Sunday, October 28, 2012

Δεινόσαυροι-στρουθοκάμηλοι ανακαλύφθηκαν στον Καναδά

  Δεινόσαυροι που έμοιαζαν με στρουθοκαμήλους, γνωστοί ως ορνιθομιμόσαυροι, βρίσκονταν στη Γη πριν εκατομμύρια χρόνια και χρησιμοποιούσαν τα τεράστια φτερά τους για να προσελκύσουν συντρόφους ή να προστατεύσουν τα μικρά τους.
  Στο πλαίσιο της έρευνας οι ερευνητές εξέτασαν τρεις σκελετούς ορνιθομιμοσαύρων (ενός ανήλικου και δυο ενηλίκων) που εντοπίστηκαν σε ιζήματα ενός αρχαίου ποταμού στη νότια Αλμπέρτα, στον Καναδά. Eξετάζοντας τα απολιθώματα οι ερευνητές εντόπισαν ίχνη πούπουλων και φτερών.
  Σημαντικό είναι το συμπέρασμα στο οποίο κατέληξαν οι επιστήμονες σχετικά με τη χρησιμότητα που είχαν τα πούπουλα και τα φτερά των ορνιθομιμοσαύρων. Πιο συγκεκριμένα, όπως αποδείχθηκε, οι ανήλικοι είχαν πούπουλα, ενώ οι ενήλικες ανέπτυσσαν δομές που έμοιαζαν με φτερά και οι οποίες δεν τους βοηθούσαν να πετάξουν, αλλά σχετίζονταν με την αναπαραγωγική διαδικασία.
   Οι ορνιθομιμόσαυροι έμοιαζαν με τις σημερινές στρουθοκαμήλους. Είχαν ράμφος χωρίς δόντια, μεγάλα μάτια, μακριά πόδια, μακρύ λαιμό και μια μακριά και χοντρή ουρά.«Αυτή είναι μια πολύ σημαντική ανακάλυψη καθώς αντιπροσωπεύει τα πρώτα δείγματα φτερωτού δεινοσαύρου στο Δυτικό Ημισφαίριο», δήλωσαν οι παλαιοντολόγοι που συμμετείχαν στη μελέτη.Τα ευρήματά τους συνηγορούν στο ότι όλοι οι ορνιθομιμόσαυροι πρέπει να είχαν φτερά.

Συρρικνώθηκε η τρύπα του όζοντος

  Συρρικνώθηκε η τρύπα του όζοντος πάνω από την Ανταρκτική, όπως προκύπτει από δορυφορικές μετρήσεις της NASA και της Αμερικανικής Εθνικής Υπηρεσίας για τους Ωκεανούς και την Ατμόσφαιρα (NOAA). Πιο συγκεκριμένα, φέτος η τρύπα του όζοντος είχε τη μικρότερη έκταση για δεύτερη φορά εδώ και είκοσι χρόνια, ωστόσο συνεχίζει να καλύπτει μια μεγάλη περιοχή ίση με τη Βόρειο Αμερική. Με βάση τις δορυφορικές εικόνες η έκταση της τρύπας του όζοντος μειώθηκε φέτος στα 17,9 εκατομμύρια τετραγωνικά χιλιόμετρα.
   Αρνητικό ρεκόρ είχε καταγραφεί το 2000, χρονιά κατά την οποία η έκταση της τρύπας του όζοντος έφτασε τα 29,7 εκατομμύρια τετραγωνικά χιλιόμετρα. Το στρώμα του όζοντος, που προστατεύει τη Γη από την επικίνδυνη υπεριώδη ακτινοβολία η οποία ενοχοποιείται για καρκίνο του δέρματος και καταρράκτη, άρχισε από το 1980 να αναπτύσσει τρύπες σε ετήσια βάση εξαιτίας της χρήσης χλωροφθορανθράκων. Βέβαια, οι χλωροφθοράνθρακες, που παλαιότερα χρησιμοποιούνταν σε ψυγεία και σπρέι, απαγορεύθηκαν το 1987 με την υπογραφή του Πρωτοκόλλου του Μόντρεαλ. Μια από τις ιδιότητές τους είναι ότι παραμένουν για μεγάλο χρονικό διάστημα στην ατμόσφαιρα, γεγονός που σημαίνει ότι πρέπει να περάσουν πολλές δεκαετίες μέχρι οι συγκεντρώσεις τους να φτάσουν τα επίπεδα πριν το 1980.
   Σε αυτό το πλαίσιο οι επιστήμονες εκτιμούν ότι η αποκατάσταση του στρώματος του όζοντος πάνω από την Ανταρκτική δεν αναμένεται νωρίτερα από το 2060.

