The Plasma Physics Of Radio Astronomy (1)

 The previous post (Nov. 29),  considering the basic principles pertaining to radio astronomy, focused on the (relatively) simple case of propagation of plane EM waves through a medium assumed to be isotropic. That is, the propagation with E, H vectors is the same in all directions.  In terms of radio sources this is far too limited to be of practical use, so it is important to also examine propagation of a plane wave in an ionized (e.g. plasma) medium in the presence of steady magnetic field.  In this case  we expect the propagation to be variable, depending on direction.  For this purpose the diagram below can be used: 

For perspective, note the direction of wave propagation is in the x-z plane and at an angle of  φ  with respect to the z-axis.  Note the electric field E lies in a plane (yz) perpendicular to the direction of wave propagation. The steady magnetic field B is in the z-direction.   The relevant force equations involving a particle of charge q and mass m in the presence of a magnetic field are:

F 1 = q( v X B)

F 2 = q E

 

F 3 = m d v/ dt

Combining these equations yields:

F  = q(E  + v X B)  =  m d v/ dt

We then divide by q to obtain the force per unit charge:

F/ q =  (E  + v X B)  =  (m/q)  d v/ dt

The preceding vector equation can then be expressed in terms of the 3 scalar components referenced to each axis, i.e.

F x / q = E x   +   v y B z  =   (m/q) dvx / dt

F y / q = E y   -   v x B z  =   (m/q) dvy / dt

F z / q = E z     =   (m/q) dv z / dt

Assume now harmonic motion for the wave and charged particle to obtain the following:

vx = { j  (m w /q) E x  + E y B z}/ B z ² -  m ² w ² /q ²

vy = { j  (m w /q) E y  + E x B z}/ B z ² -  m ² w ² /q ²

^{vz = - j q E}z  /m w

^{The preceding relations enable one to infer the charged particle moves in a helical motion with axis coincident with z-direction, e.g.}

The condition:  

B z ²  =  

m ² w ² /q ²

corresponds to the condition  of gyro-resonance, whereby the gyro frequency:

w g   = (q/ m) B z

See e.g.

Brane Space: Space Plasma Physics Revisited (1) (brane-space.blogspot.com)

From one of Maxwell's curl equations we have, after  letting q=e the electron charge ( 1.6 x  10^-19 C ):

Ñ x H  =  J  +   j  wD    +  N e v  + j w ε_o E  

Where N is the number of  charged particles per unit volume.  We assume a movement of the charged particles constitutes a conduction current.  The  above Maxwell equation can also be expressed in terms of the three rectangular curl components, i.e.

^{1)  (Ñ x H)} x  =  Ne vx  +   j w ε_o Ex  

^{2)  (Ñ x H) y  =}  Ne v y  +   j w ε_o Ey  

^{3)  (Ñ x H) z  =}  Ne vz  +   j w ε_o Ez  

Where the permittivity of free space:  ε_o   =  8.85 x 10^-12 Farad/m

If  we now substitute  the values for vx , v y  and  vz  earlier obtained into equations (1),  (2) and (3) and further assume the frequency w  is much greater than the gyro frequency and further that:

N e ² / ε_o  m  w ² =   1

Then a condition occurs for which the permittivity and index of refraction of the medium become zero.  This critical  frequency we denote by  w_o  so that:

w_o        =       N e ² / ε_o  m

If: 

  w_o        =  2 p f _o 

Then:

 f _o     =    e /2 p    Ö N/ ε_o  m

This can be simplified to:

f _o     =   9 Ö N

Thus, if we know the critical frequency f _o  for a radio source (in cycles per second) we can obtain the plasma  number density of the source.

Suggested Problems:

1) Substitute  the values for vx , v y  and  vz  earlier obtained into equations (1),  (2) and (3) giving Maxwell's  curl H equation in terms of rectangular components to get the 3 resulting plasma frequency equations. Then show if the frequency is much greater than the gyrofrequency,  i.e.

 

w    >>   w g 

All the equations become identical in form

2) The Earth's ionosphere has a plasma number density of  

 10 ¹²     electrons per cubic meter.  Find the (critical)  radio frequency of this source.

