A new population of exploding stars must 'switch off' their radio transmissions before collapsing into a Black Hole. But they emit one last strong beam of highly energetic radiation, known as a gamma-ray burst, before they die.

It was thought all gamma-ray bursts were followed by a radio afterglow.

"But we were wrong. After studying an ultra-sensitive image of gamma-ray bursts with no afterglow, we can now say the theory was incorrect and our telescopes have not failed us," Centre for All-sky Astrophysics (CAASTRO) at Curtin University research fellow Dr. Paul Hancock said.

For most of its life, a star is pretty stable, slowly consuming the fuel at its core to keep it shining brightly, but once most of the hydrogen that stars use as fuel has been consumed, some stars evolve into very different beasts -- pulsating stars. They become unstable, expanding and shrinking over a number of days or weeks and growing brighter and dimmer as they do so.

It's not well known but astronomers actually cannot see what our Galaxy, the Milky Way, really looks like. We are on the inside looking out so scientists instead deduce its shape by observation of its stars and their distances from us. 

In the 1950s, astronomers used radio telescopes to map our Galaxy. Their observations focused on clouds of gas in the Milky Way in which new stars are born, revealing four major arms. More recently, NASA's Spitzer Space Telescope scoured the Galaxy for infrared light emitted by stars but in 2008 it was announced that Spitzer imaging had found about 110 million stars, yet only evidence of two spirals. Did the Milky Way have missing arms? Were they ever there?

Astronomers recently took precise measurements of the closest pair of failed stars to the Sun, the binary brown dwarf system WISE J104915.57-531906.1, and the results suggest that the system harbors a third, planetary-mass object.

Failed stars are known as brown dwarfs and have a mass below 8% of the mass of the Sun—not massive enough to burn hydrogen in their centers. This particular system, Luhman 16AB, was discovered earlier this year and is only 6.6 light-years away.

Astronomers have discovered huge active plumes containing water vapour being released from the surface of Jupiter's moon Europa. 

Jupiter's moon Europa has been a focus of extraterrestrial research for some time now as there were clear indications that it harbors a liquid ocean beneath its icy crust. Lorenz Roth of the Southwest Research Institute in San Antonio, Texas and Joachim Saur of the University of Cologne have used the NASA/ESA Hubble Space Telescope to prove that there is water vapor erupting near its south pole.

The water plumes are in comparison to earth geysers immensely large and reach heights of approximately 200 km. Europa has a circumference of 3200 km and is thereby comparable in size with the Moon.

This is an interesting question I was asked recently on the space show. It's inspired by this 5 note theme from the 1970s movie.

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It's the theme tune from Close Encounters of the Third Kind (composed by John Williams), of course, the music the extraterrestrials use to communicate with humans in the movie. Is that just a rather fun movie idea? Or was the director Spielberg on to something, might we be able to communicate with ETs perhaps more readily in music than in other ways?

Over a year after being launched, NASA's Van Allen Probes mission continues to unravel the mysteries of Earth's high-energy radiation belts that encircle our planet and pose hazards to orbiting satellites and astronauts - termed the Van Allen Radiation Belts.  

Astronomers have identified the glowing wreck of a star that exploded a mere 2,500 years ago — the blink of an eye in astronomical terms - and revealed an astrophysical novelty of the Milky Way.

A model has shown that the subsurface ocean on Jupiter's moon Europa may have deep currents and circulation patterns with heat and energy transfers capable of sustaining biological life.

Astronomers believe Europa is one of the planetary bodies in our solar system most likely to have conditions that could sustain life, an idea reinforced by magnetometer readings from the Galileo spacecraft detecting signs of a salty, global ocean below the moon's icy shell. Without direct measurements of that ocean, scientists have to rely on magnetometer data and observations of the moon's icy surface to account for oceanic conditions below the ice.

Separate teams of scientists have found faint signatures of water in the atmospheres of five distant planets, the first study to conclusively measure and compare the profiles and intensities of these signatures on multiple worlds.

The five planets - WASP-17b, HD209458b, WASP-12b, WASP-19b and XO-1b - are hot Jupiters, massive worlds that orbit close to their stars. The strengths of their water signatures varied. WASP-17b, a planet with an especially puffed-up atmosphere, and HD209458b had the strongest signals. The signatures for the other three planets, WASP-12b, WASP-19b and XO-1b, also are consistent with water.