# Can we travel to any other galaxy?

We have not even traveled to another planet in Solar system..Man have only reached Moon the satellite of earth .With present technology it is impossible.to go to another galaxy.

#### Explanation:

Our milky way galaxy alone stretch about 100,000 light years..Nearest Galaxy Andromeda. is about 2.5 million light years away.
Eevn if we travel at speed of light it will take 2.5 million years to reach there.Maximum man made probes traveled is about 23 kilometers/second.Speed of light is 300,000 kilometers per second.

Dec 25, 2015

If we could construct a spacecraft that generates $1$g acceleration for $28$ years, then that would be sufficient to reach the Andromeda galaxy. (Figures from Wikipedia article on Special Relativity).

#### Explanation:

Though a trip to the Andromeda galaxy would be limited by the speed of light, the time experienced by the traveller would be shorter due to the time dilation effects of special relativity.

For example, if a ship that provides $1$g acceleration accelerated for $14$ years towards Andromeda, then decelerated for $14$ years for the second part of the journey, that would be approximately sufficient to travel the $2$ million or so light years to Andromeda.

From the perspective of an observer on Earth the journey would take $2$ million years and any message the traveller managed to send back would take $2$ million years to return, but the traveller would only age by $28$ years on their journey.

A suitable power source to sustain $1$g acceleration for $28$ years would probably have to be nuclear in nature. Apart from that, the traveller would be exposed to a lot of radiation from collisions with particles, let alone the likelihood of eventual collision with larger objects at very high speed (at least while in galactic space).

Such a journey would probably be of little practical use to those who remain behind.

Beyond these considerations, what about faster-than-light (FTL) travel?

Possible mechanisms for FTL travel are troublesome due to violations of causality according to our current understanding of physics. How about travelling through some kind of wormhole or suchlike? The theoretical models for wormholes which have been constructed so far tend to collapse when there's some whiff of the possibility of information travelling faster than light.