Artist's impression of a planet ejected from the early solar system.
Image: Southwest Research Institute
Within our solar system, an extra giant planet, or possibly two, might once have accompanied Jupiter, Saturn, Neptune and Uranus.
Computer models showing how our solar system formed suggested the planets once gravitationally slung one another across space, only settling into their current orbits over the course of billions of years.
During more than 6,000 simulations of this planetary scattering phase, planetary scientist David Nesvorny at the Southwest Research Institute in Boulder, Colo., found that a solar system that began with four giant planets only had a 2.5 percent chance of leading to the orbits presently seen now. These systems would be too violent in their youth to end up resembling ours, most likely resulting in systems that have less than four giants over time, Nesvorny found.
Instead, a model about 10 times more likely at matching our current solar system began with five giants, including a now lost world comparable in mass to Uranus and Neptune. This extra planet may have been an "ice giant" rich in icy matter just like Uranus and Neptune, Nesvorny explained.
The computer model allowed Nesvorny to create a video of the potential extra planet's departure from our solar system.
When the solar system was about 600 million years old, it underwent a major period of instability that scattered the giant planets and smaller worlds, researchers said. Eventually, gravitational encounters with Jupiter would have flung the mystery world to interstellar space about 4 billion years ago.
As fantastic as these findings might sound, a large number of free-floating worlds have recently been discovered in interstellar space, Nesvorny noted. As such, the ejection of planets from solar systems might be common.
"The work raises interesting questions about the early history of the outer solar system," Nesvorny told SPACE.com. "For example, traditionally, most research was focused on the giant planets, their satellites, Kuiper belt objects, and their interaction — that's what we have in the outer solar system now. But how about Mars to super-Earth-size bodies? Have such objects formed on the outer solar system and were eliminated later? If not, then why?"
"This is just a beginning," Nesvorny said. "It will need quite a lot of work to see if there actually was the fifth planet. I am not fully convinced myself."
Nesvorny's research is detailed online in the journal Astrophysical Journal Letters.
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17 Comments
Add CommentHey wait: "a large number of these..." doesn't compute. The linked article at space.com says that only 10 such rogue planets were found. That's a big number coming from a relatively small sampling survey for a relatively short time, but "10" is not a large number.
Reply | Report Abuse | Link to thisIn addition, the very idea isn't that old or well developed, it's just a theory for now and must be worked on and analyzed more thoroughly.
If this theory does get confirmation: it's just another reason to feel insecure about our large and impersonal Universe. Happy thoughts!
This brings up the obvious comparisons to the ancient Sumerian myths about Nibiru, the supposed extra planet with a huge orbit that takes it far beyond Pluto, and returns every 3600 years.
Reply | Report Abuse | Link to thisThe strata lines on Vesta and Phobos, and other data, support a hypothesis that a planet was in between Mars and Jupiter, but was somehow reduced to the rubble we call the asteroid belt.
Reply | Report Abuse | Link to thishttp://ecocosmology.blogspot.com/2011/08/exploded-planet-hypothesis.html
The crop circles tells us to watch between Uranus and Neptune dec 2012 .
Reply | Report Abuse | Link to thisAnd no doubt that info. came straight from Uranus (sorry, couldn't resist it)...?!
Reply | Report Abuse | Link to thisBTW, unfortunately for the former planet theory, the asteroid belt's low combined mass is only about 4% of the mass of the Earth's Moon.
The link to the video is a scam - the site just plays ads over and over again, obscuring the video.
Reply | Report Abuse | Link to thisShame on you Scientific American!
yes, it must be the klingons .
Reply | Report Abuse | Link to thisI see another Nobel Prize in the offing. Most of them that have to with theoretical science will not help humanity a hoot. See the Nobel Prizes given for black holes. Gravity Control, a Canadian invention that could have hundreds of applications and could create thousands of jobs, is happily ignored by Nobel Laureates, as they would have to propose the inventor.
