Pluto's killer renamed: Eris

All fans of Lucy Lawless will have to accept the fact that the largest dwarf planet is no longer called

• 2003 UB_{313} (nicknamed Xena)

but rather

• 136199 Eris (nickname Eris).

Its moon, formerly known as Gabrielle, is now known as Dysnomia. Recall that Eris, an object larger than Pluto, was the main reason why Pluto was eventually downgraded to a dwarf planet.

The demotion of Pluto has ignited a lot of public discord. That makes a good case for the new name because Eris is the Greek goddess of discord - the nemesis of Harmonia.



If you have forgotten, by now, what is the new name of the moon, don't worry: a marked difficulty in remembering names is called dysnomia, too. ;-)

According to the page you will see if you click the picture, Eris often helped her brother Ares to cause quarrels and lawlessness. So the name "Lawless" can still be found in the description of the new name of the planet. In fact, it is even more striking with Dysnomia who was also a daughter of Eris: Dysnomia is actually translated as lawlessness. ;-)

Pluto demotion and public sentiment

When the meeting of the International Astronomical Union in Prague decided that Pluto was no longer a planet, I was feeling certain that it was a huge victory for astronomy on many fronts.

First of all, the decision undoubtedly increases the status of astronomy as a coherent enterprise. Suddenly it is joining the family of fields of human activity in which rational arguments and quantifiable characteristics are more important than mythology. Astronomy is becoming another science in which a careful investigation of a question plays a more important role than superficial dogmas that we have memorized at school.

Second of all, astronomy appeared in thousands of articles. I thought it was a cute story that would lead most people to appreciate the progress in astronomy, although the progress didn't require as deep an analysis as the progress in fields that are arguably more intellectually or technologically demanding.

My first assumption was correct but my second assumption was not.

It is clear that the decision indeed moves astronomy further away from mythology and closer to science. There is simply no way to rationally justify why Pluto should be one of nine planets if there exist other celestial bodies in the Solar System that are larger and more important and "planet-like" than Pluto. If there had been a natural scientific definition of a planet that would keep the list unchanged, I am sure that they would have accepted such a definition. But because more complete information about the Solar System is now available, we know that such a definition simply doesn't exist.




If science matters, the list of planets had to be either expanded or Pluto must be removed from it. I don't really care which of the possibilities was ultimately chosen because the cutoff is a matter of convention. For pedagogical purposes, it is probably better to have a shorter list because children don't have to memorize too many words without an essential scientific value.

Unfortunately, I was wrong about the public sentiment. For example, 83 percent of the people who participated in a Discovery Channel poll wanted to save their Pluto. The list of unsatisfied people includes the students from New Mexico who prefer if the discoverer of Pluto - who was 24 years old when he discovered it - is more important than what he actually will be in 100 years. The list of critics of a new definition most likely includes a majority of the kids at basic schools, politically correct Madison City Council that used to support Ho Chi Minh, British composers with a clash of interests, hundreds of astronomers who write petitions, rock bands, Bruce Cameron and other Walt Disney's fans, uncountable freelance writers from the countryside, Elizabeth Davies the conspiracy theorist, much of Canada, New Mexico, Indiana, and Kenya, Asian astrologers, Mary Latham-Hampo who created a Pluto from black licorice, and even a blogging string theorist who supports these "conservatives" as much as he can.

I just can't believe how stupid most people are. Some of these reactions are just fun but most of them are not. It's the teachers' job to educate a new generation that will be less idiotic and that will know that in science, facts matter and sentiments don't. It is not an issue of national pride of a God-fearing nation, Cassie. But feel free to hijack an airplane and smash it into the Prague Castle. ;-) Many people are surprised by the outcry just like I am.

Many scientists often complain that only 50% of Americans or so understand that evolutionary biology is more correct than creationism. But in this case we get numbers like 83% in the context of a question that is arguably much simpler than the validity of evolution. I thought this was the 21st century. The list of planets that we have learned at school was a scientifically ill-defined random list of sufficiently independent objects orbiting the Sun that were large enough and lucky to be seen before the Second World War. However, such a definition is a piece of history or a fairy-tale, not science. When science obtains more accurate data, it must update its conclusions and definitions - shockingly enough for 83% of the humankind.

