The idea ofan additional large planet orbiting far outside our solar system has beenaround for a long time. It may wellexist. It may even be a brown dwarf thatwe simply can not see.
However, Ithink that a circular orbit is unlikely. Sitchen predicted his plane X to have a long elliptical orbit thatbrought the planet into the inner solar system.
We have evenbetter evidence that we orbit through the Sirius cluster every 200,000 years orso. Such an event could well look likeplanet orbiting us.
It wouldlikely produce a distorted orbit for a distant solar planet.
Meanwhile, wehave learned that disturbing a comet is not an easy trick without a big objectand that the presence of comets is confirmation of perturbation. Something(s) is out there. Yet perturbed orbits could still be artifactsof the pass through Sirius over a 100 thousand years ago.
There may beroom for everything, but if we give credence to any of the material, I find thepass through Sirius satisfying because it gives us a large hot object thatcould meet the requirements of purported eye witness reports that Sitchenreported.
There ispresently no obvious evidence of any recent comet disturbances which suggeststhat any hypothetical planet is a long ways away for now.
Massive dark object 'lurking on edge ofsolar system hurling comets at Earth'
Last updated at 8:50 AM on 8th December 2010
Amassive dark object may be lurking on the edge of our solar system, accordingto scientists.
Mostcomets that fly into the inner solar system seem to come from the outer regionof the Oort cloud - a region of icy dust and debris left over from thebirth of the solar system.
Thecloud starts from a point about 93 billion miles from the Sun and stretches foraround three light years and contains billions of comets, most of them smalland hidden.
A Nasagraphic which illustrates how the Oort Cloud surrounds our solar system.Scientists believe that an object with a huge mass may be pushing cometstowards Earth from the cloud
Now newcalculations suggest a large object that is up to four times as big as Jupitercould be responsible for sending them in our direction.
Thescientists have analysed the comets in the Oort cloud and deduced that 25per-cent of them would need a nudge by a body of at least Jupiter size beforethey changed orbit.
AstrophysicistsJohn Matese and Daniel Whitmire at the
came up with theory said that 'something smaller than a Jovian mass would notbe strong enough to perform the task'. University of Louisiana
Theybelieve that our solar system has a hidden 'companion' that has so far remainedundetected.
Thescientists have been studying the cloud using WISE, Nasa's infra-red spacetelescope that is capable of detecting dark objects.
Matesesaid: 'I think this whole issue will be resolved in the next five to 10 years,because there’s surveys coming on line that will dwarf the comet sample we havetoday.
'Whetherthese types of asymmetries in the directions that comets are coming fromactually do exist or not will definitely be hammered out by those surveys,'Matese added. 'We anticipate that WISE is going to falsify or verify ourconjecture.'
About3,200 long-period comets are known, one of the most famous being Hale-Boppwhich was visible to even the naked eye during 1996 and 1997.
Halley'sComet, which reappears about every 75 years, is a 'short-period' comet from adifferent part of the Solar System called the Kuiper Belt.
A largeplanet that is in orbit outside the solar system may be pushing comets towardsEarth
If itexists the new planet is so freezing cold it is difficult to spot, researcherssaid.
It couldbe found up to 30,000 astronomical units from the sun. One AU is the distancebetween the Earth and the sun, about 93 million miles.
Scientistshave already proposed that a hidden star, which they call 'Nemesis,' mightexist a light-year or so away from our sun.
Theysuggest that during its orbit it would regularly enter the Oort cloud, jostlingthe orbits of many comets there and causing some to fall toward Earth.
Theseoccasional comet showers could be why the mass extinctions on Earth are soregular, some scientists believe.
Theresearch appeared in the online edition of the journal Icarus.
'Mostplanetary scientists would not be surprised if the largest undiscoveredcompanion was Neptune-sized or smaller, but a Jupiter-mass object would be asurprise,' Matese told SPACE.com
'If theconjecture is indeed true, the important implications would relate to how itgot there — touching on the early solar environment — and how it might haveaffected the subsequent distributions of comets and, to a lesser extent, theknown planets.'