Does a Massive Planet Lurk in the Outer Solar System?

[bystander]

Up telescope! Search begins for giant new planet
The Independent | 2011 Feb 13

Tyche may be bigger than Jupiter and orbit at the outer edge of the solar system

Search on for Tyche, believed to be largest planet in the solar system
The Daily Mail | 2011 Feb 14

Largest planet in the solar system could be about to be discovered - and it's up to four times the size of Jupiter

The Mystery of the Giant Planet Hidden In Our Solar System
Gizmodo | 2011 Feb 14

There's a giant planet right here, hiding in our Solar System. One that nobody has ever seen, even while it is four times larger than Jupiter and has rings and moons orbiting it. At least, that's what two astrophysicists say.

No, there’s no proof of a giant planet in the outer solar system
Discover Blogs | Bad Astronomy | 2011 Feb 14

I’m getting a lot of email and tweets about NASA supposedly having proof of a giant, Jupiter-sized planet orbiting the Sun way beyond Pluto. Let me be clear: while certainly possible, this idea is not at all proven, and in my opinion still pretty unlikely. As usual, this started as a more-or-less accurate media story and is getting inflated as it gets re-reported. As far as I can tell, the original report was in the UK paper The Independent.

Here’s the deal. Two astronomers, John Matese and Dan Whitmire, have theorized about the possibility of a previously-undiscovered planet way beyond Pluto for some time. This is not a crazy idea; we see planets orbiting other stars way out, and there’s other evidence big planets can be pretty far out from the Sun (mind you, evidence does not mean proof). As it happens, there are lots of chunks of ice orbiting the Sun pretty far out as well. Some of these have orbits which bring them into the inner solar system, and we seem them as long-period comets.

What Matese and Whitmire did was wonder how a big planet would affect the orbits of these comets. If you measured enough of them, would you see the effects of the gravity of this planet? They claim you can, and even gave the planet a tentative name: Tyche.

I read their papers, and thought the data were interesting but unconvincing. The sample size was too small. A bigger study was done, but again the effects weren’t quite enough to rise to the level of breakthrough. I’m not saying the astronomers are wrong — the data were certainly provocative, and potentially correct! Just not firm enough.

What I want to see are observations of this planet. And our best hope may be in the NASA satellite WISE — the Wide-field Infrared Survey Explorer, which has scanned the entire sky over the past year or so. A planet in the outer solar system may be warm enough to glow in the IR and be spotted in the WISE data.

The article in The Independent talks about this, saying:

But scientists now believe the proof of its existence has already been gathered by a Nasa space telescope, Wise, and is just waiting to be analysed.

The first tranche of data is to be released in April, and astrophysicists John Matese and Daniel Whitmire from the University of Louisiana at Lafayette think it will reveal Tyche within two years. "If it does, John and I will be doing cartwheels," Professor Whitmire said. "And that’s not easy at our age."

Note that first line: it makes it seem as if the proof of the planet is already in the data. We just need to find it!

But that’s not really the case. This planet may not exist at all. It might, and I’d love for that to be true. But at the moment we just have interesting but inconclusive evidence supporting the idea of a large planet in the deep dark recesses of the solar system. That’s a long way from proof.

I’ll note the popular site Gizmodo has an article on this that starts off well, but then goes even farther than the Independent did: "[Matese and Whitmire] claim that data already captured by NASA’s Wide-field Infrared Survey Explorer proves its existence. It only needs to be analyzed… over the next two years".

The Independent said that the astronomers believe the proof is there, but that’s different than actually claiming it’s there. I think the article in The Independent is fairly well-measured, but Gizmodo took it a bit too far. And in either case, I’m quite sure that lay people reading these articles will walk away thinking the planet’s reality is a given.

But at this point, we don’t know. And it’s possible that the planet exists and WISE won’t see it; it may be too dim to spot. There are many variations here. Basically it boils down to only one statement that can be said with certainty: if WISE sees it, it exists. But if it’s not seen in the WISE data, that doesn’t prove anything one way or another; it narrows the possibilities down and gives us an upper limit on how big, distant, and warm the planet might be. But we’d need to keep looking for it.

There’s been a spate of overblown stories dealing with astronomy lately. I think this is a coincidence, but it’s certainly keeping me busy. And I’m still not done yet. Stay tuned.

Astronomers Doubt Giant Planet 'Tyche' Exists in Our Solar System
Space.com | Natalie Wolchover | Life's Little Mysteries | 2011 feb 15

A duo of planetary astronomers has grabbed media attention by claiming a planet four times the size of Jupiter may be lurking in the outer solar system. They call the planet Tyche.

