Five Asteroids That Could Fly Past Earth in the Second Half of 2026

Several asteroids ranging from the size of large buildings to objects wider than five football fields are expected to make relatively close flybys of Earth during the second half of 2026. While such encounters often attract attention, NASA says none of the known objects poses an impact threat to the planet.

According to NASA’s Center for Near-Earth Object Studies (CNEOS), dozens of near-Earth asteroids pass within 0.05 astronomical units of Earth every month. These flybys give astronomers valuable opportunities to improve orbital calculations, study asteroid characteristics and strengthen planetary defense systems designed to detect any future hazards well in advance.

Despite the dramatic headlines that often accompany asteroid flybys, “close” in astronomical terms still means a considerable distance. Even the nearest of the major objects expected during the second half of 2026 will remain more than 1 million kilometers (about 645,000 miles) away, nearly three times farther than the Moon’s average distance from Earth.

Five asteroid flybys to watch

Among the many near-Earth objects expected to pass safely by Earth, five stand out because of their size or relatively close distance.

• 523808 (2007 ML24)
  Closest approach: July 4, 2026
  Estimated size: 400-800 meters
  Distance from Earth: About 3.48 million kilometers (2.16 million miles)
  Why it matters: The largest asteroid among the upcoming flybys makes it an important target for continued observations.

• 173561 (2000 YV137)
  Closest approach: Aug. 9, 2026
  Estimated size: About 520 meters
  Distance from Earth: About 5.02 million kilometers (3.12 million miles)
  Why it matters: One of the biggest near-Earth asteroids is making a safe pass this year.

• 2019 NY2
  Closest approach: Aug. 10, 2026
  Estimated size: 150-300 meters
  Distance from Earth: About 2.52 million kilometers (1.57 million miles)
  Why it matters: Large enough to remain under regular monitoring while offering another opportunity to refine orbital data.

• 2025 AL2
  Closest approach: Aug. 16, 2026
  Estimated size: 80-170 meters
  Distance from Earth: About 1.04 million kilometers (645,000 miles)
  Why it matters: One of the closest notable flybys is expected during the second half of the year.

• 523609 (2005 PJ2)
  Closest approach: Aug. 27, 2026
  Estimated size: 300-700 meters
  Distance from Earth: About 7.08 million kilometers (4.4 million miles)
  Why it matters: Another large asteroid whose orbit continues to be tracked as part of NASA’s long-term monitoring program.

Why do scientists pay attention to every close pass

Each close approach allows researchers to learn more about an asteroid’s orbit, size, shape, rotation, and, in some cases, even its surface composition. As additional observations are collected, scientists can calculate an object’s future path with increasing precision.

NASA defines near-Earth objects as asteroids and comets whose orbits bring them within about 195 million kilometers (120 million miles) of the Sun, allowing them to pass through Earth’s orbital neighborhood. Most never come particularly close to our planet, but a small fraction receive additional attention because of their size and orbital characteristics.

An asteroid is classified as a Potentially Hazardous Asteroid (PHA) if it is larger than roughly 140 meters (460 feet) and can approach Earth’s orbit within 7.5 million kilometers (4.6 million miles). The designation does not mean an impact is expected. Instead, it simply identifies objects that deserve careful long-term monitoring because future gravitational interactions can slightly alter asteroid orbits over decades or centuries.

NASA currently tracks more than 42,000 known near-Earth objects, including approximately 11,600 estimated to be larger than 140 meters and 872 measuring roughly one kilometer or more in diameter. More than 2,500 are classified as potentially hazardous, yet none is currently predicted to threaten Earth during the next century.

How NASA keeps watch over Earth’s cosmic neighborhood

Tracking asteroids is a global effort involving professional observatories, space missions, and amateur astronomers. Much of NASA’s discovery work comes from surveys such as Pan-STARRS, the Catalina Sky Survey, and the NEOWISE mission, while observatories around the world continue collecting follow-up observations after new objects are discovered.

At NASA’s Jet Propulsion Laboratory, CNEOS uses these observations to calculate asteroid trajectories and predict future close approaches. The agency’s Sentry system continuously analyzes the long-term orbits of known asteroids for any potential impact scenarios, while the Scout system rapidly evaluates newly discovered objects that may require immediate follow-up observations.

NASA is also preparing for the next generation of asteroid detection with the NEO Surveyor mission, a space telescope specifically designed to discover previously unseen near-Earth asteroids, particularly those that are difficult to detect from ground-based observatories because they approach from the direction of the Sun.

Together, these systems form the backbone of NASA’s planetary defense strategy, providing scientists with years or even decades of warning should a future object require closer attention.

Although asteroid flybys often capture public attention, the second half of 2026 serves as another reminder that Earth’s cosmic neighborhood is constantly active. Rather than signaling danger, these encounters demonstrate how advances in telescopes, computing power, and orbital modeling now allow astronomers to monitor thousands of space rocks with remarkable accuracy.