NASA Schedules News Briefing About Unusual Solar Object

It's another world . . . but is it our 10th planet?
It's another world . . . but is it our 10th planet?
By Louise Milligan and agencies
15mar04 - The Australian

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.

Interesting BBB. Thanks

The sizes of planets in our solar system
Scientists find '10th planet'
Monday, March 15, 2004 Posted: 12:07 AM EST (0507 GMT)

The Spitzer Space Telescope has sent back stunning images, including this one of a star formation region.

(CNN) -- Scientists may have discovered the solar system's 10th planet, more than 3 billion kilometers further away from the sun than Pluto.

NASA is set to make an official announcement later Monday U.S. time.

The object -- about 10 billion kilometers from Earth -- has been given the provisional name of Sedna after the Inuit goddess of the sea.

Dr. Michael Brown of the California Institute of Technology and his team of astronomers, using the recently launched high power Spitzer Space Telescope, found Sedna during an ongoing three-year outer solar system project.

The Tenagra Observatory in Arizona was used to provide a verifying second set of measurements for the object.

Sedna is the largest object to be found circling the sun since Pluto was discovered in 1930.

The discovery has also sparked debate over what constitutes a planet.

Initial details indicated Sedna to be made of ice and rock and to be of a smaller size than Pluto, with a diameter of almost 2,000 km.

Many astronomers say Pluto, with a diameter of 2,300 km, is too small to be a termed a planet and is actually just one of many minor objects in the outer reaches of the solar system.

But those who argue Pluto is a planet are likely to push the claim for Sedna to become the 10th planet in the solar system.

Dr. Brown will present the discovery during a NASA briefing on Monday at 1:00 p.m. EST (1800 GMT).

The Spitzer Space Telescope was launched in August last year and is the fourth of NASA's Great Observatories. The program also includes the Hubble Space Telescope.

Our solar system

Mercury Diameter: 4,880 km, Mean distance from sun approx. 58 million km.

Venus 12,140 km, 108 million km.

Earth 12,756 km, 150 million km.

Mars 6,787 km, 228 million km.

Jupiter 142,800 km, 778 million km.

Saturn 120,660 km, 1,.4 billion km.

Uranus 51,118 km, 2,9 billion km.

Neptune 49,528 km, 4.5 billion km.

Pluto 2,300 km, 5.9 billion km.

Diameter of 2000 km... Anyone know what earth's is, just for comparisen's sake?

Thanks for the post Bumblebee, I always love to learn more about astronomy

Kevin
Kevin, Earth: Earth 12,756 km, 150 million km.

wow, cool.