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Archive for the ‘astronomy’ Category

Voyager near Solar System’s edge

In astronomy, extraterrestrial, technology on December 14, 2010 at 6:37 pm

This marvelous piece of engineering, after 33 years, is still contributing to science!

According to reports from NASA it is soon reaching the edge of the solar system!

See how BBC news report it, and a brief story of this legendary spacecraft here!

Next report: the interstellar space...

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What does NASA’s new life-form discovery mean?

In astronomy, evolution, extraterrestrial on December 3, 2010 at 4:37 pm

What does NASA’s new life-form discovery mean?

Scientists’ announcement of a new form of microbe raises questions about extraterrestrial life. An expert explains

By Christopher R. Walker

 

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What does NASA’s new lifeform discovery mean?

Jodi Switzer Blum/NASA

GFAJ-1 grown on arsenic, left, and the Mono Lake Research area

 

In a much anticipated press conference yesterday afternoon, NASA astrobiologists announced the discovery of an amazing new kind of microbes, which extend the boundaries of what we may rightly call life. According to the press release, “NASA-funded astrobiology research has changed the fundamental knowledge about what comprises all known life on Earth.” Discovered in Mono Lake, an extremely salty and alkaline body of water near Yosemite National Park in California, the microorganism is the first known specimen to substitute arsenic for phosphorus in its cell components, and has raised questions about what the discovery means for extraterrestrial life.

 

To find out what it really means, we called Robert Shapiro, a professor of chemistry at New York University who has written extensively about life’s origins on earth and its potential existence in outer space.

What does this mean for the discovery of life in our solar system or universe?

Not much, except that people may need to broaden their perspectives, and that we should be less “Terracentric” as we seek out new forms of life. Mostly, this discovery adds a new extremophile [organism that lives in an extreme environment] to our inventory — it pushes the boundaries out a little farther. The grand prize would be to discover an independent origin of life: life with its very own chemistry. Such a discovery wouldn’t just say that evolution is robust, it would say that life is abundant. But this discovery doesn’t do that: These organisms are not completely different in their chemical makeup from what we already know.

 

From what I can tell, the microbes prefer to live “normally” but may insert arsenic as a substitute for phosphorus when conditions demand it — arsenic can play the same role that phosphorus would play under normal circumstances. This is a great novelty. Arsenic is bigger and heavier than phosphorus, and its compounds are less stable. These organisms would not have done this unless they didn’t have any other choice. Just like Dr. Gerald Joyce, who was quoted in the New York Times today, I feel sorry for these creatures. Their living conditions are horrible — their environment would be poisonous to most other life on Earth.

Are there any lessons about where to focus our search for extraterrestrial life?

 

Broader searches are better searches. I always marveled at how parochial the searches were that focused on existing genetic assumptions. Hopefully, these findings will shift attention at NASA from [Jupiter moon] Europa — where life may be more familiar, but trapped under a deep ice cap — to [Saturn moon] Titan — where surface life could exist, but conditions are most hostile to traditional life-forms.

That said, it does reinforce Paul Davies’ “Shadow Biosphere” theory that suggests we may be missing major strains of life right here on Earth — either in places traditionally deemed too hostile to life or maybe even right under our noses. An obvious question, then, would be to ask how alternate forms of life could have escaped our notice all this time. Some argue that carbon life may have evolved from mineral life with no carbon of its own, and one could imagine experiments to test this hypothesis. You could simply introduce a carbon-free broth to a carbon-free environment, for example, and see what grows. Or as some people suggest, there could be benefits to testing radioactive environments.

You mentioned that arsenic is poisonous. Are there any industrial applications of these critters that spring to mind?

 

No, there’s no obvious industrial applications. It just shakes up our thinking about what’s possible.

 

So what’s the takeaway, then?

 

It’s an exciting time for risky ideas. Let’s try them. If one in 10 or one in 100 work, wow!

 

Source: salon.com

Infant, 30-Year-Old Black Hole -Youngest Ever Discovered

In astronomy, physics, science on November 16, 2010 at 2:23 pm

It’s estimated that there are millions of unseen black holes in the Milky Way. The ghosts of once massive stars. This composite image by astronomers using NASA’s Chandra X-ray Observatoryby shows a supernova within the galaxy M100 that may contain the youngest known black hole in our cosmic neighborhood. The 30-year-old black hole could help scientists better understand how massive stars explode, which ones leave behind black holes or neutron stars, and the number of black holes in our galaxy and others.

