With an impact like that, wouldn’t even thermophiles and resistant spores be wiped out?
Since some bacteria can live in rocks almost two miles underground, I wouldn’t bet on it.
Turns out Pluto is larger, although Eris was thought larger at first. That’s because Eris is more massive, about 20% more. However the difference is diameter is not much – about 50 km or so. What this means is that Eris has a greater amount of rock in its compostition.
Largest body for which there’s a silly argument about what it’s called?
Largest (and smallest) solar system body that has a Disney cartoon character named after it?
–Mark
Ariel (the Little Mermaid), a moon of Uranus with a diameter of 1,160 km, is smaller. 
I figured I was forgetting one.
However, I wonder if the character was really named after the moon. It seems more likely that she, like the moon, was named after the Shakespearean character. The dog Pluto, on the other hand, was definitely named after the planet.
–Mark
Obligatory T-shirt link: http://mediacdn.snorgcontent.com/media/catalog/product/b/a/backinmyday_fullpic_4.jpg
That gives me an idea for a Halloween costume: a toga printed with “Back in my day, we have five planets.” Maybe in Latin.
–Mark
Όταν ήμουν νέος είχαμε πέντε πλανήτες
But in the days when a toga would be appropriate wear, they had 7 planets.
If we take Mr. Kobayashi’s simulation in Universe Sandbox at face value, it looks like the entire crust is hot enough to be incandescent, and is molten enough to completely erase every geological feature. Living two miles underground won’t help much in that case…
Though in even the most extreme scenarios, there’s also the possibility that some bacteria will survive on the ejecta from the initial impact. A lot of the ejecta will stay in near-earth orbits, and some will return to the earth after the crust has cooled.
I would never bet against bacteria. 
As Stephen Jay Gould said, (paraphrasing), forget all this you hear about the “Age of Fishes”, “Age of Reptiles”, “Age of Mammals”, etc. We are now, and always have been in the Age of Bacteria. Bacteria have always been the dominant life form on Earth.
–Mark
Of course, what we’re in the Age Of depends on just how you lump together organisms. It’s not like you’ve got “bacteria”, on the one hand, weighed against “humans”, on the other. That only sounds fair from our biased perspective, but it’s pitting a single species against an entire empire of life (possibly two empires, if you count the archae as bacteria, as seems to be implied by “always have been”).
If you only look at individual species, and count by total biomass, we just might actually be in the Age of Humans right now.
OK, I just looked it up. Antarctic krill (Euphausia superba) have us beat, but only by a factor of 5 or so, and Bos taurus also seems to be a little bit ahead of us. So far as I can tell, though, we’re still in third place. I’m having a hard time finding figures for various tree species, though, which might also be contenders.
Biomass is just one way of estimating dominance. Here is one of Gould’s essays on the topic. He argues that bacteria win (compared to EVERYTHING ELSE) in terms of duration (easily), indestructibility (also easily), taxonomy (by far; look at a modern “tree of life” and try to find any branch that isn’t bacteria; all non-bacterial life is on a tiny barely noticable twig), ubiquity, utility, and MAYBE biomass. We don’t really have an even remotely accurate estimate for bacterial biomass because (1) we don’t know where they live (it’s only recently been found that they live much farther underground and at higher temperatures than previously thought, and (2) most bacteria don’t grow in culture media, so traditional sampling methods missed up to 99% of them. Gould estimated (in 1996 admittedly) that bacterial biomass exceeds that of all other life combined. The current Wikipedia article says “The total live biomass of bacteria may be as much as that of plants and animals or may be much less.”
–Mark
But on the plus side, there wouldn’t be any tsunamis, which is what the OP seems to be worried about.
Bacteria do not win in terms of duration, because the archae have them beat on that. And if we’re going to argue “all non-eukaryotes combined vs. all eukaryotes combined”, then they still don’t win, because one might just as well say “all non-elephants combined outnumber all elephants combined”. Or, for that matter, “all non-E. coli combined vs. all E. coli combined”. The statement doesn’t say anything about the organisms themselves, only about the arbitrary way we’ve chosen to categorize them.
Yes, I’m sure Gould meant to include archaea in what he calls bacteria. Other than that, your argument is just sophistry. Comparing the group “bacteria” to “non-elephants” is ridiculous. These categories are not arbitrary names, they are based on objective differences in evolutionary history and genetics. Compared to bacteria/archaea, elephants are basically identical to humans, to all other mammals, to all animals, and to all plants for that matter. These groupings are based on genetic similarity and cladistic analysis, not just arbitrary names.
–Mark
No, that’s quite wrong. Elephants represent a clade, while non-elephants do not. Elephants are more closely related to each other than they are to other organisms, while many non-elephants are more closely related to elephants than they are to other non-elephants. Likewise E. coli are a clade, non-E. coli are not. Clades are not arbitrary groupings.
Bacteria, Archaea, and Eucaryotes are all clades and not arbitrary groups. And since Archaea and Eucaryotes appear to be more closely related to each other than either is to Bacteria, Bacteria vs non-Bacteria are both legitimate clades. So comparing the abundance and diversity of Bacteria to that of everything else is a fair comparison.
A useful guide to at least the land mammals if nothing else: xkcd: Land Mammals
Odd, but I had occasion to post this same link in a different thread today. What are the odds?