Home » skeptic

Category Archives: skeptic


Science and Discovery channels no longer teaching science

At one time, the development of the Science Channel, the Discovery channel, and Animal Planet,  was a major force for good in public education.

However, in the last decade the people running these networks have made very clear that they do not value education or scientific responsibility whatsoever. Both of these networks are now focused solely on making money, often by deliberately programming pseudoscience, crank theories, and even outright hoaxes, such as

“Megalodon: The Monster Shark Lives” hoax

“Mermaids: The Body Found” hoax

(This is a placeholder for a future article.)

Doctor Evil dimisses History Channel Discovery MTV and FOX - Copy

A painfully funny analysis of the situation from the popular webcomic, SMBC:

SMBC Science Channel pseudoscience

By Zach Weinersmith, from SMBC, Aug 16, 2014


Learning Objectives

A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012)
Implementation: Curriculum, Instruction, Teacher Development, and Assessment
“Through discussion and reflection, students can come to realize that scientific inquiry embodies a set of values. These values include respect for the importance of logical thinking, precision, open-mindedness, objectivity, skepticism, and a requirement for transparent research procedures and honest reporting of findings.”



Global warming isn’t natural, and here’s how we know

This is a copy of an article for our students from thelogicofscience.com

The cornerstone argument of climate change deniers is that our current warming is just a natural cycle, and this claim is usually accompanied by the statement, “the planet has warmed naturally before.” This line of reasoning is, however, seriously flawed both logically and factually. Therefore, I want to examine both the logic and the evidence to explain why this argument is faulty and why we are actually quite certain that we are the cause of our planet’s current warming.

The fact that natural climate change occurred in the past does not mean that the current warming is natural.

I cannot overstate the importance of this point. Many people say, “but the planet has warmed naturally before” as if that automatically means that our current warming is natural, but nothing could be further from the truth. In technical terms, this argument commits a logical fallacy known as non sequitur (this is the fallacy that occurs whenever the conclusion of a deductive argument does not follow necessarily from the premises). The fact that natural warming has occurred before only tells us that it is possible for natural warming to occur. It does not indicate that the current warming is natural, especially given the evidence that it is anthropogenic (man-made).

To put this another way, when you claim that virtually all of the world’s climatologists are wrong and the earth is actually warming naturally, you have just placed the burden of proof on you to provide evidence for that claim. In other words, simply citing previous warming events does not prove that the current warming is natural. You have to actually provide evidence for a natural cause of the current warming, but (as I’ll explain shortly) no such mechanism exists.

Natural causes of climate change

Now, let’s actually take a look at the natural causes of climate change to see if any of them can account for our current warming trend (spoiler alert, they can’t).


The sun is an obvious suspect for the cause of climate change. The sun is clearly an important player in our planet’s climate, and it has been responsible for some warming episodes in the past. So if, for some reason, it was burning hotter now than in the past, that would certainly cause our climate to warm. There is, however, one big problem: it’s not substantially hotter now than it was in the recent past. Multiple studies have looked at whether or not the output from the sun has increased and whether or not the sun is responsible for our current warming, and the answer is a resounding “no” (Meehl, et al. 2004Wild et al. 2007Lockwood and Frohlich 20072008Lean and Rind 2008Imbers et al. 2014).

It likely caused some warming in the first half the 20th century, but since then, the output from the sun does not match the rise in temperatures (in fact it has decreased slightly; Lockwood and Frohlich 20072008). Indeed, Foster and Rahmstorf (2011) found that after correcting for solar output, volcanoes, and El Niños, the warming trend was even more clear, which is the exact opposite of what we would expect if the sun was driving climate change (i.e., if the sun was the cause, then removing the effect of the sun should have produced a flat line, not a strong increase).

Finally, the most compelling evidence against the sun hypothesis and for anthropogenic warming is (in my opinion) the satellite data. Since the 70s, we have been using satellites to measure the energy leaving the earth (specifically, the wavelengths of energy that are trapped by CO2).

Thus, if global warming is actually caused by greenhouse gasses trapping additional heat, we should see a fairly constant amount of energy entering the earth, but less energy leaving it. In contrast, if the sun is driving climate change, we should see that both the energy entering and leaving the earth have increased.

Do you want to guess which prediction came true? That’s right, there has been very little change in the energy from the sun, but there has been a significant decrease in the amount of energy leaving the earth (Harries et al. 2001Griggs and Harries. 2007). That is about as close to “proof” as you can get in science, and if you are going to continue to insist that climate change is natural, then I have one simple question for you: where is the energy going? We know that the earth is trapping more heat now than it did in the past. So if it isn’t greenhouse gasses that are trapping the heat, then what is it?