Many astronomers, however, say it probably isn't there.

The claim by John Matese and Daniel Whitmire of the University of Lousiana-Lafayette is not new: They have been making a case for Tyche since 1999, suggesting that the giant planet's presence in a far-flung region of solar system called the Oort cloud would explain the unusual orbital paths of some comets that originate there.

"There's evidence that some Oort cloud comets display orbital peculiarities," Matese said. "We're saying that perhaps the pattern is indicative that there's a planet there."

Although their argument is similar to the one they originally made, "what's new is that this pattern has persisted," Matese told Life's Little Mysteries. "It's possible that it's a statistical fluke, but that likelihood has lessened as more data has accumulated in the past 10 years."

Matese says NASA's WISE telescope may have already collected infrared data from Tyche that would be hard to pick out from within the telescope's immense database.

"The spectrum we have predicted is uncertain, and there may be a great many signals that are similar to what are expected for our object. So this may take time," Matese said. It could be two years before a signal from Tyche — if it's there — is located, he added.

Not everyone is as optimistic.

Required: 'Incredible proof'

Matthew Holman, a planetary scientist at the Harvard Smithsonian Institute of Astrophysics, is not a Tyche believer.

Though he hasn't read the latest version of Matese's and Whitmire's argument, Holman told Life's Little Mysteries, "Based on past papers that I've seen looking at where long-period comets came from in the sky, and finding signatures of large perturbers of the Oort cloud, I was not persuaded by the evidence."

Hal Levison, a planetary scientist at the Southwest Research Institute in Boulder, Colo., who recently authored a paper on the Oort cloud for Science Magazine, seconded that opinion.

"I haven't read this version of his paper, which he claims now has better statistics than the previous attempts, where he also claimed that he saw evidence of this object," Levison said. "But in previous papers, I really think he did his statistics wrong. Incredible claims require incredible proof and I really believe that he doesn't understand how to do this statistical analysis correctly."

"What Matese claims is that he sees an excess of comets coming from a particular place, which he attributes to the gravitational effects of a large planet in the Oort cloud. I have nothing against the idea, but I think the signal that he claims he sees is very subtle, and I'm not sure it's statistically significant," Levison told Life's Little Mysteries.

"There's another group in England that claims the same thing, but with Jupiter on the other side of the sun," Levison said. "And they also claim to explain the excess of comets."

As always, it's difficult to prove or disprove anything that you can't see or touch, but for now, considering that most astronomers aren't even sure that such an excess of comets exists in the first place, it may be too early to get psyched about Tyche.

Does a Massive Planet Lurk in the Outer Solar System?
Discovery News | Ian O'Neill | 2011 Feb 16

There's a planet, possibly four times the mass of Jupiter, composed of hydrogen and helium, potentially with a system of moons, hiding in the furthest-most reaches of the solar system. That's according to two University of Louisiana scientists anyway.

No, the sun's evil twin Nemesis hasn't been found, and the pretend purveyor of doom, Planet X, hasn't been spotted either. This is a different kind of world, possibly as complex and interesting as Jupiter, but living in a region of space that is as mysterious as the world itself.

Dubbed "Tyche," this hypothetical planet is causing a small buzz. If it does exist, the confirmed number of planets in our solar system would grow back to nine (sorry Pluto, you're still a dwarf planet) and Jupiter would be relegated to second fiddle.

What's more, the International Astronomical Union (IAU) might need to create a new planetary class for this object, as it would have most likely formed around another star, only to have been kidnapped by the sun's gravity eons ago.

Oort Cloud Hide-and-Seek

Astrophysicists John Matese and Daniel Whitmire from the University of Louisiana at Lafayette arrived at this theory after analyzing comets passing through the inner solar system. They found that many of the comets had strange orbits, contradicting widely accepted cometary theories.

Matese and Whitmire have been trying to track down Tyche since 1999 and it's their belief that there must be a massive world crawling through the outer Oort cloud.

The Oort cloud is a hypothetical volume of space encapsulating our entire solar system and is thought to be the birth place of the long-period comets we see speed through our solar system. It's unimaginably vast, well beyond our heliosphere, up to around 1 light-year distant. That's a quarter of the way to the next star.

Comets are thought to have formed in the Oort cloud since the birth of the solar system and, occasionally, they get disturbed by the gravity of a passing star, causing them to plunge toward the sun, like a high diver jumping off the platform toward the pool below.

