Case of Sedna's Missing Moon SolvedWhen the distant planetoid Sedna was discovered on the outer edges of our solar system, it posed a puzzle to scientists. Sedna appeared to be spinning very slowly compared to most solar system objects, completing one rotation every 20 days. Astronomers hypothesized that this world possessed an unseen moon whose gravity was slowing Sedna's spin. Yet Hubble Space Telescope images showed no sign of a moon large enough to affect Sedna. New measurements by Scott Gaudi, Krzysztof (Kris) Stanek and colleagues at the Harvard-Smithsonian Center for Astrophysics (CfA) have cleared up this mystery by showing that a moon wasn't needed after all. Sedna is rotating much more rapidly than originally believed, spinning once on its axis every 10 hours. This shorter rotation period is typical of planetoids in our solar system, requiring no external influences to explain... While these data solve one mystery of Sedna, other mysteries remain. Chief among them is the question of how Sedna arrived in its highly elliptical, eons-long orbit.
Harvard-Smithsonian Center for Astrophysics
April 14, 2005
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Astronomers claim discovery of 10th planet in solar system
Posted by Srirangan
On News/Activism 07/30/2005 12:09:55 AM PDT · 95 replies · 1,521+ views
Outlook | July 30,2005 | AFP
A US astronomer has said he had discovered a 10th planet in the outer reaches of the solar system that could force a redrawing the astronomical map. If confirmed, the discovery yesterday by Mike Brown of the respected California Institute of Technology would be the first of a planet since Pluto was identified in 1930 and shatter the notion that nine planets circle the sun. "Get out your pens. Start re-writing textbooks today," said Brown, a professor of planetary astronomy, announcing what he called "the 10th planet of the solar system," one that is larger than Pluto. "It's the farthest...
Astronomers to Detail Aspects of Sedna (8 billion miles away, 400 below zero Fahrenheit)
Posted by NormsRevenge
On News/Activism 03/15/2004 9:17:45 AM PST · 31 replies · 166+ views
Yahoo! News | 3/15/04 | Andrew Bridges
LOS ANGELES - It is a frozen world more than 8 billion miles from Earth and believed to be the farthest known object within our solar system. † NASA (news - web sites) planned a Monday press conference to offer more details about Sedna, a planetoid between 800 miles and 1,100 miles in diameter, or about three-quarters the size of Pluto. Named for the Inuit goddess who created the sea creatures of the Arctic, Sedna lies more than three times farther from the sun than Pluto. It was discovered in November. "The sun appears so small from that distance that...
Astronomy Picture of the Day 03-16-04
Posted by petuniasevan
On General/Chat 03/15/2004 9:43:44 PM PST · 7 replies · 159+ views
NASA | 03-16-04 | Robert Nemiroff and Jerry Bonnell
Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 March 16 Sedna of the Outer Solar System Illustration Credit: R. Hurt (SSC-Caltech), JPL-Caltech, NASA Explanation: What is the most distant known object in our Solar System? A new answer to this centuries-old question was announced yesterday by NASA with the discovery of a dark red object dubbed Sedna. Although over twice the distance to Pluto, Sedna is near its closest approach to the Sun. Sedna's highly...
Astronomy Picture of the Day 06-04-04
Posted by petuniasevan
On General/Chat 06/04/2004 1:05:48 PM PDT · 3 replies · 109+ views
NASA | 06-04-04 | Robert Nemiroff and Jerry Bonnell
Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 June 4 Sedna at Noon Illustration Credit: Adolf Schaller, ESA, NASA Explanation: Standing on Sedna - the solar system's most distant known planetoid - your view of the Sun at high noon might look something like this. An artist's dramatic vision, the picture shows the Sun suspended above the nearby horizon as a bright star immersed in the dusty ecliptic plane. Within the dust-scattered sunlight are more...
It's another world ... but is it our 10th planet?
Posted by Tumbleweed_Connection
On News/Activism 03/14/2004 11:46:12 AM PST · 122 replies · 2,335+ views
The Australian | 3/15/04 | Louise Milligan
SCIENTISTS have found a new world orbiting the solar system ñ more than 3 billion kilometres further away from the Sun than Pluto and 40 years away from Earth in a space shuttle. NASA is expected to announce today the discovery of the space object, which some experts believe could be a new planet. It is provisionally known as Sedna, after the Inuit goddess of the sea. The discovery of Sedna ñ 10 billion kilometres from Earth ñ is a testament to the new generation of high-powered telescopes. Measurements suggest Sedna's diameter is almost 2000km ñ the biggest find...
Distant object found orbiting Sun
Posted by AdmSmith
On News/Activism 07/29/2005 6:29:42 AM PDT · 73 replies · 1,728+ views
BBC News website | 29 July 2005 | Dr David Whitehouse
Astronomers have found a large object in the Solar System's outer reaches. It is being hailed as "a great discovery". Details of the object are still sketchy. It never comes closer to the Sun than Neptune and spends most of its time much further out than Pluto. It is one of the largest objects ever found in the outer Solar System and is almost certainly made of ice and rock. It is at least 1,500km (930 miles) across and may be larger than Pluto, which is 2,274km (1,400 miles) across. The uncertainty in estimates of its size is due to...
