The reason for this brief article is that whilst writing the 'Guide to Space' section I found myself describing real asteroid belts and generating a self contained retcon for the Hoth system.
Rather than bog that artcile down too much in detail, I decided to fill it out here.
The main problem with Hoth in TESB is that it's asteroid field is simply out of place with what we know of real asteroids.
To whit, there are far too many of them.
When we sent the Voyager series through our own asteroid field we didn't even bother planning for the event as the odds on striking anything were so remote as to be laughable.
There was a much greater statistical probability of the launch vehicle being hit by a meteorite, and we didn't bother planning for that one either.
Millenia ago the Hoth system was dominated by a huge gas giant, the sixth planet. Hoth VI featured an unusually large ring system and many moons, including at least one in excess of the 6mk diameter limit defiing minor planets, upon which, paleontological evidence suggests, life was abundant. The ring system is very dense, and has generally been referred to as the 'Asteroid Belt' by those few soles who visit the world.
The atmosphere of Hoth was simple, mainly consisting of hydrogen and helium. A metallic core lay at the heart of this obese world, itself mainly composed of simple and unremarkable minerals.
Approximately 4.6ga past, Hoth experienced a stellar event, and collapsed from a red giant down to a yellow dwarf. In doing so the star expended a great deal of energy and mass, an apocalyptic event which struck Hoth VI minutes later.
Incandescent stellar material immolated the atmopshere, in turn causing the hydrogen to ignite.
Hoth VI's largest moon was sterilised mainly by the massive dose of beta and gamma radiation. Her atmosphere was rendered away in an instant.
As Hoth VI's atmosphere burned away it's mass was consequentlly reduced. A critical mass formed over a few thousand years, and in a secondary explosion the vast majority of it slewed off into space. The remaining gaseous layers appear to have undergone reduction fission, and settled down to a stable form composed of nitrogen, hydrogen, and oxygen.
The stellar event had induced erratic motion into Hoth VI's ring system and moons, and during the evolution of the world, all but three of the moons were destroyed, probably by simple kinetic impact with ring fragments. These moon debris pieces entered the ring system, forming large chunks of mass.
As the atmosphere of Hoth VI cooled, the hydrogen and oxygen started the inevitable process of valent bonding and the rains began on the desolate rock ball.
Estimates vary, but for at least 20ma, the rain fell ceaselessly. Hoth VI was already a much cooler planet than it had been, and the water settled into ice. As the ice thickened over time pressure caused the lowermost levels to liquify and heat, and gradually the great ice floes began to rise from the sea beds.
At the lowest points of these new seas, geological activity began, driven by the immense presure of the ice caps. Exotic chemical reactions began, and life was formed.
Hoth VI's entire ecology is built from these deep sea, deep freeze life forms. Naturally Hoth VI's eco-system is advanced enough for plants to have begun to colonise the surafe in the equatorial zones. Mainly in the form of lichens and some basic mosses. Several species of aquatic life have evolved the ability to survive on the surface long enough to use it as a refuge for laying eggs. These creatures are able to exploit the great fissures that lead from the water to the atmosphere. Their evolutionary adaptions to this task include primitive lungs, and strong manipulator libs, both features biologists suggest could indicate an unusually rapid transition from aquatic beast to surface tool user, if it is allowed to continue unmolested.
This seems unlikely, however, as over thousands of years several non-indigenous species have made Hoth VI their home, culminating in the large Wampa creatures, and the herds of Taun Taun nomdic herbivores.
In the meantime the giant fragments of Hoth VI's largest moon hid an enigma, of sorts. One of the moon's species was evidently a carnivorous worm used to burrowing very deep into the mantle of the moon. There must have been some kind of ecosystem at these depths (as much as twenty kilometers down, it has been estimated) as ther can be little doubt some of the beast survived the mini-nova, and even the break-up of the moon itself. Their descendants are the famous space slugs. These creatures inhabit some of the larger rocks of the Hoth ring system. It is unkown how large the population would have been after the break up, but evidently some of these chunks' ecosystems were able to survive intact as more than six hundred worm hole rocks are documented.
These worms have evolved to live very slowly. Almost completely inert they derive energy through their skin by chemical osmosis of their surroundings. Some worms have only this form of ingestion, and will certainly die in time. Other worms have had the luck to exist in giant rocks with an ecosystem that allows them to feed, albeit infrequently, on other forms of life. It seems improbable that even these beasts will survive indefinately.
Because of the improbability of survival under these circumstances, it has been suggested that the worms are able, to a degree as yet unknown, to detect the traces of life in other rocks as they pass by, and if there's sufficient motivation, they are able to leave their tunnels and attempt to actually leap to another fragment where they can burrow in, and survive. This theory suggests that on the rare occasion this occurs, and two worms meet, they would either contest the space and fight to the death, or if possible mate, with the parents sacrificing themselves as source material for the ecosphere, and therefore for the larval worms that will grow.