"When it's still in space it's a meteoroid, it becomes a meteor when it's in the earth's atmosphere and that's when you see the really bright light when it's burning up, its going pretty fast and its burning up.
"The colour of the light depends on what its made of. A lot of the meteorites we get tend to be iron, and thats a nice yellow light. If it's another metallic substance it can be a blue-green light or a green one some can even be violet."
There has been speculation that the bright object was part of a Russian rocket re-entering the Earth's atmosphere, and Sundar noted that "anything's a possibility" to explain what the "ball of fire" was.
"If there was any left over debris it may be a rocket, but I couldn't really say."
She said reports of sightings like this one were common worldwide.
"All over the world you get a few thousand a year, they're reported all the time, however actually seeing one in New Zealand... I haven't seen that many so it's always really exciting when you get to see one."
One woman posted on Facebook that she saw the light in Lower Hutt.
"Yup saw it clearly in Lower Hutt. It was huge and the tail colorful."
Other eyewitnesses reported sightings in Blenheim, Porirua, Lake Ferry, Martinborough and Dunedin.
