Earth-Venus smash-up possible in 3.5 billion years: study

Jun 10, 2009 by Marlowe Hood
This undated handout illustration provided by Nature Publishing group shows what a collision between Earth and Venus might look like. 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.

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 Wednesday.

The good news is that the likelihood of such a smash-up is small, around one-in-2500.

And even if the did careen into one another, it would not happen before another 3.5 billion years.

Indeed, there is a 99 percent 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.

After that, the Sun will likely expand into a red giant, engulfing Earth and its other inner planets -- Mercury, and Mars -- in the process.

Astronomers have long been able to calculate the movement of planets with great accuracy hundreds, even thousands of years in advance. This is how eclipses have been predicted.

But peering further into the future of celestial mechanics with exactitude is still beyond our reach, said Jacques Laskar, a researcher at the Observatoire de Paris and lead author of the study.

"The most precise long-term solutions for the orbital motion of the Solar System are not valid over more than a few tens of millions of years," he said in an interview.

Using powerful computers, Laskar and 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.

To get a more fine-grained view of how this might unfold, Laskar and Gastineau ran an additional two hundred computer models, slightly changing the path of Mars each time.

All but five of them ended in a two-way collision involving the Sun, Earth, Mercury, Venus or Mars. A quarter of them saw smashed to pieces.

The key to all the scenarios of extreme orbital chaos was the rock closest to the Sun, found the study, published in the British journal Nature.

"Mercury is the trigger, and would be be the first planet to be destabilised because it has the smallest mass," explained 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.

"The simulations indicate that Mercury, in spite of its diminutive size, poses the greatest risk to our present order," noted University of California scientists Gregory Laughlin in a commentary, also published in Nature.

(c) 2009 AFP

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superhuman
5 / 5 (4) Jun 10, 2009
To get a more fine-grained view of how this might unfold, Laskar and Gastineau ran an additional two hundred computer models, slightly changing the path of Mars each time.
All but five of them ended in a two-way collision involving the Sun, Earth, Mercury, Venus or Mars. A quarter of them saw Earth smashed to pieces.

Disappointed simulations only came up with one near miss in 2501 scenarios scientists decided to cheat to get more drama.
LuckyBrandon
3.6 / 5 (5) Jun 10, 2009
yea did ya notice the picture too...i would tend to think that venus colliding into earth will not leave us with that crystal clear of a sky :)
VOR
4 / 5 (4) Jun 10, 2009
Mercury must be destroyed!
axemaster
5 / 5 (4) Jun 10, 2009
"A force known as orbital chaos"

It's not a force. It's a phenomenon. For most of us, this doesn't matter, but for others it could be a source of confusion. Its like saying "coriolis force" or "centrifugal force" - neither is correct.

"the so-called "angular momentum""

What's "so-called" abut angular momentum? It's a very useful mathematical treatment for linear momentum with vector change over time.
Birger
3 / 5 (2) Jun 11, 2009
Since Mercury and Venus both have very slow axial rotation, future super-civilizations might very well deliberately induce close encounters between them, making the tidal friction speed them up. The released heat would also make their thick crustal plates melt, paving the way for Earth-style plate tectonism (A civilization capable of this should have no problems with the unsuitably hot zone near the sun, I am thinking orbital shades). Drastic, but far less so than a Dyson Sphere. :-)
mo411
1 / 5 (1) Jun 11, 2009
The solar system will have far more interesting encounters as we pass through the next spiral arm of the our galaxy... objects far larger then the earth reside there just waiting to impart material our way... but then again one can%u2019t presume to calculate just how much fun that%u2019s going to be.
omatumr
1 / 5 (2) Jun 11, 2009
WORLDS IN COLLISION RE-DISCOVERED?

This sounds to me like the work of Immanuel Velikovsky.

Oliver K. Manuel
http://myprofile....anuelo09

Doschx
not rated yet Jun 11, 2009
I'm kinda wondering when the plasma physics zealots are going to show up... they always seem to be lurking in the space related articles >.>
barakn
2 / 5 (4) Jun 12, 2009
An iron/neutron Sun zealot already posted. The plasma physics zealots like to associate with the iron/neutron Sun zealots.
jeffsaunders
not rated yet Jun 14, 2009
Just thinking that if I have to wait 3.5 Billion years for the Earth to crash into Venus or Mars or If I am lucky I only have to wait another billion years more and the Sun will expand and get the lot of us.



What I was thinking is that, that is nearly one third of the entire age of the Universe as currently estimated by the majority of Cosmologists. Which to me seems hardly any time at all yet here we are already semi-civilised, and considering our eventual demise.



I hardly think we are likely to last that long to worry about it - as has been pointed out we have to pass through another Spiral Arm - maybe twice before that happens.

Besides - I am a Dynamic Equilibrium nut.
jeffsaunders
not rated yet Jun 14, 2009
Of course omatumr has a very good point in his postulates about the sun. We should consider that on the whole the planets in our solar system do tend to chemicals of greater mass - the closer they get to the sun.

If you extend the same tendency to it's logical conclusion then in all likelihood the sun should consist of more elements of greater mass than the planets.
smiffy
not rated yet Jun 15, 2009
We should consider that on the whole the planets in our solar system do tend to chemicals of greater mass - the closer they get to the sun.
I'm afraid it's far from certain that the outer planets are made of lighter materials than the inner four 'rocky' planets. Of course they are predominately gaseous (Hydrogen and Helium) but it's hypothesized that they have or did have rocky cores. Here's an extract from Wikipedia on Jupiter-
The core is often described as rocky, but its detailed composition is unknown, as are the properties of materials at the temperatures and pressures of those depths (see below). In 1997, the existence of the core was suggested by gravitational measurements.[25] indicating a mass of from 12 to 45 times the Earth's mass or roughly 3%-15% of the total mass of Jupiter.[24][27] The presence of a core during at least part of Jupiter's history is suggested by models of planetary formation involving initial formation of a rocky or icy core that is massive enough to collect its bulk of hydrogen and helium from the protosolar nebula.