Distant planetoid Sedna gives up more secrets
Posted by LibWhacker
On News/Activism 04/15/2005 11:23:49 PM PDT · 17 replies · 596+ views
New Scientist | 4/15/05 | Maggie McKee
The distant planetoid Sedna appears to be covered in a tar-like sludge that gives it a distinctly red hue, a new study reveals. The findings suggests the dark crust was baked-on by the Sun and has been untouched by other objects for millions of years. Sedna appears to be nearly the size of Pluto and was discovered in November 2003. It is the most distant object ever seen within the solar system and travels on an elongated path that stretches from 74 to 900 times the distance between the Sun and the Earth. Astronomers have struggled to explain such an...
Distant Sedna Raises Possibility of Another Earth-Sized Planet in Our Solar System
Posted by LibWhacker
On News/Activism 03/18/2004 2:00:00 PM PST · 25 replies · 106+ views
Space.com | 3/16/04 | Robert Roy Britt
Our corner of the galaxy got a little stranger this week with the discovery of Sedna, the most distant object ever spotted in the solar system. Now astronomers are puzzling over how it got there. The most intriguing idea is that there might be another world as big as Earth, a gravitational bully lurking in some unexplored corner of the solar system. Here's the problem: Scientists can't figure out how Sedna, which is about three-fourths as big as Pluto, came to have such a strange orbit around the Sun. Sedna's path is highly elliptic. It ranges from 76 astronomical units...
Scientists Find an Icy World Beyond Pluto
Posted by neverdem
On News/Activism 03/15/2004 10:40:39 PM PST · 17 replies · 100+ views
NY Times | March 16, 2004 | JOHN NOBLE WILFORD
Far beyond Pluto, out where the Sun is only a pinpoint of pale light, a frozen world has been found on the dark fringes of the solar system. Astronomers say it is by far the most distant object known to orbit the Sun and the largest one to be detected since the discovery of Pluto in 1930. With one discovery, it seems, the solar system has gotten much bigger, glimpses of its outer reaches bringing a sense of reality to what had been a remote frontier of hypothesis. And perhaps it has gotten stranger, too. "There's absolutely nothing else like...
Scientists Find Another PLANET in our solar system!
Posted by vannrox
On News/Activism 03/16/2004 6:57:47 PM PST · 33 replies · 3,188+ views
Space DOT com - Breaking News | posted: 03:51 pm ET 15 March 2004 | By Robert Roy Britt Senior Science Writer
Scientists Find Another Huge Mini-World in Outer Solar System The most distant object ever seen orbiting the Sun is nearly as large as Pluto, expanding astronomers notions of how the solar system formed and what resides in its outskirts. The round world is currently three times farther away than Pluto from the Sun, a distance that expands even further on its 10,000-year orbit. It sits in a part of the solar system that some astronomers had thought empty. It is redder and brighter than anything astronomers have seen in the outer solar system, and scientists don't know why. The object...
It's remarkable and ironic how using logic to proceed from invalid assumptions leads later people to surprises when actual observations are done in attempts to verify the old models.Did Jupiter Bully Other Planets in Sibling Rivalry?One possible explanation, discussed in Thursday's issue of the journal Nature, is that Uranus and Neptune formed much closer to the center of the action than their current positions might indicate. In this scheme, Jupiter and Saturn were bullies of a protoplanetary playground, shoving the other two future giants out of the way.
by Robert Roy Britt
8 December 1999Jupiter gave birth to Uranus and NeptuneNot too long ago, scientists regarded the orbits that the planets circle our Sun as being the ones they were born in. Now they are realising that this is not the case. Uranus and Neptune may have migrated outwards and Jupiter may have come in from the outer cold. Scientists have always been slightly puzzled by the positions of Uranus and Neptune because in their present locations it would have taken longer than the age of the Solar System for them to form. Scientists from Queen's University suggest that the four giant planets started out as rocky cores in the Jupiter-Saturn region, and that the cores of Uranus and Neptune were tossed out by Jupiter's and Saturn's gravity.
by Dr David Whitehouse
8 December 1999Jupiter's Composition Throws Planet-formation Theories into DisarrayExamining four-year-old data, researchers have found significantly elevated levels of argon, krypton and xenon in Jupiter's atmosphere that may force a rethinking of theories about how the planet, and possibly the entire solar system, formed. Prevailing theories of planetary formation hold that the sun gathered itself together in the center of a pancake-shaped disk of gas and dust, then the planets begin to take shape by cleaning up the leftovers. In Jupiter's current orbit, 5 astronomical units from the sun, temperatures are too warm for the planetesimals to have trapped the noble gases. Only in the Kuiper belt -- a frigid region of the solar system more than 40 AU from the sun -- could planetesimals have trapped argon, krypton and xenon.
by Robert Roy Britt
Nov 17 1999
While lead researcher Tobias Owen does not put much stock in the idea that Jupiter might have migrated inward to its present position, other scientists on the team say the idea merits consideration. Owen expects the probes will find similarly high levels of noble gases in Saturn, Uranus and Neptune. Hints of these gases have even been found in the thick atmosphere of Venus, another planet now begging more study.
Retrograde satellites lose momentum to the parent body and slowly spiral inward, which puts an upper limit on the length of time the retrograde moons have spent as satellites, and obviously, will spend as satellites.Newfound Moons Tell Secrets of Solar SystemThe fact that most of the satellites' orbits are retrograde and eccentric speaks volumes about their origins: They had to have come from elsewhere, and been captured by the planets at some point. If they formed at the same time as the planets, from the spinning nebular disk, their orbits would be nearly circular and in the same direction as the planets' rotation, like the "regular" moons... In the case of the irregular satellites, they could not have shifted from an orbit around the Sun to an orbit around one of the giant planets without slowing down -- through friction in an atmosphere, perhaps; the influence of gravity; or a collision with another object... But there are two other possibilities for capture, Dr. Nesvorny said. One is that rapid growth of the core led to a corresponding increase in gravity, enough to pull down a nearby object. The other is that captured objects were a result of a collision between two planetesimals, the force of the collision being enough to dissipate the energy of at least one of them. Either of these two theories may be a more likely explanation for the satellites of Uranus and Neptune, which formed differently from Jupiter and Saturn, without the large amounts of gas.
by Henry Fountain
August 12, 2003
Planet Formation In Hundreds Of Years?The British astronomer W.H. McCrea concluded in the '60s, as others have since, that minor planets could not form by accretion inside the orbit of Jupiter because of its disruptive tidal effects, and R.A. Lyttleton showed in a fluid dynamic analysis of Jupiter's core that its rotation and accretion rates would cause it to become periodically unstable and fission to throw off excess mass. We're told that the gas giants don't have rock cores, but that has always struck me as preposterous, since even if they formed from pure gaseous concentrations initially, bodies of that size would surely attract heavier material thereafter. So conceivably gas giants formed rapidly in the way the Pittsburgh simulation depicts represent the first phase of a process that accumulates fast-spinning cores of heavier material that gets compressed down to rocky densities, and ejects them as a planet and comet factory.
Posted on January 27, 2003
Yet another instance of something that Velikovsky was ridiculed and vilified for proposing, finding its way quietly into respectable science though the back door fifty years later.
Am I missing something? This article is a year old...
artist's conceptions:
the view from Sedna:
http://imgsrc.hubblesite.org/hu/db/2004/14/images/e/formats/web_print.jpg
with objects identified:
http://imgsrc.hubblesite.org/hu/db/2004/14/images/f/formats/large_web.jpg
Did Our Sun Capture Alien Worlds?Between 30 and 50 astronomical units from the sun – that is, 2.8 billion to 4.7 billion miles from the sun – several Kuiper belt objects larger than 600 miles in diameter are known to orbit the sun. Sedna, discovered in 2003, is similar to these cold, rock-and-ice worlds, but orbits 70 to 1,000 astronomical units from the sun. It has a high-inclination orbit, which means it does not travel around the sun in the same plane as the major planets. Sedna's orbit also is highly elliptical or elongated.
by Jill Johnston West
University of Utah
Bromley says Kuiper belt objects are influenced by Neptune's gravity, but Neptune alone is too far away to have launched Sedna on its bizarre path, he says.
What caused Sedna's elongated orbit? Answering this question was a key goal of Bromley and Kenyon's study. Their simulations show there is a 5 percent to 10 percent chance Sedna formed within our solar system, probably closer to Neptune or Pluto, and was later launched into its current orbit when our solar system was "buzzed" by another.
Big-orbit Object Confounds Dynamicists
Source: Sky & Telescope Magazine
Published: Thursday, April 5 2001 Author: J. Kelly Beatty
Posted on 04/07/2001 11:46:54 PDT by vannrox
http://www.freerepublic.com/forum/a3acf609e1367.htm
"In the months that followed, an international team led by Brett Gladman (Nice Observatory) quietly tracked the dim interloper. Thanks to their year-long pursuit, it's now clear that 2000 CR105 has a highly eccentric orbit that stretches out to roughly 400 a.u. -- more than 10 times Pluto's mean distance from the Sun and far larger than that of any known Kuiper Belt object. But more puzzling to dynamicists is the orbit's perihelion distance. At 44.5 a.u. (6.7 billion km), it is well beyond the perturbing influence of Neptune, whose gravity has flung countless other bodies out to the solar system's most distant fringes. So how did 2000 CR105 end up stranded out there?"
just a bump to an old topic, with a link to one much older:
Big-orbit Object Confounds Dynamicists
Source: Sky & Telescope Magazine
Published: Thursday, April 5 2001 Author: J. Kelly Beatty
Posted on 04/07/2001 11:46:54 PDT by vannrox
http://www.freerepublic.com/forum/a3acf609e1367.htm
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