The 30-year-old object is a remnant of SN 1979C, a supernova in the galaxy M100 approximately 50 million light years from Earth.
Data from Chandra, NASA’s Swift satellite, the European Space Agency’s XMM-Newton and the German ROSAT observatory revealed a bright source of X-rays that has remained steady during observation from 1995 to 2007. This suggests the object is a black hole being fed either by material falling into it from the supernova or a binary companion. “If our interpretation is correct, this is the nearest example where the birth of a black hole has been observed,” said Daniel Patnaude of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. who led the study. The scientists think SN 1979C, first discovered by an amateur astronomer in 1979, formed when a star about 20 times more massive than the sun collapsed. Many new black holes in the distant universe previously have been detected in the form of gamma-ray bursts (GRBs). However, SN 1979C is different because it is much closer and belongs to a class of supernovas unlikely to be associated with a GRB. Theory predicts most black holes in the universe should form when the core of a star collapses and a GRB is not produced. “This may be the first time the common way of making a black hole has been observed,” said co-author Abraham Loeb, also of the Harvard-Smithsonian Center for Astrophysics. “However, it is very difficult to detect this type of black hole birth because decades of X-ray observations are needed to make the case.” The idea of a black hole with an observed age of only about 30 years is consistent with recent theoretical work. In 2005, a theory was presented that the bright optical light of this supernova was powered by a jet from a black hole that was unable to penetrate the hydrogen envelope of the star to form a GRB. The results seen in the observations of SN 1979C fit this theory very well. Although the evidence points to a newly formed black hole in SN 1979C, another intriguing possibility is that a young, rapidly spinning neutron star with a powerful wind of high energy particles could be responsible for the X-ray emission. This would make the object in SN 1979C the youngest and brightest example of such a “pulsar wind nebula” and the youngest known neutron star. Casey Kazan via JPL/NASA

Where are the Missing Neutron Galaxies of the Early Universe?

In astronomy on August 4, 2010 at 3:16 pm

Big-1

Ultradense cosmic cannonballs used to tear around the universe, punching through regular galaxies like a bullet through candyfloss, going their own way and heaven help whatever got in their way – and scientists don’t know where they are now.  Luckily this is cosmology, not cinema, or the answer would be “Right behind you!”

Because of the speed of light, staring into space is essentially looking back in time, and scientists have seen ultra-intense galaxies zipping around the first five billion years of existence.  Similar in principle to the intense density of neutron stars ( a collapsed star with a core so dense that a single spoonful would weigh 200 billion pounds) these galaxies were a thousand times denser than regular star-scatterings, packing as much mass as the Milky Way into 0.1% of the volume and far before regular galaxies had time to form.

Scientists suspect that these objects collapsed directly from vast clouds of proto-star material, unlike regular galaxies which form by multiple mergers of smaller galaxies.  But more important than where they came from is finding out where they went.  Three hundred billion stars isn’t the kind of thing you lose down the back of the sofa.

It’s unlikely they merged with other galaxies, since they’d punch through regular star collections like an armor-piercing round with only minimal effects on themselves, and collision with another ultra-dense galaxy would only create an even bigger wildly intense star selection.  Other processes which could hide them, such as building up a diffuse gas cloud or expanding due to stellar detonations, would seem to take longer than the universe has actually had so far.  Despite being awesome.

Space.  Every time we look there’s something cooler.

Has Life Spread Virally Through the Universe?

In astronomy, evolution, extraterrestrial on August 2, 2010 at 3:05 pm

Life originated in a nebular cloud, over 10 billion years ago, but may have had multiple origins in multiple locations, including in galaxies older than the Milky Way according to Rudolf Schild of Harvard-Smithsonian Center for Astrophysics and Rhawn Joseph of the Brain Research Laboratory. Multiple origins, they believe, could account for the different domains of life: archae, bacteria, eukaryotes.

The first steps toward life may have been achieved when self-replicating nano-particles initially comprised of a mixture of carbon, calcium, oxygen, hydrogen, phosphorus, sugars, and other elements and gasses were combined and radiated, forming a nucleus around which a lipid-like permeable membrane was established, and within which DNA-bases were laddered together with phosphates and sugars; a process which may have taken billions of years.

DNA-based life, they propose, may be a “cosmic imperative” such that life can only achieve life upon acquiring a DNA genome. Alternatively, the “Universal Genetic Code” may have won out over inferior codes through natural selection. When the first microbe evolved, it immediately began multiplying and spreading throughout the cosmos via panspermia carried by solar winds, Bolide impact, comets, ejection of living planets prior to supernova which are then captured by a newly forming solar system, galactic collisions and following the exchange of stars between galaxies.

Bacteria, archae, and viruses, act as intergalactic genetic messengers, acquiring genes from and transferring genes to life forms dwelling on other planets. Viruses also serve as gene depositories, storing vast numbers of genes which may be transferred to archae and bacteria depending on cellular needs. The acquisition of these genes from the denizens of other worlds, enables prokaryotes and viruses to immediately adapt to the most extreme environments, including those that might be encountered on other planets.

