Selected Questions- Answers From All Experts Astronomy Forum (Becoming An Astronomer)

 

Question:  I am 16 in high school and interested in an astronomy career. Can you answer the following for me?

A) How much does the average astronomer make and what are the health benefits, opportunities for overtime etc.?
B). What are the chances for promotion in the field, i.e. to become boss astronomer?
C) What courses do I need to take, including in college?
D) What is the typical work day like?

Answers:

First, no one I know goes into astronomy for pay, health benefits, paid overtime or the like. You can probably find better options in a corporation! If benefits and remuneration are one's primary concern, it's probably better to re-think his or her choice of career. The average astronomer's salary, by the way, depends on many factors, not least is the institution with which one is affiliated, and the seniority of position.  But most base pay for the starting astronomer (associate professor, say) is in the range of $55,000 - 75,000 per annum.

 'Promotion' is a loaded term, because it implies that those in senior positions will soon retire - to make way for younger staff. This doesn't always happen, or at least as quickly as the younger staff want it in a field like astronomy.   For many, it may be necessary, therefore  - to work only in 'adjunct' or part time positions with few or no benefits. People understand this when they go into the field. (Especially as government funding for many astronomy projects has gone way down in the past 6 yrs. or so)

 The main promotion criterion is how many papers one has had published, and the quality of research. The key indicator in that regard - if one is university based - is getting tenure. Tenure may be conferred based on quantity and quality of research papers produced, but alternatively - in terms of academic works, books published.

Regarding necessary skills, of course, a great deal of mathematical and observational skills are needed, and computer skills certainly are indispensable - mainly since so much numerical modeling is done these days in astronomy departments. Perhaps above all, one needs an abiding curiosity in nature and the larger universe.

Re: education and skills needed - these are usually formidable.  In high school for example take all the math and physics courses available. 'Astronomy' is actually quite a large area to try to explain at one time because it includes a number of large sub-areas:

 astrometry - the study of star positions and how these change over time with celestial coordinates

 celestial mechanics - the prediction of the future positions of the planets, Moon

 stellar astrophysics - the study of the physics of the stars, and their evolution, changing properties

 solar physics - the study of the Sun, its physics and properties, as well as terrestrial effects

galactic dynamics  - the study of the dynamics and physics of the galaxies and galactic clusters

cosmology-  the study of the large scale motions and expansion of the universe including the derivation of its past properties from currently observed phenomena.

 Each one of these would probably take several large books to even survey, far less 'explain'. What this shows is that like many other scientific disciplines, astronomy has grown and developed beyond simple description or being one simple science. When people become astronomers today, in fact, they have to specialize in one area, say solar physics - they can't just do 'astronomy' - it's too much!

 The core courses needed for a specialist astronomy (B.Sc.) degree include:

Math:  Calculus, Advanced Calculus, Linear Algebra, Differential equations, Complex Analysis, Numerical Analysis.

 Physics: General Calculus-based Physics (with labs); Electricity & Magnetism, Thermodynamics,  Classical Mechanics, Quantum Mechanics, Statistical Mechanics, Optics, Plasma Physics.

 Astronomy: Geodesy & Astrometry (coordinate systems, fundamental star positions and determinations); Celestial Mechanics (application of classical mechanics to celestial motions), Stellar

 

Astrophysics, cosmology, radio astronomy, Stellar evolution, Binary stars, astronomical observing and measuring.

 

The "typical working day"   depends on which type of astronomer you mean, which specialty field. To make it simple - let's assume the person is in a university- where most research astronomers are.

 The typical day probably then begins with giving a class, say in astrophysics, then holding at least one hour for office time - to allow students to come in and ask questions.

 Then there may be a need to prepare a lab - and if not, one can make use of the campus library to get caught up on the research - and also - look to preparing one or more papers in one's field. In general, research astronomers are allocated more time for this (as opposed to teaching) because it is expected they will publish more.

 Lots of time may also be spent going over data - say obtained from a telescope or other facility. It may also be necessary to go to the Observatory and re-do photographic plates, or spectra if it is thought better resolution is needed. (Better optical results to determine what is going on with the objects under study.)

 

If one is. senior academic, then supervising research students will also be part of the day's duties.

 

A Welcome Addition To Basic Astrophysical Literature: "Welcome To The Universe"

As Black Friday dawned yesterday it was almost a certainty that 99 percent of people would be flooding big box stores to snatch up the latest electronic wonders including the new 55"  "Ultra HD" TV sets to make their debuts as Walmart and Best Buy. But a much more sensible option,  as opposed to more electronic titillation,  would have been to invest in Neil De Grasse Tyson's new book, Welcome to the Universe: An Astrophysical Tour.'

The book, a breathtaking overview of astrophysics and especially how we obtain the knowledge we do, is indispensable to getting to know the universe as science knows it   It is distinct from most other basic texts because most of those - as De Grasse Tyson noted on a recent CBS Early Show appearance -  are "a mile wide and an inch deep".  By contrast, this 472 -page book is a "mile wide and a mile deep."  Well, not quite but pretty close and hey, it even includes algebraic equations where necessary - so ignores the old rule that each equation given "decreases sales by one percent" - or some such jabberwocky.

Some of the topics covered include: stellar evolution (the lives and deaths of stars), the search for life in the galaxy, the interstellar medium, the Milky Way, the expansion of the universe, the early universe, quasars and Einstein's special and general theories of relativity. Also: black holes, cosmic strings, inflation and the shape of the universe.

The content actually represents a division of labor between Neil De Grasse Tyson, Michael A. Strauss and J. Richard Gott. For example, the three chapters on special and general relativity were very ably done by Gott.  If you truly wish to get a handle on these abstruse theories there is perhaps no place better then Gott's trio of chapters, so long as you're ok with some intermediate algebra to assist in the task.

