Bennu Time Capsule: OSIRIS-REx Samples Unlock the Solar System's Ancient Secrets

Be Smart host Tim McCoy, a Smithsonian curator, shows a 4.5 billion year old rock and a sample from the Bennu asteroid, explaining why space rocks preserve the early solar system so well. The video describes how NASA's OSIRIS-REx mission collected material from Bennu and returned it to Earth in a pristine state to avoid Earthly contamination. It delves into how the samples will be studied with advanced instruments to reveal minerals, water, and organic molecules that could illuminate how life formed on Earth and how water may have arrived. It also touches on space resources like water for future travel and the challenges of dating rocks that have never touched Earth. The talk invites curiosity about what else the time capsule might reveal.

Introduction

Be Smart’s Tim McCoy explains that some rocks hold the history of the solar system in their minerals and grains. He highlights a 4.5 billion year old rock that is older than Earth’s oldest rocks, illustrating why space rocks are crucial to understanding planetary origins.

The Bennu Mission and OSIRIS-REx

The video describes NASA's OSIRIS-REx mission to Bennu, a near Earth asteroid. After mapping Bennu's surface for two years, the mission selected a safe landing site. The surface was described as a loose ball pit, and the spacecraft touched down for about five seconds. A gas release device fluidized the regolith and captured material, which was sealed in a capsule and launched back to Earth. In late 2023 the sample capsule returned after a seven year journey.

Why Pristine Rocks Matter

McCoy discusses Earth contamination: rocks that land on Earth acquire Earth life and chemistry, complicating the study of pre Earth chemistry. In contrast, asteroids do not have plate tectonics or weather, so their rocks remain snapshots of the early solar system. pristine samples from Bennu thus serve as time capsules.

How Scientists Study the Sample

Inside the lab, a scanning electron microscope with energy dispersive X ray spectroscopy identifies elements and minerals. A grain showing iron and sulfur reveals sulfide minerals, suggesting formation in the presence of water on the asteroid about 4.5 billion years ago.

Key Discoveries and Implications

Analyses have detected water bound in minerals, supporting the idea that Earth’s oceans could have been delivered by asteroids in the young solar system. Water in space rocks could also be a critical resource for future space exploration, reducing the need to launch water from Earth. The samples are dark because of carbon and organics, and some tiny light flecks remain mysterious to researchers. The grains are micron sized, and tens of thousands of grains exist in even a small rock, offering vast opportunities for study over generations.

Looking Ahead

The video ends with reflections on how the Bennu sample might illuminate life’s origins and whether other planetary systems could harbor Earth-like worlds. It also notes the public engagement aspect of naming Bennu by a student and invites viewers to imagine future discoveries.