We hear the term “light-years” almost anytime a new star or exo-planet is discovered. But how long would it take to travel one light year?
The fastest human-made vehicle, NASA’s Parker Solar Probe, would take 1,698 years to travel one light-year, the sum of roughly 5.88 trillion miles (9.46 trillion kilometers), the distance light travels in one year.
In September 2023, NASA’s Parker Solar Probe set a new record, clocking a blistering speed of 394,736 miles per hour (635,266 kilometers per hour)—the fastest ever recorded.
But 1,698 years is an incredibly long time. The Parker Solar Probe would have just completed a distance of one light year if it had left during the 4th century (326 A.D.) and maintained its top speed the entire journey.
Let’s look more closely at the speed of light and what it means to travel one light-year.
Understanding
Light Years
Speed of Light
Over one hundred years ago, Albert Einstein’s theory of relativity deciphered the math of a cosmic limit. It says nothing can go faster than the speed of light, which is approximately 186,282 miles per second (299,792 km/s) within the vacuum of space.
To help understand how fast light speed is, we’ll compare it to the longest intercontinental flight in the world today.
A flight from New York to Singapore covers 9,526 miles (15.332km) and, on average, takes 18hrs 40 minutes. If a commercial airliner could travel the speed of light, symbolically, it could make that trip almost 20 times in one second!
Measuring Distances
Understanding the vastness of space begins with grasping the concept of a light-year. It’s a unit of measurement scientists use to note the length of astronomical distances.
Astronomers use two common measurements to help make an incredibly long distance, a huge number, more manageable.
Astronomical Unit (AU): It’s the distance the Sun’s light takes to reach the Earth. This distance is approximately 93 million miles (150 million kilometers) and takes eight light minutes.
Light-Year (LY): It represents the unit of distance that light travels in one Earth year, which is approximately 5.88 trillion miles (9.46 trillion kilometers).
So, the time it takes Light to travel one light year? One Earth year or roughly 365 days.
When speaking of distances in the universe, an astronomer refers to distances in an (AU) or (LY) depending on how great of a distance.
For example, when referring to the distance of the Andromeda Galaxy from Earth, it is stated as 2.5m (LY) light years(i). However, the shorter distance to Neptune from the Sun is noted as approximately 30.7 (AU)(i).
Since a light-year is a larger unit of distance than (AU) it is more likely to be used when expressing bigger numbers.
Travel Time
If we could travel the distance of one light-year from Earth, we would end up in the mid-region of the Oort cloud.
It is the outermost area of our solar system before reaching the realm of deep outer space. The time it would take to journey this one light-year would greatly depend on our mode of transportation.
I’ve put together several calculations using a light-year (ly) calculator. Using the average miles per hour (mph) for current technology we use today. It makes the complexity of traversing such an immense distance very obvious.
See the infographic I have provided below, which has a link to the calculator within the caption.
All calculations were made using a light year calculator.
Let’s look at some of the examples the infographic highlights in relation to how long it takes to travel a light-year.
If you decide to put on some walking shoes and head off towards the mid-region of the Oort cloud, a light year away, be sure to pack lunch. At a normal pace of 3/mph, it would take nearly 224 million years to get there without stopping to eat, sleep, or bathroom breaks.
Walking (3/mph) >>> One Light Year >>> 224M Years
You could pull the car cover off the Corvette stored in the garage for a quicker ride. Even then, traveling at an average speed of 100 mph would take six million and seven hundred thousand years (6.7m years) to travel a light year . That’s without stopping or slowing down.
Drive (100/mph) >>> One Light Year >>> 6.7M Years
How about a ticket on the “Big ol’ Jet Airliner”? It would still take you over one million years (1.118m yrs) to span the distance of one light year on a commercial Jet.
Commercial Jet (600/mph) >>> One Light Year >>> 1.18M Years
The point is that the distances between objects in our solar system, galaxy, and universe are so vast it’s very challenging for our minds to grasp and comprehend it.
As of today, we do not have technology that can travel the distance of a light-year within the span of a human life, but there are future concepts. Let’s take a look.
Future Concepts
to Travel
Light-Years
Considering our Milky Way galaxy stretches across 100,000 light-years. Even at the speed of light, it takes 100,000 Earth years to journey from edge to edge. To bridge that distance, we’ll need to inspire some new ideas through quantum physics.
But some interesting concepts are in the works right now to dramatically shorten the length of time it takes to travel a light year.
Breakthrough Starshot
In 2016, Physicist Yuri Milner announced an engineering endeavor named “Breakthrough Starshot,” with backing support from such notable figures as Stephen Hawking (now deceased), and Mark Zuckerberg.
Their aim is to develop a fleet of light sail centimeter-sized probes called StarChips. These probes are designed to travel to the Alpha Centauri star system, located 4.37 light-years away, potentially within 20 to 30 years at speeds of 15-20% the speed of light.
Currently, using the Parker Solar Probe’s top speed, to travel 4 light-years would take over 7000 years, so that would be an amazing feat.
The project proposes a flyby mission to our next closest star beyond our Sun, Proxima Centauri. It is believed to be home to an Earth-sized exoplanet in the habitable zone.
The concept will leverage advanced laser technology to propel the spacecraft. Current estimates for launch are 2036.
Helical Engine
A space and aeronautics engineer has developed a concept that, in theory, would reach 99% of the speed of light without conflicting with Einstein’s theory of relativity.
Dr Burn, now a former engineer from NASA’s Space Flight Center in Alabama, believes that a system where instead of expelling propellant, it is retained, could generate an almost limitless specific impulse and open the door to interstellar space exploration.
This method involves accelerating ions near the light speed limit within a closed circuit, adjusting their speed to modify momentum. Thrust is generated by oscillating the ions back and forth in the direction of travel.
It’s Designed for long-term satellite operations without the need for refueling or powering voyages across vast distances; this engine operates without any mechanical components, relying solely on ions circulating in a vacuum loop contained by electric and magnetic fields.
If this concept is proven and successful it would mean we could travel a light-year in a little more than one year!
Warp Drive
It’s impossible to talk about traveling at the speed of light without discussing the theory of warp drive, which was popularized by the 1960s Star Trek series.
NASA has explored this concept and will continue to do so as science and modern physics expand with future breakthroughs.
The idea behind warp drive is to manipulate the fabric of spacetime to create a bubble or a wave, often referred to as a “warp bubble,” that would contract space in front of the ship and expand it from behind, allowing the vessel to move from one point to another faster than light would in normal space.
It would theoretically enable interstellar travel within human lifetimes without violating the fundamental principles of Einstein’s theory of general relativity, which states that nothing can travel faster than the speed of light in a vacuum.
If this concept is ever proven, it will be a game changer for space travel in our cosmic neighborhood and beyond.
Conclusion
For now, the Parker Solar Probe’s top speed makes it the fastest vehicle to span the distance of a light year. The enormity of the universe will make reaching distant stars and exoplanets impossible until we can develop technologies like the Warp Drive, Starshot, or Helical engine.
It’s a humbling distance across our Milky Way. But scientists continue to unlock the mysteries of the cosmos, and one day, we may crack the code to bridge the vast galactic space within the universe.