Tyson himself is responsible for chapters:  1, 2, 4, 5, 6, 7, 9 and 10. The only one I really had issues with was Chapter 9, 'Why Pluto Is Not A Planet'.   For one thing, Pluto is not specifically an object for astrophysical inquiry but rather planetary astronomy. Hence, the chapter's inclusion can only be attributed to Tyson having already spent a lot of ink on the subject, so why not include it (since it's firmly in his academic 'wheelhouse') in a new book?

But as I noted in previous posts the arguments given don't make any physical sense. For example, Alan Stern, executive director of the Space Science & Engineering Division of the Southwest Research Institute – and Principal Investigator for NASA’s New Horizons mission to Pluto- observed that the new planet definition was “sadly flawed, particularly due to the vagueness of the third condition- clearing the neighborhood around its orbit - which might also disqualify Earth”.

He added: “A lot of people are going to ignore the (new) definition because it doesn’t make sense.” (Source: Eos Transactions of the American Geophysical Union, Vol. 87, 29 August, p. 350). The other aspect is that Pluto’s dethroning was done by a subjective vote at an IAU meeting, not by any objective measures or consistency. The problem is the IAU definition overlooks the neighborhood of the object.  Pluto just happens to be in the Edgeworth –Kuiper belt with thousands of other objects. This is a condition of happenstance, not of actual intrinsic property.

If Earth were to interchange its position with Pluto it would also be in the same belt, and because other substantial objects (e.g. Neptune) crossed its path, it would have to be demoted – by De Grasse Tyson and the IAU's definition. So what to call it, a “demi-Earth”? A jumbo dwarf planet or jumbo shrimp planet? Give me a break!

Tyson is on much firmer ground - as well within the proper astrophysical sphere -  when he explores the lives and deaths of stars, as well as the scale of the cosmos, how stars radiate energy and stellar spectra. The last two are especially important cornerstones of astrophysics, and Tyson does a stand up job. One also hopes that when curious readers finish his chapters they will move on to Lawrence Aller's  (and now also Leo Goldberg's) 'Atoms, Stars and Nebulae' - which remains the standard for elementary astrophysics in terms of deciphering the nature of stars.

But Tyson and company excel in their own approach presenting the (usual) less advanced reader with numerous examples borne out by superb diagrams such as Fig. 2.4 showing Kepler's laws, and Fig. 6.2 showing the energy levels and associated spectral line series for hydrogen. I also liked how Tyson delved into the historical background, e.g. for the Balmer series, discovered in 1885.

The H-R diagram (Fig. 7.1) is also one of the best, most beautiful I've seen in any astrophysics text, with the relative sizes of specific stars - like Betelgeuse and Aldebaran - in color and projected against their evolutionary tracks. It's also interesting just how the famous diagram was composed: "From a catalog of stellar luminosities and temperatures Hertzsprung and Russell started filling in the diagram and discovered stars did not occupy just any place". Well, no, because it plots the stellar spectra (or surface temperature) vs luminosity so because each stars has distinct pairs of these, it will have differing positions on the H-R grid.

One warning here: Tyson uses an unorthodox form for describing nuclear fusion reactions in stars. For example (p. 101):

ppn + ppn  =  ppnn + p + p

As opposed to say,

³ He + ³ He ®  ⁴ He + ¹H + ¹H  + 12.85 MeV

with the energy given off.    But truth be told, this notation of his would probably only irritate purists or pedants

What really sets the text apart is all the calculations shown, all very basic, such as the total energy a star will generate over its lifetime by multiplying the star's luminosity L by the lifetime. T. In fact, all the math used which leads to so many fascinating insights, is fairly basic. None of it ought to be beyond a person who has taken at least first year algebra though the derivation of  E = m c²       in Appendix I will likely require at least an intermediate algebra background to follow. .

What makes this book so special is that it offers the reader so many more useful insights and "tidbits" - for lack of a better word- than most astrophysics texts would at this level. One learns, for example (p. 51) "Superman can indeed throw an object 5 miles per second . The object will also fall under the influence of gravity but its curved trajectory now matches the curvature of the Earth such that it never hits the surface and ends up in a circular orbit."

De Grasse Tyson's conversational style, which served him so well in his  2014 reprise of 'COSMOS'  e.g.

http://brane-space.blogspot.com/2014/03/new-cosmos-series-is-well-worth-look.html


is apparent throughout his chapters in the current work. For example, on p. 88, we read:

"You can think of the outermost layer of a star as a tree. Do you know what is coming toward the tree (from inside the star)?  Mixed nuts. We have a mixed nut cannon (the interior of the star) firing mixed nuts (photons at different frequencies) into the tree, and in the tree we have squirrels. My squirrels like acorns (the photons) - these are acorn squirrels. They see all these mixed nuts coming through but they are grabbing only the nuts they like, the acorns, on the other side. (outside the star) come mixed nuts minus the acorns (the thermal radiation minus the H-alpha  photons)"

The reader has to understand that this sort of description is uniquely Tyson's, You won't find it in the chapters by Gott or Strauss, though theirs do remain in a colloquial mode.

The takeaway here is that if you enjoyed the COSMOS series you should find a lot  to enhance your reading in this book. There is all one could ask for to gain a foothold in grasping the basic principles of astrophysics - as well as other topics not specifically related to it, such as how the zodiacal constellations came to be (including why astrology is off) and, of course, why Tyson doesn't regard Pluto as a planet.

"Calculus is so last century"? Hardly!

Two months ago a WSJ op-ed ('Calculus Is So Last Century') by Tianhul Michael Li caught the eyes of many mathematicians as well as physicists (and I can assure you, many space and solar physicists). In it Li basically argued that calculus is primarily of the last century as it "is the handmaiden of physics - invented by Newton to explain planetary and projectile motion."

