Worlds For Man - Part 6 - Ceres

[jordan179]

Introduction

Ceres is not often thought of as a "planet," and is thus often overlooked. But it is a perfectly respectable "dwarf planet," equal in mass to a medium-sized moon (though much smaller than our own giant Luna). It contains about a third of all the mass in the Asteroid Belt, and hence is the "failed planet" filling the Keplerian orbit

Comments

[polaris93]

I think the designation "dwarf planet" is extremely counterproductive, as for most people it seems to signify that these bodies are not worth considering for exploration or colonization. Whatever the hell the IAU had in mind when it came up with that idiotic label, the result of that labeling has been tremendous confusion compounded with enormous anger. One reason given for that label was that "people can't remember more than 8 planets at a time." Yeah, right. A much more intelligent categorization of bodies of the Solar System would be: inner, rocky planets (Mercury, Venus, Earth, Mars); Ceroids (bodies of the asteroid belt, including Ceres, a planet); gas giants (Jupiter, Saturn); ice giants (Uranus, Neptune); Centaurs (comet-like bodies in significantly elliptical orbits between the orbits of Neptune and Jupiter); Kuyper-Belt bodies (Pluto, Eris, Haumea, etc.); Oort Cloud bodies (comets and whatever else is out there); Apollo (Earth-crossing) asteroids; Apohele asteroids (those whose orbits are entirely contained by

[polaris93]

Pardon, that's "jazz," not "jass."

[polaris93]

Anyway, we very much need to explore Ceres along with the rest of the main asteroid belt, for the same reason we have always needed to explore our world and universe: to learn as much about everything as possible. Not to want to do so isn't to be unhuman -- it's to be something other than a living organism.

[firstashore]

A man could easily make or land from a vertical leap of around 100 feet (equivalent to 3 feet on Earth), though the many minutes it would take to reach the bottom would make this tedious at the start of the fall, and dreamlike or frightening at the end.

Might want to check your calculation for this one? I get a figure of just under 15 seconds for a 100 foot drop.

Falling on Ceres

[jordan179]

You're right! I made a decimal error.

Btw, continuing my program I found that in a full minute you would fall only 0.5 km; your velocity of about 16m/sec would be less than you'd reach in two seconds falling some 30 meters on Earth! More than enough to kill you, though.

Terminal velocity in atmosphere on Earth is around 60m/sec for a human body. On Ceres you would reach this velocity after falling for 225 seconds, a distance of over 6,864 meters (roughly: I used a simple spreadsheet and did not allow for the fact that the gravity field of Ceres would have fallen off a little at the top of that range). After that, you would fall faster on Ceres than on Earth, though you would still accelerate much more slowly.

Because small planets are less smooth than big ones, Ceres may well have 7-kilometer cliffs, somewhere. It would be interesting to drop something off one of them and watch it fall!

Re: Falling on Ceres

[galadrion]

Especially since, with the long falling times combined with Ceres's relatively rapid rotation, you'd see a definite curve to the object's path relative to the frame of reference (Ceres itself). It would be an interesting optical effect.

Re: Falling on Ceres

[unixronin]

What might be an interesting technique on Ceres is the following: Assume a heavy pack containing a significant fraction of your body mass. Jump off a high point with the pack. As you drop, maneuver the pack into position below your feet. When you estimate you're about five seconds from impact, jump off the pack as hard as you can.

I haven't done the math, but back-of-envelope says on Ceres you may well actually be able to get enough braking from the technique to make a four or five hundred foot jump without injury. If the pack is half your mass, then you get roughly half of whatever delta-V you can apply to the pack in braking; and unlike Earth, not only would you actually get time to do it, but the delta-V could actually be a worthwhile fraction of your velocity.

[kalance]

Quasi related topic:

Multicelular life-forms that require no oxygen to live/reproduce.

This basically narrows the known material requirements for life to develop to just water, and a few minerals.