Can Conflicting Scientific Theories Really Be Reconciled?

 

                                         

An intriguing proposal posed by WSJ science columnist Matt Ridley some ten years ago was that in certain cases "scientific tribal polarization" can be trumped and two competing theories reconciled or bought together to become one. His premise was that scientific  polarization occurs because excessive "academic tribal energy" goes into one or both theories and hence any full -bodied compromise yielding a hybrid theory becomes impossible.

As an example, he uses the extinction of the dinosaurs some 65 million years ago, accepted by most astronomers as being caused by an asteroid impact that delivered an explosion equal to two million hydrogen bombs and forming the 110-mile diameter Chicxulub crater. The explosion would not have been the immediate cause of the dinosaur's demise, but rather the injection of more than 4 trillion tons of dust and debris into the atmosphere because of it. This then led to the phenomenon of "nuclear winter" in which so much sunlight would have been impeded by the atmospheric debris that most of the green flora would have perished. This would have led to the extinction of the vegetarian dinos, and thence the meat eaters which depended on them in the food chain.

Another competing theory for the dinosaurs' extinction, proposes massive volcanic eruptions that burst through the skin of the Indian subcontinent at about the same time and poisoned the dinos and 67% of other life via high concentrations of sulphur and CO2 in the atmosphere. Ridley then cites new "more powerful evidence" for this volcanic theory, though more work clearly needs to be done.

Ridley then asks why both theories might not simply be unified, and thereby we have "an impact and a consequent eruption, both of which contributed to poisoning the atmosphere and the ocean to the point that few species could survive".

To be sure, this might have merit, depending on whether further work shows that: a) the volcanic eruptions were really consequent on the impact, and b) the eruptions delivered the needed levels of toxicity to claim two thirds of all the then life on Earth. Another question to be addressed: Could the volcanic eruptions alone have been enough to cause mass extinction?

Even if the two extinction theories can be integrated into a workable hybrid, it doesn't mean all scientific theories can be handled in the same way. For example, Newton's theory of gravitation and Einstein's are impossible to reconcile because one (Einstein's) is a tensor theory predicated on the geometry of space -time being curved in the vicinity of large masses, while Newton's is a scalar theory dependent on "action at a distance" within an absolute space, no space-time!

In like manner, it would have been impossible to reconcile the Big Bang theory with Fred Hoyle's steady state theory. The reason is that each mandates separate predictions which must be validated for the theory's acceptance. There are no overlapping predictions! Since the Big Bang theory was vindicated by postulating a 2.7 K isotropic background radiation, it was the winner.

In the field of solar flares, meanwhile, two divergent paradigms have emerged, one (B-v) peculiar to solar physics and based on the magnetic field intensity (B) and surface flow vector velocity (v) and the other (E-J) peculiar to space physics which is based on the electric field intensity and the current density.

One implication of the E-J paradigm models is that adequate power for flares can be provided once sufficiently large field-aligned potential drops can occur (as in double layers) arising from sufficiently large longitudinal (J‖) current densities. (cf. Kan et al, Solar Physics, Oct. 1983). Unfortunately, there seems to be no way to track these changes in the pre-flare phase, at least for specific solar active regions and sunspots.

Meanwhile, the unloading force-free field energy system, for the B- v paradigm, has become the centerpiece template for use in most solar physics applications. According to this view, convective fluid motions with characteristic velocity v warp and deform the magnetic field B, leading directly to

curl B = m ₀ J

Where B is the magnetic induction, J the current density, and m ₀ is the magnetic permeability of free space (m ₀   =   4p  x 10^-7  H/M) . In this paradigm, free magnetic energy accumulated during the shearing of force-free fields incepted by (v x B) , or the cross product of the velocity flow and the magnetic field strength. (Imagine the local magnetic fields being twisted up like you would a rubber band. The more twist imparted to the rubber band the more "free energy" it's stored. When you let it go, that energy gets released).