If the word "planet" is supposed to have a scientific meaning that is applicable outside the Solar System - and the astronomers are likely to need such a definition in the future - mythology is simply not enough. Everyone can still informally use the word "planet" for Pluto as long as he realizes that he uses a scientifically incorrect terminology. Everyone can believe that Pluto is equal to other planets and shouldn't be discriminated against and that size doesn't matter as long as he realizes that his belief is patently false.

Elements

Consider another word: "element". The ancient scholars used to believe that there were four major elements: fire, water, air, and earth. However, we have learned certain new things about the composition of matter. Our idea about the list of elements has changed quite dramatically. It happened that most people have accepted by now that the elements are things like the hydrogen and helium.

Needless to say that there are people who still believe otherwise. For example, the astrologers assign three zodiac signs to each ancient "element". But many people kind of understand that astrology is not a science.

In the case of planets, you may face 83% of opposition. Many of these people are hysterical imbeciles and people who confuse cartoon heroes with rocks. When someone obtains a scientific result such as the fact that one can't consistently define planets to have 9 of them including Pluto, he or she is guaranteed to face more serious threats today than Copernicus had to face when he figured out that the Earth was orbitting around the Sun, not the other way around. The astronomers are lucky that the demotion is a collective decision of thousands of people - 450 of them actually voted. If this were a discovery of one person, she would already have been assassinated.

What a surprise that these people will also buy nonsensical books of greedy crackpots about high-energy physics - crackpots who are so immoral and well-organized that they now need a few hours only to erase any inconvenient review from amazon.com.

Most people want to believe so many wonderful things that we must conclude, together with Feynman, that it's not a scientific world.

And that's the memo.

Prague defenestration of Pluto

Democracy may be a tough thing. Last week, we reported about the proposal to have 12 planets.



Figure 1: The dwarf planet Pluto and its friends

However, 9000 astronomers who gathered in Prague have just voted differently. The vote was overseen by Jocelyn Bell-Burnell and her teddy bear. It is still true that a planet is an object that is spherical because of its gravity that orbits around the star. However, a new adjective was added.

Which adjective? The asteroid Ceres was promoted to a dwarf planet. Pluto was downgraded to a dwarf planet. Charon, previously known as Pluto's moon, was downgraded from a moon to a "small solar system body". On the other hand, the piece of rock 2003 UB313 was promoted to a dwarf planet, too.

The adjective "dwarf" means that the celestial body is not large enough to clear its orbit from other objects.




There are some good news for Charon: Pluto and Charon can also be called a double planet. This new equality is no reason for feminists to celebrate because both Pluto and Charon are male. On the other hand, feminists have succeeded in adding another female member among the planets so that Venus doesn't feel so lonely and discriminated: the dwarf planet 2003 UB313 will be promoted to a woman called Xena.



Figure 2: Xena, a new dwarf planet. She is actually larger than Pluto. Her moon is informally called Gabrielle. To make things more complicated, Gabrielle's sister in the movie was Lila, and Lila is also an alternate nickname for the dwarf planet Xena herself, chosen after a newborn daughter (Lilah) of one of the discoverers Michael E. Brown. ;-)

This humiliating experience that has affected Pluto's life may be viewed as the fourth defenestration of Prague, after the events in 1419, 1618, and 1948. Congratulations to Ceres, Charon, and 2003 UB313. Once again, the main reason of Pluto's bad luck is not its size or the crappy stuff that it is made of; instead, it is the fact that its path is perturbed by the Neptune. In other words, Pluto has not yet cleared its orbit.

NASA has sent a $700 million spacecraft to Pluto and argues that it won't discriminate against Pluto just because it is size-challenged. According to the new convention, there are eight dwarf planets in the solar system.

Prague assembly: there are 12 planets

The International Astronomical Union gathered here in Prague. What problems do the astronomers have? Do they have to face mentally challenged articles that astronomy is just a passing fad on a daily basis?

