![theatlantic:
For Scientists of the 18th Century, the Transit of Venus Was The Final Chance to Measure the Solar System
Later today, as the planet Venus glides across the face of the sun, people all around the world will gather to watch. For 21st-century observers, the event — known as the transit — is a chance to see the orbits of the solar system at work as they come into a momentary alignment. Another transit will not occur until 2117. Unless you are very young and plan to live for a very, very long time, this is it for you.
Miss out now and you’ve lost your chance. But that pressure is nothing — nothing — compared to the pressure on British Captain James Cook and the crew of the HMB Endeavour, as they set sail in 1768 to reach Tahiti in time to watch the 1769 transit. It was their hope that accurate measurements of the transit could finally give scientists the data they needed to answer one of the big questions in astronomy at that time: Just how far away was the Earth from the sun? If they could answer that, they could calculate the size of the solar system as a whole.
Read more. [Image: NASA]](http://24.media.tumblr.com/tumblr_m55eencJet1qcokc4o1_500.gif)
Later today, as the planet Venus glides across the face of the sun, people all around the world will gather to watch. For 21st-century observers, the event — known as the transit — is a chance to see the orbits of the solar system at work as they come into a momentary alignment. Another transit will not occur until 2117. Unless you are very young and plan to live for a very, very long time, this is it for you.
Miss out now and you’ve lost your chance. But that pressure is nothing — nothing — compared to the pressure on British Captain James Cook and the crew of the HMB Endeavour, as they set sail in 1768 to reach Tahiti in time to watch the 1769 transit. It was their hope that accurate measurements of the transit could finally give scientists the data they needed to answer one of the big questions in astronomy at that time: Just how far away was the Earth from the sun? If they could answer that, they could calculate the size of the solar system as a whole.
Read more. [Image: NASA]
