MANAGUA, Nicaragua, Sept. 12 (UPI) -- Astronomers, including experts at NASA, have questioned whether the blast and crater, reported earlier this week outside the Nicaraguan capital, were actually the product of a meteorite. 
 
 Initial reports, including information issued by the Nicaraguan government, suggested a piece of space rock broke off from a larger asteroid passing between the Earth and its moon -- creating a sizable crater, measuring roughly 40 feet across, near Managua's international airport. 
 
 But NASA officials say the lack of eyewitness accounts raises doubts about that scenario. Plus, astronomers say, the timeline doesn't work out. 
 
 "This event was separated by 13 hours from the close Earth approach of 2014 RC, so the explosion and the asteroid are unrelated," NASA asteroid expert Don Yeomans told National Geographic. "There was no obvious optical fireball or debris trail seen prior to the explosion, so it seems unlikely that the explosion in Nicaragua was related to a meteorite impact." 
 
 Yeomans' doubts are shared by Bill Cooke, head of NASA's Meteoroid Environment Office. Cooke says the energy needed to create such a crater would be the equivalent of a single ton of dynamite. 
 
 "For something to produce a hole in the ground that big, it would have generated a very bright fireball. And nothing was reported ... despite the population," Cooke told Sci-Tech Today. "So I'm very skeptical." 
 
 Nicaraguan officials are apparently now quite confused themselves, and have asked the U.S. to help sort the whole thing out. 
 
 "Considering the small amount of experience and the lack of research means, Nicaragua desires to request the good offices of the (US) embassy to get the support of the US Geological Survey," the country's deputy foreign minister, Orlando Gomez, wrote in a letter to the U.S. Ambassador in Managua, Phyllis Powers. 
 
 It's not yet clear whether the U.S. will provide investigative assistance -- or what the assistance would look like. 
 
 Whatever created the hole in the woods near Managua's airport, it packed a serious punch. The government says its scientists recorded the impact at 24 seismic stations. 

 View Images The Nicaraguan army distributed this photo of an impact crater outside Managua on September 7. Scientists are skeptical about the origin of the crater. 
 
 Photograph by Nicaraguan Army, AP 
 
 An explosion and a crater reported near the capital of Nicaragua raised suspicions on Monday that a meteorite had split off from an asteroid that passed by Earth this weekend and struck our planet. But NASA scientists have now cast doubt on whether the blast outside Managua was even a meteorite at all. 
 
 The blast left a hole 40 feet (12 meters) wide and 19 feet (5 meters) deep outside the international airport serving Nicaragua's capital. Some Nicaraguan astronomers quoted in early news reports attributed the blast to a chip off a weekend asteroid flyby. 
 
 But outside meteorite experts later downplayed links to the small asteroid, dubbed 2014 RC, which passed harmlessly by Earth over the weekend. About the size of a house, 2014 RC passed within 22,000 miles (36,000 kilometers) of our planet on Sunday. 
 
 "Information is limited, but the miss distance of 2014 RC actually precludes any related meteorite impact" at the Managua crater, says MIT asteroid expert Richard Binzel, by email. 
 
 Managua Meteorite? 
 
 Managua residents reported the blast just after midnight. In some news reports, geophysicist Wilfried Strauch of Nicaragua's Institute of Earth Studies attributed the crater to a meteorite impact. 
 
 However, NASA asteroid expert Don Yeomans, author of Near-Earth Objects: Finding Them Before They Find Us, says that outside experts suspect the crater wasn't caused by an impact. 
 
 "This event was separated by 13 hours from the close Earth approach of 2014 RC, so the explosion and the asteroid are unrelated," says Yeomans, because the Earth moves about 870,000 miles (1.4 million kilometers) in 13 hours. "There was no obvious optical fireball or debris trail seen prior to the explosion, so it seems unlikely that the explosion in Nicaragua was related to a meteorite impact." 
 
 Russian Roulette 
 
 Meteorite impacts have occurred at the same time unconnected asteroid flybys in the past, most notably in the February 15, 2013, Chelyabinsk impact, which damaged buildings across central Russia. (See "Chelyabinsk Meteor: The Animated Movie.") 
 
 That meteorite impact sprang from an object roughly the size of 2014 RC exploding in the atmosphere above Russia, with about 500 kilotons of energy, bright enough to sunburn some watchers. A larger asteroid had passed harmlessly over the Southern Hemisphere on the same date. 
 
 Update: In a late Monday report on RC 2014, astronomers at NASA's Near-Earth Object Program based at the Jet Propulsion Laboratory in Pasadena, California, revised size estimates for the asteroid. Radar observations indicate that the asteroid is about 40 feet (12 meters) across and rotates rapidly, several times a minute. That makes it roughly half the size of the 2013 Russian meteorite. 
 
 The NASA update also called the meteorite report from Managua "unrelated" to RC 2014, citing the 13-hour difference in the asteroid flyby and the crater explosion. "As yet, no eyewitness accounts or imagery have come to light of the fireball flash or debris trail that is typically associated with a meteor of the size required to produce such a crater," noted the statement.
– When an asteroid passed by Earth and then a huge crater showed up in Nicaragua, the government there put two and two together and figured an errant piece of space rock was responsible for the hole. But scientists have since cast doubt on the theory, and now Nicaragua is asking for US help in solving the mystery, reports UPI. One of the main reasons scientists are skeptical is that anything capable of digging a crater 40 feet wide and 19 feet deep would have created a huge fireball on the way down, and nobody seemed to see anything. Given that the hole showed up near the airport and an air force base in the capital of Managua, that's hard to explain. Plus, as a NASA expert tells National Geographic, the time of the asteroid's closest pass to Earth and the creation of the hole is off by about 13 hours. "The explosion and the asteroid are unrelated," asserts Don Yeomans. So what then? It beats Nicaragua. "Considering the small amount of experience and the lack of research means, Nicaragua desires to request the good offices of the (US) embassy to get the support of the US Geological Survey," the country's deputy foreign minister wrote to the American ambassador in Managua. No word yet on whether the US will send a team to investigate.