NASA astronaut spots mysterious bright green flash while on the ISS

A NASA astronaut aboard the International Space Station (ISS) captured a stunning video of a bright green explosion that occurred more than 250 miles above Earth.

Astronaut Matthew Dominick captured a video of the mysterious light and asked the public for help identifying the source of the flash.

'I showed this to a couple of friends yesterday to see what they thought. They both thought it was a meteor exploding in the atmosphere - a rather bright one called a bolide,' he wrote on X.

A bolide is an exceptionally bright meteor that is spectacular enough to be seen over a very wide area and explodes in Earth's atmosphere, according to NASA's Center for Near Earth Object Studies. 

Bolides are a type of 'fireball,' which are meteors that reach a brightness greater than magnitude -4. That's roughly as bright as the planet Venus seen in the morning or evening sky, according to the American Meteor Society (AMA) 

The difference between boldies and fireballs is that boldies explode upon entering Earth's atmosphere, like the one that Dominick captured on video.

When a meteor enters Earth's atmosphere, friction causes it to simultaneously slow down and heat up. 

The force of the impacting meteor causes a 'bow shock' to form in front of it. A bow shock is a shock wave that forms when a supersonic object moves through a medium, like atmospheric gases.

The bow shock heats and compresses the atmospheric gases in front of the meteor, and some of this energy is radiated back into the meteor. This causes the meteor to 'ablate' - or erode away - and eventually break apart. 

The resulting fragmentation increases the amount of objects impacting the atmosphere, and therefore enhances atmospheric ablation and causes the meteor to slow down even more.

The meteor explodes when the force from the unequal pressures on its front and back sides exceeds its tensile strength, which is the maximum amount of stress an object can withstand before it breaks apart. 

When a meteor destructs in this way, it is thereafter known as a 'boldie.' 

Thousands of meteors of fireball magnitude occur in Earth's atmosphere each day. according to the AMA. But not all of them become boldies. 

These exploding meteors are relatively rare and quite difficult to spot because their flashes only last a few seconds. 

Dominick was lucky to capture this one while filming a timelapse of Earth as the ISS flew over North Africa. 

Just after the space station passed over Cairo, Egypt, a brilliant explosion flashed green and then white over our planet.

'Timelapse was setup over Northern Africa where it was very dark with lightning. I got greedy with ISO (25600) and when the timelapse got to Cairo the cities were overexposed,' he wrote in a post on X, formerly Twitter. 

'I was greedy because I wanted the Milky Way Core. When I went to review the shots afterwards I found the bolide.'

The astronaut posted two videos of the event: a frame-by-frame time-lapse that shows the flash in slow motion, and a faster version. 

Both show the meteor streaking over Cairo, Eqypt before bursting into flames. 

Dominick launched on a mission to the ISS in March as the commander of NASA's SpaceX Crew-8 mission.

Over the last five months, he has shared numerous photos and videos taken from his vantage point high above our planet.