Most models based on the B-v paradigm concentrate on the energy generation (or storage) aspects, while ignoring energy dissipation other than as a passing afterthought. Clearly, this is unsatisfactory and leaves unanswered the question of detailed energy balance in a specified flare volume (coronal loop, arcade etc.). In particular, it leaves unanswered whether driven flare energy models (based on release of magnetic free energy from force-free fields) are adequate to ever be refined into full, self-consistent theoretical descriptions, as opposed to assorted ansatzes cobbled together or “cartoon” depictions.

The E-J models DO address the energy balance issues, but in most cases invoke artifacts common to magnetic substorms - such as V, -S potentials, and "neutral winds" which are not recognized by solar physicists as integral and physical parts of the flare process.

In a 1994 paper session for the joint meeting of the American Geophysical Union and Solar Physics Division in Baltimore, I presented a theoretical model that melded aspects of solar and space physics, by incorporating the respective B-v and E-J themes. Though numerous observers were “shocked” that a space physics basis could be incorporated to describe the flare process, others expressed interest and curiosity.

The basic model, depicted in Fig. 2, entailed successive weak double layer (WDL) formation in a Vlasov-Maxwell (upper coronal loop) plasma subject to anisotropic distribution of electrons in velocity space. The key point in the above model is that WDLs are needed to confine potential drops to extremely localized regions (in this case, also characterized by anomalous resistivity) . Meanwhile, the "feet' of the loop were anchored in a high beta plasma regime which was subject to the distorting motions of convective flows and their action in twisting the ambient (photospheric) magnetic field - leading to mutual polarity intrusion and magnetic gradients that could trigger flares. The activation arose when the potential drops in the upper part of the loop became large enough to tip the overall loop into instability. For example, if the twist of the loop was near T = 2π, then even a small micro-instability might act as the specific trigger.

The gist of the above illustrations is that yes, it is certainly possible in some cases to achieve a hybrid model or theory, but one must be aware all the time of the contexts, and also whether the resulting hybrid can make the predictions needed for acceptance. Alas, cross checking my theory must await the arrival of a higher resolution solar telescope that can identify the weak double layers in the upper corona.

See Also:

• The Limits Of Scientific Inquiry & Research (1)

And:

• The Limits Of Scientific Inquiry (2): Research Paper Examples...

As Roe Goes So Will The Supreme Court - "In The Toilet" Or Lawful

 

"Will this institution survive the stench that this creates in the public perception that the Constitution and its reading are just political acts? I don't see how it is possible.”-   Justice Sonia Sotomayor, Wednesday - on possibility of Supreme Court overturning Roe v. Wade

 As anyone paying attention is aware, on Wednesday the Supreme Court heard oral arguments in a case (Dobbs v. Jackson Women’s Health Organization) asking the court to uphold a Mississippi law that would ban almost all abortions after 15 weeks of pregnancy. Less appreciated, is if the court allows the Mississippi law to stand, they would effectively be overturning Roe and the fundamental right to have an abortion until the point of viability about 24 weeks of pregnancy.  This is despite the fact in a previous SC ruling 24 weeks had been adopted as the standard.  What gives?   

Well, the bodily autonomy of a woman. Either she has autonomy and control of her body, OR she can be forced into being a receptacle for a conglomeration of protoplasm growing inside her that she doesn't want.  And no, the moron, religious extremist Amy Coney Barrett's solution, i.e to just have the baby and then drop it at a church door- is not one any sensible woman would want. Especially if she was unfortunate to be carrying a rapist's seed. 

So if the right to  a woman's bodily autonomy - the right to choose to terminate a pregnancy  in this case - is taken away, then effectively what one has is a de facto regime of forced pregnancy. This is a goal the hypocritical  conservative douches have been fighting for over literal decades.   These are the same moralistic little miscreants who yap endlessly about the "sanctity of life" but won't lift a finger to help pass one damned bill to allow paid parental leave for a mom to care for her child, OR allow state-supported child care or health care.

