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Meet the real shooting stars

 

A SHOOTING STAR just doesn’t live up to the drama of its name. It promises a flaming stellar projectile fired from the canon of the gods, but in reality, a shooting star is less colossal spherical inferno and more a speck of cosmic dust that lost a battle with friction. Luckily, the Universe (that great purveyor of baffling wonderment) has some real shooting stars up its sleeve.

Sometimes called rogue, runaway or hypervelocity stars, these are stars that have been liberated from the gravitational bonds of the galaxy and set free to travel the cosmos at almost unimaginable speeds.

The existence of hypervelocity stars was first proposed in 1988 but the first wasn’t discovered until 2005. Since then dozens of these intergalactic speed demons have been found careering around the cosmos like stellar boy racers. Most of the Milky Way’s hundred billion or so stars orbit the galactic centre at a relatively pedestrian 400,000mph or so, but hypervelocity stars can be traveling at two million mph and some might be streaking along at many times that speed. 

Now THAT's what I call a mobile home

 

THE BRUNT ICE SHELF is not what you’d call the ideal location to build a manned scientific research station. More than 16,000km from home, this floating shelf of ice sits beneath a hole in the ozone layer, experiences temperatures exceeding -50C; is regularly pummeled by 145kph blizzards and endures winters that, for 50 days of year, blanket the area in 24-hour darkness.

Over the winter, snow accumulates at such a rate that buildings are swiftly buried in a tomb of crushing snow and ice. As if that wasn’t bad enough, the seemingly solid ice on which it is built, is actually a relentless frozen conveyor belt that carries anything on it towards a watery grave.

Despite these overwhelming odds, the British Antarctic Survey have been building scientific research stations on the Brunt Ice Shelf since 1957. Their latest, the Halley VI Antarctic Research Station has just opened for business and is the culmination of almost sixty years of hard lessons and against-the-odds architectural and technological evolution.

The greatest show on Earth (maybe)... well not ON Earth

Above: Comet McNaught displays its beautiful plumage to stargazers in 2007 (Image: ESO)

THERE'S NO SHORTAGE OF COMETS scooting about the solar system and most of them are happy to pass by in relative anonymity – their quiet passage through the inky black of night marked only by astronomers and automated robotic telescopes. But, every so often, a comet comes along that is destined for greatness – a comet that shines so bright that it can break through the glare of the Sun and impose its presence on the daytime skies.

We have only been visited by these so-called ‘great comets’ 32 times in the last 1,000 years. Some, like the famous Haley’s Comet, visit once in a lifetime (twice if you live longer than 76 years) while others are even more reclusive and might only stop by once in every hundred millennia. Yet there is a chance that we will be visited two great comets in 2013 (well, maybe one) and one of them could be the brightest in history (but it might not).

'Indestructible' rover still truckin'

NASA’S CURIOSITY ROVER has been hogging the Martian limelight since the one tonne robotic behemoth made its daring descent in August last year, but when it comes to Mars exploration, it is just the new kid on the block.

It’s predecessor, Opportunity rover, might not have the superstar bravado of his shiny new cousin, but it really is remarkable little robot. 

Originally tasked with a 90-day mission in which it was expected to travel 600 metres across the Martian landscape, the plucky little rover has just celebrated the start of its tenth year of operations (in which time it has covered an astonishing 35.4 km).

Opportunity landed on January 25, 2004 three weeks after its twin rover, Spirit. Their mission: to seek out evidence of water in Mars’ ancient past. 

Between them, Spirit and Opportunity revealed that Mars was once a much wetter and warmer world than the planet’s current frigid, rusty wasteland would suggest. Spirit became the first rover to drill into the surface of another world and, in 2007, uncovered an ancient hydrothermal system that in the distant past might have provided the two key ingredients for life – liquid water and a source of energy.

"We are made of star stuff"

“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood... were made in the interiors of collapsing stars” Carl Sagan

IN THE BEGINNING there was the void. The Universe was formless and empty, darkness was over the surface of the deep. Then there was light and the light was good.

The light was energy and from that energy came matter. But the matter was simple and disparate, which was not good.

Then matter was drawn together and the first stars illuminated the darkness. From within the belly of the inferno, simplicity begat complexity and the first heavy elements were born.

Hydrogen begat helium. Helium begat carbon and oxygen. Carbon begat magnesium and aluminum and these begat silicon and iron.

Heavy with their elemental progeny, the stars burst forth and spread their seed into the darkness. From the star’s seed, came forth the Sun and the Earth.

On the land, hydrogen married oxygen and together they became water. The elements came together and created complex chemicals and these in turn created amino acids and proteins.

From the amino acids and proteins was brought forth life and soon the waters were pregnant with living creatures. The living creatures were fruitful, increased in number and filled the waters of the seas, the lands of the Earth and the vaults of the sky. 

One of these creatures came to be called man and he looked to the heavens and asked “where did I come from?”

A cosmic identity crisis

(It's not a star, it's not a planet) Meet the brown dwarf

[Above: Artist’s impression of a brown dwarf based on data from Nasa’s Hubble and Spitzer space telescopes. Image: Nasa]

IN A UNIVERSE POPULATED by the bizarre and unusual it takes a special talent to be singled out as a space oddity but if there is one celestial object that deserves this moniker it is the lowly brown dwarf.

Stuck in a strange no-man’s land between stars and planets, and accused of being dull, smelly (their atmosphere’s rich with eggy hydrogen sulphide and uriney ammonia), underachieving loners; brown dwarfs are one of the Universe’s most maligned objects – a sort of cosmic hobo if you will. 

Formed from the collapse of clouds of gas and dust, brown dwarfs start their lives full of the promise of stardom. But they never manage to gather enough mass to ignite full-blooded hydrogen fusion in their cores and, instead of becoming blazing stars surrounded by supplicant planets, they resemble enormous Jupiter-like planets – doomed to billions of years of cold obscurity.

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