Milankovitch cycles

Other important drivers of the earth’s climate are long-term cycles called Milankovitch cycles, which involve shifts in the earth’s orbit, tilt, and axis (or eccentricity, precession, and obliquity, if you prefer). In fact, these appear to be one of the biggest initial causes of prominent natural climate changes (like the ice ages). So it is understandable that people would suspect that they are driving the current climate change, but there are several reasons why we know that isn’t the case.

First, Milankovitch cycles are very slow, long-term cycles. Depending which of the three cycles we are talking about, they take tens of thousands of years or even 100 thousand years to complete. So changes from them occur very slowly. In contrast, our current change is very rapid (happening over a few decades as opposed to a few millennia). So the rate of our current change is a clear indication that it is not being caused by Milankovitch cycles.

Second, you need to understand how Milankovitch cycles affect the temperature. The eccentricity cycle could, in concept, directly cause global warming by changing the earth’s position relative to the sun; however, that would cause the climate to warm or cool by affecting how much energy from the sun hits the earth. In other words, we are back to the argument that climate change is caused by increased energy from the sun, which we know isn’t happening (see the section above).

The other cycles (precession and obliquity), affect the part of the earth that is warmed and the season during which the warming takes place, rather than affecting the total amount of energy entering the earth. Thus, they initially just cause regional warming. However, that regional warming leads to global warming by altering the oceans’ currents and warming the oceans, which results in the oceans releasing stored CO2 (Martin et al. 2005Toggweiler et al. 2006Schmittner and Galbraith 2008Skinner et al. 2010).

That CO2 is actually the major driver of past climate changes (Shakun et al. 2012). In other words, when we study past climate changes, what we find is that CO2 levels are a critically important factor, and, as I’ll explain later, we know that the current increase in CO2 is from us. Thus, when you understand the natural cycles, they actually support anthropogenic global warming rather than refuting it.


At this point, people generally resort to claiming that volcanoes are actually the thing that is emitting the greenhouse gasses. That argument sounds appealing, but in reality, volcanoes usually emit less than 1% of the CO2 that we emit each year (Gerlach 2011). Also, several studies have directly examined volcanic emissions to see if they can explain our current warming, and they can’t (Meehl, et al. 2004Imbers et al. 2014).

Carbon dioxide (CO2)

A final major driver of climate change is, in fact, CO2. Let’s get a couple of things straight right at the start. First, we know that CO2 traps heat and we know that increasing the amount of CO2 in an environment will result in the temperature increasing (you can find a nice list of papers on the heat trapping abilities of CO2 here).

Additionally, everyone (even climate “skeptics”) agree that CO2 plays a vital role in maintaining the earth’s temperature. From those facts, it is intuitively obvious that increasing the CO2 in the atmosphere will result in the temperature increasing. Further, CO2 appears to be responsible a very large portion of the warming during past climate changes (Lorius et al. 1990Shakun et al. 2012)Note: For past climate changes, the CO2 does lag behind the temperature initially, but as I explained above, the initial warming triggers an increase in CO2, and the CO2drives the majority of the climate change

At this point, you may be thinking, “fine, it’s CO2, but the CO2 isn’t from us, nature produces way more than we do.” It is true that nature emits more CO2 than us, but prior to the industrial revolution, nature was in balance, with the same amount of CO2 being removed as was emitted. Thus, there was no net gain. We altered that equation by emitting additional CO2.

Further, the increase that we have caused is no little thing. We have nearly doubled the CO2 compared to pre-industrial levels, and the current concentration of CO2 in the atmosphere is higher than it has been at any point in the past 800,000 years. So, yes, we only emit a small fraction of the total CO2 each year, but we are emitting more CO2 than nature can remove, and a little bit each year adds up to a lot over several decades.

Additionally, we know that the current massive increase in CO2 is from us because of the C13 levels. Carbon has two stable isotopes (C12 and C13), but C13 is heavier than C12. Thus, when plants take carbon from the air and use it to make carbohydrates, they take a disproportionate amount of C12. As a result, the C13/C12 ratios in plants, animals (which get carbon from eating plants), and fossil fuels (which are formed form plants and animals) have more C12 than the C13/C12 ratios in that atmosphere.

Ratio C13 to C12 in coral

Therefore, if burning fossil fuels is responsible for the current increase in CO2, we should see that ratio of C13/C12 in the atmosphere shift to be closer to that of fossil fuels (i.e., contain more C12), and, guess what, that is exactly what we see (Bohm et al. 2002Ghosh and Brand 2003;Wei et al. 2009). This is unequivocal evidence that we are the cause of the current increase in CO2.