But make no mistake, if the Court rules in Mississippi`s favor, that right to bodily autonomy  - which has existed for nearly 50 years under Roe - would be wiped out for millions almost immediately.  This is given that 22 states already  have laws on the books that would outlaw abortion all in most cases. And most of these so-called trigger laws are designed to go into effect if Roe is gutted.  Given this, Justice Sotomayor is correct that if that occurs while Roe will be gutted, so will this Supreme Court -which will lose its credibility and legitimacy in perpetuity.  It will have accreted a fecal stench of political activism that never existed before the "libertine" Trump appointed his pet pawns: Amy Coney Barrett and Brett Kavanaugh.

Irin Carmon, Senior Correspondent for New York magazine, hit the hail on the head Wednesday night on All In, when she remarked:

"So as you mentioned, the conservative legal movement made a deal with a buffoonish libertine on the theory that it would get them closer to imposing traditional gender roles by forcing pregnancy and birth."

The 'buffoonish libertine' is, of course, Donald Trump - who has about as much moral standing as Jeffrey Dahmer before he started eating his victims and stacking their heads in his fridge in Milwaukee. Hell, we already know he was getting spanked by Stormy Daniels even as his wife - Melania- had to deal with her newborn, Barron, e.g.

Report: Stormy Daniels Once Claimed She Spanked Trump With a Magazine (thedailybeast.com)

 So the fact this walking turd could appoint three "moral" justices  (Kavanaugh, Coney Barret, Gorsuch)  to the Court to overturn Roe is a howler of the first magnitude. (And yeah, I believe Ms. Daniels over a guy that had reeled off 30,000 + lies (including about the coronavirus) by the time he was forced out of office.  Hell, I also believe former M16 spook Christopher Steele that the orange maggot probably let the two  Russian whores urinate all over him after they sprayed the bed that Obama and Michelle had slept in at the Moscow Ritz-Carlton some years before.  No one who hadn't participated in such an incident would be saying in public: "Ya know, I'm really not into golden showers!"   

Then you shouldn't have had to say it!   

On a more serious note, a warning shot for the midterms ensues if  the Supreme Court abases itself and overturns a near 5 decade old constitutional right.  Yeah, it IS constitutional because it falls under unenumerated rights covered in the Ninth Amendment. (Read Garry Wills book: ‘A Necessary Evil: A History Of American Distrust of Government’,  the chapter, 'Constitutional Myths', p. 108)

Again, and for the nth time, this is not about "pro life" or "sanctity of life".  Not at all. The Repuke extremists are quite content to let poor infants starve to death by removing funding for Medicaid and the SNAP program to divert it to the Pentagon- as our Colo. Rep. Doug Lamborn wanted to do back in 2014.  Nor did these rats give two craps about spreading Covid to oldsters during the height of the pandemic a year ago.  (Recall TX Lt. Gov. Dan Patrick saying seniors ought to sacrifice their lives for the economy, e.g.

Texas Lt. Governor: Old People Should Volunteer to Die to Save the Economy | Vanity Fair

So spare me evangelical hypocrites' balderdash for not taking a word they say about being pro-life seriously.   Especially given they are following the lead of a confirmed libertine, serial sexual assaulter and deviant.  Let's clear away all the distraction and brain scrapple. Former Ethics professor Chery Mendelson nailed what is at the root of this pro -life B.S. in her book, 'The Good Life', e.g. p. 157:

The premoral mind confuses the disgusting with the wrong and retains an infantile fear of things sexual. Its rationality is overcome by emotion, fantasy, wish and projection. The belief that extracting a 10-week fetus from a woman's womb is murder rests to a large extent on the sense of disgust aroused by the thought of destruction of living tissue.

When fundamentalists insist on risking the life of the mother to deliver an anencephalic fetus they take this tendency to an extreme. People who think this way are unable to override disgust with rational appreciation of the objective characteristics of the fetus. The ability to do so is an indispensable trait of the moral mind.

