Asteroid Bennu dust reveals building blocks of life

The discovery of ancient building blocks of life in samples from asteroid Bennu has provided intriguing insights into the early solar system, suggesting that the raw materials necessary for life were widespread and potentially gave rise to habitable environments on various celestial bodies.

A team of scientists from over 40 institutions worldwide, including geoscientists from Goethe University Frankfurt, analyzed 122 grams of dust and rock collected by NASA’s OSIRIS-REx space probe from the surface of asteroid Bennu, which is believed to have originated from a protoplanetary body that formed over four billion years ago.

By examining the mineral grains’ structure and chemical composition using advanced techniques such as transmission electron microscopy and trace element tomography, researchers detected a range of minerals that form when salty liquid water evaporates, including evaporites similar to those found on Earth in dried-out salt lakes.

Furthermore, other teams discovered precursors of biomolecules, including amino acids, indicating that Bennu’s parent body had the necessary ingredients for life, including water and energy, which were preserved for over 4.5 billion years, shedding new light on the potential for simple life to have evolved in similar environments elsewhere in the solar system.

Introduction to Asteroid Bennu and its Significance

The asteroid Bennu, a 500-meter agglomerate of unconsolidated material, has been the subject of intense scientific interest in recent years. In 2023, NASA‘s OSIRIS-REx space probe returned from Bennu with a sample of 122 grams of dust and rock, which was then recovered in the desert of Utah. This sample has provided scientists with a unique opportunity to study the composition and structure of the asteroid and gain insights into its formation and evolution. The sample analysis has been carried out by a large team of scientists from over 40 institutions around the world, including geoscientists from Goethe University Frankfurt.

The study of Bennu is significant because it can provide clues about the early solar system and the formation of planets. Asteroids like Bennu are thought to be remnants of the protoplanetary disk that formed around the Sun over 4.5 billion years ago. By analyzing the composition and structure of Bennu, scientists can gain insights into the conditions and processes that occurred in the early solar system. The discovery of certain minerals and organic compounds on Bennu can also provide evidence for the presence of water and energy sources essential for life.

The analysis of the Bennu sample has been carried out using a range of techniques, including transmission electron microscopy and trace element tomography. These techniques have allowed scientists to study the mineral grains in detail and determine their chemical composition. The results of these studies have provided evidence for the presence of evaporites, which are minerals that form when salty liquid water evaporates and precipitates. This suggests that Bennu’s parent body had a liquid water environment at some point.

Composition and Structure of Bennu

The analysis of the Bennu sample has revealed a complex composition and structure. The sample contains a range of minerals, including silicates, oxides, and sulfides, which are common in meteorites and asteroids. However, the sample also contains evidence of evaporites, which are less common in these types of objects. The presence of evaporites suggests that Bennu’s parent body had a liquid water environment at some point in its history, which is significant because it provides evidence for the presence of a potential habitat for life.

The study of the mineral grains in the Bennu sample has also provided insights into the conditions and processes that occurred on the asteroid. The grains are typically small, ranging from a few micrometers to several hundred micrometers in size, and have a range of shapes and textures. Some of the grains show evidence of alteration, which suggests that they have been affected by water or other fluids at some point in their history. The presence of these altered grains provides further evidence for the presence of a liquid water environment on Bennu’s parent body.

Implications for the Search for Life

The discovery of evaporites and other minerals on Bennu has significant implications for the search for life beyond Earth. The presence of a liquid water environment on Bennu’s parent body suggests that it may have had a habitable environment at some point in its history. Although the break-up of Bennu’s parent body interrupted these processes, other celestial bodies, such as Saturn’s moon Enceladus or the dwarf planet Ceres, may still have liquid oceans or remnants of them under their ice shells. These objects are potential targets for future missions and sample studies, which could provide evidence for the presence of simple life forms.

The study of Bennu also highlights the importance of sample return missions in the search for life beyond Earth. The analysis of samples from asteroids and other celestial bodies can provide insights into their composition and structure, as well as the conditions and processes that occurred on them. By studying these samples, scientists can gain a better understanding of the potential for life to exist elsewhere in the solar system and beyond.

Future Research Directions

The study of Bennu has opened up new avenues for research into the early solar system and the formation of planets. Future missions and sample studies will focus on other celestial bodies that are thought to have had habitable environments, such as Enceladus and Ceres. These studies will provide further insights into the potential for life to exist elsewhere in the solar system and beyond.

The analysis of samples from these objects will require the development of new techniques and technologies, such as advanced microscopy and spectroscopy methods. These techniques will allow scientists to study the composition and structure of the samples in detail and gain a better understanding of the conditions and processes that occurred on the parent bodies.

In conclusion, the study of asteroid Bennu has provided significant insights into the early solar system and the formation of planets. The discovery of evaporites and other minerals on Bennu suggests that it may have had a habitable environment at some point in its history, which is significant for the search for life beyond Earth. Future research directions will focus on other celestial bodies that are thought to have had habitable environments, and the development of new techniques and technologies will be essential for the analysis of samples from these objects.