Wild Little Mercury to Cause Interplanetary Smashup? Maybe.
Written by Anne Minard
Artistic design : J Vidal-Madjar; planet textures from NASA; copyright: IMCCE-CNRS
The chaotic evolution of the planetary orbits in the Solar System could cause a close approach or even a collision within the next 5 billion years, according to a paper in this week's issue of Nature.
The odds are small, but that didn't stop NASA from releasing a series of really fun "what-if" images (below) …
Mercury is the wild card, according to co-authors Jacques Laskar and Mickael Gastineau of the Paris Observatory. If its orbit elongates, our puniest neighbor could throw the whole block in peril.
Because its orbit resonates with that of Jupiter, Mercury could become the planet gone wild (eccentric in astronomy speak), colliding with Venus.
The chance is slim, the authors point out — around 1 percent. But the finding — revealed through thousands of computer simulations — was a surpise.
"More surprisingly, in one of these high-eccentricity solutions, a subsequent decrease in Mercury’s eccentricity induces a transfer of angular momentum from the giant planets that destabilizes all the terrestrial planets," the authors write, "with possible collisions of Mercury, Mars or Venus with the Earth."
Gregory Laughlin, an astronomer at the University of California Santa Cruz who wrote an accompanying editorial about the new paper, couched it as "a note of definite cheer" in the midst of "a seemingly endless torrent of baleful economic and environmental news." Indeed, there's a 99 percent chance that the planets will not engage in a destructive round of planetary billiards, and that's a good thing.
"With 99 percent certainty, we can rely on the clockwork of the celestial rhythm — but with the remaining 1 percent we are afforded a vicarious thrill of danger," he writes.
Presumably inspired by that vicarious thrill, NASA teamed up with space artist J. Vidal-Madjar to craft the following smash-up images, which were provided by Nature. Enjoy!
Artistic design : J Vidal-Madjar; planet textures from NASA; copyright: IMCCE-CNRS
Artistic design : J Vidal-Madjar; planet textures from NASA; copyright: IMCCE-CNRS
Artistic design : J Vidal-Madjar; planet textures from NASA; copyright: IMCCE-CNRS
Artistic design : J Vidal-Madjar; planet textures from NASA; copyright: IMCCE-CNRS
Filed under: Astronomy, Solar System
Related stories on Universe Today
Comment policy: Be nice and brief. Don't advertise your stuff, or promote your personal theories. We'll delete any comments that break these policies. Click here for more details.
June 10th, 2009 at 11:30 am
Very interesting…
Hopefully Humanity will be out there somewhere colonizing other solar systems 5 billion years from now.
Unless we have already destroyed ourselves by then.
Cheers,
Yan
June 10th, 2009 at 12:03 pm
If we make it another 500 years I'd be surprised.
I'm betting Hollywood will throw together a film about a planetary impact, likely directed by Michael Bay.
June 10th, 2009 at 1:46 pm
A "tiny" probability seems to be the operative word.
But is there any dynamic that would speed up the process?
There is a small group of folks who shall remain nameless that suggested this had happened in the past.
This suggestion is possibly one of the reasons why electromagnetism has such a "bad rap" in astronomical circles.
June 10th, 2009 at 2:00 pm
Anaconda,
A black hole passing through the solar system?
"There is a small group of folks who shall remain nameless that suggested this had happened in the past."
Why do you need to be so secretive? Who are these people and what did they say? Did they suggest a new dynamic, as you put it?
June 10th, 2009 at 2:11 pm
The major perturbative driver of the terrestrial planets is Jupiter. It is nudjing the Earth outward slightly, about 1 meter a year. Much the same is happening with Mars, Venus and Mercury. Other multibody interactions, which are chaotic, might bring the planets into collisions. However, I think the probabilities are tiny.
In 5 billion years Earth will most likely look similar to Venus. The heating of the sun will have turned this planet into a hothouse, or a cooler version of Venus. Life on Earth will have ceased to exist 3 billion years prior to this terminal phase of the solar system.
Humanity will of course long since ceased to exist. If we can make it a couple of centuries into the future we might be doing well. The only thing I hold out for is that we can understand the foundations of the universe before we implode with the ongoing mass-extinction we are engineering. I just hope we hold on for that long. Life will be ticking away fine 25 million years from now. It will be very different from todays array of species and ecosystems — and highly unlikely H. sapiens or any continuation of our species will exist.
Lawrence B. Crowell
June 10th, 2009 at 2:18 pm
"about 1 meter a year."
Is the orbit being increased by 1 meter a year? That sounds rather significant?
June 10th, 2009 at 3:43 pm
@ ND:
Are you kidding me?
One meter (=10^0m) compared to 1,5*10^11m – if you call this significant then I don't know what could be insignificant to you!
