The question of how long it would take to drive to the Sun is a fascinating thought experiment that uses an everyday object, a car, to help us grasp the truly immense scale of our solar system. While the idea of a cosmic road trip is physically impossible, applying simple arithmetic to astronomical distances provides a tangible answer to this hypothetical journey. By setting a constant speed and establishing the distance to our star, we can quantify the sheer amount of time required for a terrestrial vehicle to reach the center of our solar system.
Setting the Stage: Defining the Astronomical Unit
To begin this interstellar road trip, we must first establish the distance of the journey, which is standardized in astronomy as the Astronomical Unit, or AU. One AU represents the average distance between the Earth and the Sun. This distance is approximately 93 million miles, or about 150 million kilometers. Because the Earth’s orbit is slightly elliptical, this distance changes throughout the year, but the average serves as a fixed value for our calculation.
For our hypothetical journey, we must make several assumptions. We must imagine a continuous, perfectly straight, and fully paved road extending from Earth to the Sun. Furthermore, we assume the car maintains a constant speed of 60 miles per hour (mph) for the entire duration of the trip. These necessary simplifications allow us to focus solely on the time-distance calculation, ignoring all the complex physics of space travel.
The Calculation: Time Spent Driving to the Sun
Using the established distance of 93 million miles and the constant speed of 60 mph, the calculation for the travel time can be performed in a straightforward manner. The total distance is divided by the speed to determine the time in hours. This initial step reveals that the journey would require 1,550,000 hours of continuous driving to cover the distance of one AU.
Converting this massive number of hours into more digestible units. Dividing the total hours by 24 gives us the time in days, which is approximately 64,583 days. This duration highlights the unsuitability of a car for interstellar travel, but the time is best expressed in years to fully appreciate the magnitude of the voyage.
Dividing the number of days by 365.25, to account for leap years, shows that the trip would take approximately 176.8 years to complete. The driver and the car would need to maintain an uninterrupted journey for nearly 177 years. This timeframe underscores how vast the distance is, requiring multiple human lifetimes to traverse the gap between Earth and the Sun at ordinary highway speeds.
Putting the Travel Time into Perspective
The 177-year travel time far exceeds the average human lifespan, meaning the original driver would be succeeded by generations of travelers before the destination was reached. The fastest spacecraft ever built, NASA’s Parker Solar Probe, is capable of reaching speeds of about 430,000 mph. At this velocity, the same distance to the Sun would be covered in just over nine days, a stark difference from the car’s multi-century trek.
Comparing the car’s journey to historical events further contextualizes its length. If the car had started its trip when the United States declared its independence in 1776, it would only have arrived at the Sun relatively recently. The time it takes for a car to cover this distance demonstrates the impossibility of using human-scale metrics to truly gauge the size of the cosmos.
Why the Hypothetical Trip Fails in Reality
Beyond the mathematical impossibility of the time involved, the hypothetical car trip immediately fails when considering the physical realities of space. The absence of an atmosphere means the car would have no oxygen for its internal combustion engine and no air to provide lift or steering. Even before leaving Earth’s immediate vicinity, the car would need an immense amount of energy just to escape the planet’s gravitational pull.
The approach to the Sun introduces the barrier of thermodynamics. As the car traveled past the orbit of Mercury, the intensity of the solar radiation would rapidly increase. The vehicle would quickly overheat and vaporize well before reaching the Sun’s surface, where temperatures soar to millions of degrees in the outer atmosphere. The vacuum of space, the lack of propulsion and life support, and the destructive heat all combine to render the car journey an impossibility.