Digest Number 735

Hi Michael!

> >Why should cosmic radiation bother the inhabitants?
>
>Because it will kill them or at least produce mutant offspring.

Ok, so if the atmosphere's deficient in bulk then get them to live in a
hab. Much cheaper, economically, to build a hab in orbit than rebuild a
planet, hectare for hectare.

> >The engineering involved ("remove all but one Earth-atmosphere", "remove
> >mass from the planet") assumes a very great deal indeed.
>
>It assumes the logistical ability. It assumes nothing about the
>engineering. It's entirely possible with current technology, the
>engineering is sound.

You and I would probably agree that it's an insane and specious idea using
current technology. Care to suggest how we might (for example) /reasonably/
power the processes needed to liquify one Earth atmosphere?

I'm looking at handwaveium physics here.

> >Why not add "add neutron star material" to increase the planet mass?
>
>OMG...because it would reduce the entire planet to a neutron star...

Howso?

>or
>expoded in the largest neutron bomb you'd ever see, assuming you survive.

How?

> >Bad maths:
>
>Bloody good math!

I really don't think so. The assumption that eccentric orbits automatically
leads to orbits that impact the atmosphere (your statement) is just plain
wrong. Not knowing the level of your maths it's hard to pitch an answer to
this that you'd find convincing.

On removing atmospheres:

>When the atmospheric pressure is reduced the mantle
>will cool faster than the core, and the hot pressurised core will push
>upwards. As the mantle is cool (and not a flowing lquid) it will crack as
>the core expands.

No. The mantle /is/ a flowing liquid. Try
http://earth.leeds.ac.uk/~greg/Conv.html for a look at convection.

As to whether the loss of an atmosphere would make any difference to the
rate of cooling, I suspect it wouldn't. Earth heat loss is something like
44 trillion watts http://www.spacedaily.com/news/early-earth-03c.html -
seems a lot, but it's less than 0.1 watts per square metre. Insolation is
up to 1380 watts per square metre. Big difference in where the planet's
energy comes from.

> Also, you cannot compare the slow effects of an eroding
>icesheet to the sudden removal of 90 atmospheres at 700 K.

Sudden? 90 atmospheres? What sort of timeframe is this technology supposed
to exist in?

Not particularly nit-picking, just questions.

Andy