Then adding this biological fact (p. 159):

Nature sloughs off early pregnancies at a high rate and we do not hold funerals for these embryos and early fetuses.  As many as 60 to 70 percent of fertilized eggs are lost overall, usually silently - without anyone ever knowing fertilization took place. Up to 15 percent of known pregnancies miscarry in the first trimester. Were we to take seriously the morbid pseudo-moralism of the fundamentalist Right, we would recognize these countless millions of miscarried embryos and fetuses as lost lives and be sunk in a vast and permanent sea of endless mourning for the unending deaths of innocents.

Ultimately this isn't about life and neither will any SC ruling that kills Roe. It is about exercising authoritarian power over women, basically fulfilling the old Nazi aspiration: keeping their women pregnant for the state - churning out future consumers and soldiers.

This ought to be a warning shot over the bough of all  sentient American women, energizing them to turn out by the tens of millions for the midterms next year.  It is particularly vile given it will affect mainly the poorest women - often minorities - in the backward red states.  They will then have to either go it alone or try to access an abortifacent (pill).  As for the "state's rights" claim - turning over the legal issue to states - that is also codswallop.  As Wills has pointed out (op. cit.) states have prerogatives, not rights.  Only flesh and blood people have rights.  As he also writes (p. 108):

The states have no natural rights. Their powers are artificial, not natural – they are things made by contract

 Understanding all this is essential in preventing the fascists from wrecking this country, which my own ancestors fought for in the American Revolution, e.g.

Brane Space: What Would My Revolutionary War Ancestors Think Of Our Nation's Present Predicament? (brane-space.blogspot.com)

Thus every effort must be made to prevent the Authoritarian fascist traitor snakes from seizing control of our government.  That also goes double for 2024, and especially to ensure the golden shower autocrat narcissist Trump can't sneak back in again!

See Also:

Women's Rights

The Disturbing Post-Roe World the Supreme Court Is Poised to Create

by John Stoehr | December 3, 2021 - 8:28am | permalink

— from Alternet

AND:

Republicans

Next Up On GOP’s Agenda: Stripping Women Of Political and Economic Power

by Thom Hartmann | December 3, 2021 - 8:05am | permalink

— from The Hartmann Report

And:

Supreme Court

There Is No Doubt Any More: The US Supreme Court Is Run by Partisan Hacks

by Robert Reich | December 4, 2021 - 7:12am | permalink

— from The Guardian

"To Breed Or Not To Breed?" The Answer Ought To Be Obvious By Now!

 

                           Crowd in San Francisco's Chinatown in September, 2012.

                               

"It is now the willingly childless woman who is the heroine of our planet. She is the one who now deserves all the kudos and praise, for helping to do what is necessary to spare humanity from the ravages of over-population" -   Isaac Asimov, from a talk at Queen's Park Theater, Barbados, Feb. 6, 1976

Despite the chronic overthinking peculiar to a number of human issues, questions, some answers ought to be obvious - so obvious that virtually no measurable decision time is needed.  One such question was raised in a header in  The Denver Post Sunday Perspective Section: To  Breed Or Not To Breed.  The question headed up an extensive piece on the decision of many young people today to forego having children. Not even one.  Extreme? No, not at all.  In a world steered off its sanity axis by pandemic isolation and chaos, political strife and climate catastrophe - not to mention critical resources in short supply - it is the most sensible choice most couples can make. 

Despite that, the author of the piece claims at one point that "there is still much debate over the idea that having fewer children is the best way to address the problem".  Basically pretending that from the instant of birth humans don't leave carbon footprints wherever they are - with the largest ones  in the most advanced nations.  This is given the much higher energy consumption and hence higher emissions.  The piece also quotes a "climate scientist", Kimberly Nichols, who claimed (in an interview with Vox in April): 

"It is true that more people will consume more resources and cause more greenhouse gas emissions. But that's not really the relevant time frame for actually stabilizing the climate, given that we have this decade to cut our emissions in half."   

However, I hate to break it to her but that ship has already sailed. The first pandemic year ended up one of the highest ever in emissions,  e.g.

Greenhouse gas levels hit a new high in 2020 : NPR

So was this past one. Every policy decision, every bill passed (or not) thus far and statistical indicator discloses that we are nowhere near seriously cutting emissions, especially in half.  That might happen if  a 50 % gas tax was imposed, but just how long does she think any government would last if it tried to do that?  And if she believes carbon trading and credits are the solution she is truly living in dreamland.

