Astronomy & Astrophysics

Astronomy & Astrophysics

  • George Dishman added an answer:
    What conditions were required for Stellar formation pre inflation epoch (as w/ the Pearlman Spiral cosmological redshift hypothesis) ?

    Assume stars formed prior to the inflation epoch as hypothesized in the Pearlman Spiral cosmological redshift hypothesis for various reasons. The stars would have been much more condense (as the universe was moving from the initial singularity) prior to the universe expanding 13B light years +- during the inflation epoch.
    Under what conditions could stars have formed during that span prior to cosmic inflation?

    these are the givens:

    • The actuality is the same as it is today, so directly observed facts are as they are, though our interpretation of them may differ than the current conventional explanations.
    • The universe had a beginning, with all matter/energy and the start of time coming into existence as an initial singularity.
    • The Earth/Sun Ecliptic is the approximate center of not just the 'observable universe.'
    • but the entire universe is 'observable', therefore we are by the center of the entire universe. As explained and illustrated in The Pearlman SPIRALL. 
    • Cosmic Inflation was on day four where the universe expanded up to about 13 Billion light years in each direction within one day 5,776 years ago.
    • The cosmological redshift is not due to an expanding universe but explained by The Pearlman SPIRALL so we are in a loitering (somewhat static universe).
    • So what are the best ways to get from the initial singularity early day one, to proto star formation prior to cosmic inflation sometime on day four?
    • assume the stars were much more dense by the start of inflation.

    Keep in mind heat, time and pressure are three variables in stellar formation just as they are in rock formation so increase the heat and or pressure to reduce the time required. 
    All the energy/matter is close at hand.
    It is OK to manipulate the laws of nature as necessary to get the job done.

    Of special interest is the source of CMB and how it relates to Stellar formation and Inflation.

    Thank you in advance for your various solutions..

    George Dishman

    "It is OK to manipulate the laws of nature as necessary to get the job done."

    No it isn't, that's your problem. You appear to trying to invent a hypothesis that matches some people's interpretation of the Bible. If so, you probably believe that there is a God and that he defined the laws by which the universe operates, and did so in a manner that led to our existence. If you then deny those and invent your own false laws, you are falsifying your own God. Is that what you want? What you will end up with is nothing but a fantasy world unrelated to reality. You can do that yourself without my help of course.

    The facts are simple: the CMB is like the light we see from the Sun, the source material was hot gas of similar composition. When we look at the Sun, we don't the hot core, we only see a few kilometres into the surface because the rest is opaque. The same is true of the CMB, at earlier times, the gas was denser and opaque. What we see after that is atoms of hydrogen. We know that because a particular atomic line in the spectrum called the "Lyman Alpha" line absorbed UV light. The light from the first stars converted the gas back to plasma making it transparent at the Lyman Alpha frequency.

    The redshift of the CMB is 1090, that of the re-ionization around 11 and the first stars at about 25 so there is no doubt whatsoever what the sequence was. There was a clear period of many millions of years after the release of the CMB before the first stars formed out of the cold gas due to gravity.

    You said (slightly rearranged):

    "I am going to edit the question like this and i hope you take another crack at it.

    Under what conditions could stars have preceded a day four cosmic inflation?
    these are the givens:

    The actuality is the same as it is today, so directly observed facts are as they are, .."

    the bottom line appears to be you can not, or will not, think of a way that it could have happened."

    The bottom line is that if you say "directly observed facts are as they are" then it is a fact that we see observe the Gunn-Peterson Trough, which is a spectral feature that only occurs of hydrogen has formed atoms and we see that ending as stars ionised the gas. We directly observe the redshifts at which those eras occurred and that means we know for a fact that there was a long period after the CMB was released when there were no stars.

    In other words, I know what you are asking and I have thought carefully about it and I can say that direct observation certainly rules out your hypothesis. That may not be the answer you would like but it reflects the facts. It is up to you now to revise your hypothesis to cope with reality, all I can do is provide you with the most accurate information I have and inform you of the technical terms that you can research further.

  • Diego Sebastian Mahecha added an answer:
    Is there a definition of 'life' sufficiently encompassing for terrestrial life and possible extra-terrestrial life?
    How we define life? Does it determine what are we going to seek in other worlds? The life on Earth is, for now, our only benchmark, but is there something universally common to the phenomena which we label as life (real or hypothetical) to be considered as a universal definition for life?
    Diego Sebastian Mahecha

    The terrestrial genetic code existed even before the earth scenario. The code existed even before of what we can consider life, or living matter. Here I share with you a recent paper of my own authorship, where it demonstrates that the probability of life tends to zero than to one and it includes more details about similar topics.

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: The search for intelligent life or any type of life involves processes with nonlinear chaotic behaviours throughout the Universe. Through the sensitive dependence condition, chaotic dynamics are also difficult or impossible to duplicate, forecast and predict. Similar evolution patterns will result in completely different outcomes. Even, the intelligent life evolution pattern, based on carbon, DNA–RNA–protein, will differ from all possible sequences. In the present paper, the stochastic dyadic Cantor set models the many possible variations of such chaotic behaviours in the Universe, yielding to a tendency to zero, for