NASA WISE: Uranus and the Planet X myth - debunked

The hunt for Planet X began after Uranus (pictured) was first discovered in 1781 with astrologers hoping it could explain the wobbly orbit of Uranus around the sun

It was an elusive planet that for 200 years appeared to explain Uranus's wobbly orbit and there was the sister sun theorised to be near our solar system that caused asteroids to swerve toward Earth.

There is just one problem: neither "Planet X" nor "Nemesis" ever existed, researchers now say. Although, there is still a trace of doubt.

"The outer solar system probably does not contain a large gas giant planet ("Planet X"), or a small, companion star ("Nemesis")," concluded University of Pennsylvania astronomer Kevin Luhman, who directed the study using NASA's Wide-field Infrared Survey Explorer (WISE) telescope.

The results were published in the most recent edition of The Astrophysical Journal.

Most theories had estimated Planet X to be up to four times the size of Jupiter—the biggest planet in our solar system.

They suggested it would be found some 1,486 billion kilometers (923 billion miles) from the sun, or about 10,000 times farther than the Earth's orbit.

But the images gathered by the telescope did not detect any object larger than Jupiter.

Luhman doesn't rule out the possibility that a planet is lurking somewhere in the asteroid belt.

It would be hard to find if it were closely aligned with a bright star that blinds the telescope or were much smaller than had been theorized.

A computer generated NASA montage obtained 29 August 2002 from images collected by the Voyager 2 spacecraft shows Neptune (Lower-L) as it would appear from a spacecraft approaching Triton, Neptune's largest moon

But after this latest survey, Luhman said the odds of finding one are very unlikely: "That is like a one in a hundred chance."

History of Planet X
Scientists first imagined the existence of Planet X in 1781, when they discovered Uranus, a gas giant that astonished astronomers with its orbital variations, apparently incompatible with Newton's laws of gravity.

Observers concluded that these irregularities could be explained by the existence of another, unknown planet that was exerting its own gravitational force.

Attempts to track this mysterious Planet X led to the discovery of Neptune in 1846. But the estimated mass of Neptune couldn't explain the deviations of Uranus's orbit.

That led astronomers to continue their search for Planet X—which, in turn, led to the discovery of Pluto in 1930. But the dwarf planet was also too small to explain Uranus's irregular path around the sun.

Finally, in the 1990s, researchers determined that they had slightly overestimated the mass of Neptune, which meant the planet could in fact be the reason for Uranus's orbital behaviour.

Yet Planet X believers were still not convinced.

Sister sun killed dinosaurs?
The existence of Nemesis, a sun-like star nearby, was first posited in the 1980s. The star, by occasionally coming closer to the sun, interfered with the orbit of comets and asteroids leading them to occasionally hit the Earth.

Collisions like these are blamed for the five mass extinctions over the last 540 million years—the most recent being the dinosaur extinction 65 million years ago.

"So over the years, there have been different pieces of evidence suggesting there might be something there," Luhman explained to reporters but the WISE telescope didn't find anything.

The hunt for Planet X and Nemesis may have turned up empty, but the study did uncover 3,525 stars and brown dwarfs, celestial objects whose mass puts them between a star and a large planet, within 500 light years of the sun.

"Neighbouring star systems that have been hiding in plain sight just jump out in the WISE data," said Ned Wright, a University of California, Los Angeles astronomer who contributed to the study.

NASA WISE survey finds thousands of new stars, but no 'Planet X'

A nearby star stands out in red in this image from the Second Generation Digitized Sky Survey (DSS). 

Image credit: DSS /NASA/JPL-Caltech

After searching hundreds of millions of objects across our sky, NASA's Wide-Field Infrared Survey Explorer (WISE) has turned up no evidence of the hypothesized celestial body in our solar system commonly dubbed "Planet X."

Researchers previously had theorized about the existence of this large, but unseen celestial body, suspected to lie somewhere beyond the orbit of Pluto.

In addition to "Planet X," the body had garnered other nicknames, including "Nemesis" and "Tyche."

This recent study, which involved an examination of WISE data covering the entire sky in infrared light, found no object the size of Saturn or larger exists out to a distance of 10,000 astronomical units (au), and no object larger than Jupiter exists out to 26,000 au.

One astronomical unit equals 93 million miles. Earth is 1 au, and Pluto about 40 au, from the Sun.

Kevin Luhman

"The outer solar system probably does not contain a large gas giant planet, or a small, companion star," said Kevin Luhman of the Center for Exoplanets and Habitable Worlds at Penn State University, author of a paper 'A SEARCH FOR A DISTANT COMPANION TO THE SUN WITH WISE' in the Astrophysical Journal describing the results.