Minus serious emission cuts and instantly - not in ten years-  most climate researchers see much higher temperature thresholds and up to 5-6 C increase by 2100. So I don't know what planet she's living on but it's not Earth. For one thing she's totally ignored the existing climate carbon burden, best represented as a series for the contributions of CO2 for all preceding years stretching back a century (given the mean lifetime of a CO2 molecule in the atmosphere is 100 years), e.g.

CO2( 2021) =   x  ₁  + x  ₂ +  x  ₃ +   x  ₄ +.............+  x  _{1 00} 

Thus  the CO2 emissions effects for a given year are not just for that year but inclusive of the cumulative emissions for all the years preceding.  This means even if humans went 'cold turkey'  from fossil fuels and halted all carbon emissions today it wouldn't be enough to prevent us hurtling past the nonsensically low Paris - as well as COP26-  thresholds (i.e. to hold warming to 1.9 C by 2100).   Even more sobering, we know the CO2 concentrations in the atmosphere have been kept artificially low by (partial) absorption in the oceans, but that can't go on forever.   See e.g.

The Antarctic Is Signaling Big Climate Trouble. - The New York Times (nytimes.com)

The evidence now is that the oceans are reaching their limits as a carbon reservoir.  

 To fix ideas, and reality, we are now headed for CO2 concentrations in the vicinity of 600 ppm by the end of this century, which is runaway greenhouse territory.  Those like Ms. Nichols can try to soft soap it all they want but the math doesn't lie. Do the math! If the current rate of CO2 concentration is increasing at 2.5 ppm/ yr., then add 75 years of increases to the current mean concentration of 415 ppm.  In 75 years that  means an additional (2.5 ppm/ yr. x 75 yrs.) =  187.5 ppm, or a total CO2 concentration:  415 ppm  + 187.5 ppm =  602.5 ppm.

  Most climate scientists I have known, such as Prof. Gunther Weller (Geophysical Institute, Univ. of Alaska-Fairbanks) take 600 ppm as the crossover threshold to a runaway greenhouse world.  In other words we are looking at a new, catastrophic global equilibrium by 2100 - and the planet would have already been climate destabilized for over 70 years. 

 The hard fact is that humans, to have avoided this fate, ought to have begun seriously curbing all fossil fuel emissions from the time of the Rio Summit in 1992.  That curbing never transpired,  so nearly  30 years of excess CO2 emissions elapsed and left exhaust pipes and coal-fired smokestacks  spewing in the interim.  And we are supposed to believe now humans will magically change behaviors?  Get real! To quote climate blogger John Atcheson: 

"Most of the climate-related estimates you hear in the news and from the IPCC have built in assumptions that we humans will take necessary actions to mitigate the worst of the climate crisis. There’s no evidence that making such assumptions is a prudent thing to do. We’ve known about this unfolding tragedy for three decades now, yet we’ve been steadily increasing the amount of greenhouse gasses we release."

In other words, he recognizes - as I do - that human behavior isn't going to change any more in the short term (say 10 years or even 5) than the long term.  

In terms of why there is no 'lead time' to reduce population one can refer to the Global Footpoint network and its graph showing we have already outrun our sustainability on this finite planet, e.g.

The interpretation of the graph is straightforward.  By June, 2030, two full Earths will be needed to support the then human population. Already we are at 1.5 Earths, or 0.5 Earths beyond where we ought to be in terms of our sustainable numbers. 

Isaac Asimov himself believed the carrying capacity of Earth had to be 3 billion, no more. We are already past that by more than 4.5 billion. Again, the severe limiting of numbers ought to have been from 30+ years ago - not acted on just now!  

Each year the Global Footpoint Network raises awareness of global ecological overshoot using its 'Earth Overshoot Day' campaign.  

  Earth Overshoot Day is the day on the calendar when humanity has used up the resources that it takes the planet a whole year to regenerate.

