A 2014 meteor is Earth’s first known interstellar visitor
Astronomers have confirmed that a suspicious space rock that hit Earth in 2014 came from another star system, predating the famous ‘Oumuamua by three years. Researchers found the meteor in the catalogue of NASA’s Center for Near Earth Object Studies (CNEOS) in 2019. At that time, some of the data about the rock’s trajectory was kept secret by the US Department of Defence (DoD), whose sensors collected them. But in March this year, the DoD released a statement confirming the measurements, allowing scientists to complete their calculation of the mysterious rock’s origin. The 0.9-metre (2.9-foot) wide mini-asteroid, which entered Earth’s atmosphere on 8 January 2014, arrived at a very fast speed of 215,974 kilometres (134,200 miles) per hour. It also followed an odd trajectory that suggested it may have come from outside the Solar System. By modelling the rock’s path into the past, the authors of a new paper confirmed the tiny asteroid was indeed a newcomer into the Sun’s corner of the Milky Way.
The confirmation makes the rock, named CNEOS 2014-01-08, the first known visitor from interstellar space, predating the asteroid ‘Oumuamua that zipped past Earth in 2017. Only one year later, astronomers discovered the second interstellar object, the 0.5-kilometre (0.3-mile) wide comet Borisov. The short interval between those discoveries led astronomers to believe that smaller interstellar rocks, only a few metres wide, must be much more common in the Solar System and even regularly cross paths with our planet.
The researchers believe that interstellar space rocks might hit Earth’s atmosphere about once per decade. Analysing those meteors could provide new insights into the chemistry of distant star systems. “By extrapolating the trajectory of each meteor backwards in time and analysing the relative abundances of each meteor’s chemical isotopes, you can match meteors to their parent stars and reveal insights into planetary system formation,” the authors said in the paper. “[Some chemical] elements can be detected in the atmospheres of stars, so their abundances in meteor spectra can serve as important links to parent stars.”
Because most meteoroids burn up in the atmosphere before making it to Earth’s surface, and because retrieving those that do is extremely timeconsuming and challenging on a technical level, the researchers propose creating a worldwide camera network capable of making spectroscopic measurements, analyses of the light-absorption fingerprints of arriving space rocks that could reveal their chemical compositions. CNEOS 2014-01-08 exploded above the ocean near Papua New Guinea, and scientists believe that some pieces of the rock may have survived the journey through Earth’s atmosphere and fallen into the sea. An expedition to attempt to retrieve some of the fragments is planned for 2023.