Transit of Venus

Tomorrow the planet Venus crosses in front of the sun. This is called a transit and it occurs in pairs, eight years apart, about every 120 years. The last time this happened was in 2004 but that was at night time in New Zealand. On June 6th this year, the transit begins before 10.30am and finishes after 4.30pm, depending on whether you live in the north or the south of the country.

We have had warnings about not looking at the sun directly, or through sunglasses or a telescope or binoculars. You could damage your eyes or even become blind. However, the weather forecast for the whole country tomorrow is not good. It’s possible we will not see the sun at all. This will be a big disappointment because the next transit of Venus will not be until 2117.

The transit of Venus is historically important to New Zealand because that was the reason Captain Cook first came to the Pacific area. When he left Britain, he went first to Tahiti to see the transit of Venus in 1769 and then he went looking for the new land in the south. That was New Zealand.

Astronomers were very interested in the transit of Venus because they hoped that timing the transit in many places in the world, would tell them the distance of the Earth from the sun. Then they could work out the size of the solar system. In fact, it was too hard to see exactly when the transit started and ended. Astronomers had to wait for this information until the late 19th century when they could use cameras.

Prefixes

• trans- across, through e.g. Trans Tasman flights are from New Zealand to Australia. transit – go across.
• tele- far (telescope)
• bi- two (binoculars)
• fore – go before (forecast)
• sol- sun (solar)
• astro – star (astronomer, astronaut)

Other vocabulary
• occurs – happens
• disappointment – an unhappy feeling when something good doesn’t happen
• astronomers – scientists who study stars
• timing – to measure the time
• work out – calculate, do the mathematics