![]() Between the years 21, the chance that Bennu will impact Earth is only 1-in-2,700, but scientists still don’t want to turn their backs on the asteroid. ![]() NASA’s Planetary Defense Coordination Office continues to track near-Earth objects (NEOs), especially those like Bennu that will come within about 4.6 million miles (7.5 million kilometers) of Earth’s orbit and are classified as potentially hazardous objects. The NASA-funded Lincoln Near-Earth Asteroid Research team discovered Bennu in 1999. THERE IS A SMALL CHANCE THAT BENNU WILL IMPACT EARTH LATE IN THE NEXT CENTURY. As Bennu continues to rotate, it expels this heat, which gives the asteroid a tiny push towards the Sun by about 0.18 miles (approximately 0.29 kilometers) per year, changing its orbit. The side of Bennu facing the Sun gets warmed by sunlight, but a day on Bennu lasts just 4 hours and 17.8 minutes, so the part of the surface that faces the Sun shifts constantly. Gravity isn’t the only factor involved with Bennu’s destiny. SUNLIGHT CAN CHANGE THE ASTEROID’S ENTIRE TRAJECTORY. Given the high cost of transporting material into space, if astronauts can extract water from an asteroid for life support and fuel, the cosmic beyond is closer than ever to being human-accessible. Water (two hydrogen atoms bound to an oxygen atom) can be used for drinking or separated into its components to get breathable air and rocket fuel. Although rare metals attract the most attention, water is likely to be the most important resource in Bennu. Closely studying this asteroid will give answers to questions about whether asteroid mining during deep-space exploration and travel is feasible. Although most aren’t made almost entirely of solid metal (but asteroid 16 Psyche may be!), many asteroids do contain elements that could be used industrially in lieu of Earth’s finite resources. …BUT ALSO PLATINUM AND GOLD!Įxtraterrestrial jewelry sounds great, and Bennu is likely to be rich in platinum and gold compared to the average crust on Earth. It would, though, further scientists’ search to uncover the role asteroids rich in organics played in catalyzing life on Earth. However, organic material like the kind scientists hope to find in a sample from Bennu doesn’t necessarily always come from biology. All Earth life forms are based on chains of carbon atoms bonded with oxygen, hydrogen, nitrogen and other elements. Because it is so old, Bennu could be made of material containing molecules that were present when life first formed on Earth. ASTEROIDS MAY HARBOR HINTS ABOUT THE ORIGIN OF ALL LIFE ON EARTH…īennu is a primordial artifact preserved in the vacuum of space, orbiting among planets and moons and asteroids and comets. The asteroid is actually in danger of flying apart, if it starts to rotate much faster or interacts too closely with a planetary body. Bennu is full of holes inside, with 20 to 40 percent of its volume being empty space. It likely took just a few weeks for these shards of space wreckage to coalesce into the rubble-pile that is Bennu. Bennu, for contrast, is about as tall as the Empire State Building. This kind of detritus is produced when an impact shatters a much larger body (for Bennu, it was a parent asteroid around 60 miles wide). Rubble-pile asteroids like Bennu are celestial bodies made from lots of pieces of rocky debris that gravity compressed together. Is Bennu space trash or scientific treasure? While “rubble pile” sounds like an insult, it’s actually a real astronomy classification. BENNU IS A “RUBBLE-PILE” ASTEROID - BUT DON’T LET THE NAME TRICK YOU. Thanks to the Yarkovsky effect - the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat - and gravitational tugs from other celestial bodies, it has drifted closer and closer to Earth from its likely birthplace: the Main Asteroid Belt between Mars and Jupiter. Not only is it conveniently close and carbonaceous, it is also so primitive that scientists calculated it formed in the first 10 million years of our solar system’s history - over 4.5 billion years ago. …AND VERY, VERY OLD.īennu has been (mostly) undisturbed for billions of years.
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