Αρχαία πόλη κάτω από το Τρίγωνο των Βερμούδων

   Στο βυθό του ωκεανού στην περιοχή του Τριγώνου των Βερμούδων μια ομάδα Καναδών επιστημόνων εντόπισε πρόσφατα μια χαμένη πόλη. Κοντά στις ακτές της Κούβας, ένα υποβρύχιο ρομπότ κατέγραψε ερείπια κτιρίων, τέσσερις γιγάντιες πυραμίδες και κάτι που μοιάζει με άγαλμα Σφίγγας.
   Οι ειδικοί εκτιμούν ότι τα βυθισμένα κτίσματα ανήκουν στην προκλασική περίοδο της ιστορίας της Καραϊβικής και της Κεντρικής Αμερικής και η αρχαία πόλη θα μπορούσε να κατοικείται από εκπροσώπους πολιτισμού, παρόμοιου με τους κατοίκους της Τεοτιουακάν (εγκαταλελειμμένη πόλη, που βρίσκεται σε απόσταση 50 χλμ. από την Πόλη του Μεξικού και έχει ηλικία περίπου 2000 ετών).
   Η πόλη βρίσκεται 183 μέτρα κάτω από τον ωκεανό και η ομάδα των ερευνητών με επικεφαλής τους Weinzweig και Zalitzki είναι πεπεισμένοι ότι είναι η Ατλαντίδα – η χαμένη πόλη για πάνω από 10.000 χρόνια.
   Τον περασμένο Ιούλιο, αμερικανοί και Γάλλοι εξερευνητές έκαναν στο βυθό της θάλασσας της Καραϊβικής μια άλλη μνημειώδη ανακάλυψη: μία μερικώς διαφανή, κρυστάλλινη πυραμίδα , πιθανότατα μεγαλύτερη από την πυραμίδα του Χέοπα, στο Κάιρο. Μέχρι τώρα όμως , δεν έχει εξακριβωθεί η ηλικία και η «καταγωγή» του μυστηριώδους αυτού κτίσματος .

Sunday, September 2, 2012

NASA's GRAIL Moon Twins Begin Extended Mission

   NASA's twin, lunar-orbiting Gravity Recovery and Interior Laboratory (GRAIL) spacecraft began data collection for the start of the mission's extended operations.
   "The data collected during GRAIL's primary mission team are currently being analyzed and hold the promise of producing a gravity field map of extraordinary quality and resolution," said Maria Zuber, principal investigator for GRAIL from the Massachusetts Institute of Technology in Cambridge. "Mapping at a substantially lower altitude during the extended mission, and getting an even more intimate glimpse of our nearest celestial neighbor, provides the unique opportunity to globally map the shallow crust of a planetary body beyond Earth."
   The science phase of GRAIL's extended mission runs from Aug. 30 to Dec. 3. Its goals are to take an even closer look at the moon's gravity field, deriving the gravitational influence of surface and subsurface features as small as simple craters, mountains and rilles. To achieve this unprecedented resolution, GRAIL mission planners are halving the operating altitude – flying at the lowest altitude that can be safely maintained.

NASA's Kepler Discovers Multiple Planets Orbiting a Pair of Stars

   Coming less than a year after the announcement of the first circumbinary planet, Kepler-16b, NASA's Kepler mission has discovered multiple transiting planets orbiting two suns for the first time. This system, known as a circumbinary planetary system, is 4,900 light-years from Earth in the constellation Cygnus.
   This discovery proves that more than one planet can form and persist in the stressful realm of a binary star and demonstrates the diversity of planetary systems in our galaxy.
   Astronomers detected two planets in the Kepler-47 system, a pair of orbiting stars that eclipse each other every 7.5 days from our vantage point on Earth. One star is similar to the sun in size, but only 84 percent as bright. The second star is diminutive, measuring only one-third the size of the sun and less than 1 percent as bright.
    In contrast to a single planet orbiting a single star, the planet in a circumbinary system must transit a 'moving target.' As a consequence, time intervals between the transits and their durations can vary substantially, sometimes short, other times long. The intervals were the telltale sign these planets are in circumbinary orbits.
Please read more and watch the video below:

Saturday, September 1, 2012

Arctic Sea Ice Shrinks To New Low In Satellite Era


Arctica as seen from Era satelite of NASA. The orange line the amount of ice that should normally exist by now. 

 The extent of the sea ice covering the Arctic Ocean has shrunk. According to scientists from NASA and the NASA-supported National Snow and Ice Data Center (NSIDC) in Boulder, Colo., the amount is the smallest size ever observed in the three decades since consistent satellite observations of the polar cap began.
The extent of Arctic sea ice on Aug. 26, as measured by the Special Sensor Microwave/Imager on the U.S. Defense Meteorological Satellite Program spacecraft and analyzed by NASA and NSIDC scientists, was 1.58 million square miles (4.1 million square kilometers), or 27,000 square miles (70,000 square kilometers) below the Sept. 18, 2007, daily extent of 1.61 million square miles (4.17 million square kilometers).
The sea ice cap naturally grows during the cold Arctic winters and shrinks when temperatures climb in the spring and summer. But over the last three decades, satellites have observed a 13 percent decline per decade in the minimum summertime extent of the sea ice. The thickness of the sea ice cover also continues to decline.
"The persistent loss of perennial ice cover -- ice that survives the melt season -- led to this year's record summertime retreat," said Joey Comiso, senior research scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "Unlike 2007, temperatures were not unusually warm in the Arctic this summer."
The new record was reached before the end of the melt season in the Arctic, which usually takes place in mid- to late-September. Scientists expect to see an even larger loss of sea ice in the coming weeks.
"In 2007, it was actually much warmer," Comiso said. "We are losing the thick component of the ice cover. And if you lose the thick component of the ice cover, the ice in the summer becomes very vulnerable."
"By itself it's just a number, and occasionally records are going to get set," NSIDC research scientist Walt Meier said about the new record. "But in the context of what's happened in the last several years and throughout the satellite record, it's an indication that the Arctic sea ice cover is fundamentally changing."