Adding:

"While its place at the core of math education may have made sense for Cold War adversaries engaged in a missile and space race, 'Minute Man' and 'Apollo' no longer occupy the same prominent role in national security and prosperity they once did."

Which makes one wonder what alternative universe and planet this guy is living on? Surely not the one that I'm on!

A feature story in Saturday's NY Times, for example, expatiated on the latest developments including "hypersonic targeted warheads" not only under development by the U.S. but China and Russia as well. The U.S. has a non-nuclear version but the take is that the Russians and Chinese are developing nuclear warheads- independent of missiles- that can be hurled into space then come down on an enemy with little or no warning time. This is in contrast to Cold War ICBMs that general gave about 30 minutes advance notice, unless launched by submarines)

Most alarming is the drive by a number of nations, including the U.S., China and Russia, to develop low yield nukes which - as the article put it- could make their use much more likely than the "mutually assured destruction"  (MAD) model of the past allowed. Indeed, the Russian already have a military posture firmly in place that permits the use of tactical nukes (with 10- 25 kt warheads) in the event that NATO forces overwhelm Russian positions in Eastern Europe. (And cruise missiles are also being outfitted with low yield nukes.)

The current U.S. proposal to "modernize" its nuclear warheads is also seen as possibly destabilizing the existing system and rousing the Chinese and Russians to action in their own warhead development.

Far from national security having switched away from H-bomb Cold War worries, we are evidently entering a new era wherein nuclear "swords of Damocles" literally hang over our collective heads, in the form of targeted hypersonic warheads, or even nuclear-armed satellites,

None of these systems will use linear algebra (the math Li mainly advocates teaching) to reach their targets, but plain old brute differential calculus, of a form I described in earlier blog posts, e.g. from May 6, 2013 (the rocket problem).

Surely then, Calculus isn't passé if it is still central to the ultimate form of nullifying any national security or 'prosperity': nuclear war,

Meanwhile, in fields as diverse as astrophysics, astronomy, quantum mechanics and plasma physics - not to mention climate science -  differential calculus is as critical as ever. While it is true algorithms and numerical simulations, models have been developed in all these fields, it is also true that differential calculus underscores that development and continued tweaking of those models depends on the actual math, not just crunching numbers into numerical or statistical data sets.

Li is correct when he asks at the outset 'Can you remember the last time you did calculus?'  But that question could also be asked about linear algebra or finite mathematics, or a course in multivariate statistics.  The point is that any form of advanced learned in high school or college will fall by the wayside if it is not used in some way later on, irrespective of how it was taught.

Li argues that he isn't saying calculus shouldn't be taught, as it is "great mental training" which is most gracious of him. But if nuclear warheads are going to be set off in detached form and land on my head, I'd be curious as to the math underlying the dynamics. I don't want to just read about it in the NY Times.

Where I do agree with him more, is when he criticizes the "single drive toward calculus in high  school and college" which "displaces other topics more important for today's economy and society".  These include "statistics, linear algebra and algorithmic thinking" (such as revealed in finite math.)

I concur because I've always been skeptical of the high school AP Calculus curricula and whether students are really of sufficient mental maturity that the courses serve any useful purpose (apart from the usual academic 'feather' in the cap to expand their choice of college). And I never saw the reason for pre-med students to be taking calculus. In each case then, perhaps some finite math course or statistics would better serve these populations as opposed to differential and integral calculus.

Calculus then, ought to be here to stay, certainly for most college math and science majors and perhaps even some others (e.g. Philosophy) interested in exploring the role of quantum mechanics in modern expositions, say involving quantum nonlocality and entanglement.

How Spurious Science - Math Websites Can Convert People Into Morons

It's actually incredibly easy. We were first warned about it in Charles Seife's excellent book, 'Proofiness: How You're Being Fooled By the Numbers, in which the author cites a number of examples of how merely tossing numbers at people can fuck up their brains. In page after page Seife decries the use of numbers not merely to lie but to baffle with bullshit. No better example of such a website is the one for the link below, which reeks of horse manure:

http://members.shaw.ca/warmbeach/INDEX3.htm

And indeed, this single site has already been responsible for at least four nincompoop questions sent to me in the astrophysics forum of All Experts. The person who sent it - who has variously gone by "Diana", "Jeanine" and most recently "Brianna" - obviously has zero clue of: a) what constitutes an astrophysics question and b) how to spot physically incongruous units at a glance. (Which can be verified merely by scrolling through the inane combinations of units served up for the unwary reader's consumption in the link above.)

In her first foray,  in October of last year, and referencing an additional bozo site, she wrote (after I refused to address her question as a serious inquiry):

"EinsteinElectricity.com plainly declares that 1 / Velocity is equal to the Tesla. Wikipedia then declares that the magnetic field of the earth is equal to .000032 Teslas. 1 / earth orbit Velocity is equal to .000032 Teslas ! (the true orbital math) And you think that that is just a coincidence ? Hello ? Jeanine"


Forcing myself to stoke up on patience, as one might with a small pup that refuses to be toilet-trained, I then referred this Canadian dolt to the fact the unit combination isn't even physically consistent, adding:

"Check them yourself! vel v = m/s so 1/v = s/m .  BUT 1 T = 1 Wb/m^2 (SI system) The first principle of any test of hypothesis or formula is to ensure the physical units are consistent!"

I also added:

"Btw, anyone can concoct and hurl together dissimilar units to make them appear valid, but garbage in = garbage out. The sure sign of pseudo-scientific claptrap and bunkum is when one reads:

"The earth in orbit is electrical, the Tesla is present due to the earth moving through the aether.  When you multiply earth Acceleration by the Diameter as well as the hidden Tesla you get the Velocity of light and its CORRECT UNITS."

