A 1.5 mile-wide asteroid is expected to make its closest approach to Earth on Christmas Eve. Asteroid 2003 SD220, also known as asteroid 163899, will pass our planet from 6.7 million miles (11 million km) away - 28 times farther than the moon. Despite its huge distance, reports have circulated the asteroid could cause earthquakes and trigger volcanoes on Earth. But experts have dismissed these claims, saying that there is no scientific evidence to back up these theories. Nasa says the space rock will make a return to Earth in 2018, but it will pose no threat to our planet...