A massive fireball from the oil refinery explosion that rocked South Philadelphia Friday morning was so hot that it was captured by weather satellites in space.

While it’s not unusual for National Weather Service infrared satellites to detect the heat signature of huge fires, "what makes this different is it was a refinery fire,” said Lee Robertson, a meteorologist with the service in Mount Holly.

"Mostly we see this with wildfires out west,” Robertson said.

Unlike a satellite that photographs images as seen by the naked eye, infrared satellites take thermal images of an area.

The dark spot captured by the infrared satellite over Philadelphia represents “an extreme hundred- or thousand-degree temperature difference” between the blaze and the cool clouds overhead, Robertson said.

In comparison, the sweeping wildfire that devastated portions of Northern California last fall was detected by both visible and infrared weather satellites.

» READ MORE: Philly had just trained for an incident like refinery fire: ‘It worked out exactly how it should have’

The three-alarm fire that ripped through the Philadelphia Energy Solutions (PES) complex was reported around 4 a.m.

South Philadelphia residents awoke to explosions and shelter-in-place messages, expecting the worst.

Five workers suffered minor injuries and were treated at the scene. Firefighters contained the blaze within a few hours, but it is still burning and has not been declared under control.

Following the explosion at PES, the largest oil refinery on the East Coast, gasoline prices in New York surged 3.7 percent as the market prepared for a shortage of supply.