OrionStarFormation

Whether the universe was created by a Big Bang Universe or an Eternal Infinite Universe, once life was established it began to evolve. Archae, bacteria, and viruses may have combined and mixed genes, fashioning the first multi-cellular eukaryote which continued to evolve. Initially, evolution on Earth-like planets was random and dictated by natural selection. Over time, increasingly complex and intelligent species evolved through natural selection whereas inferior competitors became extinct. However, their genes were copied by archae, bacteria, and viruses. If the first steps toward life in this galaxy began 13.6 billion years ago, then using Earth as an example, intelligent life might have evolved within this galaxy by 9 billion years ago. As life continued to spread throughout the cosmos, and as microbes and viruses were cast from world to world, genes continued to be exchanged via horizontal gene transfer and copies of genes coding for advanced and complex characteristics were acquired from and transferred to eukaryotes and highly evolved intelligent life.

Eventually descendants of these microbes, viruses, and their vast genetic libraries, fell to the new born Earth. The innumerable genes stored and maintained in the genomes of these viruses, coupled with prokaryote genes and those transferred to eurkaryotes, made it possible to biologically modify and terraform new Earth, and in so doing, some of these genes, now within the eurkaryote genome, were activated and expressed, replicating various species which had evolved on other worlds. Genes act on genes, and genes act on the environment and the altered environment activates and inhibits gene expression, thereby directly influencing the evolution of species.

On Earth, Schild and Joseph conclude, “the progression from simple cell to sentient intelligent being is due to the activation of viral, archae, and bacteria genes acquired from extra-terrestrial life and inserted into the Earthly eukaryote genome. What has been described as a random evolution is in fact the metamorphosis and replication of living creatures which long ago lived on other planets.”

Jason McManus via Journal of Cosmology

Το γήινο μαγνητικό πεδίο είναι ηλικίας 3,45 δισ. ετών

In astronomy, physics on March 19, 2010 at 5:37 pm

Το γήινο μαγνητικό πεδίο, το οποίο μας προστατεύει από τα φορτισμένα σωματίδια του ηλιακού ανέμου, ξεπήδησε από τον πυρήνα της Γης πολύ νωρίτερα στην ιστορία του πλανήτη μας από ό,τι θεωρούσαν μέχρι τώρα οι επιστήμονες. Σύμφωνα με νέα στοιχεία που ανακαλύφθηκαν, το γεω-μαγνητικό πεδίο υπήρχε ήδη πριν από 3,45 δισ. χρόνια, αν και ήταν ασθενέστερο από το σημερινό.

Η νέα μελέτη έγινε από διεθνή ερευνητική ομάδα με επικεφαλής ερευνητές του αμερικανικού πανεπιστημίου του Ρότσεστερ, υπό τον γεωφυσικό Τζον Ταρντούνο, και δημοσιεύτηκε στο περιοδικό “Science”, σύμφωνα με τα “Scientific American”, “New Scientist” και “Physics World”.

Οι ερευνητές βάσισαν τα συμπεράσματά τους στην ανακάλυψη ιχνών του αρχαίου μαγνητικού πεδίου σε ηφαιστειακά πετρώματα (πυριτικούς κρυστάλλους) της Νότιας Αφρικής, που χρονολογούνται πριν από περίπου 3,45 δισ. χρόνια, δηλαδή όταν εκτιμάται ότι εμφανίστηκαν οι πρώτες πολύ απλές μορφές ζωής στον πλανήτη μας και περίπου ένα δισεκατομμύριο χρόνια μετά το σχηματισμό της Γης. Μέχρι σήμερα, τα αρχαιότερα ίχνη μαγνητικού πεδίου στη Γη είχαν βρεθεί το 2007, επίσης σε ηφαιστειακά πετρώματα στη Ν.Αφρική, ηλικίας 3,2 δισ. ετών, συνεπώς η νέα ανακάλυψη μεταθέτει κατά περίπου 250 εκατομμύρια χρόνια στο παρελθόν την ύπαρξη μαγνητικού πεδίου στον πλανήτη μας.

Τα ηφαιστειακά πετρώματα λειτουργούν ως καταγραφείς του μαγνητικού παρελθόντος της Γης, επειδή, όταν στερεοποιήθηκε το αρχαίο μάγμα από το οποίο προήλθαν, τα μαγνητικά μικροσκοπικά σωματίδια που είχαν παγιδευτεί στο εσωτερικό τους, ευθυγραμμίστηκαν με το μαγνητικό πεδίο του πλανήτη, αποκαλύπτοντας σήμερα την ισχύ και την μορφή του, με τη βοήθεια ειδικών συσκευών (μαγνητόμετρων).

Το γήινο μαγνητικό πεδίο δημιουργείται από την κίνηση του λιωμένου σιδήρου βαθιά μέσα στον εξωτερικό πυρήνα του πλανήτη μας, που αποτελεί ένα είδος γεω-γεννήτριας. Σήμερα, το πεδίο εκτείνεται στην μαγνητόσφαιρα, που φτάνει σε απόσταση έως 60.000 χιλιομέτρων από την επιφάνεια της Γης (περίπου 10,7 φορές μεγαλύτερη από την ακτίνα του πλανήτη μας) στην πλευρά που βλέπει προς τον ήλιο και αρκετά πιο μακριά στην απέναντι πλευρά. Η μαγνητόσφαιρα τελειώνει στην λεγόμενη «μαγνητόπαυση», το σύνορο όπου το μαγνητικό πεδίο της Γης συναντά τον ηλιακό άνεμο.

