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[EFLtrainer]

[jinglejangle]

[EFLtrainer]

[jinglejangle]

[mithridates]

70 000 000 000 000 000 000 000 stars in the universe, each with a few trillion comets and who knows what in between.

For each insect on Earth there are about 7000 stars in the universe.

[mithridates]

The nice people on Wikipedia responded to my request on what it would look like to live on a planet in the system at about the same distance as the Earth is from the sun.

[EFLtrainer]

Tenth Planet stuff previously refered to:

http://www.space.com/scienceastronomy/astronomy/outer_planets_991014.html

In the October 11 issue of the Monthly Notices of the Royal Astronomical Society, Dr. John Murray, an astronomer from the Open University in the United Kingdom proposed that a large object in the extreme outer realms of the solar system may be gravitationally affecting the orbits of long-period comets. He theorizes that the object would have to orbit the sun 32,000 times farther away than Earth (about 3 trillion miles) and would have to be at least as massive as Jupiter, if not more so. Given its distance, it would also be extremely faint and slow moving.

In other research, a professor of physics at the University of Louisiana at Lafayette, Dr. John J. Matese, is making a case for the existence of a 2- to 3-Jupiter mass object orbiting some 2.3 trillion miles from the sun. In a paper soon to be published in the planetary journal, Icarus, Dr. Matese asserts that this object, too, has created a "concentration" of Oort cloud comets and is responsible for sending a significant number of them - perhaps as much as 25 percent - into the inner solar system.

None of this speculation would be possible if it weren't for a family of billions of comets that hardly ever divert into the inner solar system. Known as long-period comets, these gravelly, mountainous icebergs are thought to inhabit a vast sphere known as the Oort cloud, which surrounds the solar system between 900 billion and 4.5 trillion miles from the sun.

The intrusive gravity of some massive object could disturb these objects like a fat man diving into a school of fish, sending them off into other orbits. But the question of what disturbs them and why some of them appear to be regularly distributed like foam in the crest of a standing wave still remains.

Murray's research suggests that the some of the incoming comets include a group coming from directions in space that are aligned in an arc across the sky. This arc, he asserts, could mark the wake of some large body moving through space in the outer part of the Oort cloud. A similar theme arises in Dr. Matese's research. His study of 82 Oort cloud comets indicates that approximately 25 percent of these have an "anomalous distribution" in the sky that can best be understood if there exits some perturbing force in the Oort cloud, i.e., a large, as yet undetected, body.

Dr. Murray rules out the notion that the object might be a heretofore undiscovered brown dwarf since, being brighter than a planet, it would probably have been detected by now. He does not, however, rule out other possible explanations for the observed entrainment of comet orbits.

Not everyone agrees with the two researchers that these results suggest the existence of a mysterious tenth planet. Dr. Anita Cochran, astronomer and comet specialist at the University of Texas at Austin, says Dr. Murray's idea doesn't hold much promise. "First of all, the long-period comet orbits ARE randomly oriented," says Dr. Cochran, "especially if one takes into account the selection effects of discovery."

Most prominent among these, she says, is the fact that there are more observers in the Northern Hemisphere to discover comets than in the Southern Hemisphere, thus a number of long-period comets are probably escaping detection and analysis. Moreover, Dr. Cochran adds that anything that would perturb the periods of comets would leave a significant gravitational signature on the outer planets in the form of slight orbital changes, and that has not been seen, or at least acknowledged.

"I am not sure what [Dr. Murray] is getting at but I think he has neglected the body of previous solutions," she says.

Dr. Matese's theory focuses on different aspects of long-period comet orbits, but nevertheless begs the question: could the darkest corner of our solar system harbor a tenth planet or a brown dwarf? A brown dwarf, he contends, would not have been detected in the previous infrared searches, such as the one conducted by the Infrared Astronomical Satellite (IRAS) in the early 1980s, because the alleged planet/brown dwarf is too near the galactic plane. To ferret out such an object in that busy IR region requires greater sensitivity than IRAS possessed at the time.

For now, it seems the mysteries of the remote solar system will remain largely hidden, as will the truth about whatever exists out there. Perhaps more telling is the fact that astronomers still don't know everything there is to know about our solar neighborhood. That may change with the advent of a new generation infrared searches of bodies in the outer solar system. If a large warm planet or brown dwarf is skulking about stirring up comets, astronomers will find it.

[EFLtrainer]

More on same:

http://www.viewzone.com/nemesis.html

In 1846, researchers noticed that Uranus was wobbling in a way that confounded Newton's Law of Motion. This meant they had two options: rewrite the most time-honoured of the laws of physics, or "invent" a new planet to account for the extra gravitational pull. Compared to Newton's reputation, an eighth planet seemed much less massive and Neptune was discovered.