Friday, August 31, 2012

Commercial Space Transportation

Florida Spaceport Stakes Claim to Commercial Missions

The three American companies building next-generation spacecraft that NASA could call on to carry astronauts into orbit in the future will perform much of their work along Florida's Space Coast, home of the agency's Commercial Crew Program (CCP).
Advances made by these companies under newly signed Space Act Agreements (SAAs) through the agency's Commercial Crew Integrated Capability (CCiCap) initiative are intended to lead to the availability of commercial human spaceflight services for government and commercial customers.‬
"Our commercial crew and cargo efforts are based on a simple but powerful principle," said NASA Administrator Charlie Bolden during the CCiCap announcement. "By investing in American companies and American ingenuity, we're spurring free-market competition to give taxpayers more bang for the buck while enabling NASA to do what we do best, reach for the heavens."
Throughout the next 21 months, Sierra Nevada Corporation (SNC) of Louisville, Colo., Space Exploration Technologies (SpaceX) of Hawthorne, Calif., and The Boeing Company of Houston will complete their spacecraft and launch vehicle designs, test their hardware, and then showcase how they would operate and manage missions from launch through orbit and landing. 

"We have selected three companies that will help keep us on track to end the outsourcing of human spaceflight and create high-paying jobs in Florida and elsewhere across the country," Bolden said.
The proposals submitted by these three companies include processing and launching from Kennedy or the center's adjacent Cape Canaveral Air Force Station (CCAFS), which could equal new jobs along Florida's Space Coast.
"The KSC team has the human capital expertise, unique facilities and specialized equipment to propel the agency into the next phase of space exploration," said Kennedy Center Director Bob Cabana, "and the Commercial Crew Program is a key part of that."

Radiation Belt Storm Probes Begin Mission

NASA's twin Radiation Belt Storm Probes lifted off from Cape Canaveral Air Force Station in Florida Thursday morning, beginning a mission to explore Earth's radiation belts. 
Information from the mission should help us protect our satellites and better understand how space weather affects communications and technology on Earth.
The RBSP mission begins with a thundering liftoff from SLC-41 at Cape Canaveral AFS on Aug. 30, 2012.

NASA's Dawn mission Leaving Vesta-Heading Toward Dwarf Planet

 NASA's Dawn spacecraft is on track to become the first probe to orbit and study two distant solar system destinations, to help scientists answer questions about the formation of our solar system.
 The spacecraft is scheduled to leave the giant asteroid Vesta on Sept. 4 PDT (Sept. 5 EDT) to start its two-and-a-half-year journey to the dwarf planet Ceres.
In the video, there is a simulated flyover of the most intriguing landmarks on giant asteroid Vesta, as seen by NASA's Dawn spacecraft.


Wednesday, August 29, 2012

NASA's InSight Mission

  On Aug. 20, NASA announced the selection of InSight, a new Discovery-class mission that will probe Mars at new depths by looking into the deep interior of Mars.
  "We are certainly excited, but our veterans on this team know the drill," said Tom Hoffman, project manager for InSight from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Which is fortunate, because one of the great things we'll get to do on Mars is drill below the surface."
  Drilling underneath the red Martian topsoil will be courtesy of InSight's HP3, or Heat Flow and Physical Properties Package – one of the four instruments the Mars lander will carry. Made by the German Aerospace Center, or DLR, HP3 will get below Mars' skin by literally pounding it into submission with a 14-inch (35-centimeter), hollowed-out, electromechanically-festooned stake called the Tractor Mole.
  "The Tractor Mole has an internal hammer that rises and falls, moving the stake down in the soil and dragging a tether along behind it," said Sue Smrekar, deputy project scientist for InSight from JPL. "We're essentially doing the same thing any Boy or Girl Scout would do on a campout, but we're putting our stake down on Mars." 
  The mole will descend up to 16 feet (five meters) below the surface, where its temperature sensors will record how much heat is coming from Mars' interior, which reveals the planet's thermal history.
  "Getting well below the surface gets us away from the sun's influence and allows us to

Tuesday, August 28, 2012

"Beautiful" New Particle Found at LHC

The CMS detector inside the Large Hadron Collider captured evidence of the new particle (file picture).
An atom-smashing experiment at the Large Hadron Collider (LHC) has detected a new subatomic particle—and it's a beauty.
  Known as Xi(b)* (pronounced "csai bee-star"), the new particle is a baryon, a type of matter made up of three even smaller pieces called quarks. Protons and neutrons, which make up the nuclei of atoms, are also baryons.
 The Xi(b)* particle belon
gs to the so-called beauty baryons, particles that all contain a bottom quark, also known as a beauty quark.
The newfound particle had long been predicted by theory but had never been observed. Although finding Xi(b)* wasn't exactly a surprise, the discovery should help scientists solve the larger puzzle of how matter is formed.
"It's another brick in the wall," said James Alexander, a physicist at Cornell University who conducts experiments with the LHC.
   
Sorting Through the Mess
 Unlike protons and neutrons, beauty baryons are extremely short-lived—Xi(b)* lasted mere fractions of a second before it decayed into 21 other ephemeral particles.
 The particle also requires extremely high energies to create, so it's found nowhere on Earth except in the hearts of atom-smashers such as the LHC, operated by the European Center for Nuclear Research (CERN) in Geneva.
 The new beauty baryon is a higher energy version of one that was detected last summer by scientists using the Tevatron particle accelerator at Fermilab in Illinois.
LHC scientists didn't detect the new particle directly. Instead they saw evidence of its decay in the messy aftermath of a proton-proton collision captured by the facility's Compact Muon Solenoid (CMS) detector.
he CMS scientists say the new particle's existence has been confirmed to a sigma level of five, which means the researchers are 99.99-percent confident that the result isn't due to chance.

Hunt Still on for Higgs
 The discovery is further confirmation that physicists are essentially correct in their understanding of how quarks are bound together, said Fermilab scientist Patrick Lukens, who was not involved in the study.
 The particle was predicted by a wildly successful theory in physics known as quantum chromodynamics, which models how quarks combine and are held together to create heavier particles.
 However, Lukens said, finding Xi(b)* has no bearing on the hunt for the Higgs boson, a particle that would explain why mass exists in the universe and that's also predicted by quantum chromodynamics.
 Cornell's Alexander added that the Higgs "is a huge pivot point for the entire theory" of quantum chromodynamics. "Whether the Higgs is or is not there—everything rests on that."

Monday, August 27, 2012

Recipe for a Resurrection

Bringing extinct species back to life is no longer considered science fiction. But is it a good idea?



Each new woolly mammoth carcass to emerge from the Siberian permafrost triggers a flurry of speculation about resurrecting this Ice Age giant. Researchers have refined at least some of the tools needed to turn that hope into reality. Last November, when a team led by Teruhiko Wakayama, a reproductive biologist based in Kobe, Japan, reported it had cloned mice that had been frozen for 16 years, the scientists conjectured that the same techniques might open the door to cloning mammoths and other extinct species preserved in

Making Mars the New Earth


   What would it take to green the red planet? For starters, a massive amount of global warming.
 Could we “terraform” Mars—that is, transform its frozen, thin-aired surface into something more friendly and Earthlike? Should we? The first question has a clear answer: Yes, we probably could. Spacecraft, including the ones now exploring Mars, have found evidence that it was warm in its youth, with rivers draining into vast seas. And right here on Earth, we’ve learned how to warm a planet: just add greenhouse gases to its atmosphere. Much of the carbon dioxide that once warmed Mars is probably still there, in frozen dirt and polar ice caps, and so is the water. All the planet needs to recapture its salad days is a gardener with a big budget.
   Most of the work in terraforming, says NASA planetary scientist Chris McKay, would be done by life itself. “You don’t build Mars,” McKay says. “You just warm it up and throw some seeds.” Perfluorocarbons, potent greenhouse gases, could be synthesized from elements in Mar tian dirt and air and blown into the atmosphere; by warming the planet, they would release the frozen CO2, which would amplify the warming and boost atmospheric pressure to the point where liquid water could flow. Meanwhile, says botanist James Graham of the University of Wisconsin, human colonists could seed the red rock with a succession of ecosystems—first bacteria and lichens, which survive in Antarctica, later mosses, and after a millennium or so, redwoods. Coaxing breathable oxygen levels out of those forests, though, could take many millennia.
Enthusiasts such as Robert Zubrin, president of the Mars Society, still dream of Martian cities; Zubrin, an engineer, believes civilization cannot thrive without limitless expansion. Only research outposts seem plausible to McKay. “We’re going to live on Mars the way we live in Antarctica,” he says. “There are no elementary schools in Antarctica.” But he thinks the lessons learned in terraforming Mars—a horrifying prospect to some—would help us manage our limited Earth better.
There is time to debate the point; Mars is in no immediate danger. A White House–appointed panel recently recommended going to the moon or an asteroid first—and pointed out the space agency lacks the budget to go anywhere. It didn’t estimate the cost of gardening a dead planet.

Organ Regeneration

Above: The synthetic scaffold of an ear sits bathed in cartilage-producing cells, part of an effort to grow new ears for wounded soldiers.
Miracle Grow

   In the future people who need a body part may get their own back—regrown in the lab from their own cells.

   More than 100,000 people are waiting for organ transplants in the U.S. alone; every day 18 of them die. Not only are healthy organs in short supply, but donor and patient also have to be closely matched, or the patient's immune system may reject the transplant. A new kind of solution is incubating in medical labs: "bioartificial" organs grown from the patient's own cells. Thirty people have received lab-grown bladders already, and

Thursday, August 23, 2012

Meteor Dust Boosts Night-Shining Clouds

Night-shining clouds glow over Alberta, Canada, in May.
Mysterious night-shining clouds and trails of smoke left by meteors share an intimate link, a new study says.

   Satellite images collected during the last five years reveal for the first time that water vapor is freezing around nanoscopic bits of meteor smoke, thus seeding the formation of high-altitude noctilucent, or night-shining, clouds.
   Such clouds appear about 50 miles (80 kilometers) above each Pole during its summer months. Yet unlike white water vapor clouds near the planet's surface, noctilucent clouds are electric blue in color, thanks to tiny crystals that preferentially scatter that color of light.
   Scientists discovered that each nanometer-size bit of meteor smoke takes up about 3 percent of each crystal's volume.