But searches of the WISE catalogue are not coming up empty. A second study reveals several thousand new residents in our Sun's "backyard," consisting of stars and cool bodies called brown dwarfs.

Ned Wright

"Neighbouring star systems that have been hiding in plain sight just jump out in the WISE data," said Ned Wright of the University of California, Los Angeles (UCLA), the principal investigator of the mission.

WISE survey finds thousands of new stars, but no 'Planet X'

Data from NASA's WISE, has found no evidence for a hypothesized body sometimes referred to as "Planet X." 

Credit: Penn State University

The second WISE study, which concentrated on objects beyond our solar system, found 3,525 stars and brown dwarfs within 500 light-years of our Sun.

Davy Kirkpatrick

"We're finding objects that were totally overlooked before," said Davy Kirkpatrick of NASA's Infrared and Processing Analysis Center (IPAC) at the California Institute of Technology, Pasadena, Calif.

Kirkpatrick is lead author of the second paper, also in the Astrophysical Journal.

Some of these 3,525 objects also were found in the Luhman study, which catalogued 762 objects.

The WISE mission operated from 2010 through early 2011, during which time it performed two full scans of the sky, with essentially a six-month gap between scans.

The survey captured images of nearly 750 million asteroids, stars and galaxies. In November 2013, NASA released data from the AllWISE program, which now enables astronomers to compare the two full-sky surveys to look for moving objects.

In general, the more an object in the WISE images appears to move over time, the closer it is. This visual clue is the same effect at work when one observes a plane flying low to the ground versus the same plane flying at higher altitude.

Though traveling at the same speed, the plane at higher altitude will appear to be moving more slowly.

Searches of the WISE data catalogue for these moving objects are uncovering some of the closest stars.

The discoveries include a star located about 20 light-years away in the constellation Norma, and as reported last March, a pair of brown dwarfs only 6.5 light-years away, making it the closest star system to be discovered in nearly a century.

Despite the large number of new solar neighbors found by WISE, "Planet X" did not show up.

Previous speculations about this hypothesized body stemmed in part from geological studies that suggested a regular timing associated with mass extinctions on Earth.

The idea was that a large planet or small star hidden in the farthest reaches of our solar system might periodically sweep through bands of outer comets, sending them flying toward our planet.

The Planet X-based mass extinction theories were largely ruled out even prior to the new WISE study.

WISE survey finds thousands of new stars, but no 'Planet X'

The third closest Binary star system to the sun, called WISE J104915.57-531906, is at the center of the larger image, which was taken by NASA's WISE. 

Credit: NASA /JPL /Gemini Observatory /AURA /NSF

Other theories based on irregular comet orbits had also postulated a Planet X-type body.

The new WISE study now argues against these theories as well.

Both of the WISE searches were able to find objects the other missed, suggesting many other celestial bodies likely await discovery in the WISE data.

"We think there are even more stars out there left to find with WISE. We don't know our own sun's backyard as well as you might think," said Ned Wright.

WISE was put into hibernation upon completing its primary mission in 2011.

In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects.

NEOWISE will also characterise previously known asteroids and comets to better understand their sizes and compositions.

Nemesis The Record Breaking Electric car

A battery-powered car has broken the UK land-speed record for electric vehicles at Elvington airfield near York, its makers have said.

The original Nemesis was a heavily modified Lotus Exige with all the conventional mechanicals removed and replaced with a couple of 125kw (168bhp) electric motors, belt reduction drives and a 200-kilogram battery pack. It was originally bought off eBay and clocked an average speed of 148mph (239km/h).

The car was designed and built by a team of British motorsport engineers in Norfolk, and driven by estate agent Nick Ponting, 21, from Gloucestershire.

The previous record was 137mph (220km/h).

The vehicle clocked an average speed of 148.419mph during two runs along the mile-long course.

Mr Ponting said: "It was brilliant. The car felt really good."'Quite straightforward'

The car runs on green electricity which has been generated by wind turbines, run by the Stroud-based company Ecotricity.

Dale Vince, OBE and Founder of Ecotricity said: "It was quite straightforward. We're putting a bit of juice back in the batteries and we're going to go again.

"The driver says it could have been faster. We think we'll top 150mph before we leave here today.

"We built the Nemesis to smash the stereotype of electric cars as something Noddy would drive - slow, boring, not cool."

The previous record had been held by Don Wales, the grandson of Sir Malcolm Campbell.

An attempt by Mr Wales's son, Joe Wales, to beat the record in Bluebird Electric last year, was thwarted after the vehicle's suspension was damaged by a pothole at Pendine Sands in Carmarthenshire.

The record still needs to be ratified by the Motor Sports Association before the record can be officially declared.

Visit EVO website and see more pictures of the Nemesis!