That's not right. Fission products are not the same as decay products. Many are considerably more dangerous in the short and medium term,

I think those particles existed, but they would have been constantly colliding with the quarks and gluons, so their "normal" behaviours would have been swamped. As a loose analogy consider any opaque solid matter. Photons probably exist in there, but they travel almost no distance before they hit an atom and they (mostly) carry much less energy than the interactions between atoms, so the properties of the matter are determined by the atoms,

The history of the end of the last ice age suggests that decent arable soils can develop in as little as a couple of millenia if the conditions are favourable. It's going to take a while.

There's safe and safe. They measures the N2O4 level at a few parts per million BEFORE the purge. Then a couple of guys in respirators did the purge and got it down to 0.5 ppm. Then they opened the hatch.

Not seeing a big problem, regolith is not going to be damaged by a methane-oxygen flame, and it turns out not to be too crushable [see Apollo]. A robot lander or rover or orbiter with a decent camera can identify a landing spot with no inconvenient boulders, and they seem to have nailed the precision vertical rocket landing with Falcon, so they should be able to get within a meter or so of the target. Worst risk is probably that the first lander gets a foot stuck and is lost there. It won't be manned, so not a big deal. The second one might need to carry a robot steamroller to make landing spot for the manned one.

Define "matter". Seriously. If you have something that is present with varying denities in different part of space, moving at less than lightspeed and interacting through gravity, what else do you need to call it "matter"?

The idea that dark matter is made of baryons (ie ordinary matter like dust and rocks) isn't consistent with CMB observation. The balance between radiation pressure and gravity in the early universe drove pressure waves whose aftermath can still (with some difficulty) be detected. That shows us that about 80% of the gravity came from particles that did *not* experience radiation pressure (ie not baryons).

and we can detect evidence of those gravitational effects. That sounds like a pretty good indirect detection. We detect other things by their effects on other forces, like light (electromagnetic forces)

SpaceX's Starship is expected to land on its own rockets. Just needs a tough flat surface to land on.

While lithium and deuterium are not technically unlimited, they might as well be. Both are common enough in seawater. As someone has already pointed out, the Sun only has a finite fuel supply

Even that shouldn't have been able to happen, and I'm sure they are working very hard right now to fix the underlying issues. In a piece of infrastructure as critical as CloudFlare (which hosts about 20% of the entire web IIRC) no single tech should have been able to put a configuration file live, even as a temporary patch during maintenance, without thorough inspection and testing.

Takeoff and landing for one -- no prospect of an airstrip.
Also flight speed, I suspect. The chopper blades can move very fast to generate lift without the whole vehicle moving.

Handy if you have a table with one leg shorter than the otherts..

This laptop fills a much needed gap in the market

The trial also gave it to patients who were on oxygen and, I think, to some in hospital who were on neither. It helped the patients on oxygen less and the ones on neither even less.

It seems Covid19 is an infection that goes through a number of different stages (not all of them in every patient) and the biological processes in each stage are different. This drug helps with some of those that happen in the most severe stages, but not the earlier stages.

Yup. Payload c 100 tons, fuel and oxidiser about 900.