Your guess is right. The astronomers don't have any problems. So those 2,500 guys and ladies discussed whether Pluto is a planet. Yes, no, what of it? Nevertheless, the original proposal to downgrade Pluto has been killed. Instead, a broader definition of a planet was accepted:

• every object that has been brought into a spherical shape by its own gravity and that orbits around a star directly is called a planet.

With this definition, there are 12 planets in our Solar system. You can see Dennis Overbye's report for more details. In fact, Pluto's status as a planet was saved because of the astrologers. Initially, the global convention of astronomers denounced Pluto as a dirty chunk of meaningless space crap. But the Universal Association of Astrologers and Star-Gazers has condemned the move abruptly. See more information about this dirty political game here. ;-)

The new definition must be approved by a vote next Friday. Clearly, it won't solve everything. How spherical is spherical enough? If a moon is almost as large as a planet - or if you have a binary planet - will you count both of them as planets or none? At any rate, I am sometimes jealous about the jobs where they don't have any serious problems and they don't need any deep thoughts. On the other hand, it could become boring quickly.

Besides 9 planets that everyone knows, the new definition would upgrade the asteroid Ceres to the planet status, much like Pluton's Charon as well as a distant object called poetically "2003 UB313". Expect additional controversies.

Global warming on other planets

Mars, Jupiter, Triton, Neptune, Pluto, and others share the fate of Earth

Jupiter

A new storm and a new red spot on Jupiter hints at climate change, USA TODAY and dozens of other sources explained yesterday. The temperatures are expected to change by as much as 10 Fahrenheit degrees at different places of the globe. At least close to the new spot and to the equator, nothing less than global warming is expected.

New observations of Jupiter's climate change were released in 2008: click the number.



Neptune

The climate of Neptune - more precisely its reflectivity - was recently changing. Lockwood and Hammel argue in Geophysical Research Letters, vol. 34 (2007) that the trends on Neptune reveal suggestive correlations of brightness of Neptune with the temperature trends on Earth, indicating their common solar origin - although I am not quite sure whether the sign is as expected.

Buy Czech President Václav Klaus' amazing book, "Blue Planet in Green Shackles". (Click.)

Triton

Triton is Neptune's largest Moon. Some people believe that it used to be an asteroid. Global warming was detected on Triton. Between 1989 and 1998, the temperature jumped by 5 percent on the absolute (Kelvin) scale. The same relative increase would raise the Earth's temperature by 22 degrees Fahrenheit in 9 years. See thousands of other pages about the global warming on Triton.

Enceladus

Another moon of Saturn's, Enceladus, would be also expected to be frozen and cold. Suddenly, Cassini has informed us that Enceladus generates its own heat. Its high temperatures seem to be incompatible with calculations based on solar energy itself, according to existing models.

Saturn

Saturn itself has a rather warm southern pole, and the temperatures in that region suddenly jumped by 3-5 Kelvin degrees. Well, it's warm because it's been exposed to sunshine for quite some time but the magnitude of the temperature jumps is not trivial to calculate.

Pluto

What's going on with Pluto? Well, yes, your guess is right. There is global warming on Pluto. Pluto's atmospheric pressure has tripled in 14 years, and the associated increase of temperature is estimated to be around 3.5 Fahrenheit degrees, despite the motion of Pluto away from the Sun.

Mars

Of course, the global warming on Mars is a well-known story. Between 1975 and 2000, Mars warmed up by 0.65 Celsius degrees, much faster than Earth: see Nature 2007. The warming has been used by this blog to discover the Martians. More seriously, we have explained that the dramatic and speedy melting of the Martian icecaps is caused by the greenhouse effect. 95% of "their" atmosphere is made of carbon dioxide; that's slightly more than 0.038% of our atmosphere.

The warming trend on Mars is undeniable. Some people have tried to blame the global warming on NASA's rovers. Such accusations are pretty serious because NASA is already preparing plans to occupy Mars using the greenhouse effect, as ordered by George Bush. ;-)




Venus

This planet doesn't belong to this list of planets where recent warming has been demonstrated. But it is interesting to talk about the greenhouse effect there.