Σύμφωνα με τις εκτιμήσεις των αμερικανών ερευνητών, όχι μόνο το γήινο μαγνητικό πεδίο ήταν πολύ ασθενέστερο (περίπου 50-70% σε σχέση με το σημερινό) πριν από 3,5 δισ. χρόνια, αλλά επίσης, την ίδια εποχή, ο ηλιακός άνεμος κατέκλυζε τον πλανήτη μας με ισχύ περίπου 100 φορές ισχυρότερη από ό,τι τώρα. Από το συνδυασμό αυτών των δύο παραγόντων, εκτιμάται ότι την εποχή εκείνη η μαγνητόπαυση βρισκόταν στην μισή απόσταση από τη Γη σε σχέση με σήμερα (γύρω στις 30.000 χλμ).

Οι συνθήκες αυτές εκτιμάται ότι είχαν εξατμίσει τεράστιες ποσότητες νερού από τη γήινη επιφάνεια πριν προλάβει ο «κύκλος του νερού» να σταθεροποιηθεί στη Γη. Με βάση αυτό το σκεπτικό, οι ερευνητές υποθέτουν ότι η αρχαία Γη περιείχε πολύ περισσότερο νερό από ό,τι νόμιζαν μέχρι τώρα οι επιστήμονες, αλλά και σε σχέση με σήμερα, ήταν δηλαδή ένας πολύ πιο υγρός πλανήτης.

Σε μια άλλη επιστημονική έρευνα, που δημοσιεύτηκε στο περιοδικό γεωφυσικής “Geophysical Research Letters”, γάλλοι ερευνητές του πανεπιστημίου «Ντενίς Ντιντερό» του Παρισιού, υπό τον Γκοτιέ Ιλό, κάνοντας προσομοιώσεις σε υπολογιστές, εκτίμησαν ότι οι πόλοι του γήινου μαγνητικού πεδίου μπορούν να αντιστραφούν σχετικά απότομα. Όπως αναφέρουν, οι επιστήμονες δεν θα είχαν πολλά χρονικά περιθώρια να προβλέψουν την – δυνητικά καταστροφική – αυτή αναστροφή και, κατά πάσα πιθανότητα, όχι περισσότερο μια έως δύο δεκαετίες πριν το γεγονός αυτό συμβεί.

Το γήινο μαγνητικό πεδίο κατά καιρούς αντιστρέφει την πολικότητά του. Σύμφωνα με μερικές εκτιμήσεις, αυτή η αντιστροφή κρατά λίγο (ένα ή δύο χρόνια), όμως άλλοι επιστήμονες εκτιμούν ότι η όλη διαδικασία μπορεί να κρατήσει δεκαετίες ή και περισσότερο, με συνέπεια η Γη και οι κάτοικοί της να παραμείνουν εκτεθειμένοι στην ηλιακή ακτινοβολία – με ό,τι αυτό σημαίνει για τις υποδομές αλλά και τη ζωή στον πλανήτη μας.

Η νέα γαλλική έρευνα δείχνει ότι η πρόβλεψη της συμπεριφοράς του μαγνητικού πεδίου είναι δύσκολη όπως η πρόβλεψη του καιρού, πράγμα ανησυχητικό, ιδίως σε περίπτωση που ισχύει το αρνητικό σενάριο περί χρονοβόρας και όχι άμεσης αλλαγής της πολικότητας του πεδίου.  Η τελευταία αντιστροφή των μαγνητικών πόλων έγινε πριν από περίπου 800.000 χρόνια. Τις τελευταίες δεκαετίες, το μαγνητικό πεδίο έχει εξασθενήσει σημαντικά, πυροδοτώντας φόβους ότι σε λίγες χιλιάδες χρόνια επίκειται νέα ανατροπή της πολικότητάς του.

Εντοπίστηκαν οι αρχαιότερες μαύρες τρύπες στο σύμπαν

In astronomy on March 15, 2010 at 11:18 am

Μια διεθνής ομάδα αστρονόμων κατάφερε να «δει» τις πιο αρχέγονες μαύρες τρύπες που έχουν ποτέ εντοπιστεί στο σύμπαν, η «ηλικία» των οποίων εκτιμάται σε 13 δισεκατομμύρια χρόνια.

Οι επιστήμονες μπόρεσαν να ανακαλύψουν αρχέγονα κβάζαρ, δηλαδή τους πυρήνες πολύ πρώιμων γαλαξιών που περιέχουν ενεργές μαύρες τρύπες, οι οποίες περιβάλλονται από λαμπερούς δίσκους (μεγέθους όσο όλο το ηλιακό μας σύστημα!) περιστρεφόμενης ύλης, η οποία «απορροφάται» σπειροειδώς προς το κέντρο της μαύρης τρύπας.

