Four "potentially hazardous" space rocks, which are between 100 and 580 feet across, will all make their closest approaches to Earth within less than 12 hours of one another on Thursday (Oct. 24). Two of them were only discovered earlier this month.

A quartet of particularly hefty asteroids, including two that were discovered earlier this month and another that is as tall as a skyscraper, will make their closest approaches to Earth on Thursday (Oct. 24) — all within 12 hours of one another. The "potentially hazardous" space rocks will all get similarly close to our planet, but pose zero threat to life on Earth.

The first asteroid to make its closest approach will be 2015 HM1, also the smallest of the four space rocks at around 100 feet (30 meters) across. It will reach its closest point to our planet at around 4:36 a.m. UTC (0:36 a.m. EDT) when it reaches a minimum distance of 3.4 million miles (5.5 million kilometers) from us, according to NASA's Asteroid Watch dashboard. (That’s roughly 14 times the average distance between Earth and the moon.)

The next visitor will be the roughly 170-foot-wide (52 m) space rock 2024 TP17, which will make its closest approach at around 8:20 a.m. UTC (4:20 a.m. EDT) and will get to within 2.9 million miles (4.7 million km) of our planet.

The final two asteroids — 2002 NV16 and 2024 TR6 — will make their closest approaches within just four minutes of each other. 2002 NV16, which is around 580 feet (177 m) across, making it the largest of the four, will reach a minimum distance of 2.8 million miles (4.5 million km) at around 15:47 p.m. UTC (11:47 a.m. EDT). It will be quickly followed by the 150-foot-wide (46 m) asteroid 2024 TR6, which will come within 3.5 million miles (5.6 million km) of Earth at 15:51 p.m. UTC (11:51 a.m. EDT).