Cosmic Rays that hit earth are very likely to also hit Mars, at the usual large distances they can cover a couple light hours of diameter. I would recommend colonizing at least 4 solar systems no less than 10 lightyears apart to avoid any and all possibility of a GRB/CRB lining up a shot.
That won't help. The closest GRB we've detected was about 100M light years away, so well outside the galaxy. If we had one happen within our galaxy that's beamed towards us, I don't think that 10ly make any practical difference in the 1/r^2 attenuated flux. Also, the beams are thought to be several degrees wide, so unless it's a very close GRB (in which case we should consider other problems), it's also unlikely that 10ly would move is out of the beam.
Source: former astrophysicist. Also if I remember correctly, the Wikipedia article on grbs is actually decent. (Edit: overstated things - need coffee, I suppose)
Still an astrophysicist. I'm a Computer Scientist. I won't cease being one even if I change professions, I will just be whatever I become in addition to a CS.
This is true and possibly one reason I think moons are a better bet for cosmic colonization.
Mars, venus, and mercury have next to no field, earth has a moderate field, and all our gas giants have very strong fields.
Some of the gas giant moons are attractive since the gravitational effects on the moons can create geo-thermal energy. Pair a large planet with a strong magnetic field and energy created from gravity and we might have something interesting worth exploring.
I do not think this is perfect though, due to the size of our atmosphere we are shielded from meteorites,, this might not be the case of these moons. We would need to consider making some way to protect ourselves like harvesting ore from surrounding areas. Even then this might not stop large collisions.
You know what's even better than dirt at stopping radiation? Water. And we have lots of it. 10km of water at the bottom of the Mariana trench should stop any amount of radiation that could hit Earth.
Both require living in some sort of pressurized container, unless you assume we could live in underground caves(but those can't be very deep so probably not good enough). Obviously the underwater one would require more engineering, but probably still less than one needed for Mars.
That depends on your perspective. We have the technology to go to Mars right now; we do not have the technology to go to the bottom of the Marianas Trench. It is a much more hostile environment than Mars is.
However, if you assumed that we were able to go the bottom of the ocean, transporting supplies there would be much easier than transporting supplies to Mars.
My Inc. article asks why we think we will solve problems off Earth that we haven't on Earth. Or if we think we can solve them there, why don't we solve them here first?
If we want to get to Mars, probably the best start is to solve the problems we have here first.
The problem with this argument is that it is a false choice. We do not need to choose between fixing our planet and expanding into space. There are seven billion of us, and collectively we’re not that bad at multitasking.
Furthermore, it is a straw man, because nobody actually believes that we should give up on Earth. You cited a number of headlines attributing this position to people like Elon Musk and Steven Hawking, when a quick reading of their actual quotes shows that they do not actually say what the headlines claim (Musk also runs a clean energy company for Pete’s sake—doesn’t sound like he wants to give up on Earth). I really want to believe that you wrote your article in good faith, but that means I must believe you did not read the articles you linked as evidence.
Fixing problems on Earth vs colonising Mars is the difference between carefully maintaining your family PC and buying a second one so you still have a working one when the first one breaks down.
Redundancy doesn't fix problems but it cushions the failure case. There are numerous ways Earth could be wiped out in a way we can't defend against.
I see this phenomenon quite a lot, even on HN. Supposing we find a planet that is conducive to life, how can we avoid exporting all of humanity's cultural and biological baggage to that new civilization? Aside from the exploitation and near-genocide that took place in the Western hemisphere, how is it really any different that the opening up of those continents, but with a bigger ocean between? I've seen other discussions try to route around this question by talking about Mars or some other hostile environment as perfect for the type of co-operative commune they imagine humanity could be, one where people must rely on each other or die. I don't see a qualitative difference between that environment and the deserts of the American West, where the climate was harsh and water scarce.
Those migrations didn't bring utopia, either to the participants or the rest of humanity.
I agree that utopian predictions have a long history of failure and should be taken with a Mars-sized grain of salt. However, I would argue that the difference is that there is not likely to be complex life on Mars or any other location in our solar system. This makes it quite a bit different from the North American example, in which immense suffering was inflicted upon the existing inhabitants of the region. If any planet or moon was found to contain life-forms capable of experiencing suffering, I and (hopefully) most people would be against human settlement there.
Not a significant difference in safety between Mars and Earth when it comes to interstellar sources of radiation. In fact Mars lacks a magnetic field and an atmosphere, two useful radiation shields here on Earth.
We'd do better to build out some element of human society underground, if interstellar radiation is our fear.
Actually, water is very good at stopping radiation, so if there was a massive gamma ray burst that killed all surface life on Earth, some small groups of humans would survive: deployed submarine crews.
Sealabs pose novel engineering challenges, could provide experiments in sustainable enclosed habitats, wouldn't risk microgravity or radiation, but would risk high pressures.
They'd also help species survivability in the event of some extinction-level asteroids, climate change, or interstellar radiation.
I think it's an even money bet whether it'd be easier to build a comfortable habitat for x people underwater or in space (for most definitions of comfort, x, and space).