Any physics student of mine that would scrawl such drivel would get an F - for the semester! An orbit being electrical? Moving through the "ether"? The ether doesn't even exist - the Michelon -Morley experiment showed the concept of ether is redundant.  The rest is pure poppycock. The waste of a mind is a terrible ting and this nonsense is an enormous waste of a mind - as well as the minds led to buy into it."

So, at least 5 months passed before the following bit of bafflegab gibberish (under the header 'Sound math')  arrived in my inbox, doubtless compliments of the selfsame Canadian twit, now using the name "Brianna":

Our SOLARMath equations work with "Kilograms" ( http://members.shaw.ca/warmbeach/INDEX3.htm )

But because Avogadro's number is atoms per mole which leads to atoms per "gram", prior to commencing the equation below, we need to convert the initial Mass of the earth to grams.

The Equation is;

The Mass of the earth divided by Gravity^4  x  Acceleration of earth in orbit  =  Avogadro's number.

5537831004648121688015772977.2114697 grams  /  (9.8)^4  =  600392689687827221617859.5082045622325038

600392689687827221617859.5082045622325038  x  .001003207246557  =  602318297074676474879.204

Now our question is;

Should this (above) "final value" be multiplied by 1,000 ?  Does the whole equation need a second x 1,000 in order to compensate for the very first conversion of kilograms to grams ?  It seems counter intuitive.  We figured the equation would need a "divided by 1,000" to compensated for the initial ( x 1,000 ) that was used to go from Kilograms to Grams.

When that final x 1,000 is done, the result gives us Avogadro's complete number = 602 318 297 074 676 474 879 204.

So that final x 1,000 gives us a correct value.

But ?  Is that final x 1,000 proper mathematics ?


I replied with a customized rejection and was as polite as possible, emphasizing that the astrophysics forum (at least for my domain of questions) had to meet at least one of the following content criteria for consideration as a legit astrophysics query. (Being painfully aware of how other subject-discipline areas were diluted by being deluged with irrelevant questions in relation to the actual category):

i)The energy processes in stars, including:  energy transfer (radiation, convection, conduction), nuclear fusion reactions (carbon cycle, proton-proton cycle, triple alpha process, etc.)

ii)the physical properties of stars: density, temperature ranges for radii, opacity, chemical composition determined by spectral class (absorption lines, emission lines, equivalent widths of spectral lines) Hydrostatic equilibrium (pressure-gravity balance in stars)

iii)Solar properties – irradiance, helicity, the alpha-omega dynamo process, sunspot emergence and associated magnetic features. Effects on Earth and also global warming.

iv)Solar flares: prediction, cause and associated physical factors – plasma instabilities and general plasma processes on the Sun that highlight the flare process. Connection to the solar corona - coronal mass ejections.

v)General plasma properties including plasma frequencies, radius of gyration, adiabatic invariants, gyro-magnetic radio emission. Also: magnetic tubes and mirrors on the Sun, relation to plasma “mirrors”, the loss-cone effect, Fermi acceleration in magnetic mirrors. The aurora and particle dynamics associated with the magnetosphere.

vi)Nebular composition and processes, detection. Emission vs. absorption nebulae. Gas dynamics and plasma properties.

vii)Plasma wave propagation in stars and nebulae, including Alfven waves, electrostatic waves, magnetosonic waves etc.

viii)General gravimetric properties of massive stellar objects, general relativity and applications to expansion of cosmos, as well as black holes (structure, angular momentum, Kerr type, rotating vds. Non-rotating), singularities, and Hawking radiation.

ix) Detection and analysis of photometry for extra-solar planets near type F, G-stars.

x)Stellar evolution and H-R diagrams. Formation of black holes neutron stars - pulsars, etc.

I had hoped she herself, whoever she was, would in the meantime take the time to see the question and its units were totally inconsistent, and then work from correct units to see the Avogadro number itself could not possibly be derived from the mass of Earth divided by the gravitational acceleration to the fourth power and multiplied by the orbital acceleration. Because all one is doing is hurling units together haphazardly to get a number  - but which has no relation to the physical dimensions or quantities!

Alas, the impudent little imp - bereft of any social graces or manners - merely responded with a rude follow-up,

"are you drunk ? this is not really an astrophysics question? If you "can't" answer the question just fess up. Mass of earth / Gravity^4 x orbit Acceleration = Na That's as "astrophysics" as you can get. Earth, Gravity, Orbit, hello ? And the math is as basic as grade 7"


It is interesting the imp writes this dreck, but her reply also shows she's as bereft of any rudimentary math education as she is manners. Maybe she lives in the backwoods of Canada and hasn't been taught any manners, or maybe her education was limited to a one-room school house where they didn't teach students how to master units and dimensions. Mayhap addition and subtraction was the extent of it. Who knows? But her idiocy is clearly at least on a par with those numskulls who peddle the "BMI" as an actual indicator of weight and obesity - which nonsense I skewered earlier, e.g.

http://brane-space.blogspot.com/2014/07/the-bmi-body-mass-index-as-ridiculous.html


Am I being overly harsh with "Bri"? You decide! The first rule of approaching any units or dimensions problem is to make sure all the units are consistent. Hence, if one is using g = 9.8 m/s ² then all the other units must be S.I. or metric to work. Thus, the mass of the Earth must be: M =
5.97 x  10 ²⁴ kg.  (All her dozen or so extra digits for that value is yet another illustration of "proofiness", as the measurement uncertainty precludes so many significant figures.) The orbital acceleration is then: 0.0059 m/s ²   So we are now in position to "do the math":


?  =  ( 5.97 x  10 ²⁴ kg) /   (9.8 m/s ²  )⁴   x [ 0.0059 m/s ²] 

Which yields on multiplication:

3.85  x 10 ¹⁸ kg -m ³  / s ⁶


Letting 1 N = 1 kg m/s ²  we can rewrite:

3.85  x 10 ¹⁸ N -m ²  / s ⁴

Which discloses that not only is the number more than five orders of magnitude less than Avogadro's constant ( 6.02 x 10²³  ) but that the units are not remotely alike! The Avogadro number is actually the number of atoms in a mole of a substance. The combination of units shown above bears  NO relation to such a number!

