Europa:Does this icy moon have the incredients for LIFE?

   Jupiter's icy moon Europa is slightly smaller than the Earth's Moon. Like the Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Unlike on Earth, however, this ocean is deep enough to cover the whole surface of Europa, and being far from the sun, the ocean surface is globally frozen over.
   Europa orbits Jupiter every 3.5 days and is phase locked -- just like Earth's Moon -- so that the same side of Europa faces Jupiter at all times. However, because Europa's orbit is eccentric (i.e. an oval or ellipse not a circle) when it is close to Jupiter the tide is much higher than when it is far from Jupiter. Thus tidal forces raise and lower the sea beneath the ice, causing constant motion and likely causing the cracks we see in images of Europa's surface from visiting robotic probes.
  This "tidal heating" causes Europa to be warmer than it would otherwise be at its average distance of about 780,000,000 km (485,000,000 miles) from the sun, more than five times as far as the distance from the Earth to the sun. The warmth of Europa's liquid ocean could prove critical to the survival of simple organisms within the ocean, if they exist.
 
 Discovery:
Europa was discovered on 8 January 1610 by Galileo Galilei. The discovery, along with three other Jovian moons, was the first time a moon was discovered orbiting a planet other than Earth. The discovery of the four Galilean satellites eventually led to the understanding that planets in our solar system orbit the sun, instead of our solar system revolving around Earth. Galileo apparently had observed Europa on 7 January 1610, but had been unable to differentiate it from Io until the next night.

2012: A Banner Year in the Hunt for Exoplanets

   The search for worlds outside our solar system has come a long way since the first exoplanets were confirmed in the early 1990s. Since then, the average rate of alien-world discoveries has shot from about three per year to between fifty and a hundred per year in the last five years. As of the end of 2012, with the tally standing at 854 newfound worlds and reports of new detections being announced nearly every week, thanks in large measure to NASA's Kepler space telescope, astronomers are calling this the golden age of exoplanet discovery.
   
    Now the race is on to find Earth's twin, the elusive Earth-size planet in the habitable, or "Goldilocks," zone around a star where liquid water can exist—and experts believe we may hit the cosmic jackpot soon.
    In 2012 astronomers came closer than ever to zeroing in on an earthly doppelganger, or what astronomers refer to as "terran" planets—or at the very least a planet considered potentially habitable.
    "However, we are far from confirming the habitability of any of these planets until we have the capability to observe their atmosphere, but that will take many years," scientists said. "The big goal now is to find an Earth-size planet in [its] star's habitable zone—something more similar to Earth."  

Γιγάντιοι πίδακες ενέργειας ξεπηδούν από τον γαλαξία μας

    Γιγάντια «ποτάμια» φορτισμένων σωματιδίων που ταξιδεύουν με υπερηχητική ταχύτητα άνω των 1.000 χιλιομέτρων το δευτερόλεπτο, ξεπηδούν αδιάκοπα από το κέντρο του γαλαξία μας και οι αστρονόμοι, που έκαναν την ανακάλυψη, πιστεύουν ότι αποτελούν προϊόν της γέννησης εκατομμυρίων νέων άστρων στην κεντρική περιοχή του γαλαξία. Οι ενεργειακοί πίδακες εκτείνονται σε απόσταση 50.000 ετών φωτός, δηλαδή καλύπτουν περίπου τη μισή διάμετρο του γαλαξία μας. Από την οπτική γωνία του παρατηρητή στη Γη, οι πίδακες (που είναι αόρατοι με γυμνά μάτια) καταλαμβάνουν σχεδόν τα δύο τρία του ουρανού, από τη μια άκρη έως την άλλη του ορίζοντα.