Τέτοιοι δίσκοι είναι ανάμεσα στα πιο φωτεινά αντικείμενα στο σύμπαν, με συνέπεια να είναι δυνατό, παρά την τεράστια απόσταση στον χώρο και τον χρόνο, οι αστρονόμοι να μελετήσουν με σχετική λεπτομέρεια τις φυσικές ιδιότητές τους.

Το φως των κβάζαρ-μαύρων τρυπών που ανακαλύφθηκαν, χρειάστηκε περίπου 13 δισ. χρόνια για να φτάσει στον πλανήτη μας, με άλλα λόγια βλέπουμε αυτές τις μαύρες τρύπες όπως ήσαν γύρω στο ένα δισεκατομμύριο χρόνια μετά το αρχικό «Μπιγκ Μπανγκ» της δημιουργίας.

Η ανακάλυψη, υπό τον Λινούα Ζιάνγκ του αμερικανικού πανεπιστημίου της Αριζόνα, με τη συμμετοχή ερευνητών των γερμανικών Ινστιτούτων Αστρονομίας και Εξωπλανητικής Φυσικής Μαξ Πλανκ, συνιστά την πρώτη φορά που παρατηρήθηκε ένα τόσο μακρινό και αρχαίο κβάζαρ, ουσιαστικά δηλαδή μια μαύρη τρύπα στο αρχικό στάδιο της εξέλιξής της.

Οι ερευνητές χρησιμοποίησαν το διαστημικό τηλεσκόπιο «Σπίτσερ» της NASA για να παρατηρήσουν υπέρυθρο φως από τα υπερβολικά μακρινά κβάζαρ, τα οποία δεν περιβάλλονταν από τεράστια νέφη ύλης, όπως οι πιο σύγχρονες μαύρες τρύπες. Το πολύ πρώιμο σύμπαν δεν περιείχε καθόλου σκόνη, συνεπώς τα πρώτα άστρα και γαλαξίες δεν περιείχαν σκόνη.

Ήσαν πολύ καυτά και ακτινοβολούσαν έντονα, όμως δεν περιείχαν σωματίδια σκόνης.

Με «φωτιά χωρίς καπνό» τα παρομοίασαν οι αστρονόμοι, που πρώτοι έκαναν την ανακάλυψη.

Οι επιστήμονες, κάνοντας υπολογισμούς, συμπέραναν ότι υπάρχει σχέση αναλογίας ανάμεσα στην μάζα (το μέγεθος) της κεντρικής μαύρης τρύπας ενός κβάζαρ και της ύλης (σκόνης) που την περιβάλλει, πράγμα που δείχνει μια εξελικτική διαδικασία: η μαύρη τρύπα διογκώνεται γρήγορα «ρουφώντας» τη γύρω ύλη της και, παράλληλα, όλο και περισσότερη καυτή σκόνη παράγεται διαχρονικά.

Η εργασία των αστρονόμων θα παρουσιαστεί αυτή την εβδομάδα στο περιοδικό “Nature”.

Stephen Hawking: The Future of Space -Manned vs Robotic Missions?

In astronomy, extraterrestrial, sci-fi, technology on March 7, 2010 at 4:06 pm

“Robotic missions are much cheaper and may provide more scientific information, but they don’t catch the public imagination in the same way, and they don’t spread the human race into space, which I’m arguing should be our long-term strategy. If the human race is to continue for another million years, we will have to boldly go where no one has gone before.”

Stephen Hawking, Cambridge University

Will unmanned robotic missions be able to detect weird microscopic life-forms they are not programmed to recognize that might be lurking below the surface of Saturn’s Titan, or beneath the murky seas of Jupiter’s jumbo moon, Europa?

The answer to this question is at the core of one of the greatest of the ongoing debates in space exploration: the question of man vs. unmanned robotic missions.

NASA currently operates more than 50 robotic spacecraft that are studying Earth and reaching throughout the solar system, from Mercury to Pluto and beyond. Another 40 unmanned NASA missions are in development, and space agencies in Europe, Russia, Japan, India and China are running or building their own robotic craft.

What is not commonly known however is that many of NASA’s leading scientists also champion human exploration as a worthy goal in its own right and as a critically important part of space science in the 21st century. The Obama administration’s new NASA strategy that strongly favors robotic exploration, has opened the debate anew.

In a past issue of Scientific American Jim Bell, an astronomer and planetary scientist at Cornell University, and author of “Postcards from Mars,”  notes that “…you might think that researchers like me who are involved in robotic space exploration would dismiss astronaut missions as costly and unnecessary.”

But he then he goes on, “Although astronaut missions are much more expensive and risky than robotic craft, they are absolutely critical to the success of our exploration program.”

