Mercury passes across the sun

Mercury passes across the sun

On Monday Mercury passed over the face of the sun, a rare event which only occurs a little more than a dozen times in 100 years.

The transit began at 11:12am UTC (11:12pm NZT) and lasted about seven and a half hours.

From Earth, we can only see a transit involving either Mercury or Venus, as they're the only planets which lie inside Earth's orbit.

NASA says the event occurs around 13 times a century. It last occurred nearly a decade ago, on November 8 2006.

"Mercury's orbit crosses Earth's orbital plane in early May and early November each year. If the Mercury is passing between the Earth and sun at that time, a transit will be seen."

The next Mercury transit is expected on November 11 2019, but the one following that isn't predicted to occur until November 2032.

While we missed out this time, both of the next transits will be partially visible from New Zealand.