Sadly, the young woman - if that's indeed what she was - could have obtained this all on her own without all the huff and puff had she even possessed a basic education in math, not to mention some common sense.

Alas, she lacked both, as well as what Bajans call "broughtupsy".

Once Again: Jason Lisle is NO Astrophysicist

Pseudo-scientist Jason Lisle: His groupies still believe he's an "astrophysicist" - so cite him often to bolster their Biblical bollocks, 'creation science' and other baloney.

Let's clear the air once more that Jason Lisle, despite his attempted "resurrection"  by some deluded fundies, is NO astrophysicist. One cannot be an astrophysicist if he doesn't adhere to basic principles of astrophysics!  One really has to wonder what intellectually deformed sort of nitwit – who calls himself an “astrophysicist”- can forego all the major postulates and principles (NOT beliefs!) of physics and astrophysics and subscribe to patently obvious bunkum like a young Earth, "young Sun" or young cosmos.

In the case of Jason Lisle, he's reputed to be an astrophysicist based on one Ph.D. doctoral thesis in which – perhaps for the first time in his academic life - he came close to doing real science. But even that had numerous holes, e.g. http://brane-space.blogspot.com/2011/06/why-jason-lisle-is-wrong-in-his-solar.html                         

And: 

http://brane-space.blogspot.com/2011/07/jason-lisle-astrophysicist-dont-make-me.html
and  http://brane-space.blogspot.com/2011/07/jason-lisle-faux-astrophysicist.html


Among the powerful arguments I made to show Lisle’s young Earth-young Sun etc. claims are bollocks (and automatically disqualify him from being any "real astrophysicist") is the fact he  rejects nuclear fusion in the Sun as the primary energy source.  Any first year astrophysics student knows that given accepted-known  nuclear fusion reactions the time taken to steer a spectral class G star through the Main Sequence- goes on for millions of years. Thus Lisle adheres to nonsense (for a thousands of years old Sun)  that NO REAL astrophysicist would hold! For example, Lisle in one dvd on “The Young Sun” attempts to convince gullible fundies and other viewers that he can show the Sun is “young” so fits in with the Genesis fairy tale that the Sun can be no more than 6,000 years old (since in Genesis the Earth was made before the Sun, an impossibility anyway as I’ve shown in a number of blogs).

Lisle's claim, supposedly made by a "real" (sic) astrophysicist, is absolutely astounding in context (especially for a "Ph.D.") - given that it stands all of stellar evolution, astrophysics and thermodynamics, statistical mechanics on its head, especially nuclear fusion: the basis for the Sun's energy! These are things EVERY budding astrophysicist is taught in his first graduate course in stellar astrophysics or stellar evolution. Thus, there are differing nuclear cross sections for differing fusion reactions and also differing time scales.

More to the point, the same arguments that torpedo Lisle’s claims for a young Earth, young Sun also torpedo D. Russell Humphreys' (another make believe "astrophysicist), e.g.



 for a young Earth and young cosmos. The reason? To embrace such codswallop would require rejecting most of modern stellar physics predicated on nuclear fusion. A key quantity in obtaining these time scales is the energy liberated per (nuclear fusion) chain defined as:

W(r) = rE, or W = (rE)/ r


which is in ergs/gram for example. (I.e. the total ergs of stellar energy given off per gram of stellar matter available for reaction.)

 

E is found from specific nuclear fusion reactions, such as p + p -> D2 +e(+) +v, where two protons fuse to yield deuterium, a positron and a neutrino(v). The key quantity is r, defined as the reactions/cm³. Obviously, the greater this value the shorter the energy generation time scale and the smaller the value the longer it will take. It is defined (see, e.g. Astrophysical Concepts, p. 331), by Martin Harwitt:
 

r = B (r)²  X1X2/ T^1.5 * exp^-3[2π^4e^4mH (Z1²)(Z2²)A'/ h^2kT]^1/3

 

where B is a proportionality constant, r is the density, h is Planck's constant (e.g. h = 6.62 x 10^-27  erg-sec), k is Boltzmann's constant = 1.38 x 10^-16 erg/K), T is absolute temperature of the reaction, i.e. in K deg, and X1 and X2 are the concentrations associated with atomic numbers Z1, Z2 while A' is the reduced atomic mass, i.e. A' = (A1 A2)/ (A1 + A2).

 Then working out 'r' for the proton-proton fusion cycle one can (after a lot of work) obtain the time scales for each chain part and the energy yielded for each, viz. (cf. Harwit, op. cit., p. 336):


p + p -> D2 +e(+) +v (1.44 MeV, Time = 14 x 10⁹   yrs.)

 

D2 + p -> He3 + y(gamma ray) [5.49 MeV, time = 6 secs)

He3 + He3 -> He4 + 2H1 [12.85 MeV, Time - 6 million years]

 

Note that the last branch of the cycle already takes 6 million years, i.e. for each fusion to furnish 12.85 Mev (millions of electron volts of energy, were 1 eV = 1.6 x 10^-19   J). Thus, this cycle alone takes almost 1,000 times longer than Lisle's time of 6,000 years, as the supposed maximum age of the Sun.
 

