
If Earth Was 50% Larger, We Might Be Stuck Here - sjcsjc
https://www.realclearscience.com/blog/2017/07/06/if_earth_was_50_larger_we_might_be_stuck_here.html
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rthomas6
How close are we to a feasible space elevator? Once we have something that can
withstand the forces involved, we can just ride up to space for a fraction of
the energy and cost, and start our propulsion from orbit instead of the
surface.

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willcipriano
As I understand it, very far. The materials science isn't there, we have yet
to conceive of a material that would be able to carry it's own weight let
alone move a useful load.

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avmich
No, the problem isn't in the material, that's relatively easy part, we already
have good prototypes in carbon nanotubes.

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willcipriano
My source:

> "No current material exists with sufficiently high tensile strength and
> sufficiently low density out of which we could construct the cable," he told
> me. "There's nothing in sight that's strong enough to do it — not even
> carbon nanotubes."

"The best that theorists can do right now is come up with a material that's
about two-thirds the strength needed to make a practical elevator," Henson
told me. "And that's a very, very short tiny tube."[0]

[0][https://io9.gizmodo.com/why-well-probably-never-build-a-
spac...](https://io9.gizmodo.com/why-well-probably-never-build-a-space-
elevator-5984371)

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scaredginger
The title should have mentioned the measure was diameter, rather than mass or
volume. They give wildly different outcomes.

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gaukes
Anyone think this is an additional factor in the Fermi paradox? i.e planets
that are too small can’t support a strong atmosphere and life. Planets that
are too big make space travel too uneconomical.

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c22
I've often considered an alien planet with an atmosphere so thick that one
couldn't see the night sky. Would inhabitants of this world even be interested
in space travel? How much longer would it take for them to discover space, or
even effective navigation of their own sphere? Maybe these people just
wouldn't be explorers.

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ncmncm
Then there is the Krikkit response to discovering a universe beyond the
clouds: "It'll have to go."

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downrightmike
Yes, but what about only 49% larger?

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perl4ever
My question is what if we were unconcerned about the risks of nuclear powered
rockets, could we get off a larger planet then?

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Asraelite
The article doesn't seem to consider non-conventional launch strategies. With
things like Project Orion, mid-air launches (by either balloon or plane), and
space elevators all being theoretically possible, it seems unlikely that any
given civilization would never be able achieve spaceflight, given enough time.

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lxmorj
Right? A balloon first stage seems like an obvious work-around...

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perl4ever
Insert xkcd about how the difficulty in getting to orbit is speed not
altitude.

This is all the more true about a larger planet than earth.

Sure, you might have a thicker atmosphere, but that's an additional challenge.
Needing a balloon (if it made sense, I couldn't do the calculation) would be a
reflection of the difficulty above and beyond the increased orbital velocity
that is the basic problem.

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lxmorj
Well sure, but the majority of your energy spent is fighting to get up to
speed while in the atmosphere. A balloon or dirigible or some buoyancy play
should be able to get you to a certain atmospheric density regardless of
planetary gravity. That cuts the bottom off of the rocket equation pyramid and
reduces drag immensely at your 'starting' point.

