It's a sight that would make many think aliens were invading or perhaps the end of the world had come: a huge fireball flying through the sky. But while the witnesses to the phenomenon in Australia thought it was a meteor falling or a plane crashing or whatever their imagination ran away with, the reality turned out to be a piece of a Russian Soyuz rocket that had been launched from Kazakhstan.

Many people called emergency officials Thursday night to report the apocalyptic fireball, including those in Australia's states of Victoria, New South Wales and Tasmania.

A number of Australians sent photos over twitter, with the hashtag #meteor. "Just saw the biggest meteor I've ever seen, going all way across the sky heading North, amazing!" Justin Nicholas tweeted that night. 

Surprisingly, the rocket piece behaved exactly according to plan, following its path of reentry perfectly. The piece was about the size of a truck, which came off the third stage for a Russian Soyuz rocket launch from Kazakhstan on July 8. The rocket had been carrying a weather satellite and other smaller satellites. The piece that fell back to earth has since been labeled "Object 4077."

"What you're seeing in that fireball is it slowing down really fast. It's belly-flopping on the world's atmosphere at 18,000 miles an hour." Jonathan McDowell, an astronomer from the Harvard-Smithsonian Center for Astrophysics, said.

As per McDowell, around 1,000 pieces of space junk have reentered orbit or our atmosphere since the beginning of the space age. Most pieces of debris melt away in the reentry before they impact on earth. It is unknown whether "4077" reached the ground in Australia. 

This kind of event happens fairly often due to all the rockets and space debris, but most do not see them when it happens. "They're not usually seen because most of the Earth is either ocean -- or very sparsely inhabited. And of course, if it comes down in the daytime, you may not notice as easily," McDowell said. 

McDowell later tweeted out a photo of the Russian rocket pre-flight.

Photo: Ed Sweeney