Night-Shining Clouds Boosted by Methane?

   Night-shining clouds are on the rise—likely due to human activities.
   "Earth's upper atmosphere [has] been changing in ways that we don't fully understand," experts say. 
   "Noctilucent clouds are occurring more often, getting brighter, and creeping down toward the Equator. I have a strong suspicion this is because of methane."
   Methane seeps out of human garbage dumps, fuel refineries, livestock, and even people themselves.
   The chemical not only serves as a potent greenhouse gas, but it also creates extra water vapor when it reaches the top of the ozone layer, about 60 miles (100 kilometers) above Earth's surface.
   This extra water vapor—an increase of 15 percent over the past 30 years, in step with the abundance of methane gas—has likely contributed to night-shining clouds being 20 to 30 percent brighter and five times more frequent.
   You need three things to make them: very cold temperatures, water vapor, and a particle for water to stick to and freeze
  We've finally identified the particle—the meteor smoke—and the methane seems to be adding extra water vapor."

Tuesday, August 21, 2012

Ο Μεσσήνιος που κατέβασε το "Curiosity" στον Αρη

Ενας Ελληνας, και μάλιστα Μεσσήνιος, με καταγωγή από τον Μελιγαλά, έλαβε μέρος στο εξαιρετικό επίτευγμα της NASA, δηλαδή την πρόσφατη προσεδάφιση στον πλανήτη Αρη του ρομποτικού εργαστηρίου Curiosity.
Από την Σάντα Κλάρα των ΗΠΑ, ο συμπατριώτης μας, Περικλής Παπαδόπουλος, καθηγητής Αεροδιαστημικής Μηχανικής στο πολιτειακό Πανεπιστήμιο του Σαν Χοσέ της Καλιφόρνια, ο οποίος για πολλά χρόνια συνεργάζεται με τη NASA στις αποστολές της για την εξερεύνηση του διαστήματος, αλλά και των πλανητών του ηλιακού μας συστήματος.

Ο Περικλής Παπαδόπουλος ήταν ο άνθρωπος από τον οποίον -και την ομάδα των συνεργατών του- εξαρτιόταν η επιτυχής είσοδος του σκάφους στην ατμόσφαιρα του Αρη, με τεράστιες ταχύτητες και θερμοκρασίες, έτσι ώστε να μπορέσει στη συνέχεια με το αποκαλούμενο Sky Crane να εναποθέσει στην επιφάνεια του πλανήτη, στον κρατήρα Γκέιλ, το ρομποτικό όχημα - εργαστήριο. Μια διαδικασία που διήρκεσε 7 λεπτά -τα “7 λεπτά αγωνίας”, όπως τα ανέφερε η NASA στις ανακοινώσεις της.

ΝΕΕΣ ΤΕΧΝΟΛΟΓΙΕΣ

Sunday, August 19, 2012

Earth's Atmosphere

 

 Protective Buffer

   The Earth's atmosphere is more than just the air we breathe. It's also a buffer that keeps us from being peppered by meteorites, a screen against deadly radiation, and the reason radio waves can be bounced for long distances around the planet.
   The air that accomplishes all of this is composed of five major layers.
   The lowest is the troposphere, which is the layer that provides most of our weather. It contains about four-fifths of the Earth's air, but extends only to a height of about 11 miles (17 kilometers) at the Equator and somewhat less at the Poles.
   The name comes from a Greek word that refers to mixing. And mixing is exactly what happens within the troposphere, as warm air rises to form clouds, rain falls, and winds stir the lands below. Typically, the higher you go in the troposphere, the colder it gets.
   Above the troposphere is the stratosphere. It extends to a height of about 30 miles (50 kilometers) and includes the ozone layer, which blocks much of the sun's harmful ultraviolet rays.
   The stratosphere is warmer than the troposphere because of the energy from the ultraviolet light absorbed by the ozone. At its base, the stratosphere is extremely cold, about -110 degrees Fahrenheit (-80 degrees Celsius). At its top, the temperature has risen back nearly to freezing.
   Next comes the mesosphere. In this layer, the air temperature drops again, down to nearly -180 degrees Fahrenheit (-120 degrees Celsius) at the top. Meteors generally burn up in the mesosphere, which extends to a height of about 52 miles (85 kilometers). This is why the Earth's surface isn't pocked with meteor craters, like the moon's.

 Entering Outer Space
   Above the mesosphere is the ionosphere. It extends to about 430 miles (690 kilometers) and is so thin it's generally considered part of outer space. The International Space Station and many satellites orbit within the ionosphere.
   The ionosphere is named for the ions created within this layer by energetic particles from sunlight and outer space. These ions create an electrical layer that reflects radio waves, allowing radio messages to be sent across oceans in the days before communication satellites. Electrical displays in the ionosphere also create the auroras called the Northern and Southern Lights.
   Beyond the ionosphere lies the exosphere. This tenuous portion of the Earth's atmosphere extends outward until it interacts with the solar wind. Solar storms compress the exosphere. When the sun is tranquil, this layer extends further outward. Its top ranges from 620 miles (1,000 kilometers) to 6,214 miles (10,000 kilometers) above the surface, where it merges with interplanetary space.

