How Far Beyond Earth Could Humanity Expand?

ElectricSpidey

Joined Dec 2, 2017
2,643
Depends on how far "humanity" will have to evolve to live outside earths biosphere and still remain "human".

And I didn't watch the video, so if it mentions that kind of thing its only coincidental.
 

dcbingaman

Joined Jun 30, 2021
1,065
I think one major problem is getting plants for food to grow beyond earth. The biosphere experiments in Arizona talk about this:

https://biosphere2.org/

One of the major challenges is the microbes that live in the soil are needed for proper growth and any 'out of balance' systems simply don't work. The earth is by far a very special place that will prove to be difficult to even simulate elsewhere.
 

GetDeviceInfo

Joined Jun 7, 2009
2,180
I suspect, given time, that we could expand substantially. We likely though will run into another life form that won’t be interested in our survival.
 

dcbingaman

Joined Jun 30, 2021
1,065
Solar System at most. The nearest star being over 4 light years away, not going to happen! First of all there is no propulsion system that can provide the necessary velocities required to even get close to that speed. Consider that any propulsion system has to eject huge amounts of matter in the opposite direction to accelerate the ship forward. The amount of fuel is astronomical and as you add more and more fuel the acceleration goes down and efficiency goes out the window. Even if you could reach such speeds, there is the problem of interstellar gas and dust. Even the smallest amount of matter in the way will either burn up the ship or cause significant damage and that at rather slow speeds like 1/10 of c. And don't forget relativity is going to have, being that from your perspective the distance to the next star say will look like 1/10 the distance at a sufficient speed, well any high energy EM wave will shorten in wavelength considerably from your perspective thus increasing the energy to possibly high energy gamma ray equivalent. Now you have to protect the ship from that as well! We now know that our sun protects us from the interstellar radiation for our solar system. Once you leave our system there is hostile gamma rays, etc. So solar system at most, but why would you want to venture out into the solar system with humans? Robots can examine it with much better results using AI for scientific research. All the other planets within our solar system are extremely hostile environments. Venus is raining down sulfuric acid at 400F. Mars has practically no atmosphere and extreme temperature changes between night and day and no 'usable' water for the most part. No matter where you go you need a space suit just to protect yourself from the harsh environments. I am not trying to be pessimistic but just realistic. The science fiction films love to make it look easy, when it is anything but easy.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
12,354
Solar System at most. The nearest star being over 4 light years away, not going to happen! First of all there is no propulsion system that can provide the necessary velocities required to even get close to that speed. Consider that any propulsion system has to eject huge amounts of matter in the opposite direction to accelerate the ship forward. The amount of fuel is astronomical and as you add more and more fuel the acceleration goes down and efficiency goes out the window. Even if you could reach such speeds, there is the problem of interstellar gas and dust. Even the smallest amount of matter in the way will either burn up the ship or cause significant damage and that at rather slow speeds like 1/10 of c. And don't forget relativity is going to have, being that from your perspective the distance to the next star say will look like 1/10 the distance at a sufficient speed, well any high energy EM wave will shorten in wavelength considerably from your perspective thus increasing the energy to possibly high energy gamma ray equivalent. Now you have to protect the ship from that as well! We now know that our sun protects us from the interstellar radiation for our solar system. Once you leave our system there is hostile gamma rays, etc. So solar system at most, but why would you want to venture out into the solar system with humans? Robots can examine it with much better results using AI for scientific research. All the other planets within our solar system are extremely hostile environments. Venus is raining down sulfuric acid at 400F. Mars has practically no atmosphere and extreme temperature changes between night and day and no 'usable' water for the most part. No matter where you go you need a space suit just to protect yourself from the harsh environments. I am not trying to be pessimistic but just realistic. The science fiction films love to make it look easy, when it is anything but easy.
It's not easy but a Solar capable craft is only a mild leap of science fiction IMO, not impossible but improbable in the short term..
All you need is a: Epstein drive
 
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joeyd999

Joined Jun 6, 2011
5,037
Solar System at most. The nearest star being over 4 light years away, not going to happen! First of all there is no propulsion system that can provide the necessary velocities required to even get close to that speed. Consider that any propulsion system has to eject huge amounts of matter in the opposite direction to accelerate the ship forward. The amount of fuel is astronomical and as you add more and more fuel the acceleration goes down and efficiency goes out the window. Even if you could reach such speeds, there is the problem of interstellar gas and dust. Even the smallest amount of matter in the way will either burn up the ship or cause significant damage and that at rather slow speeds like 1/10 of c. And don't forget relativity is going to have, being that from your perspective the distance to the next star say will look like 1/10 the distance at a sufficient speed, well any high energy EM wave will shorten in wavelength considerably from your perspective thus increasing the energy to possibly high energy gamma ray equivalent. Now you have to protect the ship from that as well! We now know that our sun protects us from the interstellar radiation for our solar system. Once you leave our system there is hostile gamma rays, etc. So solar system at most, but why would you want to venture out into the solar system with humans? Robots can examine it with much better results using AI for scientific research. All the other planets within our solar system are extremely hostile environments. Venus is raining down sulfuric acid at 400F. Mars has practically no atmosphere and extreme temperature changes between night and day and no 'usable' water for the most part. No matter where you go you need a space suit just to protect yourself from the harsh environments. I am not trying to be pessimistic but just realistic. The science fiction films love to make it look easy, when it is anything but easy.
There should be an "agree" button in addition to "like" (I have many times "liked" posts I've disagreed with).

The biggest problem (among many!) is radiation. Exposure is cumulative. The longer the travel time, the greater the effect, regardless of shielding (which has its own insurmountable problems).

Imagine the mutations that would result from intergenerational space travel*!

*Assuming, of course, that humans would even remain fertile after the first generation or two.

https://fertilitypedia.org/edu/risk-factors/radiation-exposure
 
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joeyd999

Joined Jun 6, 2011
5,037
Yes, radiation is a problem but there are passive/active countermeasures possible if we develop fusion power scale engines using high-temperature superconductors.
https://digitalcommons.library.tmc.edu/cgi/viewcontent.cgi?article=2070&context=utgsbs_dissertations
https://www.nasa.gov/sites/default/...radiationprotectionandarchitecture_tagged.pdf
If only!

I know you need not be told how many "ifs" there are.

I fantasize about space travel as much as anyone.

But there is no there there.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
12,354
If only!

I know you need not be told how many "ifs" there are.

I fantasize about space travel as much as anyone.

But there is no there there.
I totally disagree. There's plenty of danger ahead but space exploration is worth it.

I'm an optimist on space travel, solar exploration and colonization. Life spreading is an intrinsic force in the universe like galaxies and stars. It won'be physics that limits us in 100 years in our own system, only our will and desire to explore.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
12,354
Remember this?
https://www.scientificamerican.com/...ruth-about-soft-landings-they-re-tough-to-do/
SpaceX Faces the Hard Truth about Soft Landings—They’re Tough to Do
The company had been hoping for a softer vertical landing so that the Falcon 9 booster could be refurbished and reused, a strategy that Musk has said could reduce launch costs “by as much as a factor of a hundred.” Despite such landings being a longtime staple of science fiction, to date no rocket has ever managed the feat. SpaceX's previous attempt, in January of this year, also ended in a Falcon 9 booster crashing into its barge.
A few years later:
 
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Thread Starter

nsaspook

Joined Aug 27, 2009
12,354
Yup.

Those are prenatal zygote steps compared to human deep space travel.
That's what makes it so exiting to me. For our solar system, we have difficult, hard steps to it but not a wall blocking it.

The long term problem is not colonizing Other Planets. It's Who Should Be in Charge?
 
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