Earth may collide with Venus
Date: Saturday, June 13, 2009 @ 16:24:07 EDT
Topic: SpaceTime


Orbital chaos may cause our Solar System to go haywire, leading to possible collision between Earth and Venus or Mars. -- PHOTO: AP


A FORCE known as orbital chaos may cause our Solar System to go haywire, leading to possible collision between Earth and Venus or Mars, according to a study released on Wednesday.

The good news is that the likelihood of such a smash-up is small, around one-in-2500. And even if the planets did careen into one another, it would not happen before another 3.5 billion years.

Indeed, there is a 99 per cent chance that the Sun's posse of planets will continue to circle in an orderly pattern throughout the expected life span of our life-giving star, another five billion years, the study found.

Using powerful computers, Mr Laskarand colleague Mickael Gastineau generated numerical simulations of orbital instability over the next five billion years.

Unlike previous models, they took into account Albert Einstein's theory of general relativity. Over a short time span, this made little difference, but over the long haul it resulted in dramatically different orbital paths.

The researchers looked at 2,501 possible scenarios, 25 of which ended with a severely disrupted Solar System. 'There is one scenario in which Mars passes very close to Earth,' 794 kilometres (493 miles) to be exact, said Laskar.

'When you come that close, it is almost the same as a collision because the planets gets torn apart.'Life on Earth, if there still were any, would almost certainly cease to exist.

The key to all the scenarios of extreme orbital chaos was the rock closest to the Sun, found the study.

'Mercury is the trigger, and would be be the first planet to be destabilised because it has the smallest mass,' explained Mr Laskar. At some point Mercury's orbit would get into resonance with that of Jupiter, throwing the smaller orb even more out of kilter, he said.

Once this happens, the so-called 'angular momentum' from the much larger Jupiter would wreak havoc on the other inner planets' orbits too. -- AFP


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