Four years ago, a rock from space tore through the atmosphere over Utah’s Wasatch Mountains, exploded into numerous pieces that sped straight west over Salt Lake City in a fiery trajectory before crashing into the playa along Great Salt Lake’s south shore.
For the last 4.5 billion years, basically since the birth of our Solar System, the rock had been cruising beyond the orbit of Mars, until Aug. 13, 2022, when it was pulled into Earth’s gravitational field and landed in Utah, according to Research Associate Professor of Geology & Geophysics Jim Karner, the University of Utah’s resident meteorite expert.
Now the largest fragment from that cosmic event is on display in the U’s Sutton Building, home of the Department of Geology & Geophysics.
“All these components, the iron-nickel metal, the sulfide grains, the chondrules, the matrix material all came together in the early solar system and then were accreted to form a bigger body, such as an asteroid,” said Karner, a research associate professor, while handling the rock with gloved hands recently. “These are coming in at cosmic velocities, 20 kilometers per second.” (That’s about 45,000 mph.)
The friction generated from contact with the atmosphere causes the rock to become extremely hot.
“They’re incandescently glowing, plus they’re emitting gases and the electrons are interacting with the atmosphere,” Karner said. “The consequences of this burning and glowing are that they are seen as a fireball coming through the atmosphere.”
The space rock is now the centerpiece of an exhibit that includes video and interpretive materials telling the story of Utah’s second known “fall” meteorite, that is, a meteorite whose plummet to Earth was witnessed by people. The first occurred in 1950 near the town of Garland in the Box Elder County. Sixty-two years later, thousands heard and then saw what became known as the Great Salt Lake meteorite when it detonated over Utah’s most populous region. Its trajectory was recorded by Doppler radar, providing a map for finding its pieces.