The past week in space exploration was all about asteroids. Elon Musk’s SpaceX launched NASA’s mission that will explore the metal-rich asteroid Psyche, and the space agency also revealed that it has detected the presence of carbon and water in a sample taken from the asteroid Bennu that landed on Earth last month. But why are astronomers and other scientists so keen on missions that explore asteroids like Bennu and Psyche? Well, to put it simply, asteroids can act as a “time capsule” of the earliest days of our solar system and, indeed, our universe. The material that was gathered from Bennu will not only help answer questions about the nature of asteroids, but it might also help us learn about the origin of life itself. The fact that preliminary analysis has revealed the presence of carbon and water, building blocks of life as we know it, is a promising step in that direction. This was revealed during an initial “quick-look” analysis of the initial material, where scientists collected images from a scanning electron microscope along with infrared measurements. They used sophisticated scanning technologies like scanning electron microscopes, X-ray diffraction and X-ray computed tomography. After creating a 3D model of one of the particles brought back from the asteroid, there was mounting evidence of the abundant presence of carbon and water. The asteroid 16 Psyche, meanwhile, is only the 16th asteroid ever discovered. Italian astronomer Annibale de Gasparis identified it in 1852 and named it after the goddess of the soul in ancient Greek mythology. What makes the metal-rich asteroid unique is that it appears to be the exposed nickel-iron core of an early planet, which is one of the building blocks of our solar system. All terrestrial planets, including Earth, have the presence of metallic cores deep within them. If we could observe and study this core directly, it would help scientists answer questions about how the solar system and the Earth formed. But on our planet, the core lies out of reach, deep beneath the rocky crust and mantle. Practically speaking, we will never reach Earth’s core. It has such high levels of pressure, heat and radioactivity that no probe we could send would survive. And if we can’t do it on Earth, we surely can’t do it on Mars or another planet. But if Psyche is such an exposed core as scientists infer it to be, it will offer a window into the history of violent collisions and accretion that leads to the creation of planets like ours. That is going to take some time, though. Psyche will take as long as six years to travel the approximately 3.6 billion kilometres to the asteroid using its solar-electric ion thrusters.
