On 31/10/20 9:19 am, Evyn Gutierrez wrote:
>
> On October 30, 2020, at 13:35, Jeffrey Schwartz
> <xxxxxx@gmail.com> wrote:
>
> >
> >
> >Fox News: Bizarre, Earth-sized rogue planet found floating in Milky Way.
> >https://www.foxnews.com/science/bizarre-earth-sized-rogue-planet-floating-milky-way?cmpid=prn_newsstand 
> >
> >In August, a separate group of researchers suggested there could be
> more "rogue" planets than there are stars in the Milky Way galaxy.
> >
> >-----
> >
> >Would it be reasonable to say that an EMS of TL 13+ would have a
> fairly easy time spotting rogue planets in a rift?
> >
> >What's the thoughts on them being useful for refueling?
> >
>
> Detecting maybe if you are in the same hex at any tech level.
>
> Depends, Brown Dwarfs would be easier to spot and refuel from.
>
> Honestly I have considered secret jump routes through the rifts based
> rocks, rogues and brown dwarfs.
>
> Evyn
>
>
Evyn,

Although I agree with you that rogue brown dwarfs would be easier to
_spot_ (due to greater size, mass, and possibly temperature - especially
if they're still lithium/deuteurium-burning) out past the black stump,
I'd have to disagree with easier to _refuel from_.

Quoting from Ken Pick at
https://www.freelancetraveller.com/features/science/gasgiants.html :
"The optimum Gas Giant for fuel skimming is between 30 and 50ME; this is
the point of minimum density and minimum surface gravity, where even a
1-G ship has enough acceleration to climb out in a worst-case
situation—all the fuel in the universe won’t help you if you can’t make
escape velocity after the skim."  (0.73G surface gravity according to
Table 1: Small Gas Giants)

Going down to table 3 : Brown Dwarfs in that article, we find a
borderline brown dwarf (13x Jupiter mass) to have a surface gravity of
16.6 G.  That strikes me as rather difficult to overcome even with TL 15
thrusters (assume 6G) and contragravity (which, iirc, screens another
6G).  That neglects other, trivial, obstacles like the violent
atmosphere which would further contaminate any collected fuel and throw
a skimming ship around to the point an unfortunate snake in a terrier's
mouth would be copping less of a beating.

Alex