Insights Fake News and Science Reporting - Comments

[Dr. Courtney]

I will call this out as another example of "Fake News". Here, the report on the UPI website went further than what the press release stated, and in the process, made a critical error.

This news article is reporting an interesting experimental result that created objects with "negative effective mass" in a superfluid. From what I can tell, the writer is basing the report not on the original paper, but rather from the press release out of Washington State University.

The error comes in at the very beginning of the news article:
I took a look at the WSU press release and in the paper itself. Nowhere in there was any claim made that this phenomenon "... ignores Isaac Newton's Second Law of Motion..." In fact, it HAS to obey the second law for it to have such a direction of acceleration.

The 2nd Law is basically F = ma.

1. For a positive mass, it means that F and a are in the same direction.

2. For a negative mass, then the 2nd law is F = -|m|a. It means that F and a are colinear, but in the opposite direction. In other words, it is the 2nd law that actually tells you that for a negative mass, if you push on it away from you, it will accelerates towards you. This is exactly OBEYING the 2nd law, not ignoring it! In fact, if the negative mass actually moves away from you the way we normally think ordinary mass should, it is only then that this mass is ignoring the 2nd Law!

The claim that this experiment "ignores the 2nd Law" is Fake Science Reporting. It is introduced to possibly make the story sexier and in the process, made a very amateurish mistake.

BTW, negative effective mass isn't new. This is common in condensed matter/solid state physics, because we have positive holes in solids, and on how we define effective mass (the curvature of the dispersion).

Zz.

I always understood that it was an inherent property of inertial mass to resist acceleration - therefore, only positive masses make sense.

I take Newton's second to be more than an equation - it is the definition of inertial mass. With this understanding, negative masses DO violate the Newton's 2nd.

Fake news? No.

News consistent with this understanding of Newton's 2nd:

The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.

See: http://www.physicsclassroom.com/class/newtlaws/Lesson-3/Newton-s-Second-Law

 

[mfb]

Objects with negative mass do resist acceleration. You have to apply a force to accelerate them, and acceleration will be proportional to the force. It just goes in the opposite direction.
F=ma, Newton's second law, is valid.

The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.

Written that way, it is wrong in special relativity and we found a counterexample decades ago - while F=ma has a natural equivalent with 4-vectors.

Why should we restrict a general formula like F=ma, that does work with negative masses, to positive masses, and then claim the more general formula would have been violated just because the artificial restriction does not work any more?

 

[Dr. Courtney]

Objects with negative mass do resist acceleration. You have to apply a force to accelerate them, and acceleration will be proportional to the force. It just goes in the opposite direction.
F=ma, Newton's second law, is valid.Written that way, it is wrong in special relativity and we found a counterexample decades ago - while F=ma has a natural equivalent with 4-vectors.

Why should we restrict a general formula like F=ma, that does work with negative masses, to positive masses, and then claim the more general formula would have been violated just because the artificial restriction does not work any more?

I'm not trying to make the case that we should. But allowing for negative masses seems like a generalization that contradicts the original understanding:

The new understanding IS new physics, just as generalizing Newton's universal law of gravitation to allow for repulsive gravitational forces would be new physics and a contradiction of our current understanding of Newton's universal law of gravitation, even though the math could all be accounted for by reckoning one of the masses as negative.

 

[ZapperZ]

I'm not trying to make the case that we should. But allowing for negative masses seems like a generalization that contradicts the original understanding:

The new understanding IS new physics, just as generalizing Newton's universal law of gravitation to allow for repulsive gravitational forces would be new physics and a contradiction of our current understanding of Newton's universal law of gravitation, even though the math could all be accounted for by reckoning one of the masses as negative.

But this isn't a "generalization" of anything Newton's laws. It is a generalization of the concept of "mass".

The 2nd Law never specified that "m" must always be positive for it to be used in the equation. It is just that at the time of its "conception", there was no other way to think of what the mass could be. So if m is positive, then the old description of the equation that we know and love is valid.

However, now that we can come up with scenario that the mass can be negative (or, to put it more accurately for this context, it is the effective mass), then the description of the equation (i.e. the interpretation) needs to be generalized. The formalism, i.e. the equation itself, needs no modification and it is still applicable.

This is no different than rethinking of the second law as being F=dp/dt, allowing for the possibility of a constant velocity situation with changing mass. The fact that F = v dm/dt is also a valid form of the 2nd law, and that it looks different than the old F=ma, does not mean that it is no longer the 2nd law.

The 2nd law equation is still valid even for negative mass. Nothing that has been discussed so far has pointed to that. It is not being "ignored" as claimed by the news article.

Zz.

 

[Dr. Courtney]

The 2nd law equation is still valid even for negative mass. Nothing that has been discussed so far has pointed to that. It is not being "ignored" as claimed by the news article.
Zz.

Yes, the equation is still valid. But I've always taught physics and preferred a public understanding of physics as physical meaning beyond the equations.

