• A total of two massive asteroids will be making their close approach with Earth today
  • The two NEAs have been identified as 2021 AC and 2016 CO247
  • The two asteroids have not been included in the ESA Risk List

Two Near-Earth Asteroids will be zipping past the planet today, according to NASA's Center for Near-Earth Object Studies. The asteroids, identified as 2021 AC and 2016 CO247, are thought to be taller than Big Ben and the Empire State Building, respectively.

At exactly 10:27 p.m. EST, asteroid 2021 AC will be passing by the planet at eight miles per second. The NEA, which has a diameter of about 328 ft (100 m), is expected to be taller than Big Ben, the tower in London that stands at about 314 ft (96 m).

CNEOS' Close Approach Data Table has considered 2021 AC an Apollo asteroid due to its Earth-crossing orbit. NEAs in this category follow semi-major axes that are larger than that of the Earth and that intersect with the Earth's orbit at a certain point -- making close approaches more likely to occur.

Following only a few minutes after 2021 AC is 2016 CO247 -- also considered by the CNEOS to be an Apollo NEA. The asteroid, which is about four times larger than the one it precedes, boasts an astonishing 1,500 ft (470 m) in diameter.

An NEA this extensive in size is about one-and-one-fourth times as tall as the Empire State Building in New York, which stands at 1,250 ft (381 m), as per The Measure of Things' calculations.

Hayabusa-2 needs to drop off its precious samples from the asteroid Ryugu - 'dragon palace' in Japanese
Hayabusa-2 needs to drop off its precious samples from the asteroid Ryugu - 'dragon palace' in Japanese JIJI PRESS / Handout

The giant NEA can be expected to make its close approach with the planet at 11:09 p.m. EST. The CNEOS data table has also indicated that 2016 CO247 will be zipping past Earth at a speed of about 10 miles per second -- faster than 2021 AC.

Luckily, none of the two giant NEAs to pass by today have been included in the European Space Agency Risk List, making it safe to carry on with the day worry-free.

"Near-Earth Objects (NEOs) are comets and asteroids that have been nudged by the gravitational attraction of nearby planets into orbits that allow them to enter the Earth’s neighborhood," explains CNEOS on its website.

"Composed mostly of water ice with embedded dust particles, comets originally formed in the cold outer planetary system while most of the rocky asteroids formed in the warmer inner solar system between the orbits of Mars and Jupiter."