NASA is currently monitoring a total of three asteroids that are set to approach Earth before the month ends. One of the asteroids from the group, which will fly closest to the planet, is almost as big as the Washington Monument.

According to the space agency’s Center for Near Earth Object Studies (CNEOS), the first asteroid that will approach Earth is called 2016 PD1. This asteroid is currently traveling at a speed of 13,000 miles per hour and has an estimated diameter of 360 feet.

2016 PD1 is classified by CNEOS as an Amor asteroid. Like other Amors, this asteroid has a very wide orbit around the Sun and Earth and does not intersect the planet’s path.

CNEOS noted that the approaching asteroid is expected to fly close to Earth on Aug. 26 at 4:35 am EDT. During its approach, the asteroid will be about 0.02898 astronomical units or around 2.7 million miles from Earth.

Trailing behind 2016 PD1 is an asteroid known as 2002 JR100. As indicated in CNEOS’ database, this asteroid is traveling at a speed of almost 18,800 miles per hour and is estimated to be 269 feet long.

2002 JR100 is expected to approach Earth on Aug. 27 at 6:37 pm EDT. During this time, the asteroid will be about 0.04963 astronomical units or roughly 4.6 million miles from the Earth’s center.

2002 JR100 is an Aten asteroid. As it orbits the Sun, this asteroid frequently intersects with the path of Earth as it approaches its farthest distance from the giant star.

The last asteroid that will zip past Earth this August is 2019 OU1. As the biggest asteroid in the group, 2019 OU1 has a diameter of about 525 feet. It is traveling at a velocity of 29,000 miles per hour.

Aside from being the biggest in the group, 2019 OU1 will also fly closest to Earth. According to CNEOS, the asteroid will approach Earth on Aug. 28 at 6:36 am EDT. During this time, it will only be about 0.00688 astronomical units or roughly 640,000 miles from the planet’s center.

2019 OU1 is classified by CNEOS as an Apollo asteroid. Like other Apollo asteroids, it flies around the Sun and Earth and intersects with the orbit of the planet from time to time.