16:11:2012 -- Did a lost star knock the Earth off its orbit?

Dear Friends,

Ya think?

http://www.dailymail.co.uk/sciencetech/article-2233992/Did-lost-star-knock-Earth-orbit-New-theory-explain-planet-circles-sun-angle-solar-equator.html

Be Well.

David

Did a lost star knock the Earth off its orbit? New theory to explain why our planet circles the sun at an angle to the solar equator

• The Earth circles around the solar system at an angle 7 degrees off the solar equator
• Theory suggests that gravity from errant star travelling near to our solar system pulled the planets out of whack

By DAMIEN GAYLE

PUBLISHED: 14:42 GMT, 16 November 2012 | UPDATED: 16:28 GMT, 16 November 2012

It has been a long standing puzzle to astronomers: why is the Earth's orbit tipped 7 degrees relative to the sun's equator?

Now a new theory suggests that violent stage of our solar system's history, an errant young star strayed close and pulled our developing planets out of whack with the sun's equator.

Konstantin Batygin of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, suggests that our star had a near stellar neighbour at the time Earth formed.

Our solar system: All the planets in our system orbit at angles to the sun's equator. A new theory suggests they may have been pulled out of whack by a nearby stellar neighbour that has long ago left the scene

It is the gravitational of this nearby star on our developing system that explains why the planets don't orbit neatly around the sun's equator.

Dr Batygin outlines his theory in a letter published in the journal Nature titled A primordial origin for misalignments between stellar spin axes and planetary orbits.

 The work explains the phenomenon of planets outside the solar system discovered following tilted or even backward orbits. 

It was thought that such planets were victims of violent events in which the gravitational force of another planet kicked them on to their odd paths.

LOST IN SPACE: THE HOMELESS PLANET WITHOUT A STAR TO ORBIT

A ‘homeless planet’ which floats through space without orbiting a star had been discovered for the first time.

Scientists have speculated on the existence of such a planet and have been trawling the night skies for more than a decade, although the hunt was described as looking for a ‘needle in a thousand haystacks’.

The isolated planet, shown below in an artist's impression, which astronomers believe may have been flung away during its formation, is not tied by gravity to a star and in 100 light years away.

But Dr Konstantin contends that young suns may develop in clusters, with the disks of matter surrounding them and nearly always spreading from the equator being tugged by a neighbouring star.

In his letter to Nature, he calculates how a young star's protoplanetary disk can be yanked off its equatorial orbit by a second star.

'I think somewhere in the Milky Way, there's a star that's responsible for tilting us,' he writes, adding that it probably then fled the after the planets formed.

Josh Winn, an astronomer at the Massachusetts Institute of Technology in Cambridge, told ScienceNOW that he thinks Dr Batygin's theory is 'an entirely plausible idea'.

'The best thing about it is we can test it,' he added, telling the online magazine that he hopes to use instruments to observe multiplanet systems and to evaluate the theory.

Nasa's Kepler spacecraft has so far measured the tilt of just one multiplanet system, Kepler 30, whose three planets all line up with their sun's equator.

Of course, there are many solar systems that still have more than one star, for example our nearest neighbour Alpha Centauri, which has three stars - one of which has a planet similar in size to our own.

'There's a good chance that astronomers will find misalignment in the Alpha Centauri system,' Dr Batygin says.