The only mildly problematical time frame in the p-p cycle is for the initial fusion, which yields 14 billion years or about three times the age of the current Sun. Thus, at face value, this translates into only about one fusion every 14 billion years for the first branch of the proton-proton reaction. While that is extremely long, the Sun fortunately has a vast number of protons available in its core, so that – at a temperature of 10 million Celsius, enough can fuse to initiate helium production and energy given off. Moreover, the key "catalyst" speeding the reaction time up is the phenomenon of "quantum tunneling" whereby a lower energy particle can surmount a higher energy barrier (what we call the "Coulomb barrier") by virtue of its wave-like properties.
 

To fix ideas, let us say a particle (say proton) of kinetic energy K, must overcome a barrier of energy V ("barrier potential"), via the process of "tunnelling". Consider a deBroglie wave of wavelength l_D =  h/p  or l_D =  h/ mv  where l_D is the de Broglie wavelength) arising from (p+) of form: U(x) ~ sin(kx) where x is the linear dimension along displacement and k, the wave number vector (k= 2π/ l_D).

 

 

Now, though the associated energy K < V (the barrier "height"), the wavefunction is non-zero within the barrier, e.g.

U(x_b)~ exp(-cx)

So, sketching axes for this:

E
!
!---------V------
!   *p
!
!
!------!-------------> x

 

with the potential (Coulomb) "barrier" at height V, for which we visualize the particle p(*) on the left side having "tunneled" over to the right side where it may have wave function, U(x) ~sin (kx + φ), where φ denotes a phase angle.  Note that if the barrier is not too much higher than the incident energy, and if the mass is small, then tunneling is significant.

Note also that the penetration of the barrier is a direct result of the wave nature of matter! In effect, this wave nature - which is uniquely quantum mechanical in origin- allows a higher energy barrier to be penetrated by a lower energy particle, something totally without parallel in classical, Newtonian physics.

In other words, without the benefit of quantum tunneling, the first reaction time in the p-p cycle would be inordinately long and have to be disallowed as unphysical.
 

Beyond this we know the photon diffusion time (the time to make it from the edge of the solar core to the Sun's surface or photosphere) is calculated to be nearly 1 million years. This takes into account all the changed random directions the released photons undergo as a result of absorption and re-emission by particles along the way out. No core photon makes it directly through, but instead undergoes millions of interactions en route resulting in collisions. Again, 1 million years for a photon's diffusion time belies Lisle's young Sun argument! It also belies Humphreys' own young Earth- young cosmos claims. (Since even the brightest O and B spectral class stars have lifetimes on the Main Sequence, much longer than this photon diffusion time)
 

In the case of  Jason Lisle, here’s another conundrum for his assorted worshippers to ponder: Lisle himself contradicts his 'Young Sun' assertion in his Ph.D.! (Introduction). Therein he concedes to the above dynamics for nuclear fusion occurring in the Sun! So one is forced to ask if he really believes that or if he LIED in his dissertation? If he lied then his Ph.D. isn’t worth an ounce of doggie lickspittle I don’t care which institution awarded it.

 

Let’s now return to Humphreys.  Let us grant, according to assorted online Wiki entries, that he is a physicist at the Institute for Creation Research (ICR), like Duane Gish. He is best known for his creationist views and his attempts to reconcile reality with the notions of young Earth creationism. As in the case of Lisle  before him, this reconciliation process entails standing long confirmed physics and astrophysics on its head, and dreaming up improbable assumptions to make the reconciliation work.  It would be roughly analogous to me using an array of misplaced physics and whacky assumptions to show an elephant could be suspended from a string and the spring’s tension would support it.

While one of Humphreys favorite sayings (cited on many fundie blogs)  is evidently that scientists –astrophysicists don’t have their own evidence but just  “believe what other scientists believe” we must take care to point out he is certainly not in the same league as many pseudoscientists.  Indeed, he appears to have far more truly scientific distinctions than Lisle.   For example, his biography at Creation Ministries International lists many commendable achievements and awards, but none of his awards appear related to his young Earth-cosmos research.

This shows two things: 1) The discontinuity in awards discloses the actual scientific establishment places no value on creationism or any of its offshoot “theories” including young cosmos, and 2) Though Humphreys cites these mainstream awards for his ICR bona fides, he technically rejects their basis since he rejects the science behind them!

This is important to note because it elicits the question of why he’d cite any mainstream awards at all. If it is to show his professional scientific acumen or capabilities then it’s mostly useless because by embracing young Earth, young cosmos bollocks he’s squandered all his scientific capital. So the awards only show a once prominent physicist who has now “gone off the rails” and in many ways has lost all credibility. In many respects this parallels what happened to the once great Nobel-winning chemist Linus Pauling who tried to parlay his many scientific awards into credibility for his whackadoodle megadose vitamin C conjectures. It didn’t work. People saw through it and concluded that a once great scientist had either become senile or that he betrayed his background to enter a fringe field.

Sadly, both Jason Lisle and  D. Russell Humphreys will continue to attract their respective, assorted acolytes and groupies - mainly anti-science fundagelicals - because the Bible isn't enough for the backward, uneducated  fundie  populace to confer gravitas on their religious bunkum. No, they all (or mostly) understand they need the patina of science - or at least scientific -sounding names, terms,  jabberwocky etc. to confer some scintilla of objective authority on their bollocks beliefs. Because that is what they are. Pure belies, based on no evidence, and no repeatable observations.

As I've noted many times before, the biggest indicator that what they're doing isn't science is the absence of any falsification tests. That is, testing their hypotheses, i.e. Young Sun, with the aim to falsify it. This is totally beyond them, but until they do it - as opposed to invoking the backward baggage of cherry-picked pseudo-scientists, they simply confirm they are all about promoting religious beliefs - not any scientific theories.
 