Finally, we can construct all of this information into a deductive logical argument (as illustrated on the left). If COtraps heat, and we have increased the CO2 in the atmosphere, then more heat will be trapped. To illustrate how truly inescapable that conclusion is, here is an analogous argument:

1). Insulation traps heat
2). You doubled the insulation of your house
3). Therefore, your house will trap more heat

You cannot accept one of those arguments and reject the other (doing so is logically inconsistent).

Note: Yes, I know that the situation is much more complex than simply CO2 trapping heat, and there are various feedback mechanisms at play, but that does not negate the core argument.

Putting the pieces together

So far, I have been talking about all of the drivers of climate change independently, which is clearly an oversimplification, because, in all likelihood, several mechanisms are all acting together. Therefore, the best way to test whether or not the current warming is natural is actually to construct statistical models that include both natural and man-made factors. We can then use those models to see which factors are causing climate change.

hansen-et-al-2005 Global Climate Forcings (warming)

Hansen et al. 2005. Earth’s energy imbalance: confirmation and implications. Science, 308:1431–1435.

We have constructed multiple of these models, and they consistently show that natural factors alone cannot explain the current warming (Stott et al. 2001Meehl et al. 2004Allen et al. 2006Lean and Rind 2008Imbers et al. 2014).

In other words, including human greenhouse gas emissions in the models is the only way to get the models to match the observed warming. This is extremely clear evidence that the current warming is not entirely natural. To be clear, natural factors do play a role and are contributing, but human factors are extremely important, and most of the models show that they account for the majority of the warming.

Correlation vs. causation

It is usually about now that opponents of climate change start to argue that scientists are actually committing a correlation fallacy, and simply showing a correlation between temperature and the CO2 that we produce does not mean that the CO2 is causing the temperature increase. There are, however, several problems with that argument.

First, correlation can indicate causation under certain circumstances. Namely, situations where you have controlled all confounding factors. In other words, if you can show that Y is the only thing that is changing significantly with X, then you can reach a causal conclusion (even placebo controlled drug trials are really just showing correlations between taking the drug and recovery, but because they used the control, they can use that correlation to reach a causal conclusion).

In the case of climate change, of course, we have examined the confounding factors. As I explained in the previous section, we have constructed statistical models with the various drivers of climate change, and anthropogenic greenhouse gasses are necessary to account for the current warming. In other words, we have controlled for the other causes of climate change, therefore we can reach a causal conclusion.

Second, and perhaps more importantly, there is nothing wrong with using correlation to show a particular instance of causation if a causal relationship between X and Y has already been established. Let me give an example. The figure to the right shows the smoking rates and lung/bronchial cancer rates in the US. There is an obvious negative correlation between the two (P < 0.0001), and I don’t think that anyone is going to disagree with the notion that the decrease in smoking is largely responsible for the decrease in lung cancers.

Indeed, there is nothing wrong with reaching that conclusion, and it does not commit a correlation fallacy. This is the case because a causal relationship between smoking and cancer has already been established. In other words, we know that smoking causes cancer because of other studies. Therefore, when you see that the two are correlated over time, there is nothing wrong with inferring that smoking is driving the cancer rates. Even so, we know from laboratory tests and past climate data that CO2 traps heat and increasing it results in more heat being trapped. In other words, a causal relationship between CO2 and temperature has already been established. Therefore, there is nothing fallacious about looking at a correlation between COand temperature over time and concluding that the CO2 is causing the temperature change.

Ad hoc fallacies and the burden of proof

At this point, I often find that people are prone to proposing that some unknown mechanism exists that scientists haven’t found yet. This is, however, a logical fallacy known as ad hoc. You can’t just make up an unknown mechanism whenever it suits you. If that was valid, then you could always reject any scientific result that you wanted, because it is always possible to propose some unknown mechanism.

Similarly, you can’t use the fact that scientists have been wrong before as evidence, nor can you argue that, “there are still things that we don’t understand about the climate, so I don’t have to accept anthropogenic climate change” (that’s an argument from ignorance fallacy). Yes, there are things that we don’t understand, but we understand enough to be very confident that we are causing climate change, and, once again, you can’t just assume that all of our current research is wrong.

The key problem here is the burden of proof. By claiming that there is some other natural mechanism out there, you have just placed the burden of proof squarely on your shoulders. In other words, you must provide actual evidence of such a mechanism. If you cannot do that, then your argument is logically invalid and must be rejected.


Let’s review, shall we?

  • We know that it’s not the sun
  • We know that it’s not Milankovitch cycles
  • We know that it’s not volcanoes
  • We know that even when combined, natural causes cannot explain the current warming
  • We know that CO2 traps heat
  • We know that increasing CO2 causes more heat to be trapped
  • We know that CO2 was largely responsible for past climate changes
  • We know that we have roughly doubled the CO2 in the atmosphere
  • We know that the earth is trapping more heat now than it used to
  • We know that including anthropogenic greenhouse gasses in the models is the only way to explain the current warming trend

When you look at that list of things that we have tested, the conclusion that we are causing the planet to warm is utterly inescapable. For some baffling reason, people often act as if scientists have never bothered to look for natural causes of climate change, but the exact opposite is true. We have carefully studied past climate changes and looked at the natural causes of climate changes, but none of them can explain the current warming.

