A huge asteroid with an old-fashioned name is passing by Earth today, but don't worry. It means us no harm, I promise you.

The asteroid known as Florence — named for Florence Nightingale, of course — is about 2.7 miles wide and will zip past Earth by about 4.4 million miles during its flyby on Friday.

Florence is also quite a record-breaker.

"While many known asteroids have passed by closer to Earth than Florence will on September 1, all of those were estimated to be smaller," said Paul Chodas, manager of NASA's Center for Near-Earth Object Studies, which tracks asteroids, said in a statement.

"Florence is the largest asteroid to pass by our planet this close since the NASA program to detect and track near-Earth asteroids began."

NASA has tracked Florence for years, ever since its discovery in 1981, and this flyby will be the closest the space rock has ever been to Earth since 1890. It won't come this close again until after 2500, NASA said.

If anything, this particular flyby is a good chance for scientists to study Florence from close range. Radar instruments on Earth will be pointed at the asteroid as it passes to more accurately measure its size and even see some surface features not studied before.

Simulation of Florence's track by Earth. Image: NASA/JPL-Caltech

While it may seem like Florence is passing close to Earth, the asteroid is still pretty far away — for scale, remember that the moon is 238,855 miles from Earth — and NASA has calculated its future orbits to be sure that Florence isn't on a collision course with our planet.

If an asteroid of that size were to slam into Earth, it could be devastating.

Although it may not wipe out life on our planet, if Florence or an asteroid similar in size were to impact Earth, it could be catastrophic, creating a huge crater and wreaking havoc in areas close to its impact point. The space rock thought to have wiped out the dinosaurs was only between 6 and 9 miles in diameter, for perspective.

And consider that in 2013, a 65-foot-long space rock exploded above Chelyabinsk, Russia, breaking windows with its airburst and injuring people in the region. That was a comparatively tiny space rock, too.

Researchers use space-based satellites to hunt for near-Earth objects that could harm us, but, as the Chelyabinsk meteor proves, even small space rocks can still do us harm.