Physics is having a moment. Almost two years ago, the world stopped in awe as the Philae lander became the first module in history to soft-land on a comet. The recent discovery of gravitational waves has also made ground-breaking progress in the work Albert Einstein began a century ago. And, most recently, NASA has announced its plans to send a mission to Bennu: a 500m long, rotating cluster of dust and rock which swings into sight of Earth every six years. The mission requires an investment of one billion US dollars and will take seven years from its launch to return. So what makes Bennu worthy of a place in the canon of recent scientific breakthroughs?
It’s not because of the internet panic about Bennu colliding with the Earth. It’s true, it might, but concerns about such an event are slightly premature: a potential collision is a century away, and most recent estimates put the chance of collision at far less than 0.1 per cent.
No, this mission is remarkable because it is an opportunity for scientists to begin to understand the early solar system. Despite the incredible developments in physics throughout the 20th century, there is still a metaphorical black hole in our understanding of the exact conditions required for life to flourish in the universe. By flying a probe close by a specific asteroid, NASA is hoping to recover a sample that can provide information on how planets form and how organic material develops into life.
This is incredible. There are in excess of 500,000 known asteroids in our solar system, but Bennu has been chosen for NASA’s cutting-edge OSIRIS-REx mission. This is because, at a distance of 190,000 miles from Earth on the closest point in its orbit, Bennu is a close neighbour of ours. And, as it is 500m in diameter, NASA will be able to safely fly a probe close to its surface, without fear of Bennu spinning too quickly and chucking out matter, which might prevent the probe from collecting material. But, most importantly, Bennu is one of a handful of asteroids that has a chemical structure that remains largely unchanged since its formation some four billion years ago. NASA hopes that retrieving material from its surface will provide new information on the early solar system.
By 2023, the OSIRIS-REx mission will have returned to Earth and physics will again be entering a new era in space exploration, with new questions for scientists to unravel. And all of this is down to the sheer power of human endeavour. What a fantastic time for physics.