The only way to account for our current warming is to include our greenhouse gasses in the models. This is extremely clear evidence that we are causing the climate to warm, and if you want to continue to insist that the current warming is natural, then you must provide actual evidence for the existence of a mechanism that scientists have missed, and you must provide evidence that it is a better explanation for the current warming than CO2. Additionally, you are still going to have to refute the deductive argument that I presented earlier (i.e., show that a premise is false or that I committed a logical fallacy), because finding a previously unknown mechanism of climate change would not discredit the importance of CO2 or the fact we have roughly doubled it. Finally, you also need to explain why the earth is trapping more heat than it used to. If you can do all of that, then we’ll talk, but if you can’t, then you must accept the conclusion that we are causing the planet to warm.

Related posts

 Literature cited

  • Allen et al. 2006. Quantifying anthropogenic influence on recent near-surface temperature change. Surveys in Geophysics 27:491–544.
  • Bohm et al. 2002. Evidence for preindustrial variations in the marine surface water carbonate system from coralline sponges. Geochemistry, Geophysics, Geosystems 3:1–13.
  • Foster and Rahmstorf. 2011. Global temperature evolution 1979–2010. Environmental Research Letters 7:011002.
  • Gerlach 2011. Volcanic versus anthropogenic carbon dioxide. EOS 92:201–202.
  • Ghosh and Brand. 2003. Stable isotope ratio mass spectrometry in global climate change research. International Journal of Mass Spectrometry 228:1–33.
  • Griggs and Harries. 2007. Comparison of spectrally resolved outgoing longwave radiation over the tropical Pacific between 1970 and 2003 Using IRIS, IMG, and AIRS. Journal of Climate 20:3982-4001.
  • Hansen et al. 2005. Earth’s energy imbalance: confirmation and implications. 308:1431–1435.
  • Harries et al. 2001. Increases in greenhouse forcing inferred from the outgoing longwave radiation spectra of the Earth in 1970 and 1997. Nature 410:355–357.
  • Imbers et al. 2014. Sensitivity of climate change detection and attribution to the characterization of internal climate variability. Journal of Climate 27:3477–3491.
  • Lean and Rind. 2008. How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006. Geophysical Research Letters 35:L18701.
  • Lockwood and Frohlich. 2007. Recently oppositely directed trends in solar climate forcings and the global mean surface air temperature. Proceedings of the National Academy of Sciences 463:2447–2460.
  • Lockwood and Frohlich. 2008. Recently oppositely directed trends in solar climate forcings and the global mean surface air temperature. II. Different reconstructions of the total solar irradiance variation and dependence on response time scale. Proceedings of the National Academy of Sciences 464:1367–1385.
  • Lorius et al. 1990. The ice-core record: climate sensitivity and future greenhouse warming. Nature 139–145.
  • Martin et al. 2005. Role of deep sea temperature in the carbon cycle during the last glacial. Paleoceanography 20:PA2015.
  • Meehl, et al. 2004. Combinations of natural and anthropogenic forcings in the twentieth-century climate. Journal of Climate 17:3721–3727.
  • Schmittner and Galbraith 2008. Glacial greenhouse-gas fluctuations controlled by ocean circulation changes. Nature 456:373–376.
  • Shakun et al. 2012. Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation. Nature 484:49–54.
  • Skinner et al. 2010. Ventilation of the deep Southern Ocean and deglacial CO2 rise. Science 328:1147-1151.
  • Stott et al. 2001. Attribution of twentieth century temperature change to natural and anthropogenic causes. Climate Dynamics17:1–21.
  • Toggweiler et al. 2006. Mid-latitude westerlies, atmospheric CO2, and climate change during the ice ages. Paleoceanography 21:PA2005.
  • Wei et al. 2009. Evidence for ocean acidification in the Great Barrier Reef of Australia. Geochimica et Cosmochimica Acta 73:2332–2346.
  • Wild et al. 2007. Impact of global dimming and brightening on global warming. Geophysical Research Letters


This website is educational. Materials within it are being used in accord with the Fair Use doctrine, as defined by United States law.
§107. Limitations on Exclusive Rights: Fair Use. Notwithstanding the provisions of section 106, the fair use of a copyrighted work, including such use by reproduction in copies or phone records or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use, the factors to be considered shall include: the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes; the nature of the copyrighted work; the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and the effect of the use upon the potential market for or value of the copyrighted work. (added pub. l 94-553, Title I, 101, Oct 19, 1976, 90 Stat 2546)

Speculative history: Possibility of prehuman civilization

Could an intelligent species have lived on Earth before humanity? Could it even have developed an industrial civilization? If one had existed on Earth – many millions of years prior to our own era – what traces would it have left and would they be detectable today?

