Διάστημα και εξερεύνησή του

Exoplanet hunters have found over 280 star systems in our neighborhood with at least one planet. On that list of star systems, with all their worlds – hot Jupiters, super-Earths, ice giants and at least one giant ball of metal – one will not find the closest star system to Sol…. the Alpha Centauri system. Only 4.4 light years away, Alpha Centauri is tantalizingly close on a galactic scale. Itʼs also fairly weird as star systems go. No one has ever seriously examined the AC system for exoplanets, despite its proximity, but now a newly funded project will do just that. Javiera Guedes, a graduate student at the University of California, Santa Cruz, and her advisor Greg Laughlin are beginning a NASA-funded project to examine the AC system and look for worlds.
Alpha Centauri is an apparent trinary. Two suns – Alpha Centauri A and B – form the core of the star system, with AC-A the larger of the two and slightly hotter and more massive than our Sun. The primary AC-A is orbited by AC-B (slightly cooler and oranger than Sol) once every 79.91 Solar years. Every 80 Solar years, AC-B swings close (11.2 AU) to AC-A, but spends most of its time coming and going from its furthest point of 35.6 AU. Put in terms of our own Solar system with AC-A as the Sun, AC-B would approach Earth not quite as close as Saturn is from us, and would swing out beyond the orbit of Neptune at each aphelion.
The third member of Alpha Centuriʼs trinary is a tiny red dwarf, Proxima Centauri, which may not actually be a permanent member of the group. Proxima is a bit over 12,000 AU from the AC-A/AC-B pair, which means that from a terrestrial planet orbiting AC-A tiny Proxima would be very faint if it was visible at all. If Proxima is a permanent part of the triplet itʼs orbit might be up to half a million Solar years long, but it might be only a passing ship in the night that will swing out and away from the double star system in a few million years.
The upshot of this layout is that terrestrial planets could plausibly exist in the Alpha Centauri system. Worlds within AC-Aʼs habitable zone would sit somewhere from ~1 AU to maybe ~2 AU at the outer HZ edge, depending on planetary characteristics like size and atmosphere. The B companion star never swings close enough to disturb the orbit of an inner terrestrial world or a terrestrial moon of a gas giant in AC-Aʼs HZ. The same thing is true, to a slightly lesser extent, for AC-B… it might have its own habitable inner planets. Or they both might. For that matter so might Proxima have planets.
Climate on any terrestrial world in the Alpha Centauri system would be strange. A world orbiting AC-A or AC-B would experience moderately strong climatic swings every 80 years, from normal to briefly very hot then back to normal again. Or from cool to mild, then back to cool. With another sun as far as Saturn, Earth would receive a bit more solar insolation… probably enough to turn winter into summer, or summer into a severe heat wave. I havenʼt done the calculations, but someone out there probably has and can tell me exactly. Depending on how much water any terrestrial planet there has, those climate shifts may or may not be a major inhibitor of biosphere development. A watery world would have a larger heat buffer to soak up extra warmth, and would keep world climate more stable… but a dry world would see much more dramatic swings in temperature. Water has a much higher heat capacity than silicate rock… which is why maritime regions on Earth are generally milder than continental interior biomes.

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στη γενια μας θα δουμε πιθανως την αποικιση του ηλιακου συστηματος..
τα παιδια και τα εγγονια μας ισως θα ταξιδεψουν σε αλλα ηλιακα συστηματα .

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Claim of Alien Signal from Planet Gliese 581g Called 'Very Suspicious'
By Denise Chow

The recent discovery of Gliese 581g, an alien planet in the habitable zone of another star, has been an exciting development for scientists probing the galaxy for signs of extraterrestrial life. At least one claim of a possible signal from the planet has already surfaced – and been met with harsh skepticism among the science community.

Following the Sept. 29 announcement of the discovery of Gliese 581g, astronomer Ragbir Bhathal, a scientist at the University of Western Sydney, claimed to have detected a suspicious pulse of light nearly two years ago, that came from the same area of the galaxy as the location of Gliese 581g, according to the U.K.'s Daily Mail online. [Alien Planet Gliese581g: FAQ]

Bhathal is a member of the Australian chapter of SETI, a non-profit scientific organization that is dedicated to research, exploration and education in the field of astrobiology.