But say if Tyche is living in the Oort cloud, stirring things up? That might be causing the oddities spotted in some long-period comets.

"Ordinary Evidence"

Interestingly, as a gas giant of this size is so massive, it would be emitting some heat as it slowly cools since being formed (in a similar fashion to Jupiter), so it could give away its location if its infrared emissions are detected. The researchers are therefore looking to analyze data from NASA's Wide-Field Infrared Survey Explorer (WISE) to find Tyche.

Before we get too excited about the possibility of an imminent historic announcement, it turns out that the majority of the astronomical community isn't particularly confident about Tyche's existence.

Ned Wright, principal investigator for the WISE mission, told Discovery News that the theory behind Tyche is based on "ordinary evidence for an extraordinary claim."

Regardless, as WISE continues to catalog a vast number of infrared sources throughout the cosmos, the mission will keep an eye open for any oddities in the Oort cloud.

"Matese and Whitmire have recently extended the mass range of their prediction down to [the mass of Jupiter] and that is getting a bit hard for WISE to detect at 0.5 light-years from Earth, so we will have to do a careful analysis of lots of faint sources to be sure we haven't missed something," Wright said.

"It should take another couple of years before we can be sure."

Comet Statistics

Dave Jewitt, professor at UCLA and PAN-STARRS scientist, is no stranger to solar system detective work and isn't overly enthusiastic about Matese and Whitmire's theory either.

"This claim is based on the statistics of comet arrivals and the argument that there is an unexpected concentration of comets that results from an unseen planet far beyond the planetary region," Jewitt explained.

According to Jewitt, new claims about the reasons behind comet clustering appear every few years, and while this clustering is interesting, observational bias could be leading us to believe there is something causing Oort cloud asymmetries (i.e. clusters of comets), rather than it being a real phenomenon.

"For example, most people live in the northern hemisphere, so it is easier to detect comets on that side of the earth than on the other, southern side," he said. "The result is that we have biased, noisy comet counts that make discerning comet excesses very tricky."

Jewitt would rather wait until WISE data can prove or disprove Tyche's existence, rather than drawing too many conclusions from comet statistics.

"People have short memories and this is one of those recurrent stories that seems to be attractive to the web surfing population again and again," Jewitt said. "A distant Jupiter is certainly on the cards, in terms of what we know about the structure, origin and evolution of the solar system, but that's because we are largely ignorant about the huge space in the solar system much beyond Neptune."

"We can't rule it out yet. But WISE should have the data to soon rule it out, or to show that it's real."

Persistent evidence of a jovian mass solar companion in the Oort cloud - JJ Matese, DP Whitmire

• Icarus 211(2) 926 (Feb 2011) DOI: 10.1016/j.icarus.2010.11.009
  arXiv.org > astro-ph > arXiv:1004.4584 > 26 Apr 2010

Cometary Evidence of a Massive Body in the Outer Oort Clouds - JJ Matese, PG Whitman, DP Whitmire

• Icarus 141(2) 324 (Oct 1999) DOI: 10.1006/icar.1999.6177 (pdf)

About that Giant Planet Possibly Hiding in the Outer Solar System…
Universe Today | Nancy Atkinson | 2011 Feb 16

[Chris Peterson]

I agree with those who say such an object is unlikely to exist. At that distance, it would be in a very unstable orbit, so not a part of our original Solar System, just an unlikely temporary visitor. And the indirect evidence for it is weak at best.

Maybe something is out there, but I'll be surprised if so.

[The Code]

Here We go Again, About something little known.

I agree with those who say such an object is unlikely to exist. At that distance, it would be in a very unstable orbit, so not a part of our original Solar System, just an unlikely temporary visitor. And the indirect evidence for it is weak at best.

Maybe something is out there, but I'll be surprised if so.

Come on Chris, 100 years of learning does not make "A" 4 billion year expert ! You Have No Idea Huh ?

Tut Tut.

tc

[swainy (tc)]

Here We go Again, About something little known.

I agree with those who say such an object is unlikely to exist. At that distance, it would be in a very unstable orbit, so not a part of our original Solar System, just an unlikely temporary visitor. And the indirect evidence for it is weak at best.

Maybe something is out there, but I'll be surprised if so.

Come on Chris, 100 years of learning does not make "A" 4 billion year expert ! You Have No Idea Huh ?

