What about travelling to Mars?
A few problems:
1. Mars has no freshwater, breathable atmosphere, or arable soil.
2. Courtesy of evolution, human biology is intricately reliant on the exact conditions found on Earth, including: our diurnal cycle, atmospheric composition and pressure, and gravitational field.
3. We're still no good at getting things there in one piece. Half the probes we’ve sent to Mars make a crater instead of landing.
Let’s say for argument’s sake that through some unlikely miracles we manage to overcome these problems and establish a successful breeding population of biologically altered humans on a terraformed Mars.
What would happen? The stupid horny thickwits do the same thing that we’ve just done on Earth. Except they would hit their own resource limits faster, because:
4. Mars is a lot smaller than Earth. It’s just over half the diameter which means it has less than one-third of Earth’s surface area:
5. And then there is a fifth blindingly obvious point:
We’re not going to transport 7.5 billion people to Mars
Successfully landing four intrepid idiots on Mars wouldn’t mean anything for the medium-term survival prospects of other 99.99999995% of the human race: