> On Earth, we are shielded from GCRs by water in the atmosphere. But it takes two meters of water to block half of the GCRs present in unprotected space. Practically, a Moon or Mars settlement would have to be built underground to be safe from this
> Underground shelter is hard to build and not flexible or easy to expand. Settlers would need enormous excavations for room to supply all their needs for food, manufacturing and daily life. We ask why they would go to that trouble. We can live underground on Earth. What’s the advantage to doing so on Mars?
It's never seriously discussed, are they expect to live full time underground on Mars? Why then? We can live same way on Earth.. Does Elon Musk knows something we don't?
Elon views Mars colonization not as a way to solve lack of habitation space in Earth, but as an off-premises security backup should something terrible happen on Earth.
If we were to invest in building a underwater 'Sealab' on the bottom of some ocean floor, say at least 100m water deep, what kind of cataclysmic event could destroy it.
A few dozen of the underwater sea-colonies seams the most practical safety net for humanity that we can do today.
I completely for exploring and colonizing space, but we still haven't mapped our own oceans fully. And sadly, I don't think my generation, or even the next few will be any closer to being able to get ourselves off this rock.
If you are looking to build 'Arks' for humanity, i'd put my money on the ocean floor.
>If we were to invest in building a underwater 'Sealab' on the bottom of some ocean floor, say at least 100m water deep, what kind of cataclysmic event could destroy it.
Maybe a sinking ship landing on the dome might be a problem. Or depth charges dropped during war. It would be considerably more difficult to destroy a colony on Mars through physical intervention, intentional or not.
... hacking in and opening all airlocks and evicting all oxygen, like fire suppression systems, on the other hand...
Off topic, sorry; but why do you use his first name only here? Normally we would refer to minor public figures like him as 'Elon Musk' or just 'Musk'. Using someone's first name is reserved for personal friends. I have also seen this with Linus Torvalds, for example, and Linux aficionados. It seems like there is an exception for some people, perhaps it just has to do with popularity within a segment of the population, in the same manner as pop stars become mononymic to the general public?
Hm it's a good question. Maybe because my native tongue is Spanish, we almost never use the full name after the person has been already named (we have long full names...) so we tend to stick with a mononym in conversation. Usually the surname but sometimes the name, if it's uncommon enough, or even a nickname.
One's surname is omitted when it's been stated already. If they're a public figure being discussed in an academic or press setting, yes, usually the last name is used. In less formal circumstances, it's perfectly acceptable to use first names only, especially when they're as uncommon as his.
The sort of proper-name forcing that you suggest is better gets really obnoxious in interviews when the interviewer continually addresses the interviewee by their full name.
e.g.
>So, Elon Musk, what do you think about Blue Origin's rocket design?
>That was a really great answer! Elon Musk, do you spend most of your time at Tesla or SpaceX?
Sure, that's why you use the surname instead. In interviews I can see the need for informality, so first names are fine there, but when commenting on an interview or story I think it's better to return to the formal, surname only, references.
> So, Elon, what do you think of Blue Origin's colour scheme?
>> I think Musk's response to the interviewer's stupid question about colours was interesting.
Whether to given name or surname is culturally specific.
I got suspicious last week when someone I don't know sent me a personal email saying "X and the others called my employer and got me fired", using the given name instead of surname for person X, like they knew that person. At first I thought it was a veiled threat, but then I realized I was thinking about how I would address that person and that someone else would address them differently.
