Dozens of people across Wyoming, Colorado and Utah spotted a fireball streaking through the sky on Thursday.<\/p>\n
The American Meteor Society (AMS) received\u00a0nearly 30 reports<\/a>\u00a0of a fireball between 9 p.m. and 9:45 p.m. Thursday.\u00a0Orion T.,\u00a0who saw it over Casper\u00a0<\/a>at 9:41 p.m., said it had a \u201clight blue and orange tail with a white body\u201d that was visible for less than two seconds before quietly disappearing.<\/p>\n \u201cFireballs\u201d are meteors, rapidly disintegrating as they descend through Earth\u2019s atmosphere. Although they\u2019re fairly common, if one looks hard enough, their short duration makes them difficult to spot.<\/p>\n Max Gilbraith, planetarium coordinator for the University of Wyoming, said the moving direction and descent angle of the fireball, along with the reports submitted to the AMS, indicate that it might have ended its journey somewhere in southwest Wyoming.<\/p>\n The fireball might have flamed out over Flaming Gorge.<\/p>\n \u201cAlmost no one’s reporting sound from this one,\u201d he said. \u201cThere might be a mineral-rich meteor in the ground in Flaming Gorge National Recreation Area.<\/p>\n Rainbow Bright<\/p>\n The AMS defines a fireball as \u201ca very bright meteor, generally brighter than magnitude -4,\u201d making it brighter than anything else in the night sky except for a full moon. Hundreds of fireballs fall to Earth every day, but most are too small to be seen or cannot be seen during daylight hours.<\/p>\n \u201cThey enter the atmosphere burning hotter than the surface of the sun,\u201d\u00a0Galbraith\u00a0said. \u201cIt can hurt your eyes if you see it.\u201d<\/p>\n Fireballs also come in\u00a0many different colors<\/a>. Those are determined by the elements in the meteor that are burned off by the extreme heat generated as it hurtles through the sky.<\/p>\n Green fireballs are fairly common, usually from the burning of iron and magnesium. Depending on the meteor\u2019s elemental composition, observers might see an entire spectrum of colors, including green, blue, yellow, purple, pink, white, and red.<\/p>\n The eyewitness reports submitted to the AMS include people seeing orange, light blue, green, and white. Gilbraith described those as \u201cfirework colors,\u201d as the colors of fireworks are created by adding specific elements to them.<\/p>\n \u201cRed, orange, and white are expected from the black body radiation of a really hot object,\u201d he said. \u201cGreen is usually iron, but other colors can come from magnesium, nickel, and stuff like that.\u201d<\/p>\n The Tree-Forest Conundrum<\/p>\n If a tree falls in the forest, and nobody\u2019s there to hear it, does it make a sound? Yes, obviously, but what about fireballs?<\/p>\n Once they reach a certain threshold, many fireballs violently explode before they hit the ground. The Chelyabinsk meteor, which exploded in the atmosphere over Russia in 2013, was 30 times more powerful than \u201cLittle Boy,\u201d the atomic bomb dropped on Hiroshima at the end of World War II.<\/p>\n \u201cWhen a large meteor burns up in the atmosphere, it can create a sonic pressure wave as it explodes that can shatter glass and cause injury,\u201d he said. \u201cIt can have sufficient force to cause hearing loss and could seriously injure someone if they got hit by one of the fragments.\u201d<\/p>\n There were no reports of sound that Gilbraith could see submitted to the AMS. It\u2019s possible the fireball exploded and no one was there to hear it, but it might also have survived long enough to impact the ground.<\/p>\n \u201cBased on these citizen science reports, it’s unlikely that it had a powerful explosion and broke up,\u201d he said. \u201cIf it didn’t make a sound, it probably didn’t explode and cause a huge shockwave.\u201d<\/p>\n Unusual But Not Uncommon<\/p>\n