Astroboy171104_2The heart of the debate is this: robotic machines will only do what they are programmed to do; they are not programmed to detect weirdness: the unimaginable, the unknown, the strange non-carbon life that we may have encountered on Mars, for example with the two Viking vehicles, in 1976. Each carried equipment for sampling the Martian soil and miniature chemistry laboratories to test the samples for signs of life.The results these automated labs radioed back to Earth were enigmatic: the chemical reactions from the Martian soil were strange, unlike anything seen on Earth. But they were also unlike any reactions that living organisms would produce.

Ben Bova, the science-fiction author of Titan and The Aftermath, his most recent novels in is his ongoing series about the expansion of the human race throughout the Solar System, points out in an interview that most scientists examining the Viking results, reluctantly concluded that was lifeless: “But the fact is that the landers were equipped only to detect signs of Earth-type life. The chemical reactions observed could have been the results of Martian life. They certainly were not ordinary inorganic chemistry.”

The debate over the meaning of the Viking results, Bova concludes, is still unsettled, more than 30 years later. But a human biologist or biochemist could have learned a lot more and settled the matter, one way or the other, within a few hours.

What are we looking for, exactly, when we search for alien life? That’s the cosmic question pondered in the report from the National Research Council, The Limits of Organic Life in Planetary Systems. For more than five years, a committee of scientists tried to imagine what life-as-we-don’t-know-it might be like. Their conclusion: Life may exist in non-carbon forms completely unlike anything we see on Earth.

The human vs.machine debate is a false construct: robotic unmanned spacecraft are directed by human beings on Earth. Unless disabled by fierce sandstorms, our rovers are in constant realtime communication with their masters at the Jet Propulsion Laboratory, as will the New Horizons spacecraft now heading for Pluto with human monitors watching over it.

Stephen Hawking, world-celebrated expert on the cosmological theories of gravity and black holes who holds Issac Newton’s Lucasian Chair at Cambridge University, has strong views on the future of the human species and space trael. At last year’s 50th anniversary for NASA. Hawking proposed that the world should devote about 10 times as much as NASA’s current budget – or 0.25% of the world’s financial resources – to space exploration. Hawking backed the space agency’s goals of returning astronauts to the Moon by 2020 and sending humans to Mars shortly after that.

The Moon is a good place to start because it is “close by and relatively easy to reach”, Hawking said. “The Moon could be a base for travel to the rest of the solar system,” he added. would be “the obvious next target”, with its abundant supplies of frozen water, and the intriguing possibility that life may have been present there in the past.

“A goal of a base on the Moon by 2020 and of a manned landing on Mars by 2025 would reignite the space program and give it a sense of purpose in the same way that President Kennedy’s Moon target did in the 1960s,” he said.

Hawking said that any long-term site for a human base should have a significant gravity field, because long missions in microgravity lead to health issues such as bone loss.

Hawking favors human space exploration, rather than just sending robots to explore space, a position taken by Nobel laureate Steven Weinberg, among others.

Eventually, Hawking said, humanity should try to expand to Earth-like planets around other stars. If only 1% of the 1000 or so stars within 30 light years of Earth has an Earth-size planet at the right distance from its star for liquid water to exist, that would make for 10 such planets in our solar system’s neighbourhood, he said.

“We cannot envision visiting them with current technology, but we should make interstellar travel a long-term aim,” he said. “By long term, I mean over the next 200 to 500 years.” Humanity can afford to battle earthly problems like climate change and still have plenty of resources left over for colonizing space, he said.

“Even if we were to increase the international [space exploration] budget 20 times to make a serious effort to go into space, it would only be a small fraction of world GDP,” he said. GDP, or Gross Domestic Product, is a measure of a country’s economic activity.

Hawking  believes that traveling into space is the only way humans will be able to survive in the long-term. “Life on Earth,” Hawking has said, “is at the ever-increasing risk of being wiped out by a disaster such as sudden global warming, nuclear war, a genetically engineered virus or other dangers … I think the human race has no future if it doesn’t go into space.”

Another of his famous quotes reiterates his position that we need to get off the planet relatively soon. “I don’t think the human race will survive the next 1,000 years unless we spread into space.”

The problems with Hawking’s solution is that while it may save a “seed” of human life- a few lucky specimens- it won’t save Earth’s inhabitants. The majority of Earthlings would surely be left behind on a planet increasingly unfit for life.

Hawking argued that the world can afford 0.25% of its collective GDP to devote to space colonization. “Isn’t our future worth a quarter of a percent?” he asked. The physicist also speculated on the reasons that SETI (Search for Extra-Terrestrial Intelligence) projects have not yet detected any alien civilizations, offering three possibilities: that life of any kind is very rare in the universe; that simple life forms are common, but intelligent life rare; or that intelligent life tends to quickly destroy itself.

