<p>Nasa are sending humans to mars because it has a background of evolution very similar to earth, meaning we can discover more about the past and future of our planet. Mars had the capability to have life in the past, and if we can work this out we can answer the fundamental question: Does life exist anywhere else?</p>

<p>Now, about humans leaving earth. Humanity will have to leave earth at some point - due to issues like overpopulation, resource shortages and NASA as well as many other scientists are planning things like human missions to asteroids, and eventually developing technology for a human mission into deep space. Astronauts on the ISS are helping us understand how the body changes in space (for example, fluids inside your body aren't pulled down by gravity). Furthermore, these astronauts are helping us prove the technologies needed for exploration into deep space. I found a site about stephen hawking talking about how we need to leave earth <a href="http://www.space.com/8924-stephen-hawking-humanity-won-survive-leaving-earth.html" rel="nofollow">http://www.space.com/8924-stephen-hawking-humanity-won-survive-leaving-earth.html</a>. <a href="http://www.theregister.co.uk/2015/02/20/hawking_alert_leave_planet_earth_stupid_humans/" rel="nofollow">http://www.theregister.co.uk/2015/02/20/hawking_alert_leave_planet_earth_stupid_humans/</a></p>

<p>However, another thing about the matter of exploration further into space, and why we haven't encountered aliens is that some scientists believe that there a many, many, many sentient civilisations out there, but they wipe themselves out so quickly they never cross paths.</p>

<p>Furthermore, there are so many things we need to think about if we will travel and colonise other planets. Like how the planet's gravity will most likely be different, the atmosphere will be at a different density. This is why we need to expand our presence in the solar system, and one day send a long term manned mission to mars.</p>

CC BY-SA 3.0
2015-12-30T18:54:09.413Z
2015-12-30T18:54:09.413Z
Featherball
<p>I think that the need to leave Earth won't be because of "limited resources" but rather that it will be too hot to stay here, when the Sun expands outward in size billions of years from now.</p>

CC BY-SA 3.0
2016-01-01T21:59:52.493Z
Nope, as you say this is going to be in billions of years. I am pretty sure that you can not assume practically anything about humanity for such a long time on. If we survive, while there are lot of factors that could wipe as out in matter of a moment (considered to time in astronomy), we will have to leave Earth much sooner.. in matter of thousands year or something. Sun's expansion wont bother us much as it never bothered us.
Vojta Klimes
CC BY-SA 3.0
2016-01-01T18:57:46.967Z
2016-01-01T18:57:46.967Z
Peter U
<p>my question is regarding  space travel and also will some countries have colonies on Mars etc cause the clear reason NASA etc are trying to send manned Mars mission is to get raw materials etc or maybe send a large part of human population to Mars because of limited resources on Earth?</p>

CC BY-SA 3.0
2016-04-14T16:48:27.227Z
I'm voting to close this question as off-topic because it is about space exploration.
called2voyage
CC BY-SA 3.0
2015-12-30T19:14:17.070Z
You're kidding, right?
Ricky
CC BY-SA 3.0
2015-12-30T23:51:25.267Z
With a rocket capable of carrying 100,000 people to Mars it would take 3190 round trips to depopulate the US. Of course, you could build 319 such ships and get away with just 10 round trips per ship. Either way, it'd take a *lot* of fuel to get that many people to Mars.
Wayfaring Stranger
CC BY-SA 3.0
2016-01-01T22:02:14.127Z
@WayfaringStranger Easy solution: depopulate locally (aka kill off a bunch of people) and *then* ship off the population.
zibadawa timmy
CC BY-SA 3.0
2016-01-02T01:06:20.307Z
Possibly the biggest import from Earth to Mars will be fertilized ova. At least at first. I don't see being able to send a large population to Mars as ever being economically feasible, while the Martian Colonists will need as much genetic variation as possible to avoid becoming an evolutionary dead end.
Howard Miller
<space>
humans leave Earth forever?
varunk
# humans leave Earth forever?

(Asked by: username_0 on 2015-12-30)

my question is regarding space travel and also will some countries have colonies on Mars etc cause the clear reason NASA etc are trying to send manned Mars mission is to get raw materials etc or maybe send a large part of human population to Mars because of limited resources on Earth?

**Tags:** space
> **Comments:**
> **username_2**: You're kidding, right?  
> **username_3**: With a rocket capable of carrying 100,000 people to Mars it would take 3190 round trips to depopulate the US. Of course, you could build 319 such ships and get away with just 10 round trips per ship. Either way, it'd take a *lot* of fuel to get that many people to Mars.  
> **username_4**: @WayfaringStranger Easy solution: depopulate locally (aka kill off a bunch of people) and *then* ship off the population.  
> **username_5**: Possibly the biggest import from Earth to Mars will be fertilized ova. At least at first. I don't see being able to send a large population to Mars as ever being economically feasible, while the Martian Colonists will need as much genetic variation as possible to avoid becoming an evolutionary dead end.  
> **username_1**: I'm voting to close this question as off-topic because it is about space exploration.  

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## 2 answers

### Answer by username_6 on 2015-12-30. Score: 1 | Accepted answer

Nasa are sending humans to mars because it has a background of evolution very similar to earth, meaning we can discover more about the past and future of our planet. Mars had the capability to have life in the past, and if we can work this out we can answer the fundamental question: Does life exist anywhere else?

Now, about humans leaving earth. Humanity will have to leave earth at some point - due to issues like overpopulation, resource shortages and NASA as well as many other scientists are planning things like human missions to asteroids, and eventually developing technology for a human mission into deep space. Astronauts on the ISS are helping us understand how the body changes in space (for example, fluids inside your body aren't pulled down by gravity). Furthermore, these astronauts are helping us prove the technologies needed for exploration into deep space. I found a site about stephen hawking talking about how we need to leave earth <http://www.space.com/8924-stephen-hawking-humanity-won-survive-leaving-earth.html>. <http://www.theregister.co.uk/2015/02/20/hawking_alert_leave_planet_earth_stupid_humans/>

However, another thing about the matter of exploration further into space, and why we haven't encountered aliens is that some scientists believe that there a many, many, many sentient civilisations out there, but they wipe themselves out so quickly they never cross paths.

Furthermore, there are so many things we need to think about if we will travel and colonise other planets. Like how the planet's gravity will most likely be different, the atmosphere will be at a different density. This is why we need to expand our presence in the solar system, and one day send a long term manned mission to mars.


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### Answer by username_7 on 2016-01-01. Score: 0

I think that the need to leave Earth won't be because of "limited resources" but rather that it will be too hot to stay here, when the Sun expands outward in size billions of years from now.

> **Comments:**
> **username_8**: Nope, as you say this is going to be in billions of years. I am pretty sure that you can not assume practically anything about humanity for such a long time on. If we survive, while there are lot of factors that could wipe as out in matter of a moment (considered to time in astronomy), we will have to leave Earth much sooner.. in matter of thousands year or something. Sun's expansion wont bother us much as it never bothered us.  

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