NASA News Briefing About Unusual Solar Object

[7/4]

It's another world ... but is it our 10th planet?

By Louise Milligan and agencies

15mar04

SCIENTISTS have found a new world orbiting the solar system – 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 – 10 billion kilometres from Earth – is a testament to the new generation of high-powered telescopes.

Measurements suggest Sedna's diameter is almost 2000km – the biggest find in the solar system since Pluto was discovered 74 years ago. It is believed to be made of ice and rock, and is slightly smaller than Pluto.

The find will reignite the debate over what constitutes a planet. Some scientists claim even Pluto is too small to count as one.

According to astronomer Michael Brown of the California Institute of Technology, who discovered Sedna, there could be many other new worlds orbiting the Sun and waiting to be discovered.

"Sedna is very big, and much further out than previous discoveries," he said. "I'm pretty sure there are other large bodies up there too."

But physicist and cosmologist Paul Davies, of Sydney's Macquarie University, said it was folly to describe Sedna as a planet. "It's fun, it's exciting, but let's keep it in proportion," Professor Davies said yesterday.

He said scientists had known for "a decade or so the solar system does not come to an abrupt halt" and there were a number of "planetessimals" or little planets, like Sedna.

[Jim Alfredson]

CooL!

[7/4]

Isn't this how the old science fiction movies started? Let's hope it isn't heading directly towards us at great speed!

[Jim Alfredson]

THE PLANET FROM OUTER SPACE!!!

[Alec]

While I like the name Sedna, I'm going to call it:

Planet Groove!

[Jazzmoose]

Sounds more like a wayward comet than a planet...

[7/4]

Sounds more like a wayward comet than a planet...

Damm big ass comet.

[Jazzmoose]

It's the extra strenght industrial Comet!

[Jim Alfredson]

"NASA News Briefing About Unusual Solar Object"

Huhhuh uhuhh... is it Uranus?

huhuhuhuh

anus

huhuhuh

[7/4]

"NASA News Briefing About Unusual Solar Object"

Huhhuh uhuhh... is it Uranus?

huhuhuhuh

anus

huhuhuh

I wasn't going to play the Uranus card, yet you did. Damm you.

And Uranus.

[Jazzmoose]

I was reading an article the other day about scientists wanting to send a probe to Uranus, but that was as far as I got; I took off fast! Hell, I was told they didn't do that until you hit 50, and I'm only 46...

[Jim Alfredson]

I wasn't going to play the Uranus card, yet you did. Damm you.

And Uranus. 

You gotta go there, dude. I mean, what kind of scientist or group of scientists would name a planet Uranus? That's like naming your kid Dickie or Beaver.

June Cleaver: "Gosh Ward, you were a little hard on the Beaver last night."

huhuhuhuhuhuhuh

[7/4]

Distant 'Planetoid' Seen in Our Solar System

Mar 15, 3:50 PM (ET)

By Deborah Zabarenko

WASHINGTON (Reuters) - Astronomers have discovered the coldest and most distant object ever found in the solar system, a dark and frigid world a bit smaller than Pluto and three times farther away.

The new "planetoid," named Sedna after an Inuit goddess who created Arctic sea creatures, is more than 8 billion miles from the sun and never gets above minus 400 degrees Fahrenheit (minus 240 Celsius), astronomers said on Monday.

"The sun appears so small from that distance that you could completely block it out with the head of a pin," said Mike Brown, an astronomer at California Institute of Technology, who led the research team.

Sedna is one of the reddest objects in the solar system, after Mars, and takes 10,500 years to travel its highly elliptical path around the sun.

Brown and the other astronomers detected Sedna on Nov. 14 during a survey of the outer solar system. As they peered into space, they saw stationary stars and other cosmic bodies, and a very slowly moving object that turned out to be Sedna.

"Anything that moves very slowly across the sky, we know it's something in the solar system: a satellite, a planet, an asteroid," Brown said at a telephone news conference. "But this is the most slowly moving object we've ever seen moving across the sky, and we knew it must be something very far away."

As distant and cold as Sedna is now, its orbit around the sun takes it more than 10 times further, to a distance of 84 billion miles.

