The main rock of the double asteroid is called Didymos and the smaller one is called Didymoon. The pair are described by the ESA as a “mountain in the sky with another rock the size of the Great Pyramid swinging around it” and an official video explaining the mission to crash a space probe into the asteroids says: “Just the seemingly tiny moon would be big enough to destroy a city.” In November European space ministers are set to back the HERA project - humanity’s first mission to orbit with a double asteroid system with additional plans to dispatch two smaller cubesats to one of the space rocks – in an attempt to figure out how to deflect it. Astrophysicist and Queen guitarist Brian May has been chosen as the public face of the European arm of the mission and has explained the perils and difficulties in a video for the European Space Agency (ESA), who will be taking on the heart-stopping mission.

He warned: “Imagine a mountain in the sky, with another rock the size of the Great Pyramid swinging around it - that’s Didymos. “And just the seemingly tiny moon would be big enough to destroy a city if it were to collide with the Earth. “But we’re going to find out if it’s possible to deflect it.” Didymos is currently 265 million miles (427 million km) away from Earth – almost twice as far as Mars. The main rock is 775m across and the smaller one is 160m wide so the project is immensely complex and ambitious. May said: “This is going to be really, really hard - aiming at a 160 metre-wide target across millions of kilometres of void.

Earth is bombarded with more than 100 tons of dust and sand-sized particles every day

Brian May explained the mission

“Could we stop an asteroid hitting our planet Earth? “The dinosaurs couldn’t, but we humans have the benefit of knowledge and science on our side.” ESA said in a statement the mission will “revolutionise our understanding of asteroids and how to protect ourselves from them”, implying that if not Didymos then the threat from some as yet unkonwn asteroid could be far greater in the not-so-distant future. The mission and associated satellite has been called Hera. READ MORE: God of Chaos: The asteroid which could blast Earth

The double asteroid is heading towards Earth

ESA said: “Hera will help ESA to find out if it would be possible to deflect such an asteroid on a collision course with Earth. The mission will revolutionise our understanding of asteroids and how to protect ourselves from them, and therefore could be crucial for saving our planet. “First, NASA will crash its DART spacecraft into the smaller asteroid - known as Didymoon - before ESA’s Hera comes in to map the resulting impact crater and measure the asteroid’s mass. “Hera will carry two CubeSats on board, which will be able to fly much closer to the asteroid’s surface, carrying out crucial scientific studies, before touching down. “Hera’s up-close observations will turn asteroid deflection into a well-understood planetary defence technique. DON'T MISS: Why ‘Trillion tonne rock hurtling towards Earth’ was 'bad news' Moment 'beach ball' sized asteroid fragment fireball crash lands NASA shares amazing video of 'flying saucers' hovering over Mount Etna

“The Hera mission will be presented to ESA’s Space19+ meeting this November, where Europe’s space ministers will take a final decision on flying the mission, as part of the Agency’s broader planetary defence initiatives that aim to protect European and world citizens.” Didymos is a sub-kilometer asteroid and synchronous binary system, classified as potentially hazardous asteroid and near-Earth object. The larger asteroid has a smaller ‘moon’ orbiting it. This gives the asteroid its name Didymos, which means ‘twin’ in Greek. Asteroids of all sizes have been pummelling Earth for billions of years.

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