“Personally, I favour the second possibility – that primitive life is relatively common, but that intelligent life is very rare,” he said. “Some would say it has yet to occur on Earth.”

Source: DailyGalaxy

Chile’s Great Observatories are Searching for Earth’s Twin

In astronomy, extraterrestrial on March 2, 2010 at 10:44 am

Among the international astronomical observatories in Chile is the Gemini Observatory (South) at 2,700 meters (8,858 ft) elevation on Cerro Pachón (a mountain in the Chilean Andes) and the European Southern Observatory’s (ESO) Very Large Telescope (VLT) on Cerro Paranal, a 2,635 meter (8,645 ft) high mountain in the Atacama desert.

Gemini South is approximately 800 km (500 miles) north of the epicenter and the VLT is approximately 1,370 km (850 miles) north of the epicenter. Undoubtedly both locations would have experienced some seismic activity.

But as you would expect Chile’s observatories such as the VLT have some novel anti-earthquake safety measures in place, with the entire telescope is designed to swing during an earthquake, and securing the primary mirror prevents it from rattling against the metal tubes that surround it.

European astronomers based here recently discovered the smallest planet yet found orbiting another star. The discovery suggests that the Milky Way is full of small-mass planets and that with more time and improved instruments like NASA’s recently launched Kepler satellite, they would eventually find Earth-like planets in orbits suitable for life around other stars.

The newly found planet could be as little as only 1.9 times as massive as the Earth and belongs to a dim red star known as Gliese 581, which lies about 20 light-years from Earth in the constellation Libra.

“The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the ‘habitable zone’ — a region around the host star with the right conditions for water to be liquid on a planet’s surface”, says Michel Mayor from the Geneva Observatory, who led the European team to this stunning breakthrough.

The Swiss, French and Portuguese astronomers manning the ESO’s La Silla 3.6m telescope were responsible for the original discovery of Gliese 581c, an exo-planet that revolves around Gliese 581. It is older than our solar system and its year lasts only 13 days, since it is 14 times closer to its star than the Earth is to the our Sun.  Astronomers also say—based on initial high-tech models and density-mass calculations—this quasi-Earth’s surface is either rocky or ocean-covered—both Earth-like geographical qualities.

ESO is the intergovernmental European Organization for Astronomical Research in the Southern Hemisphere. On behalf of its thirteen member states ESO operates a suite of the world’s most advanced ground-based astronomical telescopes located at the La Silla Paranal Observatory in the Atacama.

Planet Gliese 581 e orbits its host star – located only 20.5 light-years away in the constellation Libra  — in just 3.15 days. “With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet”, says co-author Xavier Bonfils from Grenoble Observatory.

From previous observations — also obtained with the HARPS spectrograph at ESO’s La Silla Observatory -a suite of the world’s most advanced ground-based astronomical telescopes-  this star was known to harbor a system with a Neptune-sized planet b and two super-Earths. With the discovery of Gliese 581 e, the planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d).

The planet farthest out, Gliese 581 d, orbits its host star in 66.8 days. “Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. “‘d’ could even be covered by a large and deep ocean — it is the first serious ‘water world’ candidate,” continued Udry

“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 — the one around 51 Pegasi,” says Mayor. “The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years.”

The astronomers are confident that they can still do better. “With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,” says Bonfils. “The hunt continues.”

La Silla is located in the epicenter of the Atacama Desert’s 5000 meter-high plateau of Chajnantor. Nearby, the European Southern Observatory’s  ALMA (Atacama Large Millimeter/submillimeter Array) Observatory project is under construction -a giant, international observatory composed initially of 66 high-precision telescopes, operating at wavelengths of 0.3 to 9.6 mm.

Alma_2 The ALMA antennas will be electronically combined and provide astronomical observations which are equivalent to a single large telescope of tremendous size and resolution, able to probe the Universe at millimeter and sub-millimeter wavelengths with unprecedented sensitivity and resolution, with an accuracy up to ten times better than the Hubble Space Telescope.

ALMA will be the forefront instrument for studying the cool universe – the relic radiation of the Big Bang, and the molecular gas and dust that constitute the very building blocks of stars, planetary systems, galaxies, and life itself.

In the meantime, odds are good that twin Earths with lukewarm temperatures will likely be discovered by the ESO team earthquke hazards notwithstanding..

Life beyond our universe: Physicists explore the possibility of life in universes with laws different from our own

In astronomy, physics on March 1, 2010 at 10:28 am

Whether life exists elsewhere in our universe is a longstanding mystery. But for some scientists, there?s another interesting question: could there be life in a universe significantly different from our own?

