How long would it take to get to Alpha Centauri with light speed?
If humans could travel at the speed of light, we could reach Alpha Centauri in four years flat. However, the laws of physics dictate that only massless light particles called photons can reach this cosmic speed limit.
How long would it take to drive to Alpha Centauri 4.4 light years away?
It would take approximately 4.77 million years to drive to Alpha Centauri at 100 km/hr. This is because Alpha Centauri is 4.4 light-years away, which is equal to 41.8 trillion kilometers. The vast distance makes it practically impossible to travel there by car.
According to NASA, the Discovery space shuttle (which was retired in 2011) travels at around 17,500 mph (28,000 km/h). Even moving constantly at this speed, it would take over 148,000 years to reach Alpha Centauri.
The technical capability to send humans to Alpha Centauri and other nearby stars is within our grasp today, with the use of nuclear pulse propulsion. It would cost trillions, probably take decades to finish, and be the biggest in-space engineering project ever undertaken by a long shot (pun intended).
What warp speed actually looks like with real-distance, in real-time!
How long would it take for Voyager 1 to get to Alpha Centauri?
Voyager 1 is currently the farthest human-made object from Earth, at about 14 billion miles (23 billion km) away. It's also the fastest of the bunch, at about 38,000 miles per hour (61,000 kph). That means it would take about 73,000 years to reach Alpha Centauri.
Proxima Centauri has two confirmed planets: Proxima b or α Centauri Cb, an Earth-sized planet in the habitable zone discovered in 2016, and Proxima d (α Centauri Cd), a candidate sub-Earth which orbits very closely to the star, announced in 2022.
How long would it take to get to Andromeda at the speed of light?
The Andromeda Galaxy is located approximately 2.5 million light-years away from Earth. Traveling at the speed of light, it would take 2.5 million years to reach the Andromeda Galaxy.
The closest extrasolar planets overall to Earth are Proxima Centauri b, c, and d, each located 4.22 light years away. Proxima b is the closest potentially habitable planet to Earth.
Alpha Centauri is about 4.37 light-years away, meaning it would take over four years traveling at the speed of light to reach it. Currently, our fastest spacecraft, such as Voyager 1, travel at speeds much slower than light, making the journey to Alpha Centauri unfeasible within a human lifespan.
Our crewed spaceships, like Apollo, reach speeds of around 39,400 km/h (24,500 mph). It would still take around 27 thousand years to travel one lightyear. A plane travelling at 965 km/h (600 mp/h) would take 1 million years to travel one lightyear.
Based on our current understanding of physics and the limits of the natural world, the answer, sadly, is no. According to Albert Einstein's theory of special relativity, summarized by the famous equation E=mc2, the speed of light (c) is something like a cosmic speed limit that cannot be surpassed.
20% of the speed of light is 59,958,491.6 meters per second, slower than light in germanium (refractive index 4.1, speed 73,120 meters per nanosecond. The speed of light in vacuum, absent acceleration, gravity, and the expansion of space, is 299,792,458 meters per second, about a foot per nanosecond.
Perhaps one of the most famous effects of special relativity is that for a human moving near the speed of light, time slows down. In this scenario, a person moving at near light speed would age more slowly.
How long would it take to cross the Milky Way at the speed of light?
The disk of our home galaxy – the Milky Way – is bigger than we previously thought. A new study shows it would take 200,000 years for a spaceship traveling at the speed of light to go across the entire galaxy.
How long would it take to travel 2.537 million light years?
If Andromeda was standing still, it would take roughly 4,000 earth years for every 1 light year, at current propulsion speeds. That means we can traverse the 2.5 million light years in 1x10^10 years or about 10 billion years (give or take).
Proxima b orbits very close to its M dwarf sun, and thus may be tidally locked, meaning it always shows the same side to the star. That isn't good for life, because one side would remain scorching hot and the other icy cold.
NASA's considers this exoplanet and its star to be the closest analog to our planet and Sun, so far. Though it is 60% larger than Earth in diameter, Kepler-452b is thought to be rocky and within the habitable zone of a G-type star similar to ours.
Indeed, in about 12.5 billion years the a Centauri triple system will be no more, having fully separated into three independently moving objects: a red dwarf star (Proxima) and two ∼0.6 M⊙ mass white dwarfs (the remnants of a Cen A and B).
Voyager 1's extended mission is expected to continue to return scientific data until at least 2025, with a maximum lifespan of until 2030. Its radioisotope thermoelectric generators (RTGs) may supply enough electric power to return engineering data until 2036.
To give you a great example of how far a light year actually is, it will take Voyager 1 (NASA's longest-lived spacecraft) over 17,000 years to reach 1 light year in distance traveling at a speed of 61,000 kph.
Mainly because they were never set to reach Alpha Centauri. They were meant to explore the outter planets of our solar system and then wander away from our sun, without a specific destination.