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"Whenever there's a clear night, I go up to the observatory and do a run on some of the celestial objects," Bhathal told the Daily Mail. "Looking at one of these objects, we found this signal. We found this very sharp signal, sort of a laser lookalike thing which is the sort of thing we're looking for – a very sharp spike. And that is what we found."

Still, there are some scientists who are skeptical of Bhathal's assertion.

"I know the scientist, and when he first announced it, I asked him for the details, and he wouldn't send them to me," astronomer and SETI pioneer Frank Drake told SPACE.com. "I'm very suspicious."

Drake is credited with conducting the first search for signals from extraterrestrial intelligences 50 years ago as part of what was then called Project Ozma. He coined the famed Drake Equation to calculate the number (N) of alien civilizations with whom we might be able to communicate

Further study would perhaps confirm or deny the supposed observation, but Drake thinks that the claim is likely a dubious one.

Strange signal, or phantom?

Bhathal claimed to have detected the puzzling signal in Dec. 2008, almost two years before researchers announced the Gliese 581g finding, and long before it was announced that habitable planets were found orbiting the star Gliese 581 itself.

"I'm not aware of the location that was claimed for the source of that light, and [Bhathal] refused to tell me where it came from," Drake said. "I think it's very unlikely that it came from the direction of Gliese 581."

Gliese 581g is one of two new worlds that was discovered orbiting the red dwarf star Gliese 581, which is located about 20.5 light-years from Earth. In total, there is a family of six planets that has been found around Gliese 581. [Tour the six Gliese 581 planets.]

Steven Vogt, a professor of astronomy and astrophysics at the University of California, and his colleague Paul Butler of the Carnegie Institution of Washington announced the Gliese 581g finding in a press conference held by the National Science Foundation on Sept. 29.

About Gliese 581g

While there are six planets known to orbit around the parent star, Gliese 581g is the only one in the so-called habitable zone – a region where liquid water can exist. Astronomers have long-thought that the presence of liquid water, which accompanies life on Earth, could be a major ingredient for life on other worlds.

Observations have shown that Gliese 581g is between three and four times the mass of Earth. While it is larger than our planet, it is still classified as a nearly Earth-sized world. Its radius is between 1.3 and two times the size of Earth, scientists have said.

The planet has not been officially named yet (nor have any other worlds in the Gliese 581 system). But Vogt has given it the nickname "Zarmina's World," in honor of his wife.

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President Obama signed legislation Monday that authorizes $19 billion for NASA in fiscal 2011, funding an additional shuttle flight, accelerating development of a new heavy lift rocket for deep space exploration and pressing ahead with plans to use commercial spacecraft to ferry astronauts to and from the International Space Station.

[SIZE=-3]President Obama signs the NASA Authorization of 2010 into law. Credit: White House photo by Pete Souza[/SIZE]

