Advanced Newtonian Gravity

The equations for advanced Newtonian gravity are discussed in the article by A Worsley entitled, “An advanced dynamic adaptation of Newtonian equations of gravity. The adaptation of Newtonian dynamics.” (Physics Essays 21, 3 (2008) pg. 222-227)

Worsley starts the article by briefly discussing the history of general relativity (GTR) and it's successes and failures, namely it's tendency to breakdown mathematically when dealing with black holes. In addition, Worsely points out, the equations become increasingly complex: a definite downside.

What is interesting is the approach that Worsley uses to arrive at his advanced dynamic adaptation of Newtonian gravity. He postulates that by reversing Einstein's process of arriving at GTR, he can reformulate the equations for gravity into a force. This method provides many advantages listed by the author. First, the method is much easier to use with far less complicated computations, it obviates the infinitely dense black hole singularity predicted by full GTR, and restores the principle of simultaneity. Worsley even goes as far as to say that the new equations of adapted Newtonian gravity can be used to shed light on the “dark matter” of the universe.

Basically, Worsley takes the curvature of space-time equations for GTR and modifies them mathematically by defining the equations in terms of geodesics. He then translates these new curvature equations back into the equations for an advanced Newtonian force of gravity. Although the actual derivations of Worsley's equations are not included in the paper, his resulting equations are.

To prove that the new equations are valid, the paper works several examples... namely the general relativistic estimate for the perihelion advance of Mercury. The results show that the advanced Newtonian equations can give results that agree almost perfectly with GTR and observed data. The author then uses his equations in higher mass density objects (like binary pulsars & black holes) with great success; the equations do not collapse.

In full GTR equations, the Schwartzchild radius seem to be the limit of the calculations... but by using the advanced Newtonian force of gravity equations, Worsley is able to estimate the forces exerted by the Schwarzschild radius and inside the black hole. Additionally, the Schwarzschild radius can now be used to define the radius for the escape velocity of light. This is important, because modern physics tells us that the speed of space-time is allowed to exceed the speed of light! (I didn't know this.. prior to the paper!)

In the end, Worsley states that advanced Newtonian gravity achieves a far greater accuracy than Newton's laws of gravity because of the use of the higher order terms. Since the equations prove valid (that is, they agree with calculations from GTR on low and medium density bodies), the author claims that they must also be valid for higher mass density objects like black holes... and by using these calculations for the force of gravity, even at the Schwarzschild radius, we can make calculations of the missing dark matter of the universe.

Lack of WIMPS in Italy

The XENON project in Italy has been looking for WIMPS for over a year now. The data for the first six months was publicly released and it detected zero Weakly Interacting Massive Particles. These particles are believed to be "dark matter" and the lack of evidence shows that there are a great number of holes in the CDM hypothesis. The inability to detect this matter is an epistemological problem for the CDM theory. The article is at http://physicsworld.com/cws/article/news/45697

Modified Newtonian Dynamics

The review article Modified Newtonian Dynamics: A Falsification of Cold Dark Matter was written by R.H. Sanders of the Kapteyn Astronomical Institute at the University of Gronigen. This article was obtained by the EBSCO Academic Search complete and was originally published in Advances in Astronomy Volume 2009. I have the original article and would be happy to email it to anyone interested in it.

This review article is written by someone who is clearly a proponent of MOND (Modified Newtonian Dynamics) instead of CDM (Cold Dark Matter). The author begins the article by laying out the problem with galactic rotation curve and the problem with Keplerian motion accounting for observed evidence. The author mentions the lack of evidence for dark matter, excluding the DAMA project which he labels as controversial, in the standard model. The author then mentions the origin of MOND as a result of rotation curves being asymptotically flat and the Tully-Fisher law of mass and luminosity relationship.

The author states that changing the the gravitational acceleration in "low gravity" areas can be modeled to fit the observational data. The gravitational acceleration is modified the term Mu(g/a0) where a0 is a new parameter and Mu is an assymptotic function which has yet to be finalized but there are three main candidates (1/x^2, 1/x, e^-x). In areas of low acceleration this allows the velocity relationship to be:

v^4 = GMa0; a0 is currently valued at 1.2 X 10^-10 m/s^2

The asymptotic nature of Mu allows the modification of Newtonian gravity to approach zero the stronger the gravitational field and therefore match the observational evidence for the inner part of galactic rotation curves. The MOND theory even accounts for pressure supported systems showing that they are finite with density falling rapidly as a function of 1/r^4

The impressive part about the MOND theory is its ability to predict the galactic rotation curve based solely on observable evidence in the near infrared region of the spectrum. This is not just the general averaged rotational velocity but very specific values based on the clumping of observable matter. The MOND theory even accounts for variation in the M/L relationship of the T-F relation based on the color of galaxies.

The most important and the most emphasized point in the paper is that every variation of surface brightness of the galaxy has a corresponding variation in the MOND curve and the observed rotational curve.