Math Drives the Universe.......And Astronomy (Part 3)

By his junior and senior year, the Astronomy major who's survived thus far has much more math to look forward to, in courses such as: Introductory Astrophysics, Celestial Mechanics, Radio Astronomy, Stellar Constitution & Evolution, and Stellar Spectroscopy. In addition he will be expected to complete an undergrad research project, and attend Astronomy seminars in the department - in which visiting 'stars' present their latest research findings.

In Introductory Astrophysics, the primary emphasis is getting the student acquainted with the Planck function and applying it to simple, plane-parallel stellar atmospheres, such as depicted below:


















The Planck function describes the distribution of radiation for a black body, and can be expressed:

B(l) = {(2 hc²)/ l⁵}  [1/ exp (hc/lkT) - 1)]


Of course, all stars are effectively black bodies, which are perfect radiators, or as close to that state as nature allows.  In the case of simple radiation transfer in a static model stellar atmosphere (e.g. nothing changes with time), we have the relation of specific radiation intensity I(l) to source function S(l):

dI(l)/ds = -k(l)  I(l) + k(l)  S(l)

 = k(l) [S(l) – I(l)] - 0   or I(l) = S(l)


For a black body, the student learns I(l) equals the Planck function:

B(l) :  i.e.  S(l) = I(l) = B(l)


And this is a condition which implies LOCAL THERMODYNAMIC EQUILIBRIUM or LTE   LTE does NOT mean complete thermodynamic equilibrium!(E.g. since in the outer layers of a star there is always large energy loss from the stellar surface) . Thus, one only assumes the emission of the radiation is the same as for a gas in thermodynamic equilibrium at a temperature (T) corresponding to the temperature of the layer under consideration.  Another way to say this is that if LTE holds, the photons always emerge at all wavelengths.  In the above treatment, note that the absorption coefficient was always written as: k(l) to emphasize its wavelength (l) dependence. 


The student will be required to do a number of challenging problems for homework, including the specific applications of the gray atmosphere approximation. In a particular integral, let the surface flux: p( F_o ) = 2 p (I(cos (q)) = p [a(l) + 2(b(l)/3 ] 

and F_lo = S(l) t(l) = 2/3 

which states that the flux coming out  of the  stellar surface is equal to the source function at the optical depth t = 2/3. This is the very important ‘Eddington-Barbier’ relation that facilitates an understanding of how stellar spectra are formed.  Once one then assumes LTE, one can further assume k(l) is independent of l (gray atmosphere) so that: 

k(l) = k;  t (l) = t  and F_lo =  B_l (T(t = 2/3) )

Thus, the energy distribution of F_l is that of a black body corresponding to the temperature at an optical depth t = 2/3.  From this, along with some simple substitutions and integrations a wdie array of problems can be done. A few HW problem  examples:


1. Estimate the specific intensity I (q=p/4) if the surface flux from the Sun is  6.3 x 10 ⁷ Jm^-2 s^-1.

2.  Find the effective temperature of the Sun and the boundary temperature (T_o) and account for any difference. (Hint: The effective temperature is related to the boundary temperature by: T_eff  = (2)^1/4 T_o   )

3. The lines of the Balmer series crowd close together as higher series members are considered. If each line was exactly one A (1 Angstrom) wide, how many Balmer lines would be individually visible without overlapping other lines?



Celestial Mechanics:

The name conveys exactly what the subject embodies: Mechanics applied to the dynamics of celestial objects. A typical diagram from my own Celestial Mechanics notes when I took it at Univ. of South Florida, is shown below:














The diagram shows assorted "orbital elements" for a planet of mass m2 (the Sun is m1) and this can be used as a basis for orbital energy analysis and also to predict future positions. Energy constants in celestial mechanics are very useful for quickly coming to terms with specific properties of an orbit such as shown in the accompanying sketch- designating a generic orbit in x-y-z space. In the diagram, w   is the argument of the perihelion, W is the longitude of the ascending node, f is the true anomaly and i is the inclination of the orbit. The critical or key parameter here is h, the angular momentum vector for the orbiting system. It may be useful here to refer to the diagram (b) in the figure used for angular momentum vector (z) in an atomic system:


Getting specific, assuming r and r' are r (radius vector) and d r/dt, respectively, the magnitude h, of the angular momentum vector is:

h = r x r’ =

(y z’ - z y’)

(z x’ - x z’) = (C1 C2 C3)

(x y’ - y z’)

so (r x r’) = (C1/ h, C2/ h, C3/h)

and inserting variables one finds:

C1/ h = sin W sin (i)

C2/ h = - cos W sin (i)

C3/h = cos(i)

Now since the inclination of Earth's orbit to the ecliptic  (i) is known (23.5 deg) and therefore cos(i) can be determined, then sin(i) can be as well.h can be determined, since: h = C3 / cos(i) = (GMm a (1 – e²)¹² where all the constants are known (a = semi-major axis of orbit, e = eccentricity of orbit)
(The energy equation is: ½V ² - u/r = C, and the C's - energy integration constants- are  found from this.)

The student is also able to ascertain that  W  = M - w  (difference between mean anomaly and argument of the perihelion) where M can be obtained from a table based on observations, and w can be obtained using a Fourier expansion of the mean anomaly, M:

e.g. w  = M + (2e – e³ / 4) sin M + 5 e²/4 sin 2M + ... etc.

Once W is known, C1 and C2 and C3 are known, the student will be asked to attempt to compute the position of a planet, say Jupiter, forty or so years in the future. On the basis of this project, the student's final grade may well depend.



Radio Astronomy:


This important area commences with the student introduced to the plasma conditions associated with the motion of charged particles, that give rise to radio wave propagation. For example, he will be expected to recognize and apply the fundamental equation of motion: m (dv/dt) = q(v X B) where q is the charge, and the cross product is for velocity and magnetic induction. The motion is such that the velocity v is always perpendicular to the force acting on the particle, so that:

 dv/dt = q/ m [v X B] is a centripetal acceleration.


