Largest Asteroid Ever Tracked to Pass by Earth on Sept. 1

August 19, 2017 Updated: August 19, 2017

The largest asteroid ever tracked by NASA will zoom nearby the planet Earth on Sept. 1, providing astronomy fans a rare treat shortly after the upcoming solar eclipse on Monday, Aug. 21.

NASA estimates asteroid Florence to measure about 2.7 miles wide. Although it will not be the closest asteroid to pass near Earth, it is by far the largest, scientists said.

“Florence is the largest asteroid to pass by our planet this close since the NASA program to detect and track near-Earth asteroids began,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object Studies at the agency’s Jet Propulsion Laboratory in Pasadena, California.


Florence will pass safely 4.4 million miles from Earth, which is about 18 times the distance between the Earth and the moon.

To get a sense of how close asteroids have come, a rock by the name 2017 AG13 buzzed within half the distance between the Earth and the moon earlier this year, according to Science Alert.

AG13 was just 50 to 111 feet in size, making it a mere pebble in comparison to the enormous Florence.

In October this year, an even closer encounter is expected when asteroid 2012 TC4 will come within just 13 percent of the distance between the Earth and the moon—about 31,000 miles.

Scientist Schelte “Bobby” Bus first observed Florence in 1981 from the Siding Spring Observatory in Australia. Bus named the space boulder after Florence Nightingale, the founder of modern nursing and a prolific writer.


Florence has not come this close to the Earth since 1890 and will not pass so close again until after the year 2500.

Scientists are excited about the giant space rock’s appearance, since they will have the chance to study it up close.

Engineers have already set up radars in California and Puerto Rico to study the asteroid’s appearance and get an accurate measure of its size. NASA expects the photos to have details as small as 30 feet.

A meteor from the Geminids meteor shower (streak at top) enters the Earth's atmosphere on December 12, 2009 above Southold, New York. (STAN HONDA/AFP/Getty Images)
A meteor from the Geminids meteor shower (streak at top) enters the Earth’s atmosphere on Dec. 12, 2009, above Southold, New York. (Stan Honda/AFP/Getty Images)

Enthusiasts can view the asteroid through small telescopes in late August and early September. It will be moving through the Piscis Austrinus, Capricornus, Aquarius, and Delphinus constellations.