Stellary Starry Universe

SYDNEY: New evidence backs up the idea that a shockwave from the explosion of massive star triggered the collapse of a dense, dusty gas cloud to form our Sun and its retinue of planets.

For many decades astronomers have postulated that the after effects of this violent supernova led to the birth of the Solar System.

But detailed models of this formation process have only produced the right results under the simplifying – and likely wrong – assumption that the temperatures during the violent events remained constant.

Devil in the details

Now, U.S. astrophysicists at the Carnegie Institution, in Washington DC, have shown for the first time that a supernova could indeed have triggered the Solar System’s formation under the more likely conditions of rapid heating and cooling.

They argue that their results, published last month in the Astrophysical Journal, resolve a long-standing debate.

“We’ve had chemical evidence from meteorites that points to a supernova triggering our Solar System’s formation since the 1970s,” said Alan Boss, lead author of the study.

“But the devil has been in the details,” he said. “Until this study, scientists have not been able to work out a self-consistent scenario, where collapse is triggered at the same time that newly created isotopes from the supernova are injected into the collapsing cloud.”

Short-lived radioactive isotopes – versions of elements with the same number of protons, but a different number of neutrons – found in very old meteorites decay on time scales of millions of years and turn into different ‘daughter’ elements.

Source: Cosmos Online – click here or title for full article

 

 

 

SYDNEY: A new study reveals that the solar wind strips away the atmosphere of Mars by ripping chunks of air away, sending them tumbling into deep space.

 

The surprisingly violent mechanism could also help solve a longstanding mystery, say researchers.

“It helps explain why Mars has so little air,” said David Brain an astronomer at the University of California, Berkeley, who presented the discovery at the 2008 Plasma Workshop, held in Huntsville, Alabama, last month.

Relentless chipping away

There have been several theories about what happened to the Red Planet’s atmosphere.

An asteroid hitting Mars long ago might have detached a large portion of the atmosphere in a single violent upheaval – or the loss might have been gradual, the result of billions of years of relentless chipping away by the solar wind.

Now, using data from NASA’s retired Mars Global Surveyor (MGS) spacecraft, Brain’s study entertains a third possibility; a daily ripping process intermediate between the other two mechanisms.

Source: Cosmos Online – click here for full article

 

 

 

Venus and Jupiter are converging for a spectacular three-way conjunction with the crescent Moon–a rare gathering some are calling ‘the sky show of the year.’ Today’s story tells when and where to look.

Nov. 24, 2008: This story ends with the best sky show of the year–a spectacular three-way conjunction of Venus, Jupiter and the crescent Moon.

It begins tonight with a sunset stroll.

At the end of the day, when the horizon is turning red and the zenith is cobalt-blue, step outside and look southwest. You’ll see Venus and Jupiter beaming side-by-side through the twilight. Glittering Venus is absolutely brilliant and Jupiter is nearly as bright as Venus. Together, they’re dynamite:

Source: Nasa Science – click here for full article

 

 

 

The World’s First Time Machine. Part 5
A 2003 BBC Documentary chronicling the work of Dr Ronald Mallett, a physicist on the brink of making time travel a reality. This documentary covers: Traveling to the past, the future, alternative universe and paradoxes that come with time travel.