Astronomy :
"Apophis" An asteroid with a dia of 340m will pass earth at a distance of 30,000 km. Which is nearer than the geo stationary satellite orbit. It's calculated to happen exactly 10 years from now.
For comparison, most of the fly by comets that create news headlines, pass outside the orbit of the moon. Like "10 times the distance to the moon". Moon is 400K km away.
The other famous asteroid that hit Siberia in early 1900s was 140m wide.