Tut Tut.

tc

This was a Bad post by me, i Am Sorry. I Understand the compulsion to know, And I realize It is very hard work, Moderating these Forums and making sure people get the info folks want. My comments were very unhelpful. And I will do my best to never replicate this. I was not prompted to make this post.

tc

[neufer]

<<Tyche is the nickname given to a hypothesized gas giant located in the Oort cloud of the solar system. Astronomers John Matese and Daniel Whitmire of the University of Louisiana at Lafayette claimed in 2011 that evidence of this object would be detectable in the archive of data that was collected by NASA's Wide-field Infrared Survey Explorer (WISE) telescope. However, several astronomers have voiced skepticism of this object's existence. Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not.

Matese and Whitmire first proposed the existence of this planet in 1999, based on a perceived bias in the points of origin for long-period comets. Rather than arriving from random points across the sky as is commonly thought, Matese and Whitmire concluded that they were in fact clustered in a band inclined to the ecliptic. Such clustering could be explained if they were disturbed by an unseen object at least as large as Jupiter, possibly a brown dwarf. The hypothetical planet—or companion of the Sun—would be located in the outer part of the Oort cloud. They suggest that such an object might also explain the trans-Neptunian object Sedna's peculiar orbit. However, their sample size was small and the results were inconclusive.

Whitmire and Mattese speculate that this object's orbit would lie at approximately 500 times Neptune's distance; equivalent to 15,000 AU from the Sun, a little less than one-fourth of a light year. This is still well within the Oort cloud, whose boundary is estimated to be beyond 50,000 AU. It would have an orbital period of roughly 1.8 million years. A failed search of older IRAS data suggests that an object of 5 MJ would need to have a distance greater than 10,000 AU. Such a planet would rotate in a different plane in orientation to our current planet orbits, and likely formed in a wide-binary orbit. The origin of wide binaries may be capture during cluster dissolution.

The discoverers speculate that the hypothesized planet could be up to four times the mass of Jupiter and have a relatively high temperature of approximately 200 Kelvin, due to residual heat from its formation. With a mass of four times that of Jupiter, it would still be too small to be a brown dwarf, the ignition of which requires an astronomical object to possess a mass of around 13 Jupiter masses. A cold hydrogen-rich gas giant more massive than Jupiter but with a mass less than about 500 M⊕, will be just slightly larger in volume than Jupiter. For masses above 500 M⊕, degenerate pressure will cause the planet to shrink.

In ancient Greek city cults, Tyche (Τύχη, meaning "fortune" or "luck" in Greek) was the presiding tutelary deity that governed the fortune and prosperity of a city, its destiny (Roman equivalent: Fortuna). The use of the name "Tyche" for the planet may also be a reference to an earlier theory of the Solar System's structure that involved the Sun having a dim companion named Nemesis as it was proposed as a cause for mass-extinctions on Earth. Tyche was the name of the sister of Nemesis.>>

By my calculation Tyche (orbiting at the speed of a jetplane) would have a "Sol sized" cross sectional "capture window" about 1 AU further out that could intercept Oort bodies orbiting in the opposite direction and transform them into quasi-parabolic comets. However, Tyche should have cleared out it's toroidal orbital region in about a hundred million years and long ago have ceased generating quasi-parabolic comets.

[bystander]

Can WISE Find the Hypothetical 'Tyche'?
NASA JPL-Caltech | Whitney Clavin | 2011 Feb 18

Background

In November 2010, the scientific journal Icarus published a paper by astrophysicists John Matese and Daniel Whitmire, who proposed the existence of a binary companion to our sun, larger than Jupiter, in the long-hypothesized "Oort cloud" -- a faraway repository of small icy bodies at the edge of our solar system. The researchers use the name "Tyche" for the hypothetical planet. Their paper argues that evidence for the planet would have been recorded by the Wide-field Infrared Survey Explorer (WISE).

WISE is a NASA mission, launched in December 2009, which scanned the entire celestial sky at four infrared wavelengths about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets relatively close to Earth. Recently, WISE completed an extended mission, allowing it to finish a complete scan of the asteroid belt, and two complete scans of the more distant universe, in two infrared bands. So far, the mission's discoveries of previously unknown objects include an ultra-cold star or brown dwarf, 20 comets, 134 near-Earth objects (NEOs), and more than 33,000 asteroids in the main belt between Mars and Jupiter.

Following its successful survey, WISE was put into hibernation in February 2011. Analysis of WISE data continues. A preliminary public release of the first 14 weeks of data is planned for April 2011, and the final release of the full survey is planned for March 2012.

