If you weren’t born yesterday, chances are you’ll never experience a transit of Venus again. Only seven of them have ever been observed and the next one is in 2117.
So here are some beautiful images to celebrate the moment a decade ago today when on June 5, 2012 it was possible to see the second rock from the sun pass in front of it as seen from the third rock from the sun.
A transit of Venus over the Sun occurs when the planet Venus passes directly between the Sun and Earth. It can be seen as a small black dot moving across the face of the sun. During the transit, Venus had an apparent diameter of almost 58 arc seconds, which is about 3% of the Sun’s apparent diameter.
A transit of Venus occurs twice in eight years, then not at all for 105 years. The last time it happened on 5/6. June 2012 and the next time it will be on 10./11. happen December 2117. Another will follow on December 8, 2125.
Because it is only observable from the day side of the planet, a transit of Venus can be a once-in-a-lifetime event or even twice. Or it can happen exactly zero times in a person’s life.
So the 2012 transit of Venus was a massive event for an entire generation of skygazers and nature lovers, especially those who missed the 2004 event. Crowds gathered at observatories around the world, solar filters in hand, hoping to catch a glimpse of the majestic event.
It was largely a Pacific event, visible in New Zealand, Japan, and much of Australia and East Asia, as well as the northwesternmost parts of North America. IT was also spotted in Europe in the morning.
Some of the best views come from above the clouds of one of the world’s largest volcanoes. “I went to Mauna Kea in Hawaii because it was one of the best places to see the entire transit, which was centered over the Pacific Ocean,” he said Tom Kerss, astronomer and author of The Squirrel That Watched the Stars. “About 300 to 400 people gathered at the visitor center, which is 9,500 feet above sea level.”
It was a poetic place to observe an event so powerful and fleeting. “I remember thinking about Venus being the most volcanic world in the solar system, and I was on top of one of the largest volcanoes anywhere,” Kerss said. “A transit of Venus is the closest our planet can ever get to another planet. For one great moment, I could almost imagine seeing another volcano on Venus pointing back at me.”
Kerss was 26 at the time. By the next transit of Venus he will be 131 years old. He took the fabulous image at the top of this article, which also shows significant solar activity while the transit of Venus was taking place.
Italian astronomer Galileo Galilei was the first to predict that a transit of Venus would occur. He was born and died between two transit periods, so he never experienced one.
From Earth it is only possible to see two planets transiting the sun’s disk – Venus and Mercury, the inner or “inferior” planets. The outer planets appear to be passing behind the sun only from Earth’s perspective.
The last transit of Mercury was on November 11, 2019 and the next will be on November 13, 2032. They are more common, taking place about 13 times per century. Venus is five times the diameter of Mercury, so a transit of Venus is much more dramatic than a transit of Mercury.
Astronomers primarily use the transit method to find exoplanets. NASA’s Kepler space telescope observed nearly 200,000 stars in a tiny speck in the sky between 2009 and 2018, looking for a slight dip in starlight as planets passed their host stars.
Kepler found a whopping 2,392 exoplanets this way. NASA’s Transiting Exoplanet Survey Satellite (TESS) is now doing the same, and some believe it could find as many as 12,519 new exoplanets by 2024.
It’s possible to see transits from other planets, although you can’t see Earth transiting over the Sun unless you’re on Mars or further out. The next transit of the Earth as seen from Mars will take place on November 10, 2084.
Perhaps people will see this from a Mars base a full 33 years before Venus next makes a journey across the face of the Sun.
I wish you clear skies and big eyes.