The bright light seen streaking across the sky over southeast Australia that captivated residents was most likely caused by remnants of a Russian rocket returning to Earth after a satellite launch, the country's space agency said Tuesday.
The fiery object appeared to leave a trail of flames the night before over Tasmania and Victoria, where it drew astonished reaction from residents of the city of Melbourne.
"Oh, my God, are you joking? I can't believe we just saw that," two women in Melbourne can be heard saying in social media footage of the fireball shared by Australian public broadcaster SBS.
"I've never seen anything like that. That is huge, whatever that is," a man says in a second video. Another Melbourne resident joked he "thought it was a UFO" coming to get him.
But the Australian Space Agency has dispelled doubts from many people on social media about whether the mysterious light show was a meteor shower.
"We have determined the flashes of light seen across Melbourne skies overnight were likely the remnants of a Russian Soyuz-2 rocket reentering the Earth's atmosphere," the agency said Tuesday.
The statement said Russian authorities gave advance notice of the launch and that "remnants of the rocket were planned to safely reenter the atmosphere into the ocean off the southeast coast of Tasmania."
The rocket was launched earlier in the evening from a Russian spaceport north of Moscow, the Australian Space Agency said, adding that "according to Russian authorities, the launch placed a new generation 'GLONASS-K2' global navigation satellite into orbit."
The agency said it would "continue to monitor the outcomes of this reentry" with government authorities.
"The Melbourne meteor was spectacular . . . and we have some unexpected space junk to thank for it!" Alan Duffy, a professor in astrophysics at Australia's Swinburne University of Technology, tweeted.
He said the colors produced as the object whizzed across the sky indicated that it was man-made and that pieces of the space junk were burning up, describing it as "one of the most dramatic re-entry videos I have ever come across."
"Pieces were coming off this object and in turn they were burning, so all of this is meaning that we're seeing up there is something very large, it's traveling very fast," he told ABC Radio Melbourne.
Some scientists said that while the glowing trail over Australia was unlikely to pose a threat to human life, it highlighted a problem of space junk increasingly congesting Earth's orbit.
Astronomer Michael Brown said it was possible small parts of the rocket crashed to Earth or into the sea, although it is not common for space junk to damage property.
"As the rocket was travelling at several kilometers every second as it entered the atmosphere, it experienced vast forces that heated and broke up the rocket, producing a spectacular light show," he said in a statement.
Brown, an associate professor at Monash University's School of Physics and Astronomy in Australia, said the reentry of space junk can be confused with meteors, which are usually shorter events. Yet with rocket launches increasing in recent years, and as "everyone has cameras in their phones, more and more people are seeing space junk re-entries and recognizing them for what they are," he said.