The Stairway of Time Geologic eras

Technosignatures of pre-human civilizations here on Earth


Did Antarctica remain entirely unvisited by humans until the early 19th century? History.Stackexchange.Com

Could an Industrial Prehuman Civilization Have Existed on Earth before Ours? Scientific American

Was There a Civilization On Earth Before Humans? A look at the available evidence. The Atlantic.

Technosignatures of ET life elsewhere in our solar system

THE BIG QUESTIONS Did Intelligent Space Aliens Once Live in Our Solar System? NBC News

The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record? Gavin A. Schmidt, Adam Frank

If an industrial civilization had existed on Earth many millions of years prior to our own era, what traces would it have left and would they be detectable today? We summarize the likely geological fingerprint of the Anthropocene, and demonstrate that while clear, it will not differ greatly in many respects from other known events in the geological record. We then propose tests that could plausibly distinguish an industrial cause from an otherwise naturally occurring climate event.

Prior Indigenous Technological Species, Jason T. Wright

One of the primary open questions of astrobiology is whether there is extant or extinct life elsewhere the Solar System. Implicit in much of this work is that we are looking for microbial or, at best, unintelligent life, even though technological artifacts might be much easier to find. SETI work on searches for alien artifacts in the Solar System typically presumes that such artifacts would be of extrasolar origin, even though life is known to have existed in the Solar System, on Earth, for eons.

But if a prior technological, perhaps spacefaring, species ever arose in the Solar System, it might have produced artifacts or other technosignatures that have survived to present day, meaning Solar System artifact SETI provides a potential path to resolving astrobiology’s question.

Here, I discuss the origins and possible locations for technosignatures of such a prior indigenous technological species, which might have arisen on ancient Earth or another body, such as a pre-greenhouse Venus or a wet Mars. In the case of Venus, the arrival of its global greenhouse and potential resurfacing might have erased all evidence of its existence on the Venusian surface. In the case of Earth, erosion and, ultimately, plate tectonics may have erased most such evidence if the species lived Gyr ago. Remaining indigenous technosignatures might be expected to be extremely old, limiting the places they might still be found to beneath the surfaces of Mars and the Moon, or in the outer Solar System.

The science wars: postmodernism as a threat against truth and reason

For now, this intro has been adapted from Wikipedia.

More references, updates, and original work will be added over the next year.

The science wars is a series of intellectual exchanges, between scientific realists and postmodernist critics, about the nature of scientific theory and intellectual inquiry. They took place principally in the United States in the 1990s in the academic and mainstream press. Scientific realists (such as Norman LevittPaul R. GrossJean Bricmont and Alan Sokal) argued that scientific knowledge is real, and accused the postmodernists of having effectively rejected scientific objectivity, the scientific methodEmpiricism, and scientific knowledge.

Postmodernists interpreted Thomas Kuhn‘s ideas about scientific paradigms to mean that scientific theories are social constructs, and philosophers like Paul Feyerabend argued that other, non-realist forms of knowledge production were better suited to serve people’s personal and spiritual needs.

Though much of the theory associated with ‘postmodernism’ (see poststructuralism) did not make any interventions into the natural sciences, the scientific realists took aim at its general influence. The scientific realists argued that large swaths of scholarship, amounting to a rejection of objectivity and realism, had been influenced by major 20th Century poststructuralist philosophers (such as Jacques DerridaGilles DeleuzeJean-François Lyotard and others), whose work they declare to be incomprehensible or meaningless. They implicate a broad range of fields in this trend, including cultural studiescultural anthropologyfeminist studiescomparative literaturemedia studies, and science and technology studies. They accuse those postmodernist critics who did actually discuss science of having a limited understanding of it.


Fake News Comes to Academia How three scholars gulled academic journals to publish hoax papers on ‘grievance studies.’

Related articles

Why does science matter?

Relativism Truth and Reality

Science denialism

Suggested reading

Higher Superstition: The Academic Left and Its Quarrels with Science, Paul R. Gross and Norman Levitt, 1994

Fashionable Nonsense: Postmodern Intellectuals’ Abuse of Science, Alan Sokal and Jean Bricmont, 1999

In 1996, Alan Sokal published an essay in the hip intellectual magazine Social Text parodying the scientific but impenetrable lingo of contemporary theorists. Here, Sokal teams up with Jean Bricmont to expose the abuse of scientific concepts in the writings of today’s most fashionable postmodern thinkers. From Jacques Lacan and Julia Kristeva to Luce Irigaray and Jean Baudrillard, the authors document the errors made by some postmodernists using science to bolster their arguments and theories. Witty and closely reasoned, Fashionable Nonsense dispels the notion that scientific theories are mere “narratives” or social constructions, and explored the abilities and the limits of science to describe the conditions of existence.


