Part 2/11:
The Mariner 10 probe first approached Mercury in 1974 after 147 days of travel. Messenger, launched in 2004, offered a more intense journey of nearly 7 years before entering Mercury's orbit in 2011. Comparing the travel time to that of Juno—five years to reach Jupiter—raises questions about the apparent disparity in time taken to reach Mercury, which is significantly closer to Earth.