Venus, our planet's evil sister, has already been identified as unusable for life because of ... yes, because of the greenhouse effect that occured in the past. Last month, the Venus express gave us some new hints why Venus has such a thick atmosphere that generated global warming.

Venus' distance from the Sun is about 70% of the distance Sun-Earth. Because of the second power, this means that there is twice as much solar radiation per area over there. Because of the fourth power in the Stefan-Boltzmann law, it means that you expect about 20% higher temperatures in comparison with Earth on the Kelvin scale which would mean, if Venus were a black body, that the temperature would still be still below 100 Celsius. But they are about 470 Celsius on Venus.

Venus is clearly not a black body and the greenhouse effect is important for raising its temperature. But you should notice that Venus' atmosphere has 90 times higher pressure than the terrestrial atmosphere and 96% of it is carbon dioxide! The Earth only has 380 parts per million of CO2, and if you divided it by 90 to get the corresponding fraction of the Venus atmosphere, you get about 4 parts per million. There is more than 100,000 times less CO2 density here than on Venus! If you used a linear relationship between the CO2 concentration and temperature boost, you would see that the expected increase of the Earth temperature due to CO2 is 400 Celsius divided by more than 100,000 which is a few millikelvins - a totally negligible amount! The actual strength of the greenhouse effect on Earth will be stronger - because the first molecules matter more - but it won't be exceedingly stronger. At any rate, when numbers are taken into account, you shouldn't expect any substantial influence of CO2 on Earth.

But let us return to the planets that are known to be currently warming.

Earth

The Earth is currently experiencing warming, too, although a less dramatic one than the previous examples. However, there is apparently a huge difference. The warming on the previous planets and moons was natural. On the other hand, the warming on Earth couldn't evolve naturally: it is caused by the humankind, evil corporations, and their intelligent design, most left-wing scientists believe. The warming trends can't have anything to do with the Sun whose activity is now highest in the last 1000 years: it is unethical to propose that the Sun plays any role, consensus scientists argue.

A comparison

You may ask the consensus scientists: why is there such a difference between the explanations for the warming of the Earth and the other planets and their moons? It's because the Earth is the center of the Universe, they would answer. You could also ask: why do all these planets and moons indicate warming? Shut up, the consensus scientists would answer.

Some of them would tell you that your paradox is resolved by the anthropic principle: the people on Jupiter, Saturn, Pluto, Mars, Triton, and other celestial bodies cannot complain about the anthropogenic global warming because... because these people don't exist! :-)

The debate is over, Al Gore, our prophet, has announced. Terrestrial global warming, caused by the human sins, is no longer a political issue: it is now a spiritual issue. Now it's time to punish the heretics who deny that the Earth as the center of the Universe is special because of the humans who were created to the image of God - and because of their sins and SUVs.




This looks like a story about some silly priests from the 16th century Catholic Church - a story about the Dark Ages that most of us heard in the basic school. But unfortunately, what we are describing here are influential people in the 21st century such as one who delivers a speech on the picture above.

People who believe, much like the Church in the 15th century, that the divine truth is determined by consensus. People who believe that we should prefer awkward hypotheses if they support our spiritual values. People who believe that questions and independent thinking should be silenced. People who will almost certainly write dozens of unsubstantiated comments below this article.

More seriously, I don't claim that the trends observed on all these celestial bodies prove their solar or cosmic origin although the agreement of the signs is suggestive. But what these trends certainly do is to remind all rational people that there is always natural variability on any celestial body as long as it has any structure or internal dynamics and the only questions are the quantitative ones: how large this natural variability is and what effects are the most important ones in driving it. Denying that there is a lot of natural climate change would be extraordinarily silly.

Other popular climate articles

• Lord Christopher Monckton
• Temperature determined CO2 concentrations, not the other way around
• The Great Warming Swindle
• Cosmic rays and sunspots: correlation with temperature
• Temperature CO2 sensitivity
• 2006: a bad year for fearmongers
• 2006: coolest year since 2001

MOND and holography

These blogs should be sources of provocative ideas that can lead to something new, which is why this article is about MOND and holography. Be sure that I find all MOND theories very unlikely but we should all be aware of interesting speculations that have shown non-trivially looking quantitative results.