Sedna revolves once every 40 days, a slow revolution that suggests it might have a moon slowing its twirl, Brown said.

To check this, he and his team plan to use the Hubble Space Telescope, which is peerless at looking at distant objects that appear close together or even fused and determining whether they are separate.

PLANETOID, BUT NO PLANET

Sedna is part of the solar system, but that doesn't mean it's a planet, according to Brian Marsden, director of the Minor Planet Center of the International Astronomical Union.

"I think it would be misleading to call it the 10th planet," Marsden said in a telephone interview. "Just as I think it's misleading to call Pluto the ninth planet."

To be called planets, astronomical objects must be a certain size, and Pluto is at the lower limit of planetary dimensions, Marsden said. They also must "participate" in the events of the solar system, and there again, he feels Pluto does not qualify -- its orbit is neither circular nor in the same plane as the other planets.

Since Sedna is smaller and far more eccentric in its path than Pluto, Marsden questioned its potential planetary status. Brown echoed this assessment, and even seconded Marsden's opinion that Pluto is no planet.

Marsden questioned the planetoid's suggested name, given by its discoverers and not yet approved by the astronomical union. The formal designation for Sedna is 2003VB12.

First detected with the Samuel Oschin Telescope near San Diego, California, Sedna was observed within days on telescopes from Chile to Spain, Arizona and Hawaii.

NASA's new orbiting Spitzer Space Telescope, which looks at the universe with infrared detectors that peer through cosmic dust, was also trained on the distant object.

The Spitzer scope found that Sedna probably has about three-fourths the diameter of Pluto, which would make it the biggest object found in the solar system since Pluto's discovery in 1930.

[7/4]

Scientists find new breed of distant ice world

Planetoid orbits at the edge of our solar system

By Alan Boyle

Science editor

MSNBC

Updated: 6:41 p.m. ET March 15, 2004

Scientists say they have found the first example of a new breed in the solar system's menagerie: a planetoid that spends all its time far beyond Pluto, in a chilly region that was once thought to be empty.

The object could be three-quarters the size of Pluto — leading to speculation in early news reports that it represented a "10th planet" in our solar system. But the head of the discovery team, astronomer Michael Brown of the California Institute of Technology, told journalists Monday that he wouldn't consider the newfound mini-world to be a planet.

Then again, he doesn't consider Pluto to be a major planet either.

Size and distance

The planetoid has not yet been given an official name by the International Astronomical Union, only a number: 2003 VB12. However, Brown and his colleagues have provisionally named it Sedna, after the goddess in Inuit mythology who created sea creatures.

Sedna is thought to be 800 to 1,100 miles (1,200 to 1,700 kilometers) in diameter. That would make it one of the largest objects found in the solar system since Pluto was first spotted in 1930.

What's most distinctive about Sedna, however, is its distance.

"There's absolutely nothing else like it known in the solar system," Brown said.

The mini-planet has an eccentric 10,500-year orbit that ranges between 8 billion and 84 billion miles (12.8 billion and 134 billion kilometers), which is much farther away than the planets and an outlying ring of frozen cosmic leftovers known as the Kuiper Belt.

This led Brown and his colleagues to conclude that Sedna is the first object ever observed in the Oort Cloud, a zone of comets that stretches halfway to the next star.

"If this object were to come into the inner solar system, we would classify it as a comet, and it would be the most spectacular comet anyone had ever seen in their life," he said. "But because it never comes into the inner solar system, it's in that region where comets live before they become comets. That's what the Oort Cloud is."

Puzzling cloud

As far away as Sedna is, scientists didn't expect that anything in the Oort Cloud would be nearly that close to the inner solar system — and that may require a change in theories about the origin of the solar system 4.5 billion years ago, Brown said.

He speculated that the sun was created within a star cluster, and that the gravitational effects of the other stars knocked Sedna and other infant worlds out of their original orbits. Today, that star cluster has dispersed, leaving the Oort Cloud as the result of all that ancient interaction.

“Very little has happened to this object since the beginning of the solar system.” Brown said. Thus, Sedna could open "a new fossil window into the solar system."