Today scientists working in the University of Louisiana have discovered a statistical anomaly of similar proportions. Professors John Matese [see below], Patrick Whitman and Daniel Whitmire have studied the orbits of comets for 20 years, and their recent findings have led to startling theories.

//

The latest effort of Matese, Whitman and Whitmire studies 82 comets from the huge cloud of comets, called the Oort cloud, that exists around our solar system. They took the aphelia of these comets, the points on their orbit that are farthest from our Sun, and plotted them on a globe. Expecting to find an even distribution, they instead found that a particular band of sky, about one sixth the total, contained more than one quarter of all the comets, and that about 25 per cent of the comets coming from this cloud have anomalous paths.

So what was affecting the orbits? They went on to theorise that the best explanation is the existence of a previously unknown body - that our solar system is made up of the Sun and a shadowy partner, either a brown dwarf or a massive planet, in a wide binary system. In effect, the solar system had two stars, the Sun and a dark companion, spinning around each other.

Now I know what you're thinking Surely I'd have noticed a second Sun in the sky? But, as Prof Whitmire explained, the process of assumption based on statistical anomalies has always been a cornerstone of scientific discovery. According to their current theory, he says, "the companion is a brown dwarf star or massive planet of mass between two and six times the mass of Jupiter". A brown dwarf is a star too small to sustain the nuclear fusion that powers our Sun, and so is relatively cool (surface temperature of less than 1500C) and so also very dim, being barely hot enough to give off light.

But it gets worse. Under their original theory, called the Nemesis theory, this small dark star, which lurks at around 90,000 times farther away than the Earth is from the Sun, may be on an orbit that, once every 30 million years, ploughs it into the densely packed inner cloud. Here its immense gravitational pull would drag out several of the Oort comets and give them the "kick" needed to send them towards the Sun on orbits perilously close to the Earth. This explains, in the professor's view, the ominous mass extinction cycle, due to regular periods of increased cometary activity every 30 million years.

However, before we head for the bomb shelters, we should take heed of the professor's words: "As a practical matter our models will never be generally accepted (and shouldn't be) until the actual object is found." However stressing that they are "sufficiently plausibleto give incentives for others to look".

Today, their current paper has moved away from the Nemesis theory and proposed, on the basis of comet orbits, a less massive planet about three times the mass of Jupiter. None the less, with an explanation for the mass extinction cycle yet to be found, he has admitted that they may not be mutually exclusive; and that there could be two dark stars, one a failed partner to our own, and another one that is acting almost as an alarm clock for doomsday. Even so, he says: "I'm still hopeful that ultimately these might turn out to be the same object.".

"An original idea in science is often a gut instinct, but this should not influence the development of the idea," says the professor. "I always try to be my own worst critic". The scientific world remains intrigued but sceptical. However, the recent bombardment of Jupiter is a reminder that if the team is right, there may not be many around to hear them say: "I told you so."



A Tenth Planet?
Disturbance of Comets Hints at Something Out There

By Kenneth Chang

[ABCNEWS.com]Oct. 7 -- Astronomers may have found hints of a massive, distant, still unseen object at the edge of the solar system -- perhaps a 10th planet, perhaps a failed companion star -- that appears to be shoving comets toward the inner solar system from an orbit 3 trillion miles away.

Two teams of scientists -- one in England, one at University of Louisiana at Lafayette --independently report this conclusion based on the highly elliptical orbits of so-called "long-period comets" that originate from an icy cloud of debris far, far beyond Pluto. "

"We were driven to this by rejecting everything else we could think of," says University of Louisiana physicist Daniel Whitmire.

Clump of Comets

A couple years ago, Whitmire, along fellow physicists John Matese and Patrick Whitman, noticed the farthest points of the comets' orbits didn't appear random but bunched together, tracing a path across the sky.

"We accidentally noticed they weren't uniform," Whitmire says.

First, they tried to explain the clumping from the gravitational pull from a main disk of stars in the Milky Way stars. "That ultimately didn't work," Whitmire says. "We've gone through several other models trying to explain this."

At around the same time, John Murray, a planetary scientist at The Open University in Great Britain, made a similar observation in similar comet data. "I started puzzling what this might could be," he says.

The most obvious but seemingly unlikely explanation would be a planet. "I thought we퉐 better rule that out," he says. But as he analyzed the orbits, the farthest points appeared to fall on a circular orbital path -- "which is exactly what you would expect if there was a planet out there."

As the planet -- estimated to have a mass between one and 10 Jupiters -- orbits, its gravitational wake disturbs the icy debris of the outer solar system, causing some of it to plunge toward the sun as comets, sort of like an elephant ambling through a china shop.

No one has yet directly observed a 10th planet, and there could still be another cause for the cluster of comets.