Reply | Report Abuse | Link to thisIs the human species a composite of bipeds that leaped froggy style from one rock to another as they migrated out of the solar system? The indigenous mountain people living on the slopes of the Andes speak a language that is without connection to any of the other human language families. All of those exhibit interaction and share language features in common. This is not so about the language used by these natives in Peru.This is why their language is used like a rosetta stone baseline for language comparison in translation processes. From where did they come with their very unique language with grammar that says remembering the future is the same as remembering the past?
Reply | Report Abuse | Link to this"... found that a solar system that began with four giant planets only had a 2.5 percent chance of leading to the orbits presently seen now. These systems would be too violent in their youth to end up resembling ours, most likely resulting in systems that have less than four giants over time, Nesvorny found."
Reply | Report Abuse | Link to thisWhy would a solar system with four giant planets be more violent in their "youth" than the Solar system is now (according to these simulations, anyway)?
Does this mean it is possible for the solar system in its current configuration to eject another planet? If so, how difficult would it be to predict that disaster ahead of time?
Reply | Report Abuse | Link to thisWhy would we expect much mass to be retained?
Reply | Report Abuse | Link to thisI didn't get a single ad, and saw the video with no problem
Reply | Report Abuse | Link to thisHere we are in the year 2012 and the best that science can come up with is the simulation model.
Reply | Report Abuse | Link to thisThere are far too many parameters to ever be able to come up with a guaranteed believable forward model.
However we DO have reasonably reliable data on what happened in the past and very very good data on what is happening now and we have IMMENSE computing power.
If we were to take all the data available from all the observatories in the world for the last 40 or so years and run it backwards; would we not see what happened in the past?
Would this not be better than the current scientific 1,000,000 monkeys with 1,000,000 typewriters methodology.
If we could get historians and geologists on board then we just might begin to get an idea of who we really are and where we came from.
Instead of proving an ad hoc suggestion of a lost planet, this study by may be a coffin nail in the accretion model of planet formation and a back-handed affirmation of the competing gravitational collapse model of planetesimal, planet and star formation, also known as gravitational instability (GI).
Reply | Report Abuse | Link to thisStars are known to form predominantly in binary pairs by GI, and a recent hypothesis suggests that the 'cold' classical Kuiper belt binaries also formed by GI. (Nesvorny and Youdin, 2010) (The same David Nesvorny.)
Why should planets be any different? An alternative hypothesis unifies binary planetesimals and stars formed by GI with planets.
Planets may also form by GI as binary pairs, not in the circumbinary protoplanetary disk, but rather deep down in the binary stellar realm in horseshoe libration orbits around the L4, L3 and L5 Lagrangian points of the binary stellar pair. Then core-collapse perturbation causes the binary planets to spiral out while the close-binary stellar and planetary pairs spiral in.
The binary planets spiral in to merge and form solitary planets, and most binary stars likewise spiral in and merge to form luminous red novae (LRNe), like the hypothesized merger of the binary stellar pair that merged at 4.567 Ga to form our Sun, creating the short-lived radionuclides, calcium aluminum inclusions (CAIs) and chondrules of our early solar system.
Nesvorny, David, Youdin, Andrew N., Richardson, Derek C., (2010), Formation of Kuiper Belt Binaries by Gravitational Collapse, The Astronomical Journal 140 (2010) 785, doi:10.1088/0004-6256/140/3/785
From what I read, nibiru was just Sumerian astronomers' term for the highest point of the ecliptic, misinterpreted by astronomer Zecharia Sitchin as being the name of a planet. http://en.wikipedia.org/wiki/Zecharia_Sitchin
Reply | Report Abuse | Link to thisFrom what I read, nibiru was just Sumerian astronomers' term for the highest point of the ecliptic, misinterpreted by astronomer Zecharia Sitchin as being the name of a planet.
Reply | Report Abuse | Link to thisIt is perhaps relevant to this article, however, since computations indicate a planet with that eccentric an orbit wouldn't stay in the same orbit more than one trip around, and would end up either in a smaller orbit or ejected.