I agree, my point is that the reason it is neither reasonable nor cost effective is because of the huge dangers around launching large amounts of fissionable material to orbit. The technology is actually relatively simple and cheap, at least compared to a chemical rocket, and the cost of the fuel is also not an issue. The problem is getting the fuel to orbit without a risk of causing widespread nuclear contamination.

Yes, go back 75 years and you'll find a world far less risk averse than today's world - but that applied to governments and companies both. The question that's relevant is NASA vs private companies in today's world because the NASA of 75 years ago no longer exists.

The private sector may be more cost-adverse but it is far less risk-adverse. There is no way a government program would have been allowed to have as many failures as we've seen with Space-X's Spaceship.

The reason nuclear propulsion has not been adopted is because of the huge risks in launching large amounts of fissionable material to orbit. Even far smaller radio-thermal power generators (RTG), such as those used by the Cassini and Galileo missions, lead to significant precautions during launch. A nuclear rocket will require orders of magnitude more fissionable material than an RTG.

Nuclear rockets are nothing new but the reason they have not seen significant use is because first you have to launch them to orbit. Rockets have a not-insignificant chance of exploding or crashing during launch and when you have them loaded with lots of fissionable material the effect is like a dirty bomb that has a good chance of scattering highly toxic, radioactive debris over a large area.

I suspect we will not see nuclear rockets until we develop a fusion-based one because, unlike fission-based designs fusion uses light, non-toxic, stable isotopes as fuel and so is likely to be no more dangerous than current chemical rockets.

Yes, it does not seem to be written in the rules but it is what the driving instructors taught my kids and what they are tested on. I also got told that when I had to do a driver safety course for work! It is also what most people seem to do since, when I first arrived in Alberta I almost got into a few accidents entering roundabouts because someone indicating right actually wanted to turn left and exit! I now basically ignore indicators on Alberta roundabouts because they provide zero information about what the driver is about to do.

So now we have AI writing a report to allow it to grow and spread further. Isn't that a key sign of life...either that or it's a sign of incredibly lazy civil servants. The irony will be that in a few years they'll be the same people complaining that the government is replacing their jobs with AI.

Blindly trusting technology is nothing new. Back when GPS navigation was relatively new there was a place up in the Yorkshire Dales, appropriately called Crackpot, where some devices would suggest cars leave the road and drive down a muddy cart track to the river Swale, drive through the river and up a track on the other side. The number of utter idiots who blindly followed those directions even though they could presumably see exactly where they were going was phenomenal. There was even an article on it in Slashdot.

If people are quite literally willing to drive off a (small) cliff into a river it's hardly surprising that they trust AI.

My experience getting a US driving licence near Chicago was an eye opener in that regard. First they suspected that I'd used their highway code book during the theory test because I got all the questions correct and then I thought I'd failed the driving test because the examiner have be drive around the block meaning that the most challenging part of the test was making a left turn back into the car park making me think that she'd cut the test short because I'd done something to fail it!

The even more amazing thing was that there was some big scandal at the time about people paying to get a licence without having taken the test which had me wondering exactly how bad a driver you had to be if needed to bribe someone because you could not drive around a block!

It's when they started getting tough on thought crime that things went down hill.

US speed limits annoyed the heck out of me when I lived there a few decades ago because they were so much lower than the UK's even when driving through the middle of nowhere without any traffic. The UK has a 70mph limit on motorways and 60mph limit on single carriageways away from towns and villages. Other than Montana, it is only recently that the US seems to have largely increased limits to the UK's or, in the west, even surpassed it slightly. Even when the limits are similar or higher in the US, every time you get near any town or city the limits drop and that's a lot rarer to see on UK motorways.

However, while the UK's speed limits were/are a bit higher than the US's you often can't drive at that speed due to the huge volume of traffic. The slow down that this causes also decreases road deaths which I suspect is a big part of how the UK's roads are safer.

They may save lives in the UK but here in Canada the rules for roundabouts are lethal. Instead of the UK rules where, on approach, you use your indicator as if you were approaching a cross-roads, here in Canada you are always supposed to indicate left when entering the roundabout even when going straight ahead. This means that when you are waiting to enter the roundabout to turn and see a car approaching that it indicating that it is turning left to stay on the roundabout - meaning that it is safe for you to enter - it might actually mean it is intending to turn right and leave across your lane in which case it is unsafe for you to enter.

I do not know which idiot came up with the Canadian rules that have you indicating left just before you turn right to exit but I think they should be sentenced to live in Milton Keynes for an extended period to get some practical training.

Ah, but then they would also target drinkers of wine or spirits - both of which have higher alcohol contents - and not just beer. I guess they are just like many of us, they just want to relax with a pint and this is the nearest they can get.

Yes, but they have also occurred frequently and the vast majority are not associated with mass extinctions at all. They are thought to be more common when the global temperature is high because that reduces the amount of dissolved oxygen in the water (and global temperatures were much higher in the period where many of these events have been foune), but they have occurred naturally throughout the geological record and are generally regional events, sometimes associated with volcanic activity and/or large dumps of nutrients into the ocean.

I'm not saying that we should not be concerned - we absolutely should be - but claiming that we are all doomed because there will be no oxygen to breathe is just silly and not at all supported by any evidence I have seen.

True, but of all the life on the planet bacteria and algae can spread far faster than just about anything else since their reproductive life cycle is so short. Short of instantaneous changes, like volcanic eruptions or meteor impact, they should be able to spread fast enough to accommodate any human-induced change. Its the larger organisms like plants and animals where the speed of change is a serious factor.

Yes, but this makes little sense. The planet has been much warmer in the past, even just a few million years ago, and there was clearly an abundance of marine life and breathing organisms back then. Global warming is going to be incredibly disruptive for our civilization but the idea that there will be no oxygen to breath is utter nonsense: if that were true life would not have survived the far warmer global temperatures it has in the past.