Book reviews

Richard Dawkins’ review of Intellectual Impostures by Alan Sokal and Jean Bricmont.


Detecting Planet X

Social media and internet searches show a plethora of articles on “Planet X”, a vaguely worded term for some supposedly mysterious planet of apparently great importance.There are also conspiracy theories about the government or NASA supposedly hiding “Planet X” for some nefarious reason.

In science, we generally never use this phrase. When a scientist does say “Planet X” he/she merely means “any undetected planet in our solar system”.

Planets beyond Pluto

Scientists never quite said “Pluto isn’t a planet anymore.” That’s a misleading statement which muddies the waters. Here’s what really is going on.

Old view

Solar system is made of one star, several planets, comets, meteors, and gas & dust particles.

More recent, yet now outdated view

Solar system is made of one star, several planets, comets, meteors, and gas & dust particles.
The planets are either terrestrial (“Earth like”) or gas giants.

New view

Solar system is made of one star, several planets, comets, meteors, and gas & dust particles.
The planets are now in categories:
terrestrial, gas giants, ice giants, or dwarf planets.

So all that really happened is that Pluto was moved from one general group, into a more specific group (dwarf planets.)

Here are some of the planets beyond Pluto, in our own solar system, already discovered. For size comparison they are shown as if they are near each other.

Ceres, Charon, Eris, Dysnomia, Pluto, Haumea, Makemake,


This picture shows the sizes of the original three dwarf planets (Eris, Ceres, and Pluto) as compared to Earth. It also shows Pluto’s large moon Charon (and its two small moons Nix and Hydra) and Eris’s moon Dysnomia to scale. The image also shows Earth’s Moon (Luna) and the planet Mars for comparison. None of the distances between objects in this image are to scale. Images courtesy of NASA, ESA, JPL, and A. Feild (STScI).

also see

Dwarf Planets Pluto Makemake Haumea Eris

Credit: Konkoly Observatory/András Pál, Hungarian Astronomical Association/Iván Éder, NASA/JHUAPL/SwRI

Why is it difficult to find new worlds?

Out there, space gets dark alarmingly fast. Planets twice as far away look 16 times dimmer: The intensity of the sunlight weakens by a factor of four going out and then four times again coming back.

At an orbital distance of 600 astronomical units (an AU is the distance between Earth and the sun), Planet Nine would be 160,000 times dimmer than Neptune is at 30 AU.

At 1,000 AU, it would appear more than 1 million times weaker.

“There’s really a brick wall, basically, at 1,000 AU,” said Kevin Luhman, an astronomer at Pennsylvania State University.” That’s partly why laying eyes on the planet has proven so tough.

Why Can’t We Find Planet Nine? Quanta Magazine

Possible large planet orbiting beyond Pluto


Planet X detection new planets

Related articles

Evidence that we’re seeing effects of a 10th planet

Looking for Planet Nine, Astronomers Gaze into the Abyss

How Astronomers Are Going to Find Planet Nine

XKCD Possible Undiscovered Planets Comic: Funny yet scientifically accurate

Swarm of asteroids instead of another plant

No Need for Planet Nine? Small Objects’ Gravity Could Explain Weird Orbits

A New Study Could Explain Away Some Evidence for Planet Nine

Goodbye, Planet Nine! New and better data disfavors the existence of a giant world beyond Neptune.

General resources



Science Bulletins: The Hunt for Planet X. American Museum for Natural History.

Astronomers find evidence of a ninth planet in the solar system – Caltech, Robert Hunt, Reuters



Learning Standards

Next Generation Science Standards
Connections to Nature of Science: Science Models, Laws, Mechanisms, and Theories Explain Natural Phenomena.
A scientific theory is a substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment, and the science community validates each theory before it is accepted. If new evidence is discovered that the theory does not accommodate, then the theory is generally modified in light of this new evidence. (HS-ESS1-2),(HS-ESS1-6)

A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012)

Some objects in the solar system can be seen with the naked eye. Planets in the night sky change positions and are not always visible from Earth as they orbit the sun. Stars appear in patterns called constellations, which can be used for navigation and appear to move together across the sky because of Earth’s rotation…. The solar system consists of the sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the sun by its gravitational pull on them. This model of the solar system can explain tides, eclipses of the sun and the moon, and the motion of the planets in the sky relative to the stars.

