Elon Musk's Mars plans for his space company, SpaceX, raises a lot of questions on how humans can colonize other planets - let alone other solar systems. Experts from different universities share their thoughts on how many people are needed to go to another solar system.

According to Popular Mechanics, University of Florida anthropologist John Moore, back in 2002, calculated that a starship with 150 passengers could leave Earth for a 2000-year journey to another solar system. As the spacecraft arrives, the original crew's descendants would colonize a new world in one of the planets there.

There was one catch, though. Everyone should be careful not to inbreed along the way.

This shows just how much we want to go to other planets and build colonies there. The nearest star systems, one of which is the Proxima Centauri, are so far from us that it would require a generational starship to reach it.

This means that generations of humans would be born and would die before the spacecraft reaches its destination. This also brings up the question on how many people would be needed to embark on an interstellar mission and sustain enough genetic diversity.

Portland State University anthropologist Cameron Smith noted that such starship would need to have a minimum of 10,000 people to ensure the journey's success. A starting population of 40,000 would be even better - in case a lot of people die along the way.

SpaceX founder and CEO Elon Musk revealed his plans for his space company to send people to Mars within 10 years. He claimed that this plan can result to a city on Mars with 1 million people or more. Moreover, this could happen in less than a century.

Musk's plan involves large, reusable rocket boosters which can launch spaceships into a "parking orbit." He revealed that these spaceships will be refueled by propellant tankers. Eventually, this mission would lead 1,000 spaceships with 100 people each to go to the Red Planet.