NASA warns of monster asteroid barreling towards Earth today

Washington, Dec 9: An asteroid 20 meters in diameter hits every 80 years or so. Since only 1% of the Earth is urban that means around 8,000 years between impacts on an urban area.

The asteroid, dubbed Asteroid 2018 WX1, is expected to pass.

NASA's scientists at the Jet Propulsion Laboratory are looking at a 9.09am GMT (UTC) flyby. The asteroid's passage is preceded by a much smaller, 91.8ft-wide (28m) rock which shot past the planet at around 6.51am GMT.

The bigger of the two asteroids is the more formidable object and is comparable in size to Big Ben's Elizabeth tower in Westminster, London.

According to the space agency, asteroids in the upper range of this size estimate have the potential to wreak havoc upon impact.

NASA said: "Space rocks smaller than about 25 meters - about 82 feet - will most likely burn up as they enter the Earth's atmosphere and cause little or no damage.

"If a rocky meteoroid larger than 25 meters but smaller than one kilometre - a little more than 1/2 mile - were to hit Earth, it would likely cause local damage to the impact area.