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

Video One Year After Thai Coup, No End in Sight for Military Rule

Since carrying out the May 22, 2014 coup, the general has retired from the military but is still firmly in charge More

Goodbye, New York

This is what the fastest-growing big cities in America have in common More

Job-Seeking Bangladeshis Risk Lives to Find Work

The number of Bangladeshi migrants on smugglers’ boats bound for Southeast Asian countries has soared in the past two years 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.
Turkey's Main Opposition Party Hopes for Election Breakthroughi
X
May 22, 2015 10:23 AM
Turkey’s main opposition Republican People’s Party has sought an image change ahead of the June 7 general election. The move comes after suffering successive defeats at the hands of the Islamist-rooted AK Party, which has portrayed it as hostile to religion. Dorian Jones reports from the western city of Izmir.
Video

Video Turkey's Main Opposition Party Hopes for Election Breakthrough

Turkey’s main opposition Republican People’s Party has sought an image change ahead of the June 7 general election. The move comes after suffering successive defeats at the hands of the Islamist-rooted AK Party, which has portrayed it as hostile to religion. Dorian Jones reports from the western city of Izmir.
Video

Video Europe Follows US Lead in Tackling ‘Conflict Minerals’

Metals mined from conflict zones in places like the Democratic Republic of Congo are often sold by warlords to buy weapons. This week European lawmakers voted to force manufacturers to prove that their supply chains are not inadvertently fueling conflicts and human rights abuses. Henry Ridgwell reports from London.
Video

Video Class Tackles Questions of Race, Discrimination

Unrest in some U.S. cities is more than just a trending news item at Ladue Middle School in St. Louis, Missouri. As VOA’s Kane Farabaugh reports, it’s a focus of a multicultural studies class engaging students in wide-ranging discussions about racial tensions and police aggression.
Video

Video Mind-Controlled Prosthetics Are Getting Closer

Scientists and engineers are making substantial advances towards the ultimate goal in prosthetics – creation of limbs that can be controlled by the wearer’s mind. Thanks to sophisticated sensors capable of picking up the brain’s signals, an amputee in Iceland is literally bringing us one step closer to that goal. VOA’s George Putic reports.
Video

Video Afghan Economy Sinks As Foreign Troops Depart

As international troops prepare to leave Afghanistan, and many foreign aid groups follow, Afghans are grappling with how the exodus will affect the country's fragile economy. Ayesha Tanzeem reports from the Afghan capital, Kabul.
Video

Video Poverty, Ignorance Force Underage Girls Into Marriage

The recent marriage of a 17-year old Chechen girl to a local police chief who was 30 years older and already had a wife caused an outcry in Russia and beyond. The bride was reportedly forced to marry and her parents were intimidated into giving their consent. The union spotlighted yet again the plight of many underage girls in developing countries. Zlatica Hoke reports poverty, ignorance and fear are behind the practice, especially in Asia and Africa.
Video

Video South Korea Marks Gwangju Uprising Anniversary

South Korea this week marked the 35th anniversary of a protest that turned deadly. The Gwangju Uprising is credited with starting the country’s democratic revolution after it was violently quelled by South Korea’s former military rulers. But as Jason Strother reports, some observers worry that democracy has recently been eroded.
Video

Video California’s Water System Not Created To Handle Current Drought

The drought in California is moving into its fourth year. While the state's governor is mandating a reduction in urban water use, most of the water used in California is for agriculture. But both city dwellers and farmers are feeling the impact of the drought. Some experts say the state’s water system was not created to handle long periods of drought. Elizabeth Lee reports from Ventura County, an agricultural region just northwest of Los Angeles.
Video

Video How to Clone a Mammoth: The Science of De-Extinction

An international team of scientists has sequenced the complete genome of the woolly mammoth. Led by the Swedish Museum of Natural History in Stockholm, the work opens the door to recreate the huge herbivore, which last roamed the Earth 4,000 years ago. VOA’s Rosanne Skirble considers the science of de-extinction and its place on the planet
Video

Video Blind Boy Defines His Life with Music

Cole Moran was born blind. He also has cognitive delays and other birth defects. He has to learn everything by ear. Nevertheless, the 12-year-old has had an insatiable love for music since he was born. VOA’s June Soh introduces us to the young phenomenal harmonica player.

VOA Blogs