Mercury to appear as tiny black dot in rare 'transit' across sun

People in Greece will be able to witness a rare celestial show on Monday as Mercury passes between the sun and Earth, a phenomenon that is not expected to occur again until 2032.

Slated to start at about 6.35 a.m.

In most of the U.S. and Canada, and New Zealand, the transit will be in progress as the sun rises.

Readers are reminded that staring at the sun or trying to view it with telescopic equipment can seriously damage the eyes or cause blindness.

Mercury's transit only happens about 13 times a century. On an average, there will be 13 or 14 transits of Mercury each century. the first transit was seen in 1631, nearly 20 years after the invention of the telescope by French astronomer Pierre Gassendi. Disposable eclipse glasses should never be used with binoculars and telescopes; magnifying lenses increase sunlight's destructive power and can melt eclipse glasses' flimsy filters, as demonstrated in a video shared to YouTube in 2017 by journalist and photographer Vince Patton. There's no harm in pulling out the eclipse glasses from the total solar eclipse across the USA two years ago, but it would take "exceptional vision" to spot minuscule Mercury, said NASA solar astrophysicist Alex Young.

Mercury will pass between Earth and the sun.

During its 2012 transit of the sun, larger and closer Venus was barely detectable by Young with his solar-viewing glasses.

How can you see it? "So Mercury's going to probably be too small". The last transit of Venus was in June of 2012, and the next will occur in December of 2117. This year, part of the 5.5-hour transit will be visible to much of North America starting at 12:36 p.m. UTC.

Although the trek will appear slow, Mercury will zoom across the sun at about 150,000 miles per hour. Local weather should cooperate and provide clear skies Monday for viewing. Advance registration is required; find more info here.

According to NASA, the Solar Dynamics Observatory's website' will be showing "near real-time" images of the transit, so you don't have to miss this rare event, no matter where you are.

Scientists have used these events for hundreds of years to study the way planets and stars move in space.

It's this kind of transit that allows scientists to discover alien worlds.

So far, two NASA space probes have visited Mercury, Mariner 10 in 1974 and 1975, and MESSENGER, which orbited the planet from 2011 until a deliberate crash landing in 2015.

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