Space & Innovation

Newfound Asteroid Just Buzzed Earth

An asteroid gave Earth a close shave Sunday (Aug. 28), a day after astronomers first spotted the object.

<p>NASA</p>

The newfound asteroid 2016 QA2 zoomed within 50,000 miles (80,000 kilometers) or so of the planet Sunday. For perspective, the moon orbits Earth at an average distance of 239,000 miles (384,600 km).

Astronomers think 2016 QA2 is between 80 and 180 feet (25 to 55 meters) wide. That means the space rock is slightly bigger than the object that exploded over the Russian city of Chelyabinsk in February 2013, injuring more than 1,200 people.

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The Chelyabinsk asteroid was probably 65 feet (20 m) or so in diameter when it hit Earth's atmosphere, scientists have said. (The Chelyabinsk object exploded high above the ground, generating a powerful shock wave that shattered thousands of windows. The injuries - none of which were fatal - were cuts caused by flying glass.)

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The SONEAR Observatory in Brazil discovered 2016 QA2 on Saturday (Aug. 27). The asteroid has a more elliptical orbit than Earth does, coming as close to the sun as 0.76 astronomical units (AU) and getting as far away as 1.18 AU, according to the Minor Planet Center. (One AU is the average distance form Earth to the sun: about 93 million miles, or 150 million km.)

The newfound asteroid completes one lap around the sun every 350 days, researchers said.

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Asteroids in 2016 QA2's size range could conceivably do serious damage on a local scale if they hit Earth. In 1908, for example, an object thought to be about 130 feet (40 m) wide exploded over Siberia, flattening trees over an 825-square-mile area (2,137 square km). (It may seem like asteroids really have it in for Russia, but the nation's higher incidence of strikes is just a result of its huge size.)

But an asteroid has to be really big - probably at least 0.6 miles (1 km) wide - to potentially wipe out human civilization or cause some other global catastrophe, astronomers have said. Scientists think they've spotted about 95 percent of the potentially hazardous, mountain-size space rocks out there, and none of those objects pose a threat for the foreseeable future.

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GALLERY: The Psychedelic Landscapes of Asteroid Vesta

NASA's Dawn spacecraft orbited the massive asteroid Vesta in 2011 and 2012, giving us an unprecedented look at the protoplanet's landscape, craters and mineral composition. The probe, which is now on its way to dwarf planet Ceres, not only revealed the evolution of Vesta, it also provided vital clues as to the evolution of our solar system. Now, in new images published by NASA, an unusually colorful Vesta landscape is on display. Using data from the mission, scientists at Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany have produced a rather psychedelic view of this otherwise bland landscape. Dawn's camera system is equipped with seven filters, each filter sensitive to a specific wavelength of light. Normally, Vesta would look gray to the naked eye, but when analyzing the ratios of light through Vesta's filters, the landscape pops with color. Shown here, the flow of material inside and outside a crater called Aelia is demonstrated. As different minerals reflect and absorb different wavelengths of light, this composite image is alive with color, each shade representing different kinds of minerals littering Vesta's landscape.

This is Antonia, a crater located inside the huge Rheasilvia basin in the southern hemisphere of Vesta. From this image, planetary scientists have been able to deduce that "the light blue material is fine-grain material excavated from the lower crust. The southern edge of the crater was buried by coarser material shortly after the crater formed. The dark blue of the southern crater rim is due to shadowing of the blocky material."

The impact crater Sextilia can be seen in the lower right of this image. The mottled dark patches are likely impact ejecta from a massive impact and the redish regions are thought to be rock that melted during the impact. The diversity of the mineralogy is obvious here. "No artist could paint something like that. Only nature can do this," said Martin Hoffman, a member of the framing camera team at Max Planck Institute.

Earlier images of Vesta have shown an unusual "pitted terrain" on the floors of the craters named Marcia (left) and Cornelia (right). Once again, the varied colors demonstrate the different minerals and processes that cover Vesta's surface.

This "global" model of Vesta shows the abundance of hydrogen on Vesta's surface. Note that the hydrogen signal is enhanced near the asteroid's equator. The hydrogen is likely from hydroxyl or water bound to minerals in Vesta's surface.

Another, earlier view of Antonia crater, demonstrating the mineral diversity of the region.

This is the distinctive Oppia crater on Vesta, an impact that occurred on a slope. This produced an asymmetric ejecta distribution around the crater -- the red/orange ejecta material is more abundant around the downward slope than around the upward portion.