| 3°C Belfast

Observers catch rare glimpse of Mercury passing the sun

However, poor weather conditions in parts of the UK made it hard for some astronomers to see the event.


Mercury starting its transit of the sun (Nasa/SDO)

Mercury starting its transit of the sun (Nasa/SDO)

Mercury starting its transit of the sun (Nasa/SDO)

Astronomers and space enthusiasts have watched as Mercury made a rare transit of the sun.

The smallest planet in the solar system could be seen as a tiny black disc moving across the glowing orb, starting in the UK at just after 12.35pm on Monday.

Members of the public were urged to join amateur astronomical societies and public observatories across the country to witness the occasion safely.

However, poor weather conditions hampered some efforts to catch the show.

The last time Mercury passed the sun this way was in 2016, but the next is not due until 2032.

Nasa revealed some of the first images of the transit, taken from its satellite monitoring the sun.

The entire event was visible from the eastern United States and Canada, the south-western tip of Greenland, most of the Caribbean, Central America, the whole of South America and some of west Africa.


In Europe, the Middle East and most of Africa, the sun set before the transit ended, so the latter part of the event was not visible.

Every 88 years Mercury completes each orbit around the sun, and it passes between the Earth and sun every 116 days.

Because the planet’s orbit around the sun is tilted, it normally appears to pass above or below our nearest star.

(PA Graphics)

A transit can only take place when the Earth, Mercury and the sun are exactly in line in three dimensions.

Looking at the sun without appropriate protection, either during the transit or at any other time, can cause serious and permanent damage to the eyes.