Saturday, August 18, 2012

The Solar System-Our Cosmic Neighborhood

                        
  From our small world we have gazed upon the cosmic ocean for thousands of years. Ancient astronomers observed points of light that appeared to move among the stars. They called these objects "planets," meaning wanderers, and named them after Roman deities—Jupiter, king of the gods; Mars, the god of war; Mercury, messenger of the gods; Venus, the goddes of love and beauty, and Saturn, father of Jupiter and god of agriculture. The stargazers also observed comets with sparkling tails, and meteors or shooting stars apparently falling from the sky.
    Since the invention of the telescope, three more planets have been discovered in our solar system: Uranus (1781), Neptune (1846), and, now downgraded to a dwarf planet, Pluto (1930). In addition, there are thousands of small bodies such as asteroids and comets. Most of the asteroids orbit in a region between the orbits of Mars and Jupiter, while the home of comets lies far beyond the orbit of Pluto, in the Oort Cloud.
    The four planets closest to the sun—Mercury, Venus, Earth, and Mars—are called the terrestrial planets because they have solid rocky surfaces. The four large planets beyond the orbit of Mars—Jupiter, Saturn, Uranus, and Neptune—are called gas giants. Tiny, distant, Pluto has a solid but icier surface than the terrestrial planets.
    Nearly every planet—and some of the moons—has an atmosphere. Earth's atmosphere is primarily nitrogen and oxygen. Venus has a thick atmosphere of carbon dioxide, with traces of poisonous gases such as sulfur dioxide. Mars's carbon dioxide atmosphere is extremely thin. Jupiter, Saturn, Uranus, and Neptune are primarily hydrogen and helium. When Pluto is near the sun, it has a thin atmosphere, but when Pluto travels to the outer regions of its orbit, the atmosphere freezes and collapses to the planet's surface. In that way, Pluto acts like a comet.
    
Moons, Rings, and Magnetospheres
  
   There are 140 known natural satellites, also called moons, in orbit around the various planets in our solar system, ranging from bodies larger than our own moon to small pieces of debris.
   From 1610 to 1977, Saturn was thought to be the only planet with rings. We now know that Jupiter, Uranus, and Neptune also have ring systems, although Saturn's is by far the largest. Particles in these ring systems range in size from dust to boulders to house-size, and may be rocky and/or icy. Our Earth, according to a new discovery, also has an invisible ring of anti-matter that can be used as fuel for spacecrafts.
   Most of the planets-as well as Earth- also have magnetic fields, which extend into space and form a magnetosphere around each planet. These magnetospheres rotate with the planet, sweeping charged particles with them. The sun has a magnetic field, the heliosphere, which envelops our entire solar system.
   Ancient astronomers believed that the Earth was the center of the universe, and that the sun and all the other stars revolved around the Earth. Copernicus proved that Earth and the other planets in our solar system orbit our sun. Little by little, we are charting the universe, and an obvious question arises: Are there other planets where life might exist? Only recently have astronomers had the tools to indirectly detect large planets around other stars in nearby solar systems.

Origins of the Universe-An Expanding World

  
    The most popular theory of our universe's origin centers on a cosmic cataclysm unmatched in all of history—the big bang. This theory was born of the observation that other galaxies are moving away from our own at great speed, in all directions, as if they had all been propelled by an ancient explosive force.
     Before the big bang, scientists believe, the entire vastness of the observable universe, including all of its matter and radiation, was compressed into a hot, dense mass just a few millimeters across. This nearly incomprehensible state is theorized to have existed for just a fraction of the first second of time.
     Big bang proponents suggest that some 10 billion to 20 billion years ago, a massive blast allowed all the universe's known matter and energy—even space and time themselves—to spring from some ancient and unknown type of energy.
     The theory maintains that, in the instant—a trillion-trillionth of a second—after the big bang, the universe expanded with incomprehensible speed from its pebble-size origin to astronomical scope. Expansion has apparently continued, but much more slowly, over the ensuing billions of years.
      Scientists can't be sure exactly how the universe evolved after the big bang. Many believe that as time passed and matter cooled, more diverse kinds of atoms began to form, and they eventually condensed into the stars and galaxies of our present universe.

Friday, August 17, 2012

Galaxies-Cosmic Collections

 
This is the Messier 81 (M81) galaxy, located about 12 million light-years away in the Ursa Major constellation. It is among the brightest of the galaxies visible by telescope from Earth.