Note added later: the readers who find this article interesting should also look at a newer article about the Pioneer anomaly.

Note added in 2006: more direct observations of dark matter have arguably falsified all published versions of MOND, great, and it is a somewhat open question whether more sophisticated versions of MOND like mine - that may involve macroscopic interference - are gone, too. The question can be settled by similar observations of the clusters in the future: if the distribution of the deduced dark matter is going to be random and independent of the visible matter, then any theory without dark matter will be dead.

What is MOND? The acronym MOND stands for "modified Newtonian dynamics", and it is an alternative to the theory of dark matter. Jacob Bekenstein gave a talk about MOND at Harvard when he was visiting us - and he is probably the most famous current advocate of this theory which is viewed as a controversial one: MOND does not quite agree with the usual picture of the Universe that emerges from general relativity. There is a lot of reasons to think that MOND is nonsense, but the goal of this article is just the opposite one. ;-)


Basic argument in favor of dark matter

In order to convince you that there can be something nice about MOND, you need to know the basic reasons why most people believe that there is a lot of dark matter around.




When we observe other galaxies, we can use the usual laws of general relativity (well, Newton's laws are enough) to predict the angular velocity of the stars in that particular galaxy as a function of their distance from the center. We think that we know the mass distribution because we know where the stars are located and what their mass is, and therefore we may calculate the gravitational field, and the motion of the stars in this gravitational field.

What results do we get from Newton's theory if we substitute the masses of the visible stars as the source of the gravitational field? The result says that the angular velocity (the velocity divided by the radius) decreases with the distance from the center (with the radius), much like in the case of planets orbiting the Sun. You know that Pluto's motion around the Sun is much slower than the motion of Mercury, and the ratio of the angular velocities is even more pronounced because Pluto is much further from the Sun and the distance appears in the denominator.

However, the direct observations of the stars' motion lead to a different result: the angular velocity is nearly constant for all stars in a single galaxy, except for a few stars near the galactic center. The rotation of a galaxy resembles the rotation of an LP recording! Although the gravitational laws have been successfully tested for planets and many other celestial bodies, the predictions of the rotation of galaxies seem to fail.

The usual response is that the true gravitational field is very different from the gravitational field of the visible stars: there is a huge amount of invisible matter (dark matter) whose gravitational field is such that the stars in the galaxy rotate like points on an LP recording. One must work with a reasonable distribution of dark matter to achieve this goal, and the theories of dark matter are pretty messy. Most of the dark matter must occupy a "halo" that is pretty far from the galactic center, and one needs to tune many parameters to make the dark matter theory agree with all the observed galaxies. Well, that's what you're forced to do if you believe that general relativity is a good description at very long, cosmological distances.


MOND basic achievements

One can measure the dependence of angular velocity on the distance from the center for different galaxies. Each galaxy gives a slightly different result. The predictions of Newton's theory are pretty good for the stars near the center - but a totally different behavior takes over once the distance from the center is greater than a certain critical distance.

In fact, the point where the angular velocity starts to deviate from Newton's laws - where it starts to be constant - always seems to be at the distance where the acceleration of the stars decreases to a certain universal critical acceleration a_0. For each galaxy, the distance of the first stars for which Newton's laws "break down" is slightly different; but their acceleration is always the same, with a rather good accuracy. That's interesting, is not it?

Moreover, the constant a_0 is a number pretty close to the Hubble constant H. In other words, a_0 is comparable to the inverse age of the Universe (multiplied by the speed of light). This fact will be important at the end of this posting.

The MOND theories, roughly speaking, say that the Newtonian laws are modified in such a way that the inverse square law (1/r^2) for gravity is continously replaced by the inverse distance law (1/r) for all objects whose acceleration is smaller than the critical value a_0. This crazy assumption allows one to reproduce the observed results from a large number of galaxies, using a minimal number of parameters - and without assuming any dark matter. (The agreement is not so great for clusters of galaxies, but this is not what we want to analyze here.)

