An asteroid larger than many downtown office buildings will make a relatively close pass by Earth on Saturday, June 27, offering astronomers a rare opportunity to study thus sizable near-Earth object. 

Asteroid 152637 (1997 NC1) is around a kilometer wide, about the distance along Fayetteville Street between the North Carolina State Capitol and Martin Marietta Center for the Performing Arts. It is a very big rock, one of only 872 a kilometer or larger that have been discovered to date according NASA’s Center for Near Earth Object Studies which currently tracks nearly 42,000 asteroids of all sizes.

Despite the name, there is no North Carolina connection. 1997 NC1 was discovered on July 5, 1997,  at the Haleakalā Observatory in Maui. NC1 means it was the 28th (C1) object discovered in the first half of July (N) in the Minor Planet Center’s naming scheme. 

You may have read headlines describing this asteroid as hazardous or even suggesting imminent danger of impact.

1997 NC1’s potentially hazardous asteroid (PHA) designation is a technical one applied asteroids larger than 50 meters (not quite twice the height of the capitol building) whose orbits bring them within 5% of the distance to the Sun or nearly 20 lunar distances away.

This does not mean an impact is expected, that NASA and others are paying a bit more attention. In practical terms, that means that the orbit will be more closely monitored and calculated than other nearly 42,000 asteroids tracked by CNEOS.

1997 NC1’s orbit keeps it mostly between Earth and Venus well away from Earth’s orbital path

Current calculations show no threat to Earth for at least the next century. 1997 NC1 spends most of its time between Earth and Venus in an orbit tilted away from the plane of the solar system.

You may have also read headlines suggesting close approaches are rare. They aren’t.

  • On Thursday (June 25, 2026), MC2 will pass inside the lunar distances (706,763 miles). Another three (2026 MY, 2026 MD1 and 2026 MN1) will pass within between 951,000 and about 140,000 miles from Earth.
  • Back on June 7, LX passed very safely within 51,250 miles.
  • In the first week of May, 2026 JM2 passed safely by at t 27,300 miles away, inside the orbit of geosynchronous satellites.

In the past year, 211 near Earth objects (NEOs) have passed within a lunar distance. Looking ahead in the next 12 months, only 2025 UK9 is expected (on Halloween) inside a lunar distance but no closer than about 54,000 miles.

Why so many in the last 12 months and so few going forward? The answer lies in the asteroids’ names. Notice that all of those previous ones were discovered in 2026. Most NEOs are smaller and discovered within weeks of a close approach.   

1997 NC1’s size does make it unusual among NEOs passing through Earth’s neighborhood. House-sized and bus-sized asteroids dominate close-approach statistics. The last time something this big passed within 10 lunar distances was when America was preparing for bicentennial celebrations back in February 1976 when 443103 (2013 WT67) passed unnoticed within 8.7 lunar distances.

These encounters are valuable opportunities for planetary defense researchers. Radar observations can reveal an asteroid’s shape, rotation, surface features and precise orbit. Every close pass helps scientists improve their understanding of the near-Earth asteroid population and refine techniques that could someday be used to deal with a truly hazardous object.