    Galaxies are sprawling space systems composed of dust, gas, and countless stars. The number of galaxies cannot be counted—the observable universe alone may contain 100 billion. Some of these distant systems are similar to our own Milky Way galaxy, while others are quite different.
     Galaxies with less than a billion stars are considered "small galaxies." In our own galaxy, the sun is just one of about 100 billion stars.
     Galaxies with less than a billion stars are considered "small galaxies." In our own galaxy, the sun is just one of about 100 billion stars.
     Spiral galaxies, such as the Milky Way, consist of a flat disk with a bulging center and surrounding spiral arms. The galaxy's disk includes stars, planets, dust, and gas—all of which rotate around the galactic center in a regular manner.
     This spinning motion, at speeds of hundreds of kilometers per second, may cause matter in the disk to take on a distinctive spiral shape like a cosmic pinwheel. Some spiral galaxies obtain even more interesting shapes that earn them descriptive names, such as sombrero galaxies.
     Older stars reside in the bulge at the center of the galactic disk. Many new stars also form in spiral systems, and their disks are surrounded by a halo, which scientists believe is rich with mysterious dark matter.
     Elliptical galaxies are shaped as their name suggests. They are generally round but stretch longer along one axis than along the other. They may be nearly circular or so elongated that they take on a cigarlike appearance.
     Elliptical galaxies contain many older stars, up to one trillion, but little dust and other interstellar matter. Their stars orbit the galactic center, like those in the disks of spiral galaxies, but they do so in more random directions. Few new stars are known to form in elliptical galaxies.
    The universe's largest known galaxies are giant elliptical galaxies, which may be as much as two million light-years long. Elliptical galaxies may also be small, in which case they are dubbed dwarf elliptical galaxies.
    Galaxies that are not spiral or elliptical are called irregular galaxies. Irregular galaxies appear misshapen and lack a distinct form, often because they are within the gravitational influence of other galaxies close by.
    Galaxies that are not spiral or elliptical are called irregular galaxies. Irregular galaxies appear misshapen and lack a distinct form, often because they are within the gravitational influence of other galaxies close by.
  
Galactic Mergers
   
    Some galaxies occur alone or in pairs, but they are more often parts of larger associations known as groups, clusters, and superclusters.
    Galaxies in such groups often interact and even merge together in a dynamic cosmic dance of interacting gravity. Mergers cause gases to flow towards the galactic center, which can trigger phenomena like rapid star formation.
    Our own Milky Way may someday merge with the Andromeda galaxy—just two million light-years away and visible to the naked eye from Earth's Northern Hemisphere.
    These intergalactic processes may be part of natural evolution by which irregular galaxies transform into one of the other shapes, and by which spiral galaxies eventually become elliptical galaxies—as scientists believe they must.

Galaxy Origins

   Most astronomers suggest that galaxies formed shortly after a cosmic "big bang" that began the universe some 10 billion to 20 billion years ago. In the milliseconds following this explosion, clouds of gases began to coalesce, collapse, and compress under gravity to form the building blocks of galaxies.
  
  Scientists are divided on just how galaxies first formed. Some believe that smaller clusters of about one million stars, known as globular clusters, formed first and later gathered into galaxies. Others believe that galaxies formed first and that only later did the stars within them begin to gather into smaller clusters.

New Type of Black Hole Found—Relic of Early Universe?

The newly identified black hole, circled, sits within a star cluster.
     After nearly three years of spying a superbright object nearly 300 million light-years away, astronomers with NASA's Chandra X-ray Observatory and SWIFT telescope recently announced the discovery of HLX-1, the first representative of a new type of black hole.
     Until recently, black holes were thought to come in only two sizes: Small stellar varieties that are several times heavier than our sun, and supermassive black holes that pack the gravitational punch of many million suns—large enough to swallow our entire solar system.
    Notorious for ripping apart and swallowing stars, extra-large black holes live exclusively in the hearts of most galaxies, including our own Milky Way.
     The new middleweight black hole is between these two types—equal to the matter of about 90,000 suns.

   New Black Hole Relics of the Early Universe?
     An international team, who discovered HLX-1 "almost by accident" in 2009, noticed the object was pumping out copious amounts of x-rays and radio flares—not from within the core of its host spiral galaxy, but some 12,000 light years beyond.
     The origin of these intermediate black holes may lie in centers of globular clusters, where hundreds of thousands of stars are densely packed together by gravity.

Thursday, August 16, 2012

Το μυστήριο της Μαύρης Τρύπας

Τι είναι μία Μαύρη Τρύπα; Πώς δημιουργείται;

Μία Μαύρη Τρύπα καθώς απορροφά φως
  Μία μαύρη τρύπα δημιουργείται από το "θάνατο" ενός αστεριού. Ονομάζεται "μαύρη", λόγω του ότι "ρουφάει" μέσα της τα πάντα, ακόμα και το φως! Οτιδήποτε "καταπιεί" δεν έχει επιστροφή. Παραμορφώνεται, συμπιέζεται ώσπου να γίνει λεπτό σαν χαρτί και διαλύεται σε απειροελάχιστα κομμάτια σαν κόκκοι σκόνης. Παρά τις αμέτρητς όμορφες φωτογραφίες που μπορούμε να βρούμε στο διαδίκτυο, οι Μαύρες Τρύπες δεν παύουν να είναι θανάσιμα επικίνδυνες.
     Μπορούν να απορροφήσουν πλανήτες, αστέρια, ακόμα και ηλιακά συστήματα σε απίστευτη ταχύτητα και αυτό θα τις καθιστούσε πανίσχυρο όπλο εάν υπήρχε η δυνατότητα να ελεγχθούν ή να καθοδηγηθούν από τον άνθρωπο. Οι επιστήμονες, παρ' όλα αυτά δεν έχουν μπορέσει να εξιχνιάσουν όλα τα μυστήρια που κρύβουν οι Μαύρες Τρύπες πίσω από τη σαγηνευτική ομορφιά τους, πάντως είμαστε τυχεροί που δεν αποτελούν έναν ζωντανό οργανισμό που να μετακινείται και να αναπτύσσεται. 
  Στην εικόνα μπορούμε να δούμε μία Μαύρη Τρύπα να "καταπίνει" αργά, μα σταθερά ένα μεγάλο αστέρι. Δυστυχώς ή ευτυχώς, δεν έχουμε τη δυνατότητα να παρακολουθήσουμε ζωντανά κάτι τέτοιο... 
  Ένα από τα πολλά μυστήρια που δεν έχουμε καταφέρει ακόμα να λύσουμε είναι το πώς, οι Μαύρες Τρύπες, παρόλο που απορροφούν ακόμη και μεγαλύτερα αντικείμενα από τον εαυτό τους, δεν μεγαλώνουν και έτσι δημιουργούν την αίσθηση πως ό,τι απορροφήσουν "τηλεμεταφέρεται" κάπου, σαν να μπαίνει σε ένα "αόρατο σακούλι με άπειρο χώρο". Δεν έχουμε πλησιάσει ποτέ όμως τόσο το φαινόμενο της αχανούς τρύπας στο διάστημα, αφού η τεχνολογική μας εξέλιξη δεν το επιτρέπει.
Άλλη μία πανέμορφη Μαύρη Τρύπα
       











