How long would it take for aliens to reach earth?

The time it would take for aliens to reach Earth depends on their technology and the distance they are traveling. For instance, if they were coming from the nearest star system, Proxima Centauri, which is about 4.24 light-years away, it would take over four years at light speed. However, with current human technology, such as spacecraft, it could take tens of thousands of years. If they possess advanced technology, like hypothetical warp drives, the travel time could be significantly reduced, but such technology remains speculative.