetta to the comet’s surface lasted about seven hours.

Rosetta and Comet 67P/Churyumov-Gerasimenko, which was discovered in 1969 by Soviet astronomers Klim Churyumov and Svetlana Gerasimenko, now lie about half way between the orbits of Jupiter and Mars, rushing towards the inner Solar System at nearly 55,000 kilometers per hour, the ESA said.
Rosetta will follow the comet for more than a year to provide a detailed scientific study of the Solar System body.
[en.itar-tass.com]
12/11/14

Τρίτη, Σεπτεμβρίου 30, 2014

Water on earth originated outside the solar system, scientists prove

Human beings have always obsessed over whether they are alone in the universe. Now scientists say they’ve proved that at least some of the water on Earth has to have originated from outside the solar system (and they add that it’s older than the sun).
The news has set the flying-saucer-sphere abuzz with the thought that other planets in the universe are therefore more likely to have had water, at some stage at least, and to therefore have developed life.
That however is not claimed by the paper published in Science Magazine on September 26, when life forms in Israel were celebration the new Jewish year.
“It isn’t news that water in the solar system is older than the sun,” explains Prof. Morris Podolak of Tel Aviv University’s Department of Geosciences, an expert on planetology and the evolution of comets: it had to be. What is news is that the water on earth cannot have originated in the protoplanetary nebular disk from which the planets, including Earth, formed.
It all started with the big bang
Current thinking is that the universe began with the big bang, which created mainly hydrogen and some helium, Podolak explains. “Things like oxygen and other heavier elements were made in secondary processes, like inside stars, which threw out the material. Our sun is second-generation, made of material that originated with an earlier generation of stars,” he says.
In other words, our sun was formed already including heavier elements such as carbon and oxygen made after the big bang but before the sun’s birth, Podolak explains.
Moreover, the universe has a huge amount of hydrogen, a lot of helium and the third most prevalent element is oxygen, says Podolak. Water consists of hydrogen and oxygen (two hydrogen atoms to one of oxygen, to be accurate).
So the interstellar void in which the solar system, and Earth, formed had water bobbing about that would by definition be older than the sun. We would expect water to be abundant in that void, says Podolak.
The weird thing discovered by the team headed by Ilsedore Cleeves of the University of Michigan’s Astronomy department is that the water on Earth doesn’t have the same chemical signature — deuterium-to-hydrogen enrichment — as primordial water in the solar system. Nor could processes in that disk have created the signature of the water on earth, the team says. So the question is where it came from.
Comet collisions or water-locking rocks
To this day the origin of water on earth remains a mystery. Some believe our oceans are actually the result of a lot of collisions by icy comets with the primordial planet, which eventually brought sufficient ice to create our oceans. Another theory is that the iron and silicate rocks that formed our planet had water in their molecular mesh. The new discovery does not necessarily tie into the comet theory better than the inside-rock-all-this-time theory, says Podolak: Theoretically the primordial water could have combined with silicates to form hydrated minerals.
However water got to earth, it’s older than the sun and solar system — which are believed to be between 4.5 billion and 5 billion years old.
“Identifying the source of Earth’s water is central to understanding the origins of life-fostering environments and to assessing the prevalence of such environments in space,” write the authors, led by Ilsedore Cleeves of the University of Michigan’s astronomy department, who has been researching the origins of planetary systems.
So water is out there in the interstellar void, as a corollary of the universe’s evolution. If our solar system is not unique in this respect, “and there’s no reason to think it is,” says Podolak, then there’s water out there in interstellar space, and theoretically other planetary systems — they have been proven to exist — could have formed with water on board too. And hence, perhaps, maybe, they have life.
Present thinking cannot conceive of life forming in a nonwatery environment, because for molecules to knock about and accidentally create life (if we may oversimplify a tad), they need an environment that enables movement. Think of tossing golf balls into a filled pool as opposed to a sand trap. In the pool, they’ll move around and knock against each other, possibly reacting; in the sand trap they’ll just sit there until a life form from elsewhere lobs them out again.
But it remains a leap to conclude that since there’s water in space, life must exist elsewhere in space too. Maybe it does. Maybe life on Earth is a cosmic accident. Man still has no clear idea how he came about, let alone the proto-ameba that gave birth to all beings, assuming there was only one. For all we know there were multiple proto-amebas and life forms spring up all over the place and some survive and some do not. 

www.haaretz.com
29/9/14

Τετάρτη, Αυγούστου 06, 2014

Rosetta space probe makes historic rendezvous with comet

European scientists announced the historic rendezvous on Wednesday between a comet and the Rosetta spacecraft after a 10-year, six billion-kilometre (3.7-billion-mile) chase through the solar system.

The scout Rosetta has now become the first envoy to orbit one of these wanderers of the solar system in deep space, the European Space Agency (ESA) said.

