When ESA’s Hera mission arrives five years later, the scene could be quite dramatic, with Dimorphos spinning wildly in its orbit around Didymos as a result of humanity’s influence. In most scenarios, however, Dimorphos should be dramatically swinging back and forth or tumbling in many directions within weeks. DART will be aiming for the center of Dimorphos, the goal being to impart the greatest amount of force so as to alter its orbit, but the more off-center it is, the more chaotic the resulting spin will be. The location of the impact will play a part too. Radar observations so far suggest it is elongated, but we won’t know until just hours before DART hits, when it gets its first views of its small target. Dimorphos’s shape will play an important part-if it’s more elongated rather than spherical, it’ll spin more chaotically. In more extreme scenarios the tidal lock with Didymos could break completely and Dimorphos might start flipping “head over heels,” says Agrusa.Įxactly what will happen will depend on a few things. Within weeks, Dimorphos could spin so much that it enters a chaotic tumbling state where it is spinning uncontrollably around its axes. To an observer on Didymos looking into the sky, this seemingly sedate satellite will take on a new form-starting to swing wildly back and forth, its previously hidden sides now coming into view.

It may start to rotate along its long axis, like a rotisserie. Dimorphos may start to spin one way and another. This wobble will grow and grow as the momentum from the impact throws the rotation of Dimorphos out of balance, with no friction in the vacuum of space to slow it down. Soon, Dimorphos will start to wobble very slightly. The force of the impact will not cause any immediate changes to Dimorphos’s spin, but within days things will start to change, according to Agrusa and his team. Statler describes it as a golf cart traveling at 15,000 miles an hour smashing into the side of a football stadium. When DART slams into Dimorphos, the energy of the impact will be comparable to three tons of TNT exploding, sending thousands of pieces of debris spewing into space.

Nasa asteroid warning 2021