Are you saying that a repulsive gravitational force would not violate Newton's universal law of gravitation, because the same equation would still work with negative mass?

I would disagree with that, because Newton's universal law of gravitation includes the idea that all gravitational forces are attractive. Reporting a repulsive gravitational force as a violation of Newton's universal law of gravitation would not be "Fake News." At worst, it might be represent a different opinion on a question of semantics. "Fake News" in regard to science reporting is not a different opinion on semantics, it is a skewed view (bad science) that is fundamentally wrong from any perspective.

 

[ZapperZ]

Yes, the equation is still valid. But I've always taught physics and preferred a public understanding of physics as physical meaning beyond the equations.

Are you saying that a repulsive gravitational force would not violate Newton's universal law of gravitation, because the same equation would still work with negative mass?

I would disagree with that, because Newton's universal law of gravitation includes the idea that all gravitational forces are attractive. Reporting a repulsive gravitational force as a violation of Newton's universal law of gravitation would not be "Fake News." At worst, it might be represent a different opinion on a question of semantics. "Fake News" in regard to science reporting is not a different opinion on semantics, it is a skewed view (bad science) that is fundamentally wrong from any perspective.

No, that is YOUR definition of what "fake news" is. That was never my definition of it within the context of this thread, and one can clearly see that in the Insight article that I wrote.

Newton's law of gravitation puts no limitation on the sign of the mass, the same way the BCS theory puts no limitation on whether the coupling must always be attractive. The mathematics doesn't care.

The news article over-reached and stated something incorrect, especially when considering that the 2nd law with negative mass stated exactly what described, not different. This is the definition of an accurate description. It is not the definition of "ignoring".

Zz.

 

[Dr. Courtney]

The news article over-reached and stated something incorrect, especially when considering that the 2nd law with negative mass stated exactly what described, not different. This is the definition of an accurate description. It is not the definition of "ignoring".

Zz.

Your disagreement is with many physics textbooks, not with the news article or with me. The news article and I are consistent with Newton's second law as it is commonly articulated in textbooks, and the new finding of negative mass DOES CONTRADICT the common textbook explanation. Quoting Wilson, Buffa, and Lou:

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The direction of the acceleration is in the direction of the applied net force.

So, is the "Fake News" wrong, or are all the textbooks wrong that say "The direction of the acceleration is in the direction of the applied net force"?

Physics is always more than just the equations. Retaining the equations but changing the understanding of how they apply to reality IS a change in understanding of the underlying physical laws. That is REAL NEWS.

 

[ZapperZ]

Your disagreement is with many physics textbooks, not with the news article or with me. The news article and I are consistent with Newton's second law as it is commonly articulated in textbooks, and the new finding of negative mass DOES CONTRADICT the common textbook explanation. Quoting Wilson, Buffa, and Lou:

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The direction of the acceleration is in the direction of the applied net force.

So, is the "Fake News" wrong, or are all the textbooks wrong that say "The direction of the acceleration is in the direction of the applied net force"?

Physics is always more than just the equations. Retaining the equations but changing the understanding of how they apply to reality IS a change in understanding of the underlying physical laws. That is REAL NEWS.

In these textbooks, the mass is automatically assumed to be positive. I see nothing wrong with that, the same way I see nothing wrong with these books continuing to claim that no matter how intense a light source is, no photoelectrons will be emitted if the energy is below the work function. I personally have done experiments to show that this is wrong. But yet, I would not change these textbooks because they are restricted to within the context that these are still correct.

But the 2nd law itself, without such restriction, still WORKS, and I've show why. Thus, claiming that when you relax that restriction that this equation is "ignored" is patently false.

Zz.

 

[russ_watters]

Are you saying that a repulsive gravitational force would not violate Newton's universal law of gravitation, because the same equation would still work with negative mass?

I would disagree with that, because Newton's universal law of gravitation includes the idea that all gravitational forces are attractive.

How would such a situation differ from, for example, not knowing about repulsion in magnetism and later discovering it?

Yes, the equation is still valid. But I've always taught physics and preferred a public understanding of physics as physical meaning beyond the equations.

Well isn't that one of the core purposes of a scientific theory? To expand knowledge by making predictions beyond what current experiments show? It's fine to assume mass always must be positive based on a lot of experiments. But it is even better to challenge that assumption by following the math wherever it leads. In that way, some scientists turn over a rock that others just assumed had nothing under it.

 

[WWGD]

Ultimately, at a subconscious level, our mind seeks to reduce anxiety, keep it under control. so, unless we pay
conscious attention, we believe what makes us feel better, what allows us to make sense of the world.

 

[Keith_McClary]

Sabine Hossenfelder:
No, physicists have not created “negative mass”

This is by no means to say that the result is uninteresting! Indeed, it’s pretty cool that this fluid self-limits its expansion thanks to long-range correlations which come from quantum effects. I’ll even admit that thinking of the behavior as if the fluid had a negative effective mass may be a useful interpretation. But that still doesn’t mean physicists have actually created negative mass.

