News / Science & Technology

Astronomers Discover New Moon Orbiting Pluto

Two images, taken about a week apart by NASA's Hubble Space Telescope, show four moons orbiting the distant, icy dwarf planet Pluto
Two images, taken about a week apart by NASA's Hubble Space Telescope, show four moons orbiting the distant, icy dwarf planet Pluto
Jessica Berman

Astronomers have discovered a fourth moon orbiting the solar-system's distant dwarf-planet, Pluto.  The speck of rock was spotted by the Hubble space telescope.

The new moon, so far known simply as "P4," is the tiniest of four satellites orbiting Pluto, a sphere of ice and rock smaller than Earth's moon that circles the Sun at a distance of more than five billion kilometers.  P4 was discovered while astronomers were searching, unsuccessfully, for rings around Pluto, which lost its official ranking as the solar-system's ninth planet in 2006.  

Mark Showalter, with the US space agency’s SETI Institute in Mountain View, California, led the team that discovered P4.

Showalter says that when scientists first observed the tiny moon in late June, astronomers thought P4 might be either Nix or Hydra, Pluto’s other smaller moons.

But further observations revealed that the object was a new moon, and an extremely small one - about 13 to 34 kilometers in diameter.

“The reason there’s such a big uncertainty [about] its size is that it all kind of depends on how bright the surface is," said Showalter. "If it’s a fairly bright surface, then it would be a smaller object.  If it’s a fairly dark body, like some of the distant outer solar objects are very, very dark, then it would have to be the larger size.  If you consider those are still remarkably small objects when you consider we are seeing it from three billion miles [4.8 Billion kilometers] away.”

Showalter says P4 is about 10 percent as bright as Nix, which was previously Pluto’s smallest moon.  

Pluto and its largest satellite Charon, which is approximately one thousand kilometers in diameter, form one of two so-called binary systems in our solar system.  The other is the earth-moon system.   

Astronomers believe such double systems were created by massive planetary impacts more than four billion years ago when the solar system was formed.  In the case of Earth, scientists believe a planet about the size of Mars collided with Earth to create our moon.

Showalter says the discovery of P4 suggests Pluto is a dynamic planetary system.

“And of course the mere fact that we have found something new raises the possibility that we should look even a little deeper to see what else might have been overlooked all these years," he said.

The latest discoveries set the stage for NASA’s New Horizons mission, which is scheduled to fly through the Pluto system in 2015.

You May Like

This US Epidemic Keeps Getting Worse

One in 4 Americans suffers from this condition More

How to Safeguard Your Mobile Privacy

As the digital world becomes more mobile, so too do concerns about eroding privacy and increased hacking More

'Desert Dancer' Chronicles Iranian Underground Dance Troupe

Film by Richard Raymond is based on true story of Afshin Ghaffarian and his friends More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Scientists Say Plankton More Important Than Previously Thoughti
X
George Putic
May 26, 2015 9:26 PM
Tiny ocean creatures called plankton are mostly thought of as food for whales and other large marine animals, but a four-year global study discovered, among other things, that plankton are a major source of oxygen on our planet. VOA’s George Putic reports.
Video

Video Scientists Say Plankton More Important Than Previously Thought

Tiny ocean creatures called plankton are mostly thought of as food for whales and other large marine animals, but a four-year global study discovered, among other things, that plankton are a major source of oxygen on our planet. VOA’s George Putic reports.
Video

Video Kenyans Lament Losing Sons to al-Shabab

There is agony, fear and lost hope in the Kenyan town of Isiolo, a key target of a new al-Shabab recruitment drive. VOA's Mohammed Yusuf visits Isiolo to speak with families and at least one man who says he was a recruiter.
Video

Video US-led Coalition Gives Some Weapons to Iraqi Troops

In a video released Tuesday from the Iraqi Ministry of Defense, Iraqi forces and U.S.-led coalition troops survey a cache of weapons supplied to help Iraq liberate Mosul from Islamic State group. According to a statement provided with the video, the ministry and the U.S.-led coaltion troops have started ''supplying the 16th army division with medium and light weapons in preparation to liberate Mosul and nearby areas from Da'esh (Arabic acronym for Islamic State group).''
Video

Video Amnesty International: 'Overwhelming Evidence' of War Crimes in Ukraine

Human rights group Amnesty International says there is overwhelming evidence of ongoing war crimes in Ukraine, despite a tentative cease-fire with pro-Russian rebels. Researchers interviewed more than 30 prisoners from both sides of the conflict and all but one said they were tortured. Henry Ridgwell reports for VOA from London.
Video

Video Washington Parade Honors Those Killed Serving in US Military

Every year, on the last Monday in the month of May, millions of Americans honor the memories of those killed while serving in the armed forces. Memorial Day is a tradition that dates back to the 19th Century. While many people celebrate the federal holiday with a barbecue and a day off from work, for those who’ve served in the military, it’s a special day to remember those who made the ultimate sacrifice. Arash Arabasadi reports for VOA from Washington.
Video

Video Kenya’s Capital Sees Rise in Shisha Parlors

In Kenya, the smoking of shisha, a type of flavored tobacco, is the latest craze. Patrons are flocking to shisha parlors to smoke and socialize. But the practice can be addictive and harmful, though many dabblers may not realize the dangers, according to a new review. Lenny Ruvaga has more on the story for VOA from Nairobi, Kenya.
Video

Video Rolling Thunder Run Reveals Changed Attitudes Towards Vietnam War

For many US war veterans, the Memorial Day holiday is an opportunity to look back at a divisive conflict in the nation’s history and to remember those who did not make it home.
Video

Video Female American Soldiers: Healing Through Filmmaking

According to the United States Defense Department, there are more than 200-thousand women serving in the U.S. Armed Forces.  Like their male counterparts, females have experiences that can be very traumatic.  VOA's Bernard Shusman tells us about a program that is helping some American women in the military heal through filmmaking.
Video

Video Iowa Family's Sacrifice Shaped US Military Service for Generations

Few places in America have experienced war like Waterloo. This small town in the Midwest state of Iowa became famous during World War II not for what it accomplished, but what it lost. As VOA’s Kane Farabaugh reports, the legacy of one family’s sacrifice is still a reminder today of the real cost of war for all families on the homefront.
Video

Video On Film: How Dance Defies Iran's Political Oppression

'Desert Dancer' by filmmaker Richard Raymond is based on the true story of a group of young Iranians, who form an underground dance troupe in the Islamic Republic of Iran. This is the latest in a genre of films that focus on dance as a form of freedom of expression against political oppression and social injustice. VOA’s Penelope Poulou has more.
Video

Video Turkey's Ruling Party Trying to Lure Voters in Opposition Stronghold

Turkey’s AK (Justice and Development) Party is seeking a fourth successive general election victory, with the goal of securing two-thirds of the seats in Parliament to rewrite the constitution and change the country's parliamentary system into a presidential one. To achieve that, the party will need to win seats in opposition strongholds like the western city of Izmir. Dorian Jones reports.
Video

Video Millions Flock to Ethiopia Polls

Millions of Ethiopians cast their votes Sunday in the first national election since the 2012 death of longtime leader Meles Zenawi. Mr. Meles' party, the Ethiopian People's Revolutionary Democratic Front, is almost certain of victory again. VOA's Anita Powell reports from Addis Ababa.

VOA Blogs