 Beyond the impending climate catastrophe there are other urgent reasons to limit human numbers.  Among them is the fact - as pointed out by Michael Shermer (2015 book, 'The Moral Arc Of Science')  that too many people means too much strife and competition for scarce resources, and hence a deformation of humanity's moral arc.  Citing this work in her essay in Free Inquiry magazine, Karen Schragg observes: :

"As a science writer Shermer knows that the Earth is a limited place and that humans are at a trophic level that is meant to be inhabited by a very limited  number of individuals.  As our numbers continue to climb in a hockey stick-like curve, 

our resources decline and our density increases. That brings with it an increase in scarcity.  This is hardly a scenario in which our collective morality will be well-incubated."

Why not? Well, because as she further notes (ibid.): 

 "Morality - encompassing such values as equal treatment under just laws, equal job opportunity, equal access to healthy food, equal access to potable water is profoundly threatened by the far -reaching implications of overpopulation."  

Adding:

"Simply put, whenever demand exceeds supply there will be immoral scramble to get one's fair share."

We all beheld this at a micro-level last year when fights broke out in super market aisles over limited toilet paper rolls- when the first supply shocks hit after the pandemic began.  Now try to imagine major food supply shortages  and the mad scramble to "get one's share".  This is why Asimov - as well as Shermer and Ms. Schragg - could see that overpopulation is a roadblock to any kind of moral progress. To put it bluntly, in a scarcity environment incepted by too many mouths to water or feed, ethics and morality are the first to go.  The "moral arc" is destroyed or blunted severely, and it is "survival of the fittest" to use the phrase of the Social Darwinists.

This is why in many respects Asimov's quote - at the top - is spot on though it may sound harsh to the baby breeders (which the Denver Post piece noted are mainly conservatives and those lacking college educations).  But those breeders, which include the extremist "pro-lifers" -  who don't give a damn about life after it's born  - e.g.

Brane Space: Anti-Abortionists "Want To Show Women Another Way"? How About Paying For Child Care? (brane-space.blogspot.com)

Need to grasp that in an overpopulated world all lawful  options to limit higher density (and scarcity) need to be on the table. That includes abortion and birth control - and I don't mean the Catholics' rhythm method.   At least one young woman (Jenna Ross)  quoted in the Post piece gets it.  In her words;  

"Harnessing the love I have for my unborn, hypothetical kid, comforts me in sparing them an inhospitable future.  In this way my choice (not to have children) is an act of love."

Many of her peers feel the same way: that it is a greater act of love to spare any potential progeny the horrors that await - in a world awash in political extremism, hate, economic imbalance and climate catastrophe (including huge migrations to escape these).  The effective choice to never have a child, and further, engage in activism to educate others to do likewise.  Why the urgency?  As Prof. Schragg notes, if the population of the U.S. and the world keeps going up, "any existing moral arc will continue to go down or even crash"
 - because humans won't behave better in a world of scarcity.  

In other words, too many humans inhabiting a limited resource planet "is a Petri dish for fostering immorality and disorder."  We see that already in everything from the sex trafficking trade to the rise of autocratic racist nationalism (see link below), to a massive global drug trade addicting millions, to the rampant homelessness in major cities - not just in the U.S. but throughout the world. Why would any sane person want to bring a kid into this world? Perhaps better, why would any sane person want to inflict more pollution, congestion, chaos and terror on this world?

Prof. Schragg's last remark is perhaps her most trenchant:

"Indeed, we overpopulation activists are the ones holding on to the reins of morality and justice...Unless we start working on this critically important issue as a moral imperative, morality itself will be rendered irrelevant, flattened by the thundering feet of billions of desperate people."

Time to wake up and take note.

See Also:

Brane Space: Meet Another Overpopulation Crackpot...Errr Advocate (Matthew Yglesias) Who Insists The U.S. Can Hold 1 Billion People (brane-space.blogspot.com)

And:

• Earth and its Carrying Capacity

And:

Conservatives and the Right

Revealed: The Racist Plot To Tear America Apart

by Thom Hartmann | December 1, 2021 - 8:42am | permalink

— from The Hartmann Report