Scientists and spectators at ESA’s mission control in Darmstadt, Germany, cheered after the spacecraft successfully completed its final thrust to swing alongside comet 67P/Churyumov-Gerasimenko.


ESA chief Jean-Jacques Dordain says the probe’s rendezvous with 67P is an important milestone in Rosetta’s life.

The goal of the mission is to orbit 67P from a distance of about 100 kilometres (60 miles) and observe the giant ball of dust and ice as it hurtles toward the sun. If all goes according to plan, Rosetta will drop the first ever lander, a robot chemistry lab, onto a comet in November.

Scientists hope this will help them learn more about the origins of comets, stars and planets.

Orbital entry was triggered by a small firing of her thrusters, lasting just six minutes and 26 seconds, starting at 0900 GMT on Wednesday, it said.

“This burn will tip Rosetta into the first leg of a series of three-legged triangular paths about the comet,” it said.

Top officials from ESA will be were at mission control in Darmstadt, Germany, waiting for the signals to start and stop this crucial final operation to be safely received by ground monitoring stations, 22 minutes later.

The “pyramidal” orbits will put the craft at a height of about 100 kilometres (60 miles) above the comet, said Sylvain Lodiot, Rosetta’s flight operations manager. Each leg of the triangle will be around 100 kilometres and take Rosetta between three and four days to complete.

The arrival will mark a key moment of the boldest project ever undertaken by ESA—a 1.3-billion-euro ($1.76-billion) investigation into one of the enigmas of the solar system.

Comets are believed by astrophysicists to be ancient ice and dust left from the building of the solar system around 4.6 billion years ago. This cosmic rubble is the oldest, least touched material in our stellar neighbourhood.

Understanding its chemical ID identity and physical composition will give insights into how the planets coalesced after the sun flared into light, it is hoped.

t could also determine the fate of a theory called “pan-spermia,” which suggests comets, by smashing into the infant Earth, sowed our home with water and precious organic molecules, providing us with a kickstart for life.

Navigational feat

Rosetta was poised to meet up with Comet “C-G” more than 400 million kilometres from where it was launched.

Getting there has been an unprecedented navigational exploit. Launched in March 2004, the three-tonne craft has had to make four flybys of Mars and Earth, using their gravitational force as a slingshot to build up speed.

It then entered a 31-month hibernation as light from the distant Sun became too weak for its solar panels. That period ended in January with a wake-up call sent from Earth.

The spacecraft is named after the famous stone, now in the British Museum, that explained Egyptian hieroglyphics, while its payload Philae is named after an obelisk that in turn helped decipher the Rosetta stone.

The four-kilometre comet is named after two Ukrainian astronomers who first spotted it in 1969.

(FRANCE24 with AP and AFP)

http://www.france24.com/en/20140806-rosetta-space-probe-comet-meeting-solar-system/
6/8/14
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Δευτέρα, Ιανουαρίου 20, 2014

Rosetta spacecraft to be woken after nearly three years, ESA awaits signs of life

The European Space Agency (ESA) is awaiting signs of life from its comet-chasing spacecraft Rosetta. The probe - now in the vicinity of Jupiter's orbit - has been in hibernation for nearly three years. 

An internal "alarm clock" aboard the Rosetta spacecraft was scheduled to go off at 1000 UTC on Monday, waking it up from nearly three years of slumber. But given the six hours Rosetta would need to power up its system, plus the time needed for its signal to traverse the 807 million kilometers (501 million miles) to Earth, the European Space Agency (ESA) said it wasn't expecting to hear anything until the early evening.

The signal is to be heard first by NASA's deep space tracking dish in Goldstone, California, then by eastern Australia's station in Canberra, and finally, by the ESA's station in Western Australia.
The ESA launched Rosetta into space in 2004with the goal of carrying out tests on the comet 67/Churyumov-Gerasimenko. If all goes well on Monday, the spacecraft will fly towards the comet in the coming months (depicted above), enter into its orbit and eventually land on its surface. Scientists hope to gather samples from the rock with its 220-pound (100 kg) lander Philae, which could reveal more about the make-up of the solar system at its earliest stages.
In the time since it was thrust into space, the comet-chaser has been gathering speed to put it on the right trajectory toward comet 67/Churyumov-Gerasimenko. It has travelled past Earth three times and Mars once.
In mid-2011, ESA scientists shut down all of its operating systems except for its computer and several heaters. Rosetta has been running on solar power since that time on its journey toward Jupiter's orbit.
The ESA has provided a link to its live broadcast as it awaits signs of life from Rosetta: ESA live transmission
kms/pfd (AP, Reuters)
DW.DE
20/1/14

Οι νεκροί Έλληνες στα μακεδονικά χώματα σάς κοιτούν με οργή

«Παριστάνετε τα "καλά παιδιά" ελπίζοντας στη στήριξη του διεθνή παράγοντα για να παραμείνετε στην εξουσία», ήταν η κατηγορία πο...