[The University of Louisiana research will be published in an upcoming issue of the journal Icarus. Murray's paper appears in the Oct. 11 issue of the Monthly Notices of the Royal Astronomical Society.]

Very Distant

What's surprising is just how far out there this supposed planet is. Both Murray and the University of Louisiana physicists put the planet in an orbit about 3 trillion miles -- or half a light-year -- from the sun. The nearest star is four light-years away.

To put this distance in perspective, consider a miniaturized version of the solar system in which Earth is one inch from the sun. On this scale, Pluto, the ninth planet would be a bit more than a yard from the sun. The new planet, by contrast, would be a half-mile distant.

At that great distance, the 10th planet would be too dim to see by current telescopes, although there is some hope that if it exists, the next generation of space-based infrared telescopes might be able to pick it up.

Murray hypothesizes the planet may have been wandering through the galaxy before being captured by the solar system퉠 gravity. Whitmire suggests it is a "brown dwarf," or a failed star, a companion to the sun that was too small to light up.

Although suggestive, the findings are not conclusive. While Murray and the Louisiana physicists agree how distant the new object is, they trace out very different orbits. Murray considers the orbits of 13 comets with the most accurately known orbits; the Louisiana team considers 82.

Too Early to Look for a Name

"It's possibly suggestive," comments Brian Marsden, associate director for planetary sciences at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "I don't want to bet on it. We're certainly not going to name it."

Whitmire agrees it's too early to say definitely there's something out there.

"Until it's found, you can never be overly confident," he says. "We know in science you can be fooled by statistics." But he adds, "If I was betting, it's better than 50-50 odds that it's there."




Astrophysical Dynamics With an Emphasis on Minor Bodies
The Oort Comet Cloud and Its Interaction With Our Milky Way Galaxy

John J. Matese
Professor of Physics
University of Louisiana at Lafayette

The bulk of my recent research activity has centered on the Oort comet cloud. In particular, the distributions of observed orbital elements can differ from the in-situ distributions because of observational selection effects and observational uncertainties. Of more interest dynamically is the imprint of the physical mechanism responsible for making these comets observable. To make a comet observable its perihelion distance, q, must be reduced to sufficiently small values that the solar insolation will create a detectable coma. Since the angular momentum of a near-parabolic orbiting Oort cloud comet is proportional to q1/2 , to reduce q we must reduce angular momentum, and the tidal torque of our Milky Way Galaxy is the dominant mechanism for doing so. Specifically, we argue that the tidal torque due to the smoothed matter density of the galactic disk leaves its own signature on these Oort cloud comet orbital element distributions. Thus "what you see is not what you've got out there."

A substellar solar companion in the Oort cloud?

The following figure illustrates the scatter on the celestial sphere of outer Oort cloud comet aphelia directions in galactic coordinates.

The pronounced deficiencies at the galactic equator and at the galactic poles are characteristic of the galactic interaction which is minimal at these locations. But we also note an anomalous concentration of points along a "great circle" which passes near the galactic poles. In an article in the journal Icarus, we have suggested that there is statistically significant evidence that this concentration, amounting to an excess of approximately 25%, could be caused by a companion to the Sun which aids the galactic tide in making Oort cloud comets observable. The companion is estimated to have a mass of 3 MJupiter and a mean distance at the interaction site of 25000 AU. Its location along the great circle is not presently predictable and that will present a problem for detection, but it is potentially observable in the radio using the VLA and should also be observable in the infrared at 5 microns using the next generation of space telescopes such as SIRTF and SOFIA. An object with these properties would be readily seen by NGSS (Next Generation Sky Survey), one of four missions selected for further Phase A study in NASA's MIDEX program. The estimated mass of the companion puts it below the nominal brown dwarf limit (~ 13 MJupiter ) where deuterium fusion can occur and would make it a planet in that context. However its location in the outer Oort cloud means that it is not possible that it formed in the protosolar planetary disk. The object could have been ejected from another stellar system and captured by the Sun in their complex star forming region.

At the IAU Symposium 202 "Planets in the Universe" we have presented supportive evidence of the solar companion conjecture. Since the Icarus paper was published twenty seven new outer Oort cloud comets have been discovered. The previously noted overpopulated band maintains an excees. This strengthens the statistical evidence for correlated orbital elements as predicted by the analysis.

[VanIslander]

[mithridates]

Want to see something even more awe-inspiring? I've used this image before but maybe you haven't seen it:

Behold, one quintillion pennies!



That little black blip down there is the Sears Tower and the white one is the Empire State Building. This is how big a quintillion pennies would be. About 400 000 Sears Towers can fit inside this one cube.

Now take this, and multiply it by 70 000. That's about how many are in the universe.

Visible stars, that is.

Then multiply that by about 100 000 objects orbiting each star. Times 15 billion years for life to have the chance to spring forth.