Venus transit may boost hunt for other worlds

Astronomers around the world will be using advanced telescopes to watch Venus cross in front of the sun on Tuesday and Wednesday in the hopes of finding clues in the hunt for other planets where life may exist.

By studying the atmosphere of a well-known planet in this once-in-a-lifetime event, scientists say they will learn more about how to decipher the atmospheres of planets outside our solar system as they cross in front of their own stars.

“There are many, many of these events that are observed for distant stars. The thing is that stars are just points of light because we are so far away, so you can’t actually see what is going on,” Alan MacRobert, astronomer and editor of Sky and Telescope magazine, said.

However, the transit of Venus, an event that will not happen again for another 105 years, or until 2117, offers a chance to practice decoding the atmosphere of a planet based on the impression it leaves on its star’s light.

“The idea is some of that starlight skims through the atmosphere of the planet and the atmosphere leaves its imprint on that tiny, tiny little bit of a star’s light,” Mr MacRobert said.

“If you can separate that from the rest of the star’s light − analysing the light before, during and after the transit and looking for the difference − you can actually tell something about the planet’s atmosphere,” he added. “And this is absolutely at the cutting edge of present day technology.”

The beginning of the transit will be visible in North America, Central America and the northern part of South America on the evening of Tuesday, as long as the skies stay clear.

The end will not be seen in these regions due to sunset.

All of the transit will be visible in East Asia and the Western Pacific. Europe, the Middle East and South Asia will get to see the end stages of the eclipse as they go into sunrise on Wednesday.

However, due to the risk of blindness or painful, permanent eye damage, people should not look directly at the sun without a proper solar filter to try and observe the tiny black dot crossing its surface.