Πάνος Ζ. & Πηνελόπη

Strange New Fish Found Deep off New Zealand

Black Swallower

Talk about a meaty find—this unknown species of black swallower was recently hauled up by scientists trawling ocean depths east of New Zealand.

Two-Tone Slickhead

Caught at about 1.5 miles (2.4 kilometers) down, the Norman's slickhead species had never before been found off New Zealand.

Young Skate


This young Richardson's skate was one of several caught at four different trawl stations of varying depths. The species is very rarely seen, presumably because it lives so deep, according to NIWA.

Slickhead

The unidentified fish pictured above is probably a type of slickhead, according to NIWA.


Nearly Eyeless Eel

This unidentified species of cusk-eel was caught about 1.5 miles (2.4 kilometers) underwater. Generally shorter than other eels, cusk-eels are mostly nocturnal, deep-dwelling fish.

Curious Rattail

Never before documented in New Zealand waters, this large white rattail of the genus Coryphaenoides was caught at about 1.6 miles (2.6 kilometers) deep

Frilled Shark

Humans rarely encounter frilled sharks, which prefer to remain in the oceans' depths, up to 5,000 feet (1,500 meters) below the surface. Considered living fossils, frilled sharks bear many physical characteristics of ancestors who swam the seas in the time of the dinosaurs. This 5.3-foot (1.6-meter) specimen was found in shallow water in Japan in 2007 and transferred to a marine park. It died hours after being caught.

Curiosity rover's Landing

         NASA's Curiosity mission was a great success, as it successfully landed on the dusty surface of the Red Planet.The apposite scientists are really proud of themselves because they made it to land the most technologically advanced Space rover in history.
         Since it landed, Curiosity has sent photographs about its location, it can scan Martian rocks and dust and it will search for the answer to the question: ''Could Mars support life a long time ago, or was it always just a red desert?''. No information has been sent yet, but the robot will sure send us much in the future...

The Birth and the Death of the Stars

Why Can't We See Evidence of Alien Life?


Saturday, April 21, 2012

Δακτύλιος αντι-ύλης γύρω από τη Γη

Ιταλοί επιστήμονες εντόπισαν την ύπαρξη ενός δακτυλίου σωματιδίων γύρω από τη Γη. Η ανακάλυψη θεωρείται πολύ σημαντική αφού δεν πρόκειται για σωματίδια της συμβατικής ύλης αλλά για για σωματίδια της «εξωτικής» αντι-ύλης. Οι ερευνητές εντόπισαν την παρουσία μεγάλου αριθμού αντιπρωτονίων τα οποία (θεωρητικώς) θα μπορούσαν να χρησιμοποιηθούν ως καύσιμα για διαστημόπλοια.

Sunday, March 25, 2012

The First Men on the Moon

    Since the 20th century, many space agencies like NASA, Russia and others had been trying to send people to the Moon. But in 1969, NASA finally made it to send a spacecraft to the Moon with a 3-people crew inside and America opened a brand new page in our technology and culture.
    The crew, Neil Armstrong, Buzz Aldrin and Michael Collins reached the Moon safely in their spacecraft called Apollo 11. Neil was the first of them to get out and the first man to walk on the Moon. He said ''That's one step for man, one giant leap for mankind'', he stepped and walked on the Moon's sandy surface and then he planted the American flag proudly.
    That mission is really historical and is a fact that changed our whole culture and lifestyle. It's something that nobody could imagine since then. 

Saturday, March 24, 2012

The Roswell Incident

 Lots of people wonder ''Are we alone in the universe?''. Well, although nobody has proved that UFOs really exist, many facts have happened that answer positively. For example, the Roswell Incident:
     One night in 1947, a farmer saw fire coming down from the sky and ran to see what it was. The only things he noticed were small pieces of metal with symbols on them which looked like ancient Greek. The other day, when he showed them to his friends, they all went to search more closely and they found some dead bodies.
     Noone knows if that's a true story, but it is logical that there is another planet capable of supporting life because the universe has no start and end.


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