A definitive answer is impossible, since we have no way of directly studying other universes. But cosmologists speculate that a multitude of other universes exist, each with its own laws of physics. Recently physicists at MIT have shown that in theory, alternate universes could be quite congenial to life, even if their physical laws are very different from our own.
In work recently featured in a cover story in Scientific American, MIT physics professor Robert Jaffe, former MIT postdoc, Alejandro Jenkins, and recent MIT graduate Itamar Kimchi showed that universes quite different from ours still have elements similar to carbon, hydrogen, and oxygen, and could therefore evolve life forms quite similar to us. Even when the masses of the elementary particles are dramatically altered, life may find a way.
“You could change them by significant amounts without eliminating the possibility of organic chemistry in the universe,” says Jenkins.
Pocket universes
Modern cosmology theory holds that our universe may be just one in a vast collection of universes known as the multiverse. MIT physicist Alan Guth has suggested that new universes (known as “pocket universes”) are constantly being created, but they cannot be seen from our universe.
In this view, “nature gets a lot of tries — the universe is an experiment that’s repeated over and over again, each time with slightly different physical laws, or even vastly different physical laws,” says Jaffe.
Some of these universes would collapse instants after forming; in others, the forces between particles would be so weak they could not give rise to atoms or molecules. However, if conditions were suitable, matter would coalesce into galaxies and planets, and if the right elements were present in those worlds, intelligent life could evolve.
Some physicists have theorized that only universes in which the laws of physics are “just so” could support life, and that if things were even a little bit different from our world, intelligent life would be impossible. In that case, our physical laws might be explained “anthropically,” meaning that they are as they are because if they were otherwise, no one would be around to notice them.
Jaffe and his collaborators felt that this proposed anthropic explanation should be subjected to more careful scrutiny, and decided to explore whether universes with different physical laws could support life.
This is a daunting question to answer in general, so as a start they decided to specialize to universes with nuclear and electromagnetic forces similar enough to ours that atoms exist. Although bizarre life forms might exist in universes different from ours, Jaffe and his collaborators decided to focus on life based on carbon chemistry. They defined as “congenial to life” those universes in which stable forms of hydrogen, carbon and oxygen would exist.
“If you don’t have a stable entity with the chemistry of hydrogen, you’re not going to have hydrocarbons, or complex carbohydrates, and you’re not going to have life,” says Jaffe. “The same goes for carbon and oxygen. Beyond those three we felt the rest is detail.”
They set out to see what might happen to those elements if they altered the masses of elementary particles called quarks. There are six types of quarks, which are the building blocks of protons, neutrons and electrons. The MIT team focused on “up”, “down” and “strange” quarks, the most common and lightest quarks, which join together to form protons and neutrons and closely related particles called “hyperons.”
In our universe, the down quark is about twice as heavy as the up quark, resulting in neutrons that are 0.1 percent heavier than protons. Jaffe and his colleagues modeled one family of universes in which the down quark was lighter than the up quark, and protons were up to a percent heavier than neutrons. In this scenario, hydrogen would no longer be stable, but its slightly heavier isotopes deuterium or tritium could be. An isotope of carbon known as carbon-14 would also be stable, as would a form of oxygen, so the organic reactions necessary for life would be possible.
The team found a few other congenial universes, including a family where the up and strange quarks have roughly the same mass (in our universe, strange quarks are much heavier and can only be produced in high-energy collisions), while the down quark would be much lighter. In such a universe, atomic nuclei would be made of neutrons and a hyperon called the “sigma minus,” which would replace protons. They published their findings in the journal Physical Review D last year.
Fundamental forces
Jaffe and his collaborators focused on quarks because they know enough about quark interactions to predict what will happen when their masses change. However, “any attempt to address the problem in a broader context is going to be very difficult,” says Jaffe, because physicists are limited in their ability to predict the consequences of changing most other physical laws and constants.
A group of researchers at Lawrence Berkeley National Laboratory has done related studies examining whether congenial universes could arise even while lacking one of the four fundamental forces of our universe — the weak nuclear force, which enables the reactions that turn neutrons into protons, and vice versa. The researchers showed that tweaking the other three fundamental forces could compensate for the missing weak nuclear force and still allow stable elements to be formed.
That study and the MIT work are different from most other studies in this area in that they examined more than one constant. “Usually people vary one constant and look at the results, which is different than if you vary multiple constants,” says Mark Wise, professor of physics at Caltech, who was not involved in the research. Varying only one constant usually produces an inhospitable universe, which can lead to the erroneous conclusion that any other congenial universes are impossible.
One physical parameter that does appear to be extremely finely tuned is the cosmological constant — a measure of the pressure exerted by empty space, which causes the universe to expand or contract. When the constant is positive, space expands, when negative, the universe collapses on itself. In our universe, the cosmological constant is positive but very small — any larger value would cause the universe to expand too rapidly for galaxies to form. However, Wise and his colleagues have shown that it is theoretically possible that changes in primordial cosmological density perturbations could compensate at least for small changes to the value of the cosmological constant.
In the end, there is no way to know for sure what other universes are out there, or what life they may hold. But that will likely not stop physicists from exploring the possibilities, and in the process learning more about our own universe.
Provided by Massachusetts Institute of Technology