How Long Would It Take to Travel to the Nearest Star?
The nearest star to the Sun is Proxima Centauri, a small red dwarf 4.24 light-years away, about 40 trillion kilometres. It even has a planet, Proxima b, in its habitable zone. How long it would take to get there depends entirely on how fast you can go, and the answers range from a few years to tens of thousands.
Travel times to Proxima Centauri
| Travelling like | Time to Proxima Centauri | Speed |
|---|---|---|
| A passenger jet | about 5 million years | 900 km/h |
| New Horizons | about 90,000 years | about 14 km/s |
| Voyager 1 | about 75,000 years | about 17 km/s |
| Parker Solar Probe at its fastest | about 6,600 years | about 192 km/s |
| A light sail at 20% of light speed (proposed) | about 21 years | 60,000 km/s |
| Light | 4.24 years | 299,792 km/s |
Even Voyager 1, the fastest spacecraft now leaving the Solar System, is not heading towards Proxima Centauri. It would take about 75,000 years at its speed, more than ten times as long as all of recorded human history.
Why is it so hard?
The problem is energy. To reach a useful fraction of light speed, a spacecraft must carry or be given an enormous amount of energy, and ordinary rockets cannot carry enough fuel to do it. The Parker Solar Probe is the fastest object ever built only because it falls towards the Sun, gaining speed from the Sun's gravity; it cannot keep that speed heading outward. Proposals such as Breakthrough Starshot would instead push gram-scale probes on thin light sails with powerful lasers from Earth, reaching about 20% of light speed and arriving about two decades later.
How far is that, really?
If the Sun were a grain of sand 1 mm across, Earth would be about 11 cm away, Neptune about 3 metres, and Proxima Centauri about 29 kilometres. Voyager 1, after almost 50 years of travel, would have gone about 19 metres. Our Cosmic Journey flies past the nearest stars to show the gap, and Second Earth shows how long it would take to reach each of the most Earth-like planets known.
Frequently asked questions
How far away is the nearest star? Proxima Centauri is 4.24 light-years away, about 40 trillion km. The two bright stars of Alpha Centauri are slightly farther, at 4.37 light-years.
How long would it take to reach Proxima Centauri at the speed of light? 4.24 years, but nothing with mass can reach the speed of light.
How long would Voyager 1 take to reach the nearest star? About 75,000 years at its current speed of about 17 km/s, though it is not travelling in that direction.
What is the fastest spacecraft? NASA's Parker Solar Probe, which reached about 192 km/s as it swung close to the Sun in December 2024.
Could humans ever travel to another star? Not with today's technology within a human lifetime. The most serious current idea sends tiny unmanned probes on light sails, which might reach Proxima Centauri in about 20 years.
Explore it yourself: Journey through the universe · Second Earth · Exoplanets and the Milky Way in 3D · Voyager 1 is about to become one light-day from Earth
Sources
- NASA, Voyager mission pages: Voyager 1 speed and distance. science.nasa.gov
- NASA, Parker Solar Probe: record speed at its December 2024 perihelion. science.nasa.gov
- Breakthrough Initiatives, Breakthrough Starshot. breakthroughinitiatives.org
Times = distance ÷ speed, with Proxima Centauri at 4.2465 light-years (4.017 × 10¹³ km) and no acceleration or slowing down. A light-year is 9.4607 × 10¹² km.