Can Humans Travel to and Inhabit Other Planets Besides Mars?
This article is not about traveling through wormholes or traveling at the speed of light to get to distant planets in another solar system or another galaxy. If that’s what you want to study, there is a lot of debate about that available elsewhere.
What this is about, something we can consider right now, is intergalactic travel that is more in line with present technology.
The idea of reaching beyond the stars and embracing the desire for the human race to inhabit other planets has been envisioned in science fiction and considered realistically by physicists. The following is based on my scientific background and my studies of human survival requirements.
I was a pre-teen when John Glenn was the first American to orbit the Earth in 1962. His success, circling three times, attracted my interest with thoughts of reaching farther out with space travel.
I remember being more impressed when Neil Armstrong went beyond Earth’s orbit with the Apollo II space mission that landed him on the Moon in 1969.
With the latest technologies we have today, I’ve been following the activities of NASA sending probes to investigate the potential to support life on Mars.
With that development, I became extremely interested in researching what it’s like to live and travel in space.
Human Trip to Mars in the 2030s
Our present robotic missions have found that there are resources on Mars to sustain human life, such as water beneath the surface. There are also other raw material resources necessary to construct the communities of the future on Mars without the need to send these raw materials from Earth.
Now that water has been discovered on Mars, even though only in frozen form, it has enticed scientists to consider a mission that may have humans traveling to Mars and eventually inhabiting the planet.
NASA is finalizing the experiments to assure the success of the long flight to Mars. It's all planned for the 2030s. 
Human Travel Beyond Mars to Other Galaxies
More futuristic thoughts involve reaching out to more distant worlds. These missions would require advanced technology that we don’t have today.
However, it’s possible that someday humans will figure out how to traverse huge distances in a heartbeat. That would solve the problem with spending time in space, which takes a toll on the human body.
Scientists think big. They imagine the impossible only to work hard at trying to solve a dilemma that stands in the way of achieving those goals. If nothing else, it’s enjoyable to entertain the thoughts of someday going to a distant planet in another solar system, or maybe even farther out to another galaxy.
These things are unimaginable right now. Its only place is in science fiction, but just think for a moment – when you were young, did you imagine carrying a phone around with you wherever you go? Furthermore, did you think you’d be able to call anyone in the world from that phone?
Yes, technology is advancing, and we already have the ability to send intergalactic space probes to extreme locations in the universe. 
The next step could be sending humans on a one-way trip that only their future generations of offspring would experience.
Who knows what’s around the corner. So let’s keep an open mind and entertain these thoughts as I discuss my views on the possibility of traveling to and inhabiting a distant planet. Inhabiting Mars won’t sound so extreme when we’re done.
Can the Human Race Survive a Trip to Another Galaxy?
In February 2017 NASA announced they discovered seven Earth-like planets 39 light years away in a solar system called Trappist-1. Any one of these planets might support life, as we know it. That’s not to say that we would find intelligent life there, but they might be inhabitable by we humans if we could only get there.
One light-year is about 9,461 billion kilometers or 5,879 billion miles, so 39 light-years is a distance of almost 230 billion miles. If we traveled at 38,000 mph (the speed of Voyager-1), it would take six million years to get to Trappist-1.
There are extremely interesting considerations to take into account if we were to take a journey that would last that long.
For one thing, it would take many human lifetimes. The people leaving would not get to enjoy the destination, only their offspring will.
We need to reproduce in space, while in transit, so that a future generation will be the ones who would carry on the human race. Successful human reproduction in space is dependent on how the weightless environment affects fertilization and growth of the fetus. 
Assuming that’s feasible, we still need to live with limited resources and recycle what we have on the spacecraft. This process is actually being studied right now with experiments conducted on the International Space Station.
Human Reproduction and Birth in the Weightlessness of Space
Giving birth to humans in space has never been tried yet. Tests are being conducted with lab rats, and a lot is being learned from this.
