Mercury transit GIFs show us incredible scale of the solar system

10 May 2016

A close-up of the Mercury transit. Image via NASA/Bill Ingalls

Did you get a chance to catch the Mercury transit across the sun yesterday? Astronomers both famous and amateur who turned their gaze (safely) towards the sun managed to see a rare and incredible sight.

The Mercury transit across the face of the sun, at least from our perspective here in the solar system, is truly one of the most humbling experiences from an astronomical perspective as the sheer scale of the universe, and even our own solar system, is revealed before our very eyes.

For seven-and-a-half hours on 9 May, the planets and star aligned in such a way that Mercury passed in front of the sun from our perspective here on Earth, which might seem like a fairly average event, but is, in fact, something that happens just 13 times a century.

Astronomy Ireland

Members of the public got to attend a viewing at Astronomy Ireland‘s headquarters in Dublin. Image via Astronomy Ireland/Facebook

The first recording of the transit of Mercury occurred in 1631, when French astronomer Pierre Gassendi saw the astronomical alignment just two decades after the telescope was invented but, sadly, the German astronomer Johannes Kepler who had predicted its transit had died in 1630.

As the smallest recognised planet in our solar system, Mercury completes an orbit of the sun every 88 days, and passes between the Earth and the sun every 116 days.

However, its orbit is tilted in relation to Earth’s, which means it usually appears – from our perspective – to pass above or below the sun and, a few times a century, results in an astronomical show like yesterday’s.

Ireland among the best countries to view it

For those who were attempting to observe the event, Ireland and the rest of western Europe, the western parts of north and west Africa, eastern North America, and most of South America were able to view the entire transit over the course of seven hours.

Given the dangers of looking at such an event using a traditional telescope without a protective filter, thousands of people tuned into feeds online, such as NASA’s, which was able to transmit the event live to a person’s device.

And it proved to be an incredible sight.

For those of you who missed it, your next chance to see it will be in three years’ time on 11 November 2019 but, after that, it will be another 13 years before we see it again on 13 November 2032.

Colm Gorey was a senior journalist with Silicon Republic