The Milky Way is a barred-spiral galaxy that is approximately 100,000 light years across, according to Space.com. This means an object traveling at the speed of light, which is the theoretical maximum speed for any object, would take a full 100,000 years to traverse the entire Milky Way galaxy.
According to NASA, the fastest object ever made by humans, the Voyager probe, is traveling at over 35,000 miles per hour. At this speed, the probe is capable of traversing a distance of one light year in about 20,000 years. To cross the Milky Way at this speed, Voyager would have to travel for around 2 billion years.