The author then lays out the current problems associated with the MOND theory. Clusters of galaxies do not match the observed rotational values with the MOND curves with MOND curves predicting 2-3 times the mass that is observed in clusters. It is suggested that we may be unable to view all of the matter and we recently discovered hot gas emitting xrays that were previously neglected. The missing mass is also theorized to be "soft bosons", unaccounted for neutrinos, and even "dark matter."

MOND began as a simple theory that has progressed over the years. The initial relationship was shown to violate conservation of angular momentum and conservation linear momentum and was modified accordingly with no loss in fitting the model. The MOND theory has also been shown to work with general relativity and is free of anomalies, the first attempt had wave propagation faster than light. MOND says there can be "dark matter" but nowhere near the amounts that are used in the current model of 20% observable matter and 80% dark matter.

After reading this paper I find it difficult to argue with the author. The MOND theory has less unknown variables, is easily modifiable to match observations, the flaws with observation can be explained, uses only one new variable (as opposed to a min of 3 in CDM) and it does not require the creation of a new form of matter. The MOND theory is also similar in structure to Maxwell's equations demonstrating that it can match existing laws of the universe. Above all the MOND theory is more scientific at this time. It is clearly falsifiable, if the mass discrepancy of the galactic clusters is unaccounted for then the theory must be modified or thrown out. CDM is impossible to test because you can not prove that something does NOT exist. From my perspective the CDM proponents seem similar to the ether proponents of the late nineteenth century (although my knowledge is limited). In the absence of other evidence I believe that the simplest explanation is the best and in my opinion that is the MOND theory.

Relativity of Wrong

Here is a link to the portion I referenced in class of the essay by Isaac Asimov. This is in response to the amount of discrepancy between observation and theory as it relates to our suppositions and the extrapolation of errors.


http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm

-David Downing

A couple of explanatory resources: Pulsars, and Relativity

Here are a couple of good educational resources that have come up in the last couple of classes. First, here's a link to the Jodrell Bank site where pulsar signals are translated into sound:

http://www.jb.man.ac.uk/~pulsar/Education/Sounds/sounds.html

And secondly, some great presentations of Einstein's arguments for Relativity, together with the counter-arguments of the time from proponents of the ether, courtesy of philosopher of science John Norton:

http://www.pitt.edu/~jdnorton/Goodies/index.html

Moon Buggy Celebrates 40th Anniversary this Year!

I don't know what it is about the show Top Gear (the UK version.. not the American one!) that has me captivated, but I am a devout fan. I love that show.. it's in the top 10 on my DVR. So, over spring break, I indulged in some idleness on the couch and caught up on missed episodes... Guess what I found.... Astromony blog fodder!!!

NASA in Clear Lake let James Ray drive the new Lunar Rover! This year marks the 40 anniversary of the lunar rover and Top Gear flew James out to drive the latest model. The new model is massive compared to the original! .... think Volkswagen Beetle meets Monster Truck!

It's pretty impressive and entertaining at the same time. James, AKA "Captain Slow", only almost crashes it twice! LOL! My favorite part is when he parallel parks the 4 ton vehicle.

The show, which is for gear heads, spends a lot of time on the rover's specs, but James does go into some of the history of the program and when, if ever (never, actually, in his opinion), the rover will ever be used for its intended purpose.

See the YouTube video link here!... but watch out when you read the blog comments... some are not intended for the younger viewers!

Book Review: "How I Killed Pluto and Why it had it coming.

I just finished this book by Dr Mike Brown of Caltech.

http://www.amazon.com/How-Killed-Pluto-Why-Coming/dp/0385531087/ref=sr_1_1?ie=UTF8&s=books&qid=1300756965&sr=8-1

He is largely credited with the reduction of Pluto to a "dwarf planet" although he himself did not participate in the discussion. The book starts of by giving a window into what it is like to be an astronomer. He tells about late nights, trying to get time on telescopes, trying to complete a dissertation, and trying to get tenure.

The majority of the book focuses on the Dr. Brown's discovery of objects in the Kuiper Belt namely: Sedna, Eris, and I forgot what he named them but they were codenamed Santa Clause and Easter Bunny. All of these objects were considered to be planets in that they were near the size of Pluto and had more regular orbits than Pluto. Dr Brown tells the story about the discovery of these objects, the potential theft of this information by a Spanish astronomer before he could publish (he is actually very cordial), and the debate on the definition of planets.

Jocelyn Bell makes an appearance in the book as the primary voice against a second resolution to play a definitions game in terms of planets so that Pluto could still be considered a planet. The idea was to have "classical planets" (MVEMJSUN) and "dwarf planets (Pluto, Xena, Eris, etc). Jocelyn Bell gave a demonstration with a beach ball, a stuffed dog, and an umbrella that prevented the motion from gaining traction. I only wish that I had finished the book prior to her lecture, I would loved to have asked her about that.

I would encourage you to pick this book up and read it yourself. It will be in the Rockwall Public Library as soon as I can get over there and return it.