Meanwhile, (v⊥ )² / r = q/ m [v⊥ B]

The quantity r is none other than the gyro-radius. Solving for it one finds:


r = m/ q [v⊥ / B] = v⊥ / (qB/m)


for which one can have either the electron, or ion gyro-frequency. These equations explain the physical basis for the origin of a preponderance of radio waves (i.e. gyro-magnetic emission).  Radiation characteristics will also be covered, and this will include treating the quantity known as the specific intensity i.e.

I_l (0,q) =   ò_o ^z  B_l(t)  exp [(-t_l / cos  q)] dt/ cos  q


where B_l(t)   is the Planck function.    The energy which flows per unit solid angle will then be based upon finding:

dE n =    I  cos  q   dw  dt  dn 


from which one will wish to obtain the total flux. 

The essentials of assorted radio telescope properties, especially for antennas, will also be introduced, along with many problems - including practical (i.e. designing a specific antenna to detect an object of given flux, and spectral output etc.).  To this end the student will distinguish between the flux emitted for an isotropic (lossless) antenna, and an anisotropic antenna with the gain (g) subject to the constraint:

ò _4p  g  dw   =   4p 


and the relation between the gain of the antenna and its effective aperture (A) such that:

g( (q ,  φ )  =   4p  A (q ,  φ)/ l² 


From here, the student will be expected to work out the beam width and beam efficiency of a given antenna, as well as compute the 'brightness temperature' for a localized source, and the antenna temperature (Ta =  1/4p  ò _4p   g T(b)  dw)  where T(b) is the brightness temp


Sensitivity of the antenna will also be considered, as well as other details such as the amplification of high frequency signals. Not the least of these will be the Stokes parameters and problems involving them.  In general the normalized Stokes parameters will always be a combination of  contributions such that:

S [s_i] = S[s] +  S{s’]

Where [s_i] is comprised of 4 components (based on received spectral power):

(so)
(s1)
(s2)
(s3)

and s =

[1- d]
[0]
[0]
[0]

and s’ =

[d]
[d cos(2Z) cos(2t)]
[d cos(2Z)sin(2t)]
[d sin(2Z)]

where the latter column vector (matrix) discloses the contribution for partial polarization such that:

cos (2Z) = (AR² – 1)/ (AR² + 1)

and:  sin(2Z) = 2AR/ (AR²  + 1)

Typical HW problem:

Three radio waves from different objects in space have the following characteristics, where d is the degree of polarization and AR denotes the axial ratio of polarization ellipse. Find the normalized Stokes parameters and the coherency matrix for each:

i) d = 1/2,   AR= 4,  t = 135 deg
ii) d = 1 , AR = -4,  t = p/4
iii) d = 1, AR = -1


Stellar Constitution and Evolution:


As if the Astronomy senior hasn't had enough math already, he will now have to confront the theory of stellar structure.  In this case, the student will be introduced to a variety of differential equations which he'll later be expected to use in the construction of an actual stellar model (which may be 50 percent of his final grade.) He learns that the force of attraction between M(r) e.g. the mass enclosed inside the stellar sphere of radius, r and r dr  (the mass of an element) is the same as that between a mass M(r) at the center and  r dr at r.   By Newton’s law this attractive force is given by:

F = G M(r)  r dr/ r²


Since the attraction due to the material outside r is zero, we should have for equilibrium:

- dP = G M(r) r dr/ r²

 
Or:     dP/dr = - G M(r) r / r²


 Consider now the mass of the shell between an outer  layer of a given star  and a deeper stellar layer. This is approximately, 4p r² r dr, provided that dr  (shell thickness) is small. The mass of the layer is the difference between M(r + dr) and M(r) which for a thin shell is:

M(r + dr) -  M(r) = (dM/ dr) dr

Equating the two expressions for the mass of the spherical shell we obtain:

dM/dr = 4p r² r

The two equations, for dP/dr and dM/dr represent the basic equations of stellar structure, without which the innards of a star would be inaccessible to investigation. A third equation of stellar structure may be derived using by using the equation for dM/dr in combination with the fact that a star’s luminosity is produced through the consumption of its own mass. This may be expressed mathematically as:
 

dL/dM = e

where e denotes the rate of energy generation. For the proton-proton cycle (for stars like the Sun- and designed for cgs units!): 

e= 2.5 x 10⁶ (r  X²).· (10⁶ /T)^2/3 exp[-33.8(10⁶ /T)^1/3]

   

Of course, to construct a stellar model as part of a course project, the student will more likely have to deal with a different 'critter' entirely -  say a star of two solar masses with a convective (as opposed to a radiative) core and with composition: X = 0.65 (i.e. 65% hydrogen), Y = 0.32 (i.e. 32% helium) and Z = 0.03 (i.e. 3 % heavy elements).  Say with an energy generation function:

e= 10^-14.2 (r  X X(CN)).· (T²⁰ )

where: X(CN) = 0.01   and :


X =  4.34 x 10²⁵  Z(1 + X)  r  T ^--3.5


This is none other than the stellar model problem construction I had to complete, and for which I received an 'A' and also an A in the course. The details of the problem were:

Neglect radiation pressure and degeneracy and assume the gas is nearly totally ionized. Utilizing Wrubel's interior integrations and Schwarzschild's and Harm's envelop solutions:

a) Construct a consistent stellar model utilizing the U-V plane fitting technique, and

b) Calculate the following physical properties of the star: L, R, T_c  ,  r _c ,  P_c  , and the mass of the convective core,  m _c .


Still want to become an Astronomy major?  Just make sure math is in your blood.