A decent-size asteroid will zoom past Earth next week, but astronomers aren’t sure exactly when the flyby will happen, or just how close the space rock is going to get. The latest observations suggest that the 100-foot-wide (30 meters) near-Earth asteroid 2013 TX68 will come within about 3 million miles (5 million kilometers) of Earth’s surface on March 8, NASA researchers said. But it’s also possible that the space rock will get much, much closer — 15,000 miles (24,000 km) or so, which is inside the planet’s ring of geostationary satellites.

Despite all of the uncertainty — researchers originally thought the flyby was going to happen on Saturday (March 5) — there is nothing to fear from 2013 TX68, scientists said. The space rock has no chance of hitting Earth on this pass, or on any future close approaches over the next century. READ MORE