Asteroid that can level cities to hit earth in next 8 years? Here’s what scientists have to say

Asteroids to hit Earth: It is simply an asteroid that is at least 140 metres across, which comes closer than 7.5 million kilometres from Earth at some point in its orbits around the Sun

Asteroids to hit Earth: The population of smaller objects such as the fictional 2019 PDC, which was estimated to be about 600 feet wide, is not so well defined

Asteroids may hit Earth in next eight years, reports suggest. The proceedings on the second day of a conference on cosmic threats to our planet was interrupted by Paul Chodas for an important message. Paul is the manager of NASA's Centre for Near-Earth Object Studies. According to the new calculations there are 10 per cent chances that an asteroid named 2019 PDC would strike Earth. This can happen anytime in next eight years and can tether enough energy to level a whole city.

Soon after he made the announcement, he asked audience, what did they want to do about it? Quickly turning sides, Paul said, “before you start stocking up on canned goods know that this was a fictional exercise. The asteroid 2019 PDC does not exist. No city on Earth is thought to be imperiled by a catastrophic impact. Indeed, analyses of more than 20,000 known near-Earth objects suggest the chance of any hitting us in the next century is less than 1 in 10,000.”
According to the Weather Network, “there are just over 20,000 known Near-Earth Asteroids. A little less than 10 per cent of those are considered 'potentially hazardous asteroids' or PHAs. A potentially hazardous asteroid is not necessarily one that is expected to hit Earth. It is simply an asteroid that is at least 140 metres across, which comes closer than 7.5 million kilometres from Earth at some point in its orbits around the Sun. The smallest PHA, if it actually hit Earth, could potentially level a city. The largest, up above 1 kilometre in diameter, could cause catastrophic damage on a planetary scale.”

The population of smaller objects such as the fictional 2019 PDC, which was estimated to be about 600 feet wide, is not so well defined. However, these objects still have the potential to demolish states and even continents. This is the seventh table top exercise NASA has participated in to help game out what scientists and emergency managers would need to consider if one of these asteroids was headed our way.
NASA’s top concern this week seemed to be making sure everyone understood this was a drill. "If you tweet about this," communications officer JoAnna Wendell urged the audience, "please use the hashtag 'exercise only.' We don't want to get into a 'War of the Worlds' scenario."