Frequently Asked Questions

Q: When could data from WISE confirm or rule out the existence of the hypothesized planet Tyche?

A: It is too early to know whether WISE data confirms or rules out a large object in the Oort cloud. Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not. The first 14 weeks of data, being released in April 2011, are unlikely to be sufficient. The full survey, scheduled for release in March 2012, should provide greater insight. Once the WISE data are fully processed, released and analyzed, the Tyche hypothesis that Matese and Whitmire propose will be tested.

Q: Is it a certainty that WISE would have observed such a planet if it exists?

A: It is likely but not a foregone conclusion that WISE could confirm whether or not Tyche exists. Since WISE surveyed the whole sky once, then covered the entire sky again in two of its infrared bands six months later, WISE would see a change in the apparent position of a large planet body in the Oort cloud over the six-month period. The two bands used in the second sky coverage were designed to identify very small, cold stars (or brown dwarfs) -- which are much like planets larger than Jupiter, as Tyche is hypothesized to be.

Q: If Tyche does exist, why would it have taken so long to find another planet in our solar system?

A: Tyche would be too cold and faint for a visible light telescope to identify. Sensitive infrared telescopes could pick up the glow from such an object, if they looked in the right direction. WISE is a sensitive infrared telescope that looks in all directions.

Q: Why is the hypothesized object dubbed "Tyche," and why choose a Greek name when the names of other planets derive from Roman mythology?

A: In the 1980s, a different companion to the sun was hypothesized. That object, named for the Greek goddess "Nemesis," was proposed to explain periodic mass extinctions on the Earth. Nemesis would have followed a highly elliptical orbit, perturbing comets in the Oort Cloud roughly every 26 million years and sending a shower of comets toward the inner solar system. Some of these comets would have slammed into Earth, causing catastrophic results to life. Recent scientific analysis no longer supports the idea that extinctions on Earth happen at regular, repeating intervals. Thus, the Nemesis hypothesis is no longer needed. However, it is still possible that the sun could have a distant, unseen companion in a more circular orbit with a period of a few million years -- one that would not cause devastating effects to terrestrial life. To distinguish this object from the malevolent "Nemesis," astronomers chose the name of Nemesis's benevolent sister in Greek mythology, "Tyche."

[neufer]

Click to play embedded YouTube video.

[owlice]

lol, neufer!! Oh, that movie loomed large in my childhood; I don't remember having gone to see it -- I think everyone else in the family went, though -- and there were riffs on triffids from that point on in my family.

[The Code]

I have been looking into this, For the last two days. The guys are saying every 27 million years, we get a bombardment of comets, etc etc. Is This True ? Whats more, When was the last time this Happened ?

How could we miss A Brown Dwarf On Our solar Door Step ? Is this A estimate Of What? Brings this To Mind. Movement of planets etc etc ? I Here 4 X Saturn.

Do you think, this would Have planets orbiting it ?

I Found This but,,, I think It may not help : http://www.darkstar1.co.uk/binary.html

tc

[Chris Peterson]

I have been looking into this, For the last two days. The guys are saying every 27 million years, we get a bombardment of comets, etc etc. Is This True ? Whats more, When was the last time this Happened ?

That assertion is not well supported by evidence. What has been argued is that mass extinction events have occurred with that periodicity, and perhaps they are caused by impacts. But there is only evidence of impact in two cases of extinction, and most people who have looked at the possible periodicity of extinctions have not found convincing evidence. So the whole idea of periodic comet bombardments is pretty speculative, at best.

How could we miss A Brown Dwarf On Our solar Door Step ?

There isn't a suggestion of a brown dwarf in this case, but of a large gas giant planet. You're talking about something that is quite dark in visible wavelengths, and might sit a quarter light year away. Something like that could go unnoticed, at least in terms of direct observation.

Do you think, this would Have planets orbiting it ?

If it exists, and has bodies orbiting it, they would be called "moons", not "planets".

I Found This but,,, I think It may not help : http://www.darkstar1.co.uk/binary.html

This is talking about Nemesis, a more distant hypothesized companion star to the Sun. It is even less likely to exist than Tyche.