 

[RogueOne]

I wasn't sure exactly where to put this one (also fits into the "March for Science" thread a bit), but it has been bugging me for a week:
http://hosted.ap.org/dynamic/stories/U/US_SCI_WINTER_WEATHER_FORECAST?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT&CTIME=2017-03-14-17-17-34

For the un-initiated, a "Nor'easter" is a storm system unique to the northeastern US, where a cold front comes in from the north west and collides with warm, moist air coming up the coast. The collision of the air masses produces a severe and rapidly intensifying storm. In the summer they rival hurricanes and in the winter, they produce massive blizzards along the Washington-Boston corridor.

Because they involve a cold and a warm air mass, there is a potentially wide variation in impacts across the storm from east to west. In the east, you might get all rain and in the west it is all snow. There will be a gradient of each, with the center generally producing the most snow, along a swath 10-50 miles wide and up to several hundred miled long.

Last week's nor'easter was late for a snowstorm, which produced a forecasting problem. Early indications were that it would be a classinc winter nor'easter, almost entirely snow, and cutting straight through the population centers from Philly to Boston. But hours before the snow started (Monday morning), the models started showing the warm air from the east would win and produce mostly rain along the coasts and a snow/sleet mix further inland, only producing all snow much further inland. These models were correct. The National Weather Service held a meeting on Monday afternoon and decided against updating the forecasts, "out of extreme caution" (quote) and "...they didn't want to confuse the public." (AP paraphrase).

Wait, what? A coherent message is more important than the quest for accuracy?

So along the east coast, we went to bed last Monday night expecting to wake up to a foot+ of snow and actually finding totals less than half of the low-end of the forecast (NYC predicted: 18-24", actual: 7"). Scientists can claim somewhat of a win in that the mass of precipitation was actually accurate, it was just denser than predicted, but that difference matters a lot in how you respond to the storm. Particularly when eastern Delaware and NJ saw mostly rain instead of a foot of snow! You can't un-cancel school if it doesn't snow. As for me, I did notice something was off when I woke up, but I was sicklazy and stayed home from work on Tuesday though many of my colleagues ended up going in.

This is from a division of the same government agency responsible for collecting, interpreting and disseminating climate data. Which begs the question: is the climate data/warming predictions we get filtered with the same bias?

In the first bolded and underlined section, it is illustrated that they were choosing between two messages based on how they wanted the public to respond. The message that was chosen to be delivered was selected because they desired the response that it would illicit from the public.

In this scenario, they have demonstrated that they do indeed believe that its okay to deliver alternative "facts" with the intent of shaping public response.

If a politician were to discover that this organization had this trait, he/she could coerce them to deliver numbers that are convenient to use as "scientific evidence" proving the need for whichever legislation he/she wanted to pass.

If you combined P-hacking with their willingness to deliver information purely based on the desired response from the public, a group of like-minded politicians would be able to "scientifically prove the existence of" faux problems that can only be solved, conveniently, by giving those politicians the very power over the means of production/commerce that they have demonstrated wanting throughout their entire career.

That is not speculation, either. Analogous things have been done before. Only, instead of basing their justification in the words of "scientists", the kings/chiefs/emperors claimed that "prophets" had delivered the word of god/gods to them. Then the peasants believed the claims of their leaders and dutifully participated in whichever war, sacrifice, or relinquishment/reallocation of resources it was that the king/chief/leader wanted them to participate in.

That's why threads like this are important for us. Bad science can be used as a political weapon, and that needs to be acknowledged.

 

[ZapperZ]

Adding more fuel to the fire...

http://physicsworld.com/cws/article/multimedia/2017/jun/15/how-politicians-misuse-and-mangle-science

Zz.

 

[Vanadium 50]

New York magazine last week published an article by David Wallace-Wells entitled "The Uninhabitable Earth". This article claims, among other things, that in 83 years or less "parts of the Earth will likely become close to uninhabitable, and other parts horrifically inhospitable". This piece has been criticized as inaccurate by, among others, Michael Mann - hardly a climate change denier. (But I confess it's fun to hear him called that)

What's interesting is the reaction by Vox and Slate and others. Their position is that scaring people is important - more important than getting the facts right - because political action is necessary. It's a thin line between that and "if we told the people the truth, they might not do what we want", which is a heck of a position for a journalist.

 

[PeterDonis]

It's a thin line

I would say it's no line at all.

 

[Dr. Courtney]

What's interesting is the reaction by Vox and Slate and others. Their position is that scaring people is important - more important than getting the facts right - because political action is necessary. It's a thin line between that and "if we told the people the truth, they might not do what we want", which is a heck of a position for a journalist.

It's seemed that way to me for a long time.