The budget cancels the Bush administration's Constellation moon program, but endorses development of a manned spacecraft for deep space exploration similar to the Orion capsule envisioned for the scrapped moon missions. It also calls for development of new technologies, continued robotic exploration and a major upgrade to the launch infrastructure at the Kennedy Space Center and the Cape Canaveral Air Force Station.
"We now have a way forward for NASA," said Sen. Bill Nelson, a Florida Democrat who flew aboard the shuttle Columbia in 1986 and who played a key role in winning approval for a modified version of the president's original budget request. "Now with the signing of this legislation into law, NASA has a blueprint, NASA has a roadmap.
"The goal is not the moon," he said. "We were there 40 years ago. The goal is Mars by a flexible path. The president has stated that goal ... and this legislation which he is signing into law will now set us on that course."
Nelson made the comments during a NASA teleconference with reporters before the president signed the legislation. NASA Administrator Charles Bolden made an opening statement but as has become standard practice, he took no questions and left the briefing in the hands of his deputy, Lori Garver.
In a written statement, Bolden said the agency will "foster a growing commercial space transportation industry that will allow NASA ... to start work on a heavy-lift architecture to take astronauts beyond low-Earth orbit and to develop a multi-purpose crew vehicle for use with our new space launch systems."
"We have been given a new path in space that will enable our country to develop greater capabilities, transforming the state of the art in aerospace technologies," he said. "We will continue to maintain and expand vital partnerships around the world. It will help us retool for the industries and jobs of the future that will be vital for long-term economic growth and national security.
The budget authorization now must go through the appropriations process, which Nelson warned is "going to be a tough session because of the need to cut back on spending with regard to the federal deficit."
"We're going to end up having an omnibus appropriations bill," he said. "But I believe there's some hope for NASA's funding because we got a unanimous support of all of the appropriations members for the NASA budget in the Senate appropriations bill that appropriated almost identically ... to what the president is signing into law today."
The president's initial budget request was formulated after an independent panel of space experts chaired by aerospace executive Norman Augustine concluded the Constellation program, and several other potential exploration strategies, could not be executed without a major boost in funding.
On the assumption NASA received an additional $3 billion a year, the panel recommended a so-called "flexible path" approach that called for bypassing the moon in favor of a variety of deep space targets. At the same time, the panel recommended extending the space station's life through at least 2020 and turning over manned flights to and from low-Earth orbit to private companies.
The Obama administration agreed with the broad outlines of the flexible path architecture and while it approved a modest increase in NASA's budget, it fell far short of what the Augustine panel said would be needed. The initial budget proposal deferred development of a new heavy lift rocket and set no timetable for deep space exploration.
The president later said he would support starting work on a new heavy lifter in the 2015 timeframe for flights to nearby asteroids by 2025 and eventual flights to the vicinity of Mars in the mid 2030s.
The compromise package signed by the president Monday accelerates the heavy lifter development, adds the additional shuttle flight and stretches out funding for development of commercial launchers.
"Probably the main thing the Augustine committee found was that the path NASA was on was not sustainable," said Sally Ride, a former shuttle astronaut and a member of the panel. "We are all excited about the new path, more of an emphasis on technologies, more of an emphasis on commercial capabilities done in the right way and with a focus on mission assurance and a good human-rating process. That would help free NASA to do the more exciting and challenging things we all believe NASA can and should be doing, getting astronauts beyond low-Earth orbit. ... In that regard, this bill is a very good step forward.
But, she warned, "the 600-pound gorilla here is the U.S. economy and the need for fiscal responsibility across all agencies."
"Would we have liked more money in the NASA budget? Yes. ... But the realities are very clear. And the fact that NASA did get an increase shows the support NASA has across the political spectrum. ... I think this is just an excellent bill that will take NASA forward."
Critics have charged that the budget does not adequately fund the new super rocket and that it will not fly by 2016 as promised without additional funding.
"The Senate bill forces NASA to build a rocket that doesn't meet its needs, with a budget that's not adequate to do the job and on a schedule that NASA's own analysis says is unrealistic," Rep. Gabrielle Giffords, D-Arizona, said during recent debate in the House. "That is not my idea of an executable and sustainable human spaceflight program."
But Nelson said Monday the budget plan would, in fact, cover that development of the new heavy lifter and that opponents were mis-informed as to how much money was potentially on the table.
"What is in this bill is eleven-and-a-half billion dollars over the next six years, anticipated, even though it's a three-year authorization, for development and testing of a heavy lift rocket," he said. "Now if we can't develop a new rocket for eleven-and-a-half billion dollars, building on a lot of the technologies that were already developed in spending nine billion (on the Constellation program's Ares rockets), if we can't do it for that, then we ought to question whether or not we can build a rocket."
Nelson also downplayed criticism of the plan's call for development of commercial crew transport by former Apollo astronauts Neil Armstrong, Gene Cernan and Jim Lovell. All three questioned the safety, cost and timetable for commercial spacecraft built by companies without prior manned space flight experience.
Since then, aerospace giant Boeing has announced plans to enter the competition, a move Nelson said reassured at least some of the critics.
"I think that changed the flavor of the whole thing, realizing you're going to have the best and the brightest aerospace companies competing for the contracts to deliver crew to and from the space station," Nelson said. "Once that became apparent, then I think there was a comfort there among these astronauts. ... I think that was one of the big things that turned it around."

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Astronauts exploring the moon's south pole should bring a shovel.

NASA's robotic mission to plunge an empty rocket stage into a lunar crater last year confirmed the presence of large quantities of water ice and hydrogen, but it also found traces of silver and mercury, scientists said Thursday.