[BMAONE23]

Remember,
If this proposed Ort Cloud body does exist (1/4ly away) and
If it's orbital period coinsides with a 27 MY event and
If 12-21-12 was in deed a valid apocalypse date then

The Comets would need to travel 1/4ly to reach us, that's 1,466,424,000,000 miles
The Comets would be traveling, at best, at approx 50,000 mph (most travel slower, McNaught is traveling at approx 21,000 mph avg.)
At that rate it would take them 53,568 years (+/-) to reach us from that distance
It would take them 325 days to reach us from Jupiter's orbit at 50K mph
It would take them 750 days to reach us from Saturn's orbit at 50K mph

IF this planetary body did exist, and IF its orbit through the Ort Cloud took it to a dense portion every 27 MY, and IF the ejected cometary bodies sustained a speed of 50,000 mph, and IF 12-21-12 was a valid apocalyptic date, the comets would already be inside the orbit of Saturn. If the trajectory speed were cut in half to 25,000mph (more likely) they would be inside the orbit of Jupiter and clearly visible to us.

To get to that point, they would need to travel past the orbits of the Ice Giants Neptune and Uranus which would attract some and past the orbits of the Gas Giants Saturn and Jupiter which would attract an order more. These planets would already be showing indications of bombardment by now but aren't.

So, why not? unless nothing is there

[neufer]

Remember,
If this proposed Oort Cloud body does exist (1/4ly away) and
If it's orbital period coincides with a 27 MY event and
If 12-21-12 was in deed a valid apocalypse date then

The Comets would need to travel 1/4ly to reach us, that's 1,466,424,000,000 miles
The Comets would be traveling, at best, at approx 50,000 mph (most travel slower, McNaught is traveling at approx 21,000 mph avg.)

You are confusing Tyche with Nemesis;
and you are confusing a comet's perihelion speed with it's average speed.

Nemesis is a hypothetical red dwarf star, white dwarf star or brown dwarf, orbiting the Sun in an elliptical orbit at a distance of about 0.8-1.5 light-years (somewhat beyond the Oort cloud) that intercepts the Oort cloud every 27 MY. The comets Nemesis would disturb at perihelion would have a semi-major axis of ~0.4 light-years and take 0.5*(1/6)^3/2x27 MY ~ 1 MY to reach us.

Tyche is a hypothetical giant planet or brown dwarf, orbiting the Sun at a distance of about 1/4 ly in a nearly circular orbit of 1.8 MY. The Oort cloud comets Tyche would disturb (at any time?) would have a semi-major axis of ~ 1/8 ly and take 0.5*(1/2)^3/2x1.8 MY ~ 300,000 years to reach us.

[BMAONE23]

either way, the relative speed at which they would be traveling, to cross Earths orbit, they would currently need to be between the orbits of Jupiter and Saturn to impact us at the proposed 2012 date. So if we aren't seeing any cometary activity in this region, (no relative increase in cometary bombardment on Jupiter or Saturn, and no prior increase in collisions with Uranus or Neptune) then this is most likely not going to happen. I wouldn't worry too much about a 27MY cycle repeating itself by 2012...(unless something is happening and the public is being kept in the dark)

[neufer]

either way, the relative speed at which they would be traveling, to cross Earths orbit, they would currently need to be between the orbits of Jupiter and Saturn to impact us at the proposed 2012 date. So if we aren't seeing any cometary activity in this region, (no relative increase in cometary bombardment on Jupiter or Saturn, and no prior increase in collisions with Uranus or Neptune) then this is most likely not going to happen. I wouldn't worry too much about a 27MY cycle repeating itself by 2012...(unless something is happening and the public is being kept in the dark)

Dec. 12, 2012? Comet McNaught was only discovered six months before perihelion:

<<Comet McNaught was discovered in a CCD image on August 7, 2006 during the course of routine observations for the Siding Spring Survey, which searches for Near-Earth Objects that might represent a collision threat to Earth. The comet was discovered in Ophiuchus, shining very dimly at a magnitude of about +17. From August through November 2006, the comet was imaged and tracked as it moved through Ophiuchus and Scorpius, brightening as high as magnitude +9, still too dim to be seen with the unaided eye. Then, for most of December, the comet was lost in the glare of the sun.>>

Being absolutely certain that there is no incoming comet between the orbits of Jupiter and Saturn is roughly equivalent to being certain that the hypothesized planet Tyche, itself, doesn't exist...which shouldn't happen until sometime after March 2012:

Q: When could data from WISE confirm or rule out the existence of the hypothesized planet Tyche?

A: It is too early to know whether WISE data confirms or rules out a large object in the Oort cloud. Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not. The first 14 weeks of data, being released in April 2011, are unlikely to be sufficient. The full survey, scheduled for release in March 2012, should provide greater insight. Once the WISE data are fully processed, released and analyzed, the Tyche hypothesis that Matese and Whitmire propose will be tested.