exchemist

For colonisers they don't seem to be doing a very good job. Unless David Icke is right about the Lizard People, I suppose.

Yes, that could be it. Though I don't buy the notion it is unsafe to eat from dishes with cracked glaze. Bacteria and fungus are all around us and I don't see why a few traces in the cracks in a glazed dish are likely to be pathogenic.

You can put glass jars into a microwave and they stay cool. Though some glazes on earthenware get hot and crack (I have found, to my chagrin).

I suppose in theory, as it is water that is absorbing the microwaves, once it has gone the silica gel should cool down, as it should be transparent to microwaves of the frequency used. So the process ought to be OK, I think.

I'm quoting Douglas Adams but the point is a serious one. The distances involved are vast and massive bodies such as spacecraft can only travel at a fraction of c*. Physical travel from one habitable planet to another would take centuries, and centuries more to get back, and to what end? My own view is that intelligent life from elsewhere would have long ago realised it would be a colossal waste of time and instead would put their efforts into remote sensing - if they were interested in our planet at all. (It fact, it may be just arrogance on our part to imagine we would be that interesting.) * If it is proposed that alien civilisations may have found out how to travel faster than light, my response is that is unjustified, whimsical, wish-driven speculation rather than science. There is no objective reason so far to distrust Relativity.

Why not? Because "in space travel the numbers are awful".

Indeed I am assuming that, since we know it to be the case. And I'm afraid you do accept these stories uncritically. We've established the Arawn story is rot. You could have questioned it. After all, its rotation period is less than 6 times that of the Earth, a far bigger body. And nowhere on the internet is there any support for the idea it could not be naturally stable. If you had checked that, it should have rung some alarm bells. But no, you just pushed it out as evidence of aliens (suitable hedged with caveats, but that is what you meant). Have you learnt from the Arawn story that the source you used for that cannot be trusted?

Except that we are not a bunch of primitives and these things have been investigated, on numerous occasions, with nothing to show for it. What has instead been revealed by many such investigations is the under-appreciated capacity of people to make mistakes in identification, to delude themselves and to fabricate. You, for example, have shown yourself willing to accept, uncritically, a number of stories, at random, with no linking feature, apparently because they support a pre-existing belief in alien visitations. When one of them is shown to be nonsense, it does not give you a moment's pause: you just move smoothly onto the next one, as if the first one had never existed. You never stop to ask yourself why you were fooled, or how to avoid being fooled again. Hence the scepticism of people like me about this stuff, when put forward by people with your sort of mindset.

I agree, regarding those anomalous reports that have been properly documented and professionally evaluated. What I was referring to is the presentation of a series of stories in which this has not been done, put forward one after another, uncritically, as if they are evidence of something. Each one can be painstakingly evaluated in turn and dismissed, only to be succeeded by yet another, normally unrelated to the previous one. So for instance here we had a story about Arawn, which we can now dismiss as false, only for it to be instantly replaced - without any sign of embarrassment or contrition - by another unrelated one about Ouamuamua (should that be Mwahmwahmwah?), or, or, what about some pictures taken behind a shed in the rural US, or, or, or.....

What industry or sector, in what country, are you talking about?

I’ve little doubt you can come up with ballocks hypotheses a lot faster than I can debunk them.😁 How many have you got on the go in this thread? That’s why people like me tend to think it’s a waste of our time. You have a long list of badly researched options that have been uncritically accepted, and we have to do all the work to show they are ballocks, one by one. It’s exhausting and after a while we are inclined to assume they will all be ballocks, automatically.

OK thanks. I had not read the link in question. Anyway, it looks as if we can dismiss the Arawn story as false. This actually raises real questions about some of the sources @Moontanman is using, since some seem to be pushing demonstrable falsehoods. (The analysis I did was for an all ice body. If it was rocky, or iron, the stability would be even more marked.)

I was addressing your comment about the rotation rate and the size of the object, in reply to @swansont. That was about Arawn, was it not?

As far as I can see the rotation rate of Arawn (5.47hrs) doesn't present any issues. Most astronomical objects rotate, either due to past collisions or due to angular momentum of the material from which they condensed.