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Σύμφωνα με νέα έρευνα μεγάλες αποθέσεις ανθρακικών πετρωμάτων είναι θαμμένες σε βάθος λίγων χιλιομέτρων κάτω από την επιφάνεια. Αν αυτά τα πετρώματα είναι άφθονα, τότε το κύριο αέριο του θερμοκηπίου θα μπορούσε να βοηθήσει τον Άρη να γίνει μια πολύ πιο υγρή και θερμή τοποθεσία εκατοντάδες εκατομμύρια χρόνια πριν.

Ο Άρης κάποτε ήταν πλούσιος σε διοξείδιο του άνθρακα, γεγονός που υποδηλώνει την παρουσία ζωής στον κόκκινο πλανήτη.

Σύμφωνα με μια δημοσίευση στο περιοδικό Nature Geoscience αυτά τα πετρώματα μας αποκαλύπτουν εκτενή κοιτάσματα του ορυκτού, σχεδόν, έξι χιλιόμετρα κάτω από τον φλοιό, που έχουν εκτεθεί σε ένα τεράστιο αριθμό συγκρούσεων με μετεωρίτες.


Η επιστημονική ομάδα πιστεύει ότι αυτά τα πετρώματα αντιπροσωπεύουν αρχαία ιζήματα που στη συνέχεια θάφτηκαν κάτω από ηφαιστειακό υλικό, που εκτοξεύτηκαν κατά τη διάρκεια εκρήξεων από το αρχαίο ηφαίστειο Syrtis Major. Το ορυκτό πιθανώς προήλθε από νερό πλούσιο σε ανθρακικό, το οποίο αλληλεπίδρασε με τους βράχους – δείχνοντας πως ο πρώιμος Άρης ήταν θερμότερος από ό,τι εθεωρείτο μέχρι σήμερα.

Ο Joseph Michalski του Πλανητικού Ινστιτούτου της Αριζόνα καθώς και ο Paul Niles του Διαστημικού Κέντρου Τζόνσον της NASA, δήλωσαν ότι η επιφάνεια του Άρη είναι πλέον ψυχρή, ξηρή, όξινη και αφιλόξενη για τη ζωή.

Ανάλογες συνθήκες μπορεί να υπάρχουν για δισεκατομμύρια χρόνια, γεγονός που υποδηλώνει ότι το καλύτερο μέρος για να ψάξει κάποιος για κατοικήσιμο περιβάλλον είναι το υπέδαφος.

Οι ερευνητές δήλωσαν ότι: “Μία υποψία για κατοικήσιμες συνθήκες σε βάθος είναι η παρουσία του ατμοσφαιρικού μεθανίου, που ενδέχεται να σχηματίστηκε μέσω υδροθερμικών διαδικασιών στο φλοιό, με την παρουσία του διοξειδίου του άνθρακα. Ενώ μνα πυκνή ατμόσφαιρα από διοξείδιο του άνθρακα σημαίνει την ύπαρξη του φαινομένου του θερμοκηπίου.

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Ένα σημαντικό ερευνητικό έργο στον τομέα της Διαστημικής Φυσικής, το πρώτο στην Ελλάδα με χρηματοδότηση από την Ευρωπαϊκή Υπηρεσία Διαστήματος (European Space Agency-ESA), ολοκλήρωσαν ερευνητές του Ινστιτούτου Διαστημικών Εφαρμογών και Τηλεπισκόπησης του Εθνικού Αστεροσκοπείου Αθηνών (ΙΔΕΤ/ΕΑΑ), σε συνεργασία με την Ομάδα Κοσμικής Ακτινοβολίας του Πανεπιστημίου Αθηνών.

Πρόκειται για το έργο «SREM Solar Particle Event Scientific Analysis», το οποίο αφορά την ανάλυση των μετρήσεων ενεργειακών ηλιακών σωματιδίων από τον ανιχνευτή σωματιδιακής ακτινοβολίας SREM της ΕSA. Το έργο αναμένεται να οδηγήσει στη δημιουργία ενός συστήματος έγκαιρης προειδοποίησης για τα εκρηκτικά ηλιακά επεισόδια που επηρεάζουν τη γήινη μαγνητόσφαιρα, αλλά και συνολικά το διαπλανητικό χώρο.

