In May 2003, when the Japanese robotic spacecraft, Hayabusa was launched to collect sample material from a near-earth asteroid, little did the researchers know that the answer to the mystery of the source of our planet’s water would unfold 16 years later.
Two cosmochemists, including one of Indian origin, from Arizona State University (ASU), have confirmed that water on Earth may have its source in the impacts from similar asteroids.
Confirming the same, Maitrayee Bose tells The Better India (TBI) exclusively,
We worked on the soil samples from the first asteroid that humans have collected rocks from, and found traces of water in the minerals. This result is tremendously exciting because it provides insights about the history of water on our planet and other planets in our solar system. Enormous amount of water covers our planet, and we confirm that asteroids provided water to Earth.
In 2010, the Japan Aerospace Exploration Agency (JAXA) spacecraft returned to earth along with 1,500 samples of which five particles were shared with the researchers Maitrayee and Ziliang Jin of ASU. In two of the five particles, the team identified the mineral pyroxene. In terrestrial samples, pyroxenes contain water in their crystal structure.
The findings came as a surprise for the Hayabusa project, “Until we proposed it, no one thought to look for water. I’m happy to report that our hunch paid off,” said Bose, who is an assistant professor at ASU.
Detailed findings of the study have been published in the journal Science Advances.
The samples procured by Bose and Jin are about half the thickness of a human hair. The findings have suggested that impacts early in Earth’s history by similar asteroids could have delivered as much as half of our planet’s ocean water.
“We found the samples we examined were enriched in water compared to the average for inner solar system objects,” Ziliang Jin said in a statement released by ASU.
Shaped like a peanut, the Itokawa asteroid is around 1,800 feet long and 700 to 1,000 feet wide. However, it was not always this shape and size. The asteroid was initially a part of a larger parent body that broke off 1.5 billion years ago, after an impact with another space rock.
Itokawa circles the sun every 18 months at an average distance of 1.3 times the Earth-sun distance. While one end of the asteroid is inside Earth’s orbit, the other end sweeps out a little beyond that of Mars.
In structure, Itokawa is a pair of rubble piles crunched together. It has two main lobes, each studded with boulders but having different overall densities, while between the lobes is a narrower section.
The particles that were analysed are from a part of Itokawa called the ‘Muses Sea’, an area on the asteroid covered with dust and is smooth.
ASU’s Nanoscale Secondary Ion Mass Spectrometer (NanoSIMS) was used to study the samples that can measure tiny mineral grains. The measurements revealed that the samples were unexpectedly rich in water. The cosmochemists have also hinted that Itokawa may harbour more water than assumed.
The Itokawa asteroid belongs to the S-Class which means that these asteroids are common and small in size. However, despite the small size, these asteroids keep the water and other volatile materials they are formed with.
The sample-return missions are an essential requirement for in-depth study of planetary objects.
“The Hayabusa mission to Itokawa has expanded our knowledge of the volatile contents of the bodies that helped form Earth,” Bose added in the official statement. “It would not be surprising if a similar mechanism of water production is common for rocky exoplanets around other stars.”
JAXA has also sent another spacecraft ‘Hayabusa 2’ to another asteroid called Ryugu to collect samples from the space rock. It is expected to return to Earth in 2020.
Featured Image Source: Arizona State University
(Edited by Saiqua Sultan)