News / Science & Technology

Asteroid's Spin Intrigues Astronomers

A simulation of asteroid 2012 DA14 approaching from the south as it passes through the Earth-moon system on Feb. 15, 2013. (/NASA/JPL-Caltech)
A simulation of asteroid 2012 DA14 approaching from the south as it passes through the Earth-moon system on Feb. 15, 2013. (/NASA/JPL-Caltech)
Suzanne Presto
Astronomers hope to learn more about Asteroid 2012 DA14's features and composition as it flies past Earth at about 7.8 kilometers per second - far faster than a speeding bullet.  But that's not all they hope to discern when the object comes within 28,000 kilometers of our planet on February 15.  

Spin

Michael Busch is a planetary astronomer at the National Radio Astronomy Observatory in the southwestern U.S. state of New Mexico.  He says the direction of DA14's spin is important in predicting the way its orbit will change over time.
   
"One of the interesting things about DA14 is we expect its spin state will change as it flies by the Earth," said Busch.  "The Earth's gravity will pull slightly more on one side of the asteroid than on the other, and that will change its spin."

Speckles

The U.S. space agency's Goldstone antenna in the western state of California will beam radio waves toward the asteroid.  Busch and his team will be about 1,000 kilometers away in New Mexico, where the National Radio Astronomy Observatory operates a pair of antennas, about 400 kilometers apart.  The two antennas will receive the waves reflected off the asteroid's uneven surface.  

Busch explains parts of the asteroid will reflect the signal differently, allowing astronomers to observe so-called "speckles."  

"That pattern is random, but it moves across the Earth as the asteroid spins, so by tracking the time difference in when a different speckle arrives at a given antenna, I can figure out how fast and in what direction the asteroid is spinning," he said.

Changes in Orbit

Busch also explains that the part of the asteroid that is in view of the sun develops a hot spot that radiates heat.  This exerts a gentle, jet-like push that can speed up or slow down the asteroid.  Over time, this can significantly alter its orbit.

Astronomers with NASA, the U.S. space agency, say 2012 DA14's next notable close approach to our planet will be in 2046, and even then, it won't strike the Earth.  
Busch notes that while scientists can - for the most part - precisely predict DA14's orbit for the next century, this space rock will yield important insights into the behavior of other asteroids.  

"With the radar observations that we'll get this weekend after the close approach and the optical infrared data that is also coming in, we will be able to much better predict where DA14 in particular is going and run that orbit out much further into the future," said Busch.  "But this also lets us begin to understand the properties of the near-Earth asteroids as a population."

The U.S. space agency says, on average, an asteroid the size of 2012 DA14 gets close every 40 years and hits every 1,200 years.

You May Like

Multimedia Obama Defends Immigration Action

Obama says with his executive action on immigration, enforcement resources will be focused on 'felons, not families; criminals, not children' More

US-Led Airstrikes in Syria Kill Over 900: Monitoring Group

British-based Syrian Observatory for Human Rights says the toll includes more than 50 civilians, five of them women and eight of them children More

Report: Obama Broadens US Combat Role in Afghanistan

The New York Times says resident Barack Obama has signed a classified order extending the role of US troops in Afghanistan for another year More

This forum has been closed.
Comment Sorting
Comments
     
by: jasper johns from: memphis
February 17, 2013 8:17 PM
There's a great, funny, novel about an asteroid heading toward earth and how people deal with it. It's called THE MYOSHI EFFECT.


by: Michael from: USA
February 15, 2013 9:59 AM
"Ah, yes space objects are so beautiful", holding breath and wiping sweat away with a cloth--

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
New Skateboard Defies Gravityi
X
November 21, 2014 5:07 AM
A futuristic dream only a couple of decades ago, the hoverboard – a skateboard that floats above the ground - has finally been made possible. While still not ready for mass production, it promises to become a cool mode of transport... at least over some surfaces. VOA’s George Putic reports.
Video

Video New Skateboard Defies Gravity

A futuristic dream only a couple of decades ago, the hoverboard – a skateboard that floats above the ground - has finally been made possible. While still not ready for mass production, it promises to become a cool mode of transport... at least over some surfaces. VOA’s George Putic reports.
Video