Από το 2005, όταν η Ελλάδα έγινε πλήρες μέλος της ESA, υπάρχουν ολοένα και περισσότερα ερευνητικά έργα χρηματοδοτούμενα από την ESA, αλλά το συγκεκριμένο είναι το πρώτο χρηματοδοτημένο έργο που αφορά την επιστημονική εξερεύνηση, «χαρτογράφηση» και κατανόηση του διαστημικού χώρου. Όλες οι άλλες περιπτώσεις αφορούν διαστημικές εφαρμογές (γεωσκόπηση, δορυφορική πλοήγηση και δορυφορικές τηλεπικοινωνίες), καθώς και ανάπτυξη διαστημικής τεχνολογίας.

Η μελέτη των εκρηκτικών ηλιακών επεισοδίων, που θέτουν σε κίνδυνο τόσο τα υποσυστήματα των δορυφόρων όσο και τους αστροναύτες επανδρωμένων αποστολών, ενδιαφέρει ιδιαίτερα την ESA και τη NASA. Οι μετρήσεις των ενεργειακών ηλιακών σωματιδίων προέρχονται από τον ανιχνευτή σωματιδιακής ακτινοβολίας SREM (Standard Radiation Environment Monitor) της ESA, που βρίσκεται εγκατεστημένος σε έξι διαστημικές αποστολές της: PROBA-1, INTEGRAL, Rosetta, Herschel, Planck και Giove-Β.

Τα εκρηκτικά ηλιακά επεισόδια ξεκινούν με την εμφάνιση ηλιακών εκλάμψεων ή εκτινάξεων ηλιακής μάζας από το στέμμα του ήλιου και καταλήγουν στην εκροή ενεργειακών πρωτονίων και ηλεκτρονίων στο διαπλανητικό χώρο, κυρίως σε περιόδους έντονης ηλιακής δραστηριότητας, δηλαδή κοντά στο μέγιστο του ηλιακού κύκλου.

Το έργο της λεπτομερούς επιστημονικής ανάλυσης των δεδομένων των μετρητών SREM ανατέθηκε από την ESA, κατόπιν ανοικτής πρόσκλησης υποβολής προτάσεων, στο Ινστιτούτο Διαστημικών Εφαρμογών και Τηλεπισκόπησης του Εθνικού Αστεροσκοπείου Αθηνών (ΙΔΕΤ/ΕΑΑ). Σκοπός της ανάλυσης ήταν η καλύτερη κατανόηση των φυσικών μηχανισμών που δημιουργούν και ελέγχουν τα εκρηκτικά ηλιακά επεισόδια, καθώς και της εξέλιξής τους στην ηλιόσφαιρα και τη γήινη μαγνητόσφαιρα, έτσι ώστε μακροπρόθεσμα να δημιουργηθούν συστήματα έγκαιρης προειδοποίησης για την προστασία τόσο των διαστημοσυσκευών όσο και των αστροναυτών.

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Keith's note: In seeing this image, I am reminded of other, similar images from science fiction. The first two images below are from "Star Trek: First Contact". The other is from "2001: A Space Odyssey".

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It's small, but it's a greenhouse for space voyagers - and for you. Paolo Nespoli will take a special greenhouse with him to the International Space Station and he's inviting young science enthusiasts to conduct an experiment with him.
Growing plants in space will be crucial for the astronauts of the future. When flying to Mars or even further, it will be necessary to produce fresh food onboard and become partially self-sufficient. Setting up greenhouses on the Moon, Mars or other planetary bodies will also be an important part of future exploration missions.

Greenhouses also provide oxygen and bring some life to the bleakness of space. Caring for plants is a good way to maintain memories of Earth and an enjoyable way to pass time during the long and possibly boring interplanetary cruise.

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Αρχική Δημοσίευση από Άγγελος:

ενα ωραιο βιντεο...
Δοκιμαστικη εκτοξευση του πυργου διαφυγης (αυτο απο κατω του ειναι η (ψευτικη) καψουλα οχημα Ωριον)για το νεο επανδρωμενο πυραυλο της Νασα..

και σε αργη κινηση..
μιλαμε για 20g σε 3 δευτερα(επιταχυνσεις της βαρυτητας)..οι αστροναυτες λιποθυμανε αμεσως,,αλλα μενουν ζωντανοι σε ενα προβλημα ή εκρηξη του πυραυλου..
πολυ εντυπωσιακο..

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