NASA’s OSIRIS-REx probe has found the building blocks of water on Bennu, an asteroid which orbits the sun at roughly the same distance, according to Reuters.
Bennu is about 1.4 million miles (2.25 million km) from Earth, considered to be relatively close. In fact, scientists are concerned that Bennu could collide with Earth in the late 22nd century. The asteroid is roughly the size of a skyscraper, about a third of a mile wide.
OSIRIS-REx launched in 2016, aiming to bring samples from Bennu back to Earth. Last week, it passed within 12 miles (19 km), and detected traces of hydrogen and oxygen, the basic ingredients of water, and therefore the basic elements of life.
The probe used a Thermal Emission Spectrometer and a Visible and Infrared Spectrometer, measuring wavelengths of light in order to determine the asteroid’s composition.
Dante Lauretta, the mission’s principal investigator and a planetary scientist at the University of Arizona, told Reuters:
“We have found the water-rich minerals from the early solar system, which is exactly the kind of sample we were going out there to find and ultimately bring back to Earth.”
NASA says the probe found “hydroxyl groups,” oxygen and hydrogen molecules bonded together, most likely connected to the asteroid’s clay minerals. They say Bennu may have broken off a larger asteroid that could have contained actual liquid water.
Scientists believe collisions with asteroids may have deposited water and organic compounds that laid the groundwork for the development of life on Earth. The surface of Ceres, our Solar System’s largest asteroid, is covered in frozen water.
The researchers plan to perform atomic-level analysis of samples from Bennu to see if the results support this theory.
“We’re really trying to understand the role that these carbon-rich asteroids played in delivering water to the early Earth and making it habitable,” said Lauretta.
“When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system,” according to a statement from NASA scientist Amy Simon.
OSIRIS-REx is now surveying the asteroid to choose an orbital path, and will pass within 1.2 miles (1.9 km) of the asteroid later this month to analyze its terrain. It will gradually tighten its orbit, and by July of 2020, it will fly within 6 feet (2 meters) of the surface, and use a robot arm to actually take a sample of Bennu to bring to Earth.