Can you explain why you think 3D printing in a vacuum or under higher ambient pressures would present a challenge? I can't see what the problem would be. So long as the material in question would not be a liquid that might boil under vacuum, that is.

I am not aware that there is any law requiring individual companies to be net zero by any deadline. What industry is this, in what country, and what pressure is there for it to achieve net zero unilaterally? Yes that went through my mind too. As did Spike Milligan's remonstration: "Look, I died in the war for people like you."

Hard to disagree with these sentiments in general. There is undoubtedly a big element of 20:20 hindsight in a lot of criticism of previous generations. We simply knew much less then. This is normal: society learns as science advances. But to be fair to Thunberg (and to my 19yr old son) it is people one or two generations older than them who are today's decision-makers. There have been inexcusable levels of complacency, and blank refusal to face facts, from a lot of people of our generation, which the coming generation understandably finds very frustrating, especially as they are the ones who will be saddled with the consequences of dilatory action by our generation. Finger-pointing is on the whole not a constructive exercise, as it makes the pointer angry and the pointee defensive. The thing to do is recognise the issue and cooperate in solving it. Thunberg has been great at raising the profile of the subject but, being autistic, is no diplomat. That should not be surprising.

Well let's see. The volume of a sphere 60km in radius will be 4/3 π . (6x10⁴)³ ~ 9 x 10¹⁴ m³ (again check my arithmetic). If it's ice with a density of 1000kg/m³, that is 9 x 10¹⁷ kg. g at the surface of this planetoid will be GM/r², i.e. 6.7 x 10⁻¹¹ x 9 x 10¹⁷/(6 x 10⁴)² ~ 1.7 x 10⁻² m/sec². , if my maths is correct. That would be about 3 times the centripetal acceleration needed to keep the body together. So if my arithmetic is right there is no issue here: the body would be expected to stay in one piece. But where does this velocity figure come from that you are quoting? By the way, I have looked up Arawn on the web and I can find plenty of references to its rotational period but no reference at all to this being anomalously fast, or any puzzle about why it does not break up, in any of them. Which is just as expected if my estimate above is of the right order of magnitude. So indeed it starts to look like ballocks.

Seems this thing has a rotation period of 5.4hrs and a radius about 60km. That would imply a centripetal acceleration at the surface, rω² = 60x 10³ x (2π/(5.4x3600))² if my arithmetic is right, which I think works out at ~ 6 x 10⁻³ m/sec². That's not huge but I suppose the gravitation of a body that size will also be small.

Yes but none of the mechanisms being speculated about are artificial. The alien stuff comes into Loeb's article as a throwaway remark at the end and does not reference any hypothesis that is being studied seriously. If indeed the excess acceleration is inversely proportional to the square of the distance from the sun, it is directly proportional to the intensity of solar radiation flux experienced by the object. Ockham's Razor would favour a number of natural hypotheses over alien space drives.

I don't know but, purely speculating, I wonder if (assuming you are right and it is true) it could be because organisms that move about can end up in a wider variety of habitats, and therefore are exposed to wider range of evolutionary pressures.

The chief effect of altitude training is to increase the concentration of red corpuscles in the blood. You have yet to give any reason why your breathing hypothesis would affect obesity. Why would more red blood cells make you thinner?

If legislation drives the desired behaviour, the ones that adapt best will be the most profitable. Legislation has the virtue that it provides a level playing field for all players in the market and the most ingenious in adapting will benefit.

Oh I see. Comparing a temperature of 10C with one of 30C and applying the gas equation pV=nRT, the change in concentration of oxygen would be 283/303 ~ 93%. So yes there would be 7% less oxygen in the air at a given altitude in a county with an ambient temperature of 30C, compared one of 10C. This is about the same change as you get by climbing 600m above sea level, i.e. a bit over halfway up a munro in Scotland. For comparison, the British rowing squad does its altitude training at 2000m (in Austria). I doubt that 7% makes much difference. You are ignoring by far the most obvious effects, which are diet and lifestyle. What the UK and the US have in common, sadly, is a rather sedentary lifestyle and bad diet, driven by the disappearance of the the culture of eating home-cooked food at family mealtimes, and the pervasiveness of soft drinks.

So you think there is less oxygen in the air in hot countries? That's untrue. Where did you get such a weird idea?