MONTREAL - Once every lifetime, the Earth, Venus and the Sun stand in perfect alignment for a moment. After the rare event this June 5, it won't happen again until 2117.
"This event is called the Transit of Venus. What we will see is the planet Venus moving slowly across the solar disk," said Sebastien Guillot, the co-chair of astro outreach committee at McGill University.
"It's exactly like an eclipse, except since Venus is much larger and at a much greater distance, it will look very small compared to the sun," said Guillot.
First observed in 1639, the alignment allowed early astronomers to estimate the distance between the Earth and the Sun.
"They were off by a third," said Guillot. "But with what they had, it was a great measurement."
Starting at 5:30 p.m. on June 5, the transit will last for seven hours.
