David Burns' Helical Engine Won't Work

There was a little bit of a kerfuffle a week or so ago about an engineer from NASA (David Burns, reportedly the Manager of the Science and Technology Office of the Marshall Space Flight Center but I’ve not been able to independently verify that).  He put up a document on a NASA page talking about an engine that could reach large fractions of the speed of light (more than 90%) with pretty much no fuel.  That document has since been removed but it can still be viewed at the Wayback Machine.

I’m astounded that it got put up at NASA in the first place.  It simply won’t work, he’s got the physics wrong.  Looking at the “Thought Experiment” which has a weight on a spring in a box, one can see that the fundamental principle is incorrect.  Within the frame of the box (or the spaceship, or whatever), the mass inside would be slightly heavier at both ends of the cycle, within the frame of the container, so there won’t be an overall forward propulsion imparted to the container.  The best you could hope for is that the container (box, spaceship, whatever) would quiver (and even then that would contribute to the mass inside losing momentum).

It all comes down to the total energy.  I’m going to explain in terms that I introduced at On Time.

A spaceship with (stationary) mass M_o, when it's stationary, has energy M_oc² – we can think of this as the rest mass times it’s “speed through time”, or v_T = c.  When at a velocity through space, v_S, spaceship has energy M(v_T² + v_S²) where, v_T ≠ c but instead (due to time dilation) v_T = c.√(1 - v_S²/c²) = √( c² - v_S²), so energy is E(v_T)=Mc².

But M ≠ M_o, instead M = M_o/√(1 - v_S²/c²), which when you work it all through, observing that 1/√(1 - v_S²/c²) ≈  1 + v_S²/c² (accurate to within 10% to about 0.68c and within 2% to about 0.47c), gives you E(v_T)=M_oc² + ½M_ov_T ² (see On Time).

This means that you need to pump ½M_ov_T² into the system – which is the extra mass he’s talking about – or you aren’t going anywhere.

To get to from zero to 297 million metres per second (0.99c, one of the numbers being bounced around), assuming no losses, that’s 88 petajoules per kilo or 88000 million megajoules and noting that liquid hydrogen has an energy density of about 120 MJ/kg (according to a guy at Stanford) you are going to need a lot of fuel to get your spaceship up to that speed, even if you ignore the fuel burden and losses and assume some magical method by which the energy in liquid hydrogen is converted directly into kinetic energy.

To be fair to David Burns, his “paper” (it’s not a paper, it’s a few PowerPoint slides!) ends with these words:

• Basic concept is unproven
• Has not been reviewed by subject matter experts
• Maths errors may exist!

It's entirely possible that the document ended up where it was by mistake (as it clearly wasn't ready for publishing to the world).  The fact that so many organisations ran with this, so uncritically, as if it were something real is simply very sad.

On Climate for a Change

As hinted at the end of A Climate of Mistrust, I have been looking at the whole climate shebang.  I’m not a climate expert and I haven’t even been working in a related field, so I am limited to trying to assess the sorts of claims made by various people and the ways in which data is presented.

I have to admit to a level of bias, I don’t think that NASA, or NOAA, or the EU or UK or Canadian or Australian equivalents, are engaged in some wild conspiracy to trick the world into thinking that the climate is doing something that it isn’t.  I think that it’s possible that people whose job or hobby is related to lobbying either way will be biased, so there will be climate change alarmists who will bend data to look worse than it is and there will be climate change deniers who will bend the same data the other way.

It’s also vaguely possible that some people in reputable organisations will have their own biases and might be tempted to skew their representations and interpretations of data, maybe even in good faith, so as to support their preconceptions.  I don’t think that such people are likely to simply make up data because that can so easily be detected and lead to a world of hurt for a professional scientist/academic/researcher.

People on the fringes on the other hand may be less scrupulous.

There are basically two fringes, the denial/minimisation fringe and the activism/alarmism fringe.  It is possible that there are fine people on both sides, and it is possible that there are also ratbags on both sides.

The media generally divides on the issue along political lines.  A more conservative news organisation will lean towards denialism while a more liberal news organisation will lean towards alarmism – and in this case I use alarmism deliberately because in the media there is little room for calm consideration, each story needs to be built up into something that engages the viewership and if that means overhyping a not very good situation into a dire one, then the ratings machine is going to win over objectivity.  I am far from suggesting that the conservative wing of the media is without fault though, they take the worse transgressions of the left wing, crank them up to eleven, inject the histrionics and then go apoplectic.