Video Falling Gas Prices Impact US Oil Extraction

With the price of oil now less than $80 a barrel, motorists throughout the United States are benefiting from gas prices below $3 a gallon. But as VOA’s Kane Farabaugh reports, the decreasing price of petroleum has a downside for the hydraulic fracturing industry in the United States.
Video

Video Tensions Build on Korean Peninsula Amid Military Drills

It has been another tense week on the Korean peninsula as Pyongyang threatened to again test nuclear weapons while the U.S. and South Korean forces held joint military exercises in a show of force. VOA’s Brian Padden reports from the Kunsan Air Base in South Korea.
Video

Video Mama Sarah Obama Honored at UN Women’s Entrepreneurship Day

President Barack Obama's step-grandmother is in the United States to raise money to build a $12 million school and hospital center in Kogelo, Kenya, the birthplace of the president's father, Barack Obama, Sr. She was honored for her decades of work to aid poor Kenyans at a Women's Entrepreneurship Day at the United Nations.
Video

Video Gay Evangelicals Argue That Bible Does Not Condemn Homosexuality

More than 30 U.S. states now recognize same-sex marriages, and an increasing number of mainline American churches are blessing them. But evangelical church members- which account for around 30 percent of the U.S. adult population - believe the Bible unequivocally condemns homosexuality. VOA's Jerome Socolovsky reports that gay, lesbian, bisexual and transgender evangelicals are coming out. Backed by a prominent evangelical scholar, they argue that the traditional reading of the bible is wrong.
Video

Video Ebola Economic Toll Stirs W. Africa Food Security Concerns

The World Bank said Wednesday that it expects the economic impact of the Ebola outbreak on the sub-Saharan economy to cost somewhere betweenf $3 billion to $4 billion - well below a previously-outlined worst-case scenario of $32 billion. Some economists, however, paint a gloomier picture - warning that the disruption to regional markets and trading is considerable. Henry Ridgwell reports from London.
Video

Video Mexico Protests Escalate Over Disappearances

Protests in Mexico over 43 students missing since September continue to escalate, reflecting growing anger among Mexicans about a political system they view as corrupt, and increasingly tainted by the drug trade. Mounting outrage over the disappearances is now focused on the government of President Enrique Pena Nieto, accused of not doing enough to end insecurity in the country. More from VOA's Victoria Macchi.
Video

Video US Senate Votes Down Controversial Oil Pipeline - For Now

The U.S. Senate has rejected construction of a controversial pipeline to transport Canadian oil to American refineries. The $5 billion project still could be approved next year, but it faces a possible veto by President Barack Obama. As VOA’s Michael Bowman reports, the pipeline has exposed deep divisions in Congress about America’s energy future.
Video

Video Can Minsk Cease-fire Agreement Hold?

Growing tensions between government troops and separatists in eastern Ukraine further threaten a cease-fire agreement reached two months ago in the Belarusian capital of Minsk. Critics of U.S. policy in Ukraine say it is time the Obama administration gives up on that much-violated cease-fire and moves toward a new deal with Russia. VOA's Scott Stearns has more.
Video

Video Chaos, Abuse Defy Solution in Libya

The political and security crisis in Libya is deepening, with competing governments and, according to Amnesty International, widespread human rights violations committed with impunity. VOA’s Al Pessin reports from London.
Video

Video US Hosts Record 866,000 Foreign Students

Close to 900,000 international students are studying at American universities and colleges, more than ever before. About half of them come from Asia, mostly China. The United States hosts more foreign students than any other country in the world, and its foreign student population is steadily growing. Zlatica Hoke reports.
Video

Video Ferguson Church Grapples with Race Relations

Many white residents of Ferguson, Missouri, say they chose to live there because of the American Midwest community's diversity. So, they were shocked when a white police officer killed an unarmed black teenager in August – and shaken by the resulting protests and violence. Some local churches are leading conversations on how to go forward. VOA’s Ayesha Tanzeem reports.

All About America

AppleAndroid