Why does science matter?

The following has been excerpted from “Science matters because it works”, by The Logic of Science website, 4/23/17.


Why should you support science? Because it works! It’s crazy to me that I even have to say that, but this is where we are as a society. Various forms and degrees of science-denial are running rampant; attacks on science are being disseminated from the highest levels. Indeed, it has gotten to the point that scientists feel compelled to take to the streets to march for science and remind everyone of the fundamental fact that science works, and is unparalleled in its ability to inform us about reality and improve our world.

Just look around you. Everything that you see was brought to you by science.

  • Batteries that power your electronic devices are a result of scientific advances in chemistry, as are the plastics that make up seemingly everything in our modern world.
  • Planes that let you travel the world in mere hours were produced by our understanding of physics.
  • Medicines that have doubled the human life expectancy came from biology, physiology, etc. Diseases that once claimed millions of lives each year are now almost unheard of thanks to advances in immunology, virology, etc.
  • Even on topics where people frequently criticize science, like cancer, there have been great advances. Our ability to fight many cancers is improving, and, at the risk of appealing to anecdotes, I personally have family members who recovered from cancers that were untreatable just a few decades ago.
  • Our entire modern world only exists because science works. Medicine, computers, cell phones, satellites, plastic, etc. all exist because science works.

Nevertheless, here we are, in a reality where some politicians [refer to global warming as a hoax], where countless celebrities go around promoting all manner of unscientific woo… a world where even a notion as ridiculous as believing that the earth is flat can enjoy a resurgence of popularity.

… At this point, inevitably lots of people are going to get offended and respond with something to the effect of, “I’m not anti-science, but…I disagree with the way that science is being done, I think that massive corporations are buying off scientists, I have anecdotes that don’t match the science, scientists have been wrong in the past, scientists are close-minded, etc.,”

Those aren’t valid responses [because] science is a method, and it either works, or it doesn’t. You can’t pick and choose when you want to accept it and when you want to reject it.

This brings me to two important points. First, the people who make, “I am not anti-science but…” arguments are nearly always people with no experience in science. They are people who are projecting their preconceptions onto a method that they know nothing about.

When people say that “scientists are just going along with the dogma of their fields” they are revealing how little they actually understand about how science operates… No one gets funding for blindly going along with something that everyone already knows. You only get funding for pushing boundaries and chasing novel ideas. Indeed, every great scientist was great precisely because they discredited the views of their day.

Arguments arise when science conflicts with someone’s personal beliefs.

For example, some people are happy enough to have science make more efficient batteries, predict tomorrow’s weather, cure their illnesses, etc., but the instant that it says that burning fossil fuels is bad, they turn on science and invent fanciful conspiracies, appeal to a minority of fringe researchers, cite discredited papers, etc.

Conversely, droves of people stand behind the science of climate change 100%, but when the same scientific method says that GMOs are safe, suddenly we are back in conspiracy land.

That’s not how this works… When thousands of papers conducted by countless scientists from all over the planet arrive at the same conclusion, you don’t get to reject that conclusion just because you don’t like it.

A final group of dissidents take things even further and directly question the validity of science itself. They claim that decades of research on vaccines is discredited by the simplistic notion that “mothers know best.” They ignore the scientific impossibility of homeopathy in favor of personal anecdotes. They insist that the fact that something has been used for thousands of years is more important than the fact that numerous studies have shown that it’s nothing but a placebo, and they embrace all manner of nonsense about energy fields, crystals, etc.

All of that is discredited by the obvious fact that science works: We had anecdotes and appeals to antiquity (or popularity, or maternal instincts) for thousands of years, but they got us nowhere. Science is the thing that allowed us to tell which of those anecdotes were based on causal relationships and which ones were based on spurious correlations,

Science is the thing that allowed us to know which natural remedies actually worked (e.g. aspirin) and which ones were hogwash. Further, science is the thing that let us improve on nature and synthesize purer and more concentrated forms of natural chemicals, as well as making medicines that aren’t even found in nature.  For example, if you have diabetes and take insulin, you get that insulin not from nature, but rather from a GMO that was produced by science. Similarly, if you need surgery, you are going to want to be knocked out using the best anesthetic that science has to offer, rather than eating some herbs.

The history of tobacco actually illustrates this well. Tobacco was used medicinally for centuries by Native Americans, it was supported by countless anecdotes, it was 100% natural, mothers thought it was best for their children, etc. Today, however, we know that not only does it fail to cure illnesses, but it is extremely carcinogenic.

Why do we know that? Because of science! Careful and systematic studies revealed that all of those anecdotes, maternal instincts, etc. were wrong.