As bad as the use and misuse of a young, outspoken girl on the autism spectrum by the left is, the bile and fury visited on her by the right is simply appalling.  They seem to have forgotten that they had the option of taking the high moral ground.

Anyway … the next few posts will be edited extracts from correspondence with a friend who is being tempted by the dark side.  It may become clear while reading but I want to make clear what I think my position is:

I think that it’s unlikely that we’ve been digging up coal and extracting oil, for about 200 years and cutting down forests since we worked out that we could use axes to kill trees as well as each other (and other animals) and there’ll be no consequences.  I don’t know what the extent of the consequences are, they might be minor, they might be beneficial, or they might not.

I find scientists working in the field (not the media on either side) to be convincing for the most part.

My own observations lead me to think that something is happening, but I am aware that there’s a huge egocentric bias involved in personal experience, perhaps I just remember youth fondly and am filtering out all those muggy warm nights during summer that I no longer experience (which might be because I now live in a far better insulated home and have access to air conditioning when necessary or might be because it was warmer during summer when I was a kid).

I don’t find hippy-type climate activists convincing.  I just find them annoying (much as I find vegan and animal cruelty activists annoying, without that meaning that I want to eat your pets or am actively in favour of torturing animals).  I don’t have a solution to their problem, if they are right in there being a problem – how to motivate a population into doing something … without being intensely annoying.

I find histrionic climate denialists far from convincing.  The more low-key climate denialists just strike me as disingenuous, and they are annoying because they take more effort to debunk.  If you drink the koolaid though, I guess they aren’t particularly annoying, it might even be soothing to rock yourself to sleep each night thinking that it’s all okay, the climate is fine, the future is rosy (and that rosiness is not due to the flames of an imminent climate apocalypse).

First off, my interlocutor made the error of referring to unnamed “top scientists” (always a bad sign):

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I think there needs to be some clarity, some delineation between “top scientists” (whoever they are), actual experts in the field, science educator types (some being scientists speaking outside their field, others being enthusiastic amateurs), climate activists (who are more likely to be the source of erroneous and/or misleading claims – in both directions), reporters (who could be divided into a number of categories, some of whom would be more reliable than others) and pundits (ie people more focused on opinion than data, who only use data [selectively] to support a pre-existing opinion).

I agree that hysteria about the climate isn’t good, but neither is complacence – particularly if there truly is a “tipping point”, if that term is more than just a buzzword.  What we do know is that systems do have equilibria, and it is possible for systems to lurch from one equilibrium to another, rapidly and at short notice.  We have examples of large-scale climate change in the past that are entirely natural that have had impact on human civilisations – for example Rome’s expansion was assisted by a warmer than normal period [the imaginatively named “Roman Warm Period].  But we aren’t in an entirely natural period, we do affect the climate – it’s rather ridiculous (and naïve) to think that all human activity has no significant impact on our environment.  What is in question is the extent and nature of the impact that we are having.

I’m not sure what political goals you think are being pursued via “irrational and unscientific discussion” on the part of “top scientists” and I don’t know how discussions by scientists are supposed to be curtailed (who is it you think are allowing these discussions to go on and, I presume, ought to step in to censor those discussions?)  I certainly agree that some news outlets will publish sensational stories because it helps either their bottom line or the political party they are aligned with (while others will publish different sensational stories about how the sensational stories from their competitors are no more than scaremongering, because it helps their own bottom line or their own allied political party).  I also understand that some people who are scientists will talk publicly in a more political capacity, but if they aren’t discussing the data or the models then they aren’t speaking in their capacity as a scientist.

In researching sea ice extent (see next post which should appear here), I found an interesting diagram (linked to the concept of an Overton window):

It appears with the following text, at the blog of Dr Michael Tobis (with a specialty in Atmospheric and Oceanic Sciences, but seems to be more into the computer modelling side of things as a Systems/Computer Engineer):

“Let's revisit the graphic I came up with, illustrating some aspects of the state of debate in climate science, and see if we can spot the stigmata of malice. Here we are factoring out policy ("business as usual", meaning the only constraints on carbon use are supply and demand, and that therefore fossil fuels will remain in use for a long time) and simplifying impact to a qualitative measure of good, indifferent, and various stripes of bad.  //  The curve is a probability density; the population is "informed opinion", by which we mean something like "people with Ph.D.'s who have spent more than 6 months full time equivalent on the subject", so the vertical axis is reasonably well defined. I admit that the horizontal axis is mathematically problematic; you can't call it a linear scale but it's obviously not logarithmic either. So the graphic can only be qualitative in nature.”