Many ways how to derive this weird new behavior from "more field-theoretical" laws, closer to GR, have been proposed - but let me say that neither of them looks natural enough. Therefore the phenomenological description with the 1/r^2 force transmuting into 1/r for small accelerations is everything we find valuable about MOND.


Why it may follow from holography?


OK, let me now switch to my speculative explanation why this weird behavior may be derivable from holography. (Jacob Bekenstein told me that a crackpot has already written a paper about this relation MOND-holography, and therefore I apologize if I am not the first one who proposes this idea haha.)

First, imagine the usual holograms in optics, invented by Dennis Gabor in the 1950s. They are two-dimensional pictures. But if you look at them carefully (in some cases, you will need laser - the same laser that is necessary to produce them), you see a three-dimensional object.

The three-dimensional illusion results from a dense network of interference patterns. These patterns reflect that wave character of light. A small piece of the hologram can still be used to reconstruct the whole three-dimensional image, although the quality is reduced. It will be important below to keep in mind that if the piece of the hologram is way too small (compared to the object that we want to see, or even compared to the wavelength of the light), the three-dimensional illusion will disappear.

In quantum gravity, we know that something like holography is important, too. 't Hooft and Susskind were the first to propose the idea (the holographic principle) that in every theory of quantum gravity (which really means in "every solution of string/M-theory"), the information about the "bulk" can be encoded on the surface of this volume, and the density of information is never bigger than roughly one bit per Planck area.

Normally, we think that the "memory" grows with the volume. The bigger volume we have, the more RAM chips we can insert into this volume. However, gravity guarantees that this can't work indefinitely. If you put too many RAM chips into a too small volume, the gravity will be so strong that the chips will collapse into a black hole. It has been realized by Bekenstein and Hawking that the entropy (or information) carried by this black hole only scales like r^2 (in four spacetime dimensions) divided by the Planck area, instead of the usual r^3 behavior. Black hole is, at the same moment, the most entropic system that can fit a given volume. It really means that large volumes can carry much less information than what we would expect from a naive proportionality law (with the volume).

Maldacena's AdS/CFT correspondence is a very rigorous example of holography in string theory: in its most popular version, a four-dimensional (gauge) theory living on the boundary of five-dimensional anti de Sitter space contains all information about quantum gravitational (and stringy) physics inside the five-dimensional "bulk" (multiplied by another five-dimensional sphere, to get the total of ten dimensions).

Forget about AdS/CFT for a while, and think about our real Universe again. OK, I'm now gonna argue that MOND may follow from holography. As I mentioned above, the three-dimensional illusion of a hologram in optics breaks down if the piece of your hologram is too small. It's not unnatural to believe that a similar limitation occurs for holograms in quantum gravity. More generally, I want to argue that holography in quantum gravity implies modifications of dynamics in the "infrared" - and we want to define "infrared" according to the acceleration.

Consider an object whose acceleration is a. The worldline in spacetime is a hyperbola, and the center of curvature of this hyperbola is at distance 1/a. If you associate de Broglie's wave with that object, the lines of constant phase will depend on the velocity, and they will intersect at the center of curvature of that hyperbola. Let's now believe that this self-intersection is necessary for the three-dimensional interpretation of our hologram to be valid. OK?

If you swallowed that, then we're done. It's simply because the 3+1-dimensional physics can only be trusted if the center of the hyperbola fits into the cosmic hologram, i.e. if 1/a is smaller than the radius of the Universe. In other words, the usual physics only occurs if a is greater than the critical acceleration. If the acceleration is smaller, you're not allowed to use the 3+1-dimensional laws to calculate the forces affecting the object. Instead, you should switch to the physics of the hologram which is 2+1-dimensional. If you allow me to make one more leap, I can even say that the usual 1/r^2 force in 3+1 dimensions is replaced by the 1/r force in 2+1 dimensions (of the hologram), which is precisely what we need for MOND to describe the rotation of galaxies without any dark matter.

What do you think about this weird proposal? :-)