A fireball or meteor explosion spotted across southeastern US

A fireball in the United States, seen near Lexington in South Carolina yesterday. Photo / Supplied

A fireball, or an exceptionally bright meteor, appears to have exploded in the skies over the southeastern United States yesterday NZT.

The American Meteor Society received nearly 150 reports of a fireball spotted at around 12.24pm Eastern time.

Most of the reports are from Georgia and South Carolina, though a few observers witnessed the event from Florida, Tennessee, and North Carolina.

In a video shared with Atlanta-based station 11Alive, a driver on Interstate 85 southbound in Upstate South Carolina captured the fireball on their dashboard camera.

In the video, the meteor passed from the top left to bottom left of the frame with a slight rightward movement. Other local journalists shared similar videos on social media.

The Goes East weather satellite logged a bright flash over the Atlanta metro at about 12.24pm; the satellite, which peers down from 35,785km above Earth, is designed to map lightning discharges.

But there weren’t any thunderstorms in the immediate Atlanta area; given the timing, it appears the flash was the meteor exploding.

Coupled with other reports, it appears that if any material reached the ground, it would have been somewhere near the Georgia-South Carolina border, between Atlanta and Greenville in the foothills of the Appalachians.

What is a meteor?

When an object is still in space, it’s a meteoroid. If it enters the atmosphere, it’s a meteor. Only if shards or fragments reach the surface is it deemed a meteorite.

The American Meteor Society is working to compile witness reports to estimate the potential track and speed of the meteor.

There have been a few unconfirmed reports of a booming sound being heard, which - coincident with the bright flash - suggests an explosion in the atmosphere. That would precede fragmentation.

When a meteor enters Earth’s atmosphere, it encounters air resistance. It may still be moving at tens of thousands of km/h; that air resistance leads to incredible friction, which, in turn, generates heat.

That leads to ablation, or a loss of mass. Some of the mass may vaporise. Sometimes, the periphery of a meteor fuses into an initially more molten material that quickly solidifies.

Once an explosion and subsequent fragmentation occurs, the final steps of a meteor’s fall towards Earth are sneakier - the meteor (or fragments) are cooler and, therefore, no longer visible as streaks of light.