Now, someone may write a comment about the time that some scientists were paid off by Big Tobacco to support smoking, or the doctors who thought smoking was safe, but those are distortions: Sure, there was a transition period when evidence was still being accumulated and scientists and doctors were not convinced. Nothing in science changes overnight. But that period didn’t last because science prevailed.

Similarly, there were a minority of scientists that were paid off, and tobacco companies put tons of money and effort into creating the illusion that there was no scientific evidence that smoking was dangerous, but that was a smoke screen created by the tobacco companies, and their efforts ultimately failed.

This is the same thing that is happening today on many issues.

  • The science on climate change, for example, is extremely clear. It is supported by thousands of studies and is agreed upon by virtually all climatologists. Nevertheless, fossil fuel companies have created an illusion of controversy. They have a handful of scientists that they publicize strongly, and they pour tons of money into promoting the notion that the science isn’t settled.
  • The anti-vaccine movement is the same thing. The science for vaccines is solid, but they have a handful of “experts” and pump so much money into it that it appears that there is a conflict, even though this is a settled issue among medical experts.
  • Similarly, big organic companies pump untold millions of dollars into opposing GMOs and making it appear that the science isn’t settled, even though nearly 2,000 studies have conclusively shown that GMOs are  safe for humans and no worse (or even better) for the environment than traditional crops.

If you want life-saving medical breakthroughs to continue, then you need to support funding for agencies like the NIH. If you want to benefit from an enhanced understanding of the universe, then you need to support funding for things like the NSF. If you understand how many technological wonders have come from the space program and want more technological advances, then you need to support funding for NASA. I could go on, but hopefully you get my point. The way that I see it, our society is at something of a crossroads, and either we will fight for science, support it, and move forward because of it, or we will reject it, downplay it, and ignore it, in which case, at best, we will stagnate and halt our progress, and at worst, we will move backwards (e.g., increased disease outbreaks as vaccination rates fall). The choice between those two options seems pretty obvious to me.

This website is educational. Materials within it are being used in accord with the Fair Use doctrine, as defined by United States law.

§107. Limitations on Exclusive Rights: Fair Use. Notwithstanding the provisions of section 106, the fair use of a copyrighted work, including such use by reproduction in copies or phone records or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use, the factors to be considered shall include: the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes; the nature of the copyrighted work; the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and the effect of the use upon the potential market for or value of the copyrighted work. (added pub. l 94-553, Title I, 101, Oct 19, 1976, 90 Stat 2546)

Action potentials

Andy Maldonado, on Quora, writes

An action potential is the way by which neurons communicate.

Neurons are negatively charged on the inside and positively charged on the outside.

This is due to the different concentrations of Na+, K+, Cl-, Ca2+, and charged proteins distributed both in and outside the neuron.

An action potential begins when a disruption of this distribution causes Na+ to flow into the neuron, through Na+ channels, causing the inside to become more positive.

The more positively charged inside of the neuron triggers adjacent voltage-gated Na+ channels to open and allow more ions to flow through.

The increase in charge inside the neuron triggers K+ channels to open – allowing for ions to flow outside of the cell, and thus lowering the inside charge back to its original state.

This increase and decrease in charge causes a wave-like motion of ions that propagates down the axon of a neuron – and ultimately causes the release of neurotransmitters from the dendrites – which stimulate the next neuron to either initiate or inhibit an action potential.

Action potentials trigger neuronal pathways which can stimulate or inhibit certain functions in our body. For example, action potentials in the motor region of the brain may stimulate a neural pathway with leads to the muscles in your arms resulting in flexion. Action potentials also facilitate communication between neuronal networks in the brain which allow us to have conscious thoughts, emotions, and memories.


action potential down axon nerve

By Laurentaylorj, on Wikimedia


As a nerve impulse travels down the axon, there is a change in polarity across the membrane.

The Na+ and K+ gated ion channels open and close in response to a signal from another neuron. At the beginning of action potential, the Na+ gates open and Na+ moves into the axon. This is depolarization. Repolarization occurs when the K+ gates open and K+ moves outside the axon. This creates a change in polarity between the outside of the cell and the inside. The impulse continuously travels down the axon in one direction only, through the axon terminal and to other neurons.

External links



Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

HS-LS1-2. Develop and use a model to illustrate the key functions of animal body systems: Emphasis is on the primary function of the following body systems… nervous (neurons, brain, spinal cord).

College Board Science Standards

LSH-PE.5.5.4 Construct a simple representation of a feedback mechanism that maintains the internal conditions of a living system within certain limits as the external conditions change.

LSH-PE.5.5.5 Construct a representation of the interaction of the endocrine and nervous systems (e.g., hormones and electrochemical impulses) as they interact with other body systems to respond to a change in the environment (e.g., touching a hot stove). Explain how the representation is like and unlike the phenomenon it is representing.