Bizarre clouds have appeared in the sky over Australia

Amazing tubular clouds "hung" in the sky over Sydney, Australia on Tuesday afternoon. Numerous eyewitnesses captured the phenomenon in photos and videos, 7NEWS reports.

Many observers have wondered what is the reason for the appearance of such formations in the sky.

"Are these aliens?" one man asked. "I feel like as a society we all have the right to really know what's going on. Should we be worried?"

Experts say that there is no cause for concern. Sydney meteorologist Angie Asimus noted that "these clouds are known as gravitational waves."

Such long clouds form when the air rises and cools in a westerly wind, flying over the mountains, and then cools and condenses on the way down.

According to Azimus, such clouds can become a problem for air passengers, as they lead to turbulence of aircraft.