Sometimes there are statements along the lines of “97% of scientists agree with the consensus on climate change” – a prime example is from Barack Obama on Twitter.  However, it should be noted that 98.23% of ridiculously precise statistics are made up.  It is possible to get that figure more reliably though, for example from NASA, who got their figure from Environmental Research Letters but it should be noted that this claim is specifically related to publishing climatologists.  If one includes non-publishing climatologists, the figures drop markedly – although there is a notable increase in certainty even on the part of non-publishing climatologists over time – 66% in 1991 (Gallup – AMS/AGU members) and 87% in 2015 (Pew – AAAS members).  There’s an interesting chart that relates:

The bottom line is that the more expertise a scientist has in the field, the greater likelihood that that scientist’s views will align with the consensus on human-caused global warming.

Scientists who are sceptical about the more extreme claims made by actual climate alarmists are just being scientists.  The scientists that I worry about are those who are claiming that there’s nothing to worry about (who fall into the chasm between right wing think tanks and those with most informed opinion).  I was curious as to who these people are and what their area of expertise is and therefore where they would appear on the chart above.  Wikipedia (which has its own reliability issues) lists four:

Indur M. Goklany: an electrical engineer linked to the Cato Institute.  His main claim to fame re an anti-climate-change stance is that he wrote “Ironically, much of the hysteria over global warming is itself fueled by concerns that it may drive numerous species to extinction and increase hunger worldwide, especially in developing countries. Yet the biofuel solution would only make bad matters worse on both counts”.  From that comment he seems more anti-biofuels than anti-climate-change per se,

Craig D. Idso: a geographer linked to the Science and Public Policy Institute which is a climate change denial mouthpiece (which is only 1/3 funded by Exxon-Mobil) and Heartland, another climate change denial mouthpiece (which might no longer be funded by Mobil-Exxon, but no longer discloses its funding sources) – note that Heartland was previously involved in tobacco lobbying,

Sherwood B. Idso: a research physicist doing something with water (brother to the geographer above) linked to the Center for the Study of Carbon Dioxide and Global Change, yet another climate change denial mouthpiece (and which funded in a small way by Mobil-Exxon and also Peabody [coalmining]) and

Patrick Michaels: another Cato guy, who used to be an environmental science research professor and who is personally funded by fossil fuel companies.  The Cato Institute doesn’t seem terribly deeply involved in climate change denial (despite a stacked council), but they are against doing anything about climate change, because it’ll be too expensive and (they claim) ineffective.

There are more people who are claiming that climate change is primarily caused by natural processes.  Wikipedia lists 30.  I think the best thing to say here is that there is a significant, albeit small minority of scientists who contest the mainstream climate change consensus.  Just how small that is compared to the numbers that agree with the consensus is unclear, and there does seem to be a direct relationship between the likelihood of conforming with the consensus and expertise in the area.

Finally, models.  There is some fuss made in some quarters about how the models are inaccurate, with some climate change minimisers accepting that there is something happening but denying that it’s as bad as it’s being made out to be.

Well, yes.  There are always going to be doomsayers who take the worst-case scenarios and give the worst possible predictions.  And models are never going to be entirely accurate, particularly for a complex system for which the parameters not only not known but also their significance is not fully understood.  As I like to say, the only fully accurate model of the universe is the universe – to a lesser extent the same applies to the Earth and it’s biosphere (which conveniently includes all the water, the atmosphere, the outer skin of the crust and all the animals and plants, but I do acknowledge that the mantle also has an effect via volcanic activity).  We can add to that the weather, which can make some people think that the climate models are incorrect when they may well be bang on the money.  I don’t think that climate scientists are going to be confused by that, but the pundits are another story.

An interesting thing about claims that models are inaccurate is that the people in charge report on the accuracy of the models, for example here - IPCC AR5 Chapter 9 – in particular “Are Climate Change models getting better?” which starts on page 824.

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I’ll probably touch on some of these issues again in later posts as I try to extract meaningful chunks from my ongoing investigation and discussion about climate change, climate change alarmism and climate change denial.