Did our sun steal ‘Planet 9’ from another star?

There are eight planets in our solar system, and have been officially ever since Pluto was reclassified as a dwarf planet in 2006. But what if there was a ninth planet, billions of miles past Neptune?

Earlier this year, researchers from CalTech announced that they had found signs of the planet, which is referred to a “Planet 9,” through modeling and computer simulations. If a ninth planet were out there, it would be a big one— ten times the mass of Earth— and very, very far away, completing just one orbit around the sun as slowly as perhaps every 10,000 to 20,000 years.

Related: Scientists may have just found a ninth planet and it’s massive

Now, scientists from Lund University in Sweden have used computer simulations to propose a new theory about how Planet 9— if it exists— came to be a member of the solar system. They propose that it was stolen by our sun from another star about 4.5 billion years ago.

“What we were arguing was that you could create this [Planet 9] around another star, and then the sun could capture it, in a close encounter,” Alexander Mustill, a researcher in the department of astronomy and theoretical physics at Lund University, explained in a video about the theory.

Related: NASA identifies 1,284 new exoplanets, most ever announced at once

“We argue that this is how you could put this planet on a wide orbit around the sun,” he added. “You first create it around another star, and then the sun captures it.”

The researchers argue that this would make this planet an exoplanet, which is the term scientists use to describe planets in other star systems beyond our own. Just last month, NASA announced that they had added over 1,200 new exoplanets to the official roster, all of them discoveries from the Kepler spacecraft that had been validated through a new statistical method.

Related: Planet discovery fuels interest in mythical world of deep space

“It’s very exciting to this that there might be an extrasolar planet in our own solar system,” Mustill said.

The study proposing the new theory about Planet 9 was published online in the Monthly Notices of the Royal Astronomical Society in April.

Source

TOP TEN SPACE PHOTOS: Most Viewed of 2008

10. Supernova Creates “Ribbon” in Space

Like a ribbon trailing from a parade float, a streamer of hydrogen gas seems to waft across the stars in an image taken by the Hubble Space Telescope.

Released in July, this festive shot of a supernova remnant was National Geographic News’s tenth most viewed space photo of 2008.

Bright stripes within the ribbon—which is actually the shock wave from the stellar explosion—appear where the wave is moving edge-on to Hubble’s line of sight.

Ribbon in Space (NASA)

9. First Picture of Alien Planet Orbiting Sunlike Star?

A faint dot above a blazing inferno is possibly the first direct view of a planet outside our solar system orbiting a sunlike star.

The infrared image, taken by the Gemini Observatory in Hawaii, was released in September. At the time astronomers weren’t sure whether the body was a planet or a planetlike object, and it remains to be seen if it is truly orbiting the star.

Two months later independent teams announced the first infrared image of an alien multiplanet system, taken using a pair of ground-based telescopes, as well as the first visible-light picture of an extrasolar planet, snapped by the Hubble Space Telescope.

First photo of alien planet orbiting a star (NASA)

Click here for Top 10 Space Photos of 2008

Signs of Weather Seen on Dwarf Planet

This artist rendering shows the dwarf planet, Eris, with hte sun in the background. The discovery of Eris by Mike Brown of Caltech was announced on July 29, 2005. (NASA/JPL/Caltech)

Signs of Weather Seen on Dwarf Planet

By Jeanna Bryner
Senior Writer
posted: 18 November 2008
08:25 am ET

Strange weather on the icy dwarf planet Eris could be causing changes that scientists are now seeing at the methane-ice sufrace of this distant object in our outer solar system.

Eris is the largest known solar-system object beyond the orbit of Neptune. It is larger than Pluto, with a diameter of ranging somewhere between about 1,490 miles and 1,860 miles (2,400 km and 3,000 km).

A team of researchers examined data on Eris collected from the MMT Observatory in Arizona. They specifically looked at concentrations of methane ice based on light-reflection and absorption information.

Their results show possibly nitrogen ice mixed in with the methane ice covering Eris’ surface. And the relative amount of nitrogen ice increases with depth into the ice, they found.

Story continues after the jump: http://www.space.com/scienceandastronomy/081118-st-dwarf-planet.html

This illustration of the largest known Kuiper Belt Objects shows Xena (later to be called Eris) slightly larger than Pluto. (NASA, ESA, and A. Feild (STScI))

Bob Ferrari writes:

Incidentally it was the discovery of this dwarf planet Eris that lead to the downgrading of Pluto from a planet down to a dwarf planet.