Mysterious interstellar object sparks intrigue, not panic

Is it a bird, is it a plane? Well, astronomers aren't quite sure what it is!

A truly rare, mysterious visitor has been spotted speeding through our cosmic neighbourhood from another solar system.

The interstellar object named 3I/ATLAS is only the third object ever recorded entering from outside our solar system and was first seen in July, moving at nearly twice the speed of typical comets.

Dr Daniel Cunnama, Science Engagement Astronomer at the South African Astronomical Observatory, said it's quite a sighting, if an ambiguous one.

"We're not entirely sure what it is yet. It does look a little bit like a comet."

One thing is for sure, and that is that 3I/ATLAS has sparked some intrigue, and even a few alarmist headlines, after some scientists initially questioned whether its behaviour was natural.

And there have even been suggestions that it could be evidence of alien life.

Not quite, says Cunnama.

"There are certain individuals who are claiming that it's an interstellar spacecraft; there's no evidence for that."

What the sighting does provide us with is information, he said.

"It gives us insight into another solar system, which is quite cool.

"We want to know what they're made of, in terms of the metals. That's quite hard to determine normally by them just passing by."

By looking at how the interstellar object is moving and orbiting, astronomers can estimate how dense they are, Cunnama explained, adding that they'd already discovered CO2 on 3I/ATLAS.

"So, carbon dioxide and water, which are mixed in an unusual way, not normal for our solar system."

To listen to Cunnama in conversation with John Maytham, use the audio player below: