Forged at the dawn of the Solar System, a fist-sized meteorite has ended its million-mile journey safe and sound at the hands of Mountain View scientists.
An analysis of the glass-coated black rock and its 600 siblings is revealing for the first time the life and death of meteors that sweep across our night sky.
“It’s like a small window into the very early times of our solar system … before there was such a thing as Earth,” said meteor astronomer Peter Jeniskens of the SETI Institute and NASA Ames Research Center. study Published this week in the journal Meteorology and Planetary Science.
Since the beginning of humanity, the explosive streak of meteors in the night sky has inspired fear and panic.
Scientists believe that asteroids are the debris of disintegrating planets created in the first chaotic million years of the Solar System.
While orbiting between what is now Mars and Jupiter, these planets collided – blown up – and created debris fields, called asteroids. In an orbiting belt known as the “blood splatter of the solar system,” asteroids collide—and sometimes the segments fall out of the belt, collide with Earth’s atmosphere and fall to the ground as meteorites.
The new research, announced this week, is remarkable because it tells the story of a meteorite’s origin.
This was possible because astronomers detected and tracked an 88-ton asteroid, called 2008-TC3, before it actually hit us. They observed that it entered Earth’s atmosphere, melted, and then exploded, showering the landscape with chunks of rock. These meteorites were recovered and the location of each fragment was mapped. From the patterns, they could prove which part of the asteroid had survived to the ground.
This was the first time that rocks could be directly linked to an asteroid observed in space.
“What makes this work particularly exciting is that scientists were able to track the incoming meteorite, to know where it would have fallen, and then was able to find specific remains,” said science teacher Andrew Fraknoi, Foothill. Emeritus Chair of the Department of Astronomy at the College in Los Altos Hills.
In the dreaded “shooting gallery” of space, “the more we know about these cosmic ‘bullets,’ the better it is for us,” he said.
The story begins in 2008, when Richard Kowalski, working with the University of Arizona, noticed a moving white dot on his computer screen at an observatory on Mount Lemmon outside Tucson, Arizona.
The twinkling object looked as if it was coming straight towards the earth. For 20 hours, computers from NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena tracked its trajectory.
The size of a small car, “it was coming into Earth’s atmosphere at unbelievable speeds,” at 8 miles per second, Jeniskens said. To travel from San Francisco to San Jose in just 7 seconds it would take the same speed.
Then, over the Nubian desert of northern Sudan, the asteroid collided with the atmosphere, releasing one to two kilotons of TNT of energy.
The light was so bright that it woke a railway station attendant in the remote desert. The pilots of the KLM airplane over Chad reported a distant flash. US government satellites also documented the explosion; Their recordings were released to scientists earlier this year.
where did it land? With so many explosions in the atmosphere, many scientists assumed that no asteroid survived the scorching race through Earth’s atmosphere.
But Jeniskens decided to investigate.
Born in the Netherlands, he fell in love with meteors at first sight When, as a graduate student, he saw a brilliant green-yellow streak across a bright black sky. He is now a global expert on the subject, investigating asteroid impacts in faraway Russia and other distant locations.
To expand the search for meteorites, Jeniskens coordinates a network of cameras in California and Nevada and invites the public to join meteor surveillance, by reporting their own fireballs, posts the video , and scans the ground to look for anything unusual. Jeniskens hopes to use its cameras to trace the origins of that meteorite back to one of the debris fields in the asteroid belt.
“Peter Jenniskens is the Indiana Jones of meteorite hunters,” said Fraknoi.
Shortly after TC3 fell to Earth in 2008, he flew to Sudan and joined Khartoum University professor Muawiyah Shaddad and 40 students in the search of the desert, hoping to survive anything. Walking side by side, they made a grid search of about 19 miles across sand plains, golden dunes and rocky hillsides and long-dried river beds. Eyes rolled up for anything extraordinary.
“There are a lot of rocks in the desert,” Jeniskens said. “But we were looking for rocks covered in a ‘fusion layer’ of dark glass.”
The very first meteorite was found in the afternoon search in just 2 1/2 hours. “Everyone started dancing and singing and shouting. We had a big party,” he recalled.
More were found in the days that followed. While all were covered in a layer of glass, they had different colors and textures from various mixtures of olivine, pyroxene, iron sulfide and other minerals, unexpectedly showing that asteroid 2008 TC3 gave rise to several types of meteorites. Gave.
Its size, spin and orientation were revealed when the asteroid struck the twinkling atmosphere as it approached Earth.
But the place where the meteorite fell was astonishing. The team found that small fragments had fallen along a 0.7-mile-wide corridor. Large fragments, which fell further downstream, were spread over a distance of four miles.
To understand why, Darrell Robertson of NASA’s Asteroid Threat Assessment Project at NASA Ames performed computer modeling to decode this pattern.
As it climbed, they found, the front of the asteroid melted. Behind it was a vacuum like awakening. As smaller fragments broke off and fell off the sides of the asteroid, they drifted into that wake and then fell to the ground in a narrow corridor along the asteroid’s path.
The last fragment to survive was at the bottom of the asteroid, the team concluded. Then that piece suddenly broke and shattered under pressure. Shock waves scattered these fragments sideways – scattered them.
Mystery solved, rocks are now preserved in plastic boxes and handled only with gloves on.
“All these meteorites tell an incredible story,” Jenniskens said. “They are little treasures.”
Have you seen the ball of fire? Report it to the American Meteor Society at: https://amsmeteoors.org/fireballs/
Did you find a possible meteorite? Take a sharp picture in broad daylight, and email it [email protected],
learn more: http://fireball.seti.org/