Video: Earthlings brace for close encounter with asteroid

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updated 6/24/2011 7:59:35 PM ET 2011-06-24T23:59:35

Here's something to dwell on as you head to work next week: A small asteroid the size of a tour bus will make an extremely close pass by the Earth on Monday, but it poses no threat to the planet. 

The asteroid will make its closest approach at 1:14 p.m. ET on June 27 and will pass just over 7,500 miles above Earth's surface, NASA officials say. At that particular moment, the asteroid — which scientists have named 2011 MD — will be sailing high off the coast of Antarctica, almost 2,000 miles (3,218 kilometers) south-southwest of South Africa.

Image: Asteroid trajectory
NASA
This chart shows the trajectory of asteroid 2011 MD during its flyby from the general direction of the sun.

Asteroid 2011 MD was discovered Wednesday by LINEAR, a pair of robotic telescopes in New Mexico that scan the skies for near-Earth asteroids. The best estimates suggest that this asteroid is between 29 and 98 feet (9 to 30 meters) wide.

According to NASA's Near-Earth Object Office at the Jet Propulsion Laboratory in Pasadena, Calif., an object of this size can be expected to come this close to Earth about every six years or so, on average.

"There is no chance that 2011 MD will hit Earth, but scientists will use the close pass as opportunity to study it w/ radar observations," astronomers with NASA's Asteroid Watch program at JPL wrote in a Twitter post Thursday.

Even if the asteroid were to enter Earth's atmosphere, it probably wouldn't reach the surface, they added.

"Asteroid 2011 MD measures about 10 meters. Stony asteroids less than 25 m would break up in Earth's atmosphere & not cause ground damage," Asteroid Watch scientists said.

The asteroid's upcoming Earth flyby will be a close shave, but not a record for nearby passing asteroids. The record is currently held by the asteroid 2011 CQ1, which came within 3,400 miles (5,471 kilometers) of Earth on Feb. 4 of this year.

A tricky skywatching target
For several hours before its closest approach, 2011 MD will be visible in moderately large amateur telescopes. But despite its close approach, actually seeing this asteroid will not be an easy task.

"These objects are so small (10 meters) that normally a sizable telescope is required," Asteroid Watch scientists warned.

You will need to have access to an excellent star atlas, and because it will be moving so rapidly you'll also need the very latest data from the Minor Planet Center to track its precise course against the background stars. The asteroid is not expected to get very bright; about 250 times dimmer than the faintest stars visible to the eye without optical aid.

The asteroid will pass so close that Earth's gravity will sharply alter the asteroid's trajectory.

After making its closest pass to Earth, the asteroid will zoom through the zone of geosynchronous satellites. The chance of a collision with a satellite or piece of space junk is exceedingly remote.

History of near-Earth asteroids
On Oct. 28, 1937, German astronomer Karl Reinmuth (1892-1979) accidentally photographed the long trail of a fast-moving asteroid. Two nights later, this asteroid passed within 460,000 miles of the Earth. Reinmuth named it Hermes, after the Olympian god of boundaries and travelers. 

Since the vast majority of asteroids (so far numbering more than 210,000) congregate between the orbits of Mars and Jupiter, astronomers at that time felt that Hermes' very close approach was an outstanding exception.

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"Astronomers of the day were somewhat biased," explained NASA asteroid scientist Paul Chodas. "They had convinced themselves that collisions were too rare to consider."

Since then, astronomers have learned that asteroids can make very close approaches to Earth with far greater frequency than previously thought. Asteroid 2011 MD's Monday pass is a prime example of that.

Of the 8,099 Near-Earth objects that have been discovered, about 827 of them are asteroids with a diameter of approximately a half-mile or larger. About 1,236 of these NEOs have been classified as Potentially Hazardous Asteroids.

NASA currently plans to launch a probe to visit one of these potentially dangerous near-Earth objects and return samples of the asteroid to Earth.

That mission will launch the OSIRIS-Rex asteroid probe in 2016 to rendezvous with the space rock 1999 RQ36 in 2020. The target asteroid is 1,900 feet wide and has a 1-in-1,800 chance of hitting Earth in the year 2170, and a 1-in-1,000 chance of slamming into us in 2182.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, N.Y.

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Interactive: Below the belt

Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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