Three large asteroids prompt Nasa to issue near-Earth object alert

Nasa has listed a warning on its "near-Earth objects" alert page as three rogue asteroids are set to speed closely past Earth today and tomorrow.

The largest of the three asteroids, which is the size of the leaning tower of Pisa, could cause a catastrophic event if it smashed into our planet.

The first asteroid, known as 2019 AT6, will pass Earth this afternoon at 4.20pm NZDT at speeds of over 7,380 km/s.

The 17-metre object will skim within 3.2 million kilometres (2 million miles) of Earth, or about eight times the distance between our planet and the moon.

The second space rock to skim pass Earth is 2019 AM8 and it is far larger than the previous asteroid - approaching us at twice the speed.

The object is big as a blue whale and will hit speeds of almost 40,555 km/s as it passes Earth at 5.03am tomorrow.

The largest of the three asteroids, which is the same size of the leaning tower of Pisa, could cause a catastrophic event if it smashes into our planet. Photo / 123RF

The asteroid will pass Earth just over 3.22 million kilometres (2 million miles) from its surface, or eight and a half times the distance between the moon and Earth.

The third asteroid to shave pass Earth, 2019 AG7, is the biggest of the three.

Measuring 51m in diameter – making it as wide as the leaning tower of Pisa is tall – 2019 AG7 is scheduled to skim past Earth on Wednesday morning at 11.43am.

Reaching speeds of 4,333 km/s it will pass closer than the previous two, flying within 1.53 million kilometres (950,000 miles) of our planet – about four times the distance between Earth and the moon.

Luckily, asteroids are actually classified as "small bodies" by Nasa, which mean they do not believe the objects pose any threat to life on Earth.