The development of the fetus in a weightless condition may cause severe neurological problems. For example, our inner ear develops before birth to achieve a sense of balance. The normal tendency to move and kick while in the womb will change due to weightlessness. The side effects with humans are not known.
Delivery of a newborn would be completely different without gravity. The amniotic fluids would just float out and become airborne. These fluids would need to be contained, probably similar to how the toilet works in the international space station – with suction.
The development of the baby's ability to survive starts from birth.
- Without daylight, the brain doesn’t develop sight properly.
- Without gravity, the brain will not be able to develop a sense of balance.
This will not be necessary while in space, but what about the final generation that makes it to a human-friendly planet.
They will have lots of trouble with balance. Their bones will not have developed properly to support the weight of their own bodies. The following 13-minute video will give you all the remarkable details.
What if You Were Born in Space?
Extra-Terrestrial Life: Life Forms Elsewhere in the Universe
Considering the possibility of settling on a new planet, the structure of the body comes to mind. If life similar to humans exists elsewhere, how would they be different?
My discussion in this last section is not about if aliens exist. That’s another topic. I’m proposing to consider what they might be like if they did exist.
The human body has evolved for survival on Earth. Life forms on other planets in the universe may be drastically different from anything we can imagine. Those who theorize about what aliens from outer space might look like usually imagine a human-like figure.
It’s easy to relate to our own form. We even have good reason for considering this. We’ve developed the way we have so that we can manipulate our environment. All living animals on Earth have evolved in such a way as to assure survival in their environment. Survival of the fittest is what guides evolution.
- Bees have hundreds of lenses in each eye.
- Deep-ocean fish have no eyes. They don’t need them.
- Bats use radar to maneuver in the dark.
- Cockroaches have an outer skeleton to provide protection.
- Humans have an opposing thumb so we can manipulate our environment.
The point is that every life form on Earth has evolved with the "tools" needed for their own survival.
As for alien forms, we have to imagine the type of environment they may live in. In addition, if they do exist, we have to think of what period in their evolution they are in. We may be ahead of them. They may be ahead of us.
Survival on Another Planet
How can the human race travel to a distant planet and inhabit it? If we do find solutions to make this journey feasible, how will our future generation survive once they settle?
One thing is for sure – we need to get our own house in order first. Rather than destroy our environment, we need to learn to survive on Spaceship Earth.
If we can't survive on our own planet and learn to live with nature, then we will never find a way to continue anywhere else.
- Journey to Mars (NASA.GOV)
- “Deep Space Probes: To the Outer Solar System and Beyond” by Gregory L. Matloff (Springer Praxis Books - Oct 21, 2010)
- Effect of space environment on mammalian reproduction (NASA.GOV)
Questions & Answers
When humans arrive on another plant (e.g Jupiter's 2nd moon Callisto), how will they get around, aside from walking?
It’s interesting that you mention Callisto as an example. Jupiter’s moon Europa is closely related to the Earth as well. Callisto has gained interest recently. It’s heavily cratered, and it’s an icy moon similar to Europa. It may even have an underground ocean.
An interesting fact about Callisto is that it’s tidally locked to Jupiter, so the same side always faces the planet, just as our moon is tidally locked to the Earth.
In the 1990s and 2000s, several flybys had taken some pictures of Callisto. A mission named JUICE (Jupiter Icy Moon Explorer) will arrive in 2030 to get more information about its environment.
As for humans walking on its surface, I doubt this will be planned in any foreseeable mission. The mean temperature on the surface of Callisto is minus 218.47 degrees Fahrenheit (that’s 139.2 Celsius).
However, having said that, as with any mission to another planet the proper equipment would always be included for mobility. Consider the moon rover for example.Helpful 2
When will we go to the Trappist-1 system?
Even though Trappist-1 has several planets that may be in the habitable zone, it’s too far away to consider with our present technology. Mars will have to be the first step. Nevertheless, what I discussed in this article would be the method for humans getting there, over many generations of a crew. It’s not something that will be considered any time soon.
© 2017 Glenn Stok