Brian Marsden, who heads the International Astronomical Union's Minor Planet Center, agreed that Sedna's location was a "puzzle," but wasn't sure he agreed with Brown's hypothesis. Marsden said the planetoid could instead have been pushed into its current orbit by an as-yet-undiscovered object on the very fringe of the solar system.

"We need to go perhaps a lot further beyond the orbit of Neptune," Marsden told MSNBC.com. "Are there in fact perturbers there in the plane of the ecliptic, like — I hesitate to use the word — planets? ... It's tempting to think there might be more Earth-size planets out there."

Cold and dark

Sedna was found as the result of a systematic search for slow-moving objects at the edge of solar system, Brown said. Researchers first detected the object last Nov. 14, using a 48-inch (1.2-meter) telescope at the Palomar Observatory near San Diego. Three hours' worth of observation told them that the object was extremely distant, and within days, telescopes in Chile, Spain, Hawaii and Arizona were put on the case, along with NASA's orbiting Spitzer Space Telescope.

Members of the research team, including the Gemini Observatory's Chad Trujillo and Yale University's David Rabinowitz, combined data about the object's temperature, spectral signature and motion to estimate how far away and how big Sedna was.

At Sedna's distance, temperatures would not get higher than 400 degrees below zero Fahrenheit (-280 degrees Celsius), making it the coldest known celestial body in the solar system, Brown told journalists.

"If you were standing on the surface of Sedna today, and you held a pin at arm's length, you could cover up the entire sun with the head of that pin," he said.

He said Sedna appears to be made up of equal portions of ice and rock. Although the object is too small and faraway to be seen as anything more than a speck, it appears to have an unusually red and shiny appearance.

"We're quite frankly baffled as to why that is," he said.

Sedna also seems to rotate every 40 days, leading researchers to speculate that a moon may be circling the planetoid in that period of time. "Observations from the Hubble Space Telescope should put that question to rest very quickly," Brown said.

Why not a planet?

So if Sedna turns out to be almost as big as Pluto, and possess a moon as well, why shouldn't it be considered the 10th planet?

"The reason it's difficult to answer that question is because astronomers don’t have an official definition of what is and what isn't a planet, and the reason ... is because for most of the history of humans there hasn't had to be an official definition," Brown said. It's only been since the discovery of Kuiper Belt objects similar to Pluto that astronomers have had to deal with the controversy. Pluto currently ranks as the biggest known object in the Kuiper Belt.

Brown said he would define a planet as a celestial body that is considerably more massive than other objects traveling in similar orbits around their parent star. In contrast, some of the objects in the Kuiper Belt are more than half Pluto's size, and it may be only a matter of time before astronomers find a Kuiper Belt object about as big as Pluto. "So by my definition, Pluto is not a planet," Brown said.

By the same token, he expected Sedna to fail the planet test.

"Our prediction is that there will be many, many more of these objects found over the next five years or over the next decade," Brown said, "and it will turn out that Sedna in fact is also not the most massive object in its orbit out there."

Marsden agreed that if more objects like Sedna are discovered, that would rule out planethood. But he said his view might be different if Sedna turned out to be the only world of its kind at that distance.

"What would I say it is then?" he asked himself. "Would I use the P-word? That's a tricky one. With a circular low-inclination orbit at, say, 90 AU (Sedna's current distance), I might be more inclined to use the P-word than I would with Pluto."

Marsden said the latest discovery demonstrated the importance of studying the solar system's fringes, with increasingly sensitive telescopes as well as space missions such as New Horizons, which would target Pluto and the Kuiper Belt in 2015. Sedna would be worth visiting as well, Marsden said.

"I'd much rather send an unmanned mission to this object than a manned mission to Mars," Marsden said. "And you can quote me on that."

[RDK]

10th planet? Hardly. Most astronomers don't even consider Pluto a planet anymore...

And if anyone disagrees, you can stick it up Uranus!

[chris olivarez]

I just finished listening to "Boss Tenors In Orbit" could their be a connection?

[chris olivarez]

I was reading an article the other day about scientists wanting to send a probe to Uranus, but that was as far as I got; I took off fast! Hell, I was told they didn't do that until you hit 50, and I'm only 46...

Jazzmoose,Jazzmoose.