Mercury transit proves to be a rare sight

Next transit to be visible on November 11, 2019, says expert

KARACHI: Holding ultra-violet protected glasses, x-ray sheets and telescope filters, students of Institute of Space and Planetary Astrophysics (ISPA) came together to observe the rare occurrence of the transit of Mercury on Monday.

The transit takes place when Mercury comes directly between the sun and Earth at an angle which allows it to be seen as a silhouette.



Gathered on the top floor of the ISPA of the University of Karachi, the students waited while their professors and teachers set up the telescope to observe the transition. From the 200 students enrolled in the department, around 70 were present along with faculty members.

Mercury, Venus, Earth and Mars are terrestrial planets. After an asteroid belt come the outer planets which are known as Jovian planets, explained Syed Faisalur Rahman, who is a teaching associate for space sciences at the institute. "Such events can only be observed on Earth when Mercury or Venus transits the sun," he added. Rahman also revealed that this rare event occurred after eight decades.

The transit was clearly visible through a telescope with filters. "It is the small black dot on the surface of sun," said a teacher Danish Faruqi while the tiny black dot appeared through the telescope. The black dot started to build on the surface at 4:10pm but it became visible at 4:15pm and was seen till 7:04pm.

Speaking about the black dot, Rahman said that the distance between Sun and Earth is about 150 million kilometres, which is why Mercury appeared so minute. In other parts of the world, the transit was visible for more than seven hours, but in Pakistan and other neighbouring countries due to sunset it was visible for not more than three hours, said Rahman.

The cycle for mercury transit cannot be decoded as it is very irregular, said ISPA associate professor Dr Jawwad Baig. "It depends on the speeds of Earth, Sun and Mercury as the transition will be next seen in November 11, 2019," he said, adding after which it will occur in 2032.



The transit is relatively rare than solar and lunar eclipses with occurring approximately 13 times in a century, mostly in November and May, said ISPA director Prof Dr Jawed Iqbal. He also mentioned the recent transit as the greatest one as Mercury passed closest to the sun's centre.

Such astronomical events should not be observed through the naked eye as it can burn the retina and causing permanent blindness, said Rahman. "We are not even allowing the students to see the transit from the telescope without filters," he added.

Correction: ISPA teaching associate Syed Faisalur Rahman was misquoted in his statement informing of the distance of the sun from the earth. It is around 150 million kilometres, not 15 million kilometres, as reported earlier. The error is regretted.

Published in The Express Tribune, May 10^th, 2016.