# How many earth years would it take to reach andromeda galaxy?

Feb 17, 2016

#### Explanation:

The distance of Andromeda galaxy from Earth is 2.537 million light years and hence it will take that many years for light to travel to Andromeda galaxy.

However, to leave planet Earth, an escape velocity of 11.2 km/s or 40,320 km/h is required and a speed of 42.1 km/s is required to escape the Sun's gravity and exit the Solar System). As these are very small fraction of velocity of light, the time taken will be much much more than billions of years.

Feb 17, 2016

With a continuous acceleration of $1 g$ for $14$ years followed by a continuous deceleration of $1 g$ for $14$ years you could reach the Andromeda Galaxy. But...

#### Explanation:

(1) Sustaining an acceleration/deceleration of $1 g$ for $28$ years would take a lot of energy/fuel.

(2) At the speeds you would reach, the radiation caused by encountering interstellar particles would probably be fatal unless some kind of powerful shield could be developed.

(3) While you would only experience $28$ years (due to the effects of special relativity), the length of time experienced by observers at home would be about $2.5$ million years. So what's the point of your journey anyway?