Will you cry, when I tell you that the moon's orbit increases by 4cm a year?
June 10th, 2009 at 4:16 pm
So, the Earth has suddenly a 1 percent probability of becoming a dwarf-planet-not-a-planet?
Oh dear. How annoying! };-D
June 10th, 2009 at 4:35 pm
If we are still around in five billion years, I'll bet we'll have ultra high tech methods for keeping Mercury well behaved and preventing such a disaster. I did a quick back-of-the-envelope calculation, and the gravitational force between Mercury and Jupiter is something like 10^17N. The Saturn V rocket that took Apollo 11 to the moon had a thrust of 3.4 x 10^7N, so you'd need about three billion Saturn V rockets to counteract Jupiter's influence on Mercury. That's way out of reach for us today, but for a five billion year old civilization? Probably child's play.
Making sure the Sun hasn't died by then is a different story, but even there I'm cautiously optimistic.
June 10th, 2009 at 4:45 pm
DrFlimmer:
I totally messed up my mental math there. I don't use it too often. I was thinking of 1 m versus 93 million MILES! and thinking over a million years those 1 meters will add up quite a bit. Apparently it's still small
phew!
June 10th, 2009 at 5:31 pm
I did this calculation and published it. A book version is in my book "Can Star Systems be Explored?" The drift I computed is actually 5 meters/year and not one. It has some interesting consequences. The Earth could have been 3.7 billion years ago at 8.5AU from the sun. This had the consequence of making the termperature of Earth around -0deg C on average, instead of -30deg C, even when a thicker CO_2 atmosphere in that time is accounted for.. This would have made the pre-biotic chemistry for the development of life more possible.
This nudging of the Earth outward almost exactly compensates for the increased heating of the sun in its evolution as a G-class main sequence star. This should continue for 1 to 2 billion years into the future. The Earth may be at around 1.05AU by then, which about compensates for solar heating up. Beyond that time the sun will heat up too fast for this gravitational 3-body mechanism to compensate. Yet this might extend the tenure for complex life on Earth from 500 million years to about a billion.
This has lead me so suspect there is some fine tuning in the structure of stellar systems. The motion of the Earth outwards is chaotic, with an average drift. If the Lyapunov exponent is much larger then the drift is outweighted by chaotic dynamics and the orbit not sustainable over the billion year time frames required for the evolution of life, or complex life. I did some analysis involving data on extrasolar systems known up to 2005, updated in the book, and only one other candidate came at all close to supporting a putative 1AU terrestrial planet in a stable manner. In all the other cases the putative 1AU planet would be either ejected from the system, crash into the Jovian or be forced into the star itself. Some statistics lead me to the ~ 1000 bio-planets per galaxy estimate.
We live in a unique and maybe highly exceptional place. Too bad we are treating it so badly.
Lawrence B. Crowell
June 10th, 2009 at 9:09 pm
Dark Gnat, about that Hollywood movie: When Worlds Collide
June 11th, 2009 at 1:38 am
Lawrence B. Crowell
I hope that you have employed a good proofreader for your book; I think that figure should be 0.85AU, not "8.5AU".
June 11th, 2009 at 4:43 am
@Anaconda: in one of your comments, elsewhere, you stated – quite clearly IIRC – that falsifiability is central in your own view of what characteristics an idea must have if it is to be judged as being scientific.
Simple yes or no answer please: are the ideas of the nameless group of people (that you indirectly refer to) falsifiable?
June 11th, 2009 at 6:49 am
Ivanman3: Yes it is .83AU, and correct in the book.
All of this is connected to Poincare's demonstration that the stability of the solar system can't be demonstrated. In fact on a long enough a time frame it is inherently unstable.
June 11th, 2009 at 1:51 pm
It's surprising to see that the continents haven't moved much in 5 billion years
June 11th, 2009 at 8:11 pm
cipater you are wrong, the continents are still adrift !
May I remind you that our small universe is not an pool table? This is an 3D event, and
the main driver of our universe is still the sun
take it away and the whole thing will fall apart!
Any one who played pool knows, that balls
hitting each other do not destroy one an other
Long before any orbiting selastial body cames near each other they will repel each other. The tidal forces will be enormous, with
deadly consequences for us. But in the end
there will be a different configuration of the
present. Some planets may no longer part of
our universe, we may end up so far from the sun, that we are no longer in the habitable
zone. I'm more concerend with the present
quiet stage of our sun? We better figure that
out fast! We defenitly do not need more bad news?
June 11th, 2009 at 8:36 pm
Old time AstronomyCast listener know that we do not have billions of years on the Earth – the Sun will brighten and the oceans will boil in the next 50 to 100 million years. Silly me, I found the news depressing – so comfortable with my years of thinking Earth would provide us a home for billions of years. I hope, that by then, we will have stable populations in O'Neil colonies and thousands of them scatter about, maybe even at other star systems by then. But, will we recognize what we will become as human? Doubtful. All bets are off once the Singularity goes non-linear
June 12th, 2009 at 4:13 am
The time frame for the sun heating up and boiling off the oceans is about 10 times or more than what you think. I predict that in a billion years the Earth will be at 1.05AU due to gravitational drifting from Jupiter. This will up to that point compensate for the heating up of the sun. Beyond that point the sun will start to heat up at a faster rate and things will start to go bad here.
Over the next billion years there will some other things which might make things tougher. The total land mass coverage of the Earth will go from 30% to maybe 40% or more as continents might continue to grow and ocean water is lost to tectonic subduction. This might change the Earth considerably, particularly if ocean coverage is split in two.
Probably a billion years from now life will begin to revert to a preCambrian type of existence as complex species become rarer. Two billion years from now Earth might come to resemble a cooler version of Venus. In 2 billion years or sooner the oceans will boil off and carbon containing dolomite rock will then be heated enough to drive off its locked up carbon into CO_2. Life might persist for some time as archaobacteria and extremophile species of prokaryotes.
Lawrence B. Crowell
June 12th, 2009 at 7:25 am
IIRC, average species lifetime is ~ 10^5 years, so we have plenty of time from now.
Actually, considering the recent publication of genome data showing that selection increased at least two orders of magnitude because of our population increase, we may already be "gone" compared to our ancestral species characteristics. It's the difference between biological (population isolation), fossil (bone variation) and anthropological (tool technique) species that makes us "still here".
As regards the biosphere this week (IIRC) there was this paper out on the sequestering effects from biologic and tectonic recycling vs stellar and radioactive heating drivers that could push the multicellular biosphere 2.5 Gy into the future by a thinning atmosphere. (And monocellular life even further – eventually the carbon dioxide running out will stop oxygenic photosynthesis and so oxygenic metabolisms, but not other pathways.)
Considering that multicellular life is but ~ 0.5 Ga, that leaves quite an impressive potential lifetime for our biosphere as we know it today. End even more for the primordial monocellular one, it may have 5-7 Gy or more total. Of course, 5 Gy into the future is pushing it even if that paper is correct.
June 12th, 2009 at 8:04 am
On the previous mentioned paper: it dealt with Earth.
It has interesting consequences for biosphere lifetimes though, when comparing tectonic biospheres vs others, or considering the future development of galactic habitable zones.
Those are the same as archaebacteria AFAIU. Bacteria can take 70-80 Celsius, at least it's a constraint for their oxygenic photosynthesis, and according to protein and DNA fold data had such a bottleneck in precambrian times. This correlates with the temperature data on cherts harking back 3.5 Ga.
[I'm not the only one noticing this. James Kasting spoke of this at the STScI -09 May symposium:
(I'm not as convinced of global or even local glaciations as Kasting.)
According to the two isotope thermometers of cherts (and correlating with the two of proteins and DNA), sea temperatures linearly decreased from ~ 80 to ~ 20 Celsius at the start of the Cambrian.
Also, while abiogenesis probably occurred in alkaline heat vents driven by redox potentials of circulating acidic sea water, it seems from the same data that the first proteins developed at moderate temperatures ~ 20 Celsius. Probably life developed before the late heavy bombardment originated the later green house carbon dioxide atmosphere. And now there is a paper showing that life probably can survive LHB.]
According to a massive genome analysis last year, supporting Cavalier-Smith's neomura theory, archaebacteria are sisters with eukaryotes. In the neomura theory they developed from actinobacteria as recent as ~ 850 Ma, which corresponds with fossil data. (Steroles which still in some cases are taken as evidence of ~ 2 Ga eukaryotes are also produced by actinobacteria.)
Extremophiles (and so the methanogens) of Earth are then late developments of evolution. While abiogenesis seems simple and robust enough, biospheres are likely a lot less easy to mature and get robust than extremophiles would indicate.
[Btw, and also less robust are then traces of methane as indicators of life, say on Mars. Albeit it could possibly been contingency that made it late here, it should be more researched.]
June 12th, 2009 at 9:44 am
So according to this things were quite warm in the late preCambrian. It is my understanding that about 700Mya the Earth did experience a considerable glacial period. This might have been a part of the 80-20C cooling.
The data as I understand it does suggest that the Earth ~ 3.5Bya was comparatively warm. This is somewhat puzzling since the sun was likely about 25-20% cooler then. I suspect the solar system was in a different configuration then, though not drastically so. The Earth may well have been in a closer orbit to the sun. The solar system is not completely stable, and it might be wrong to suppose it had the same configuratio then that it does now.
Lawrence B. Crowell
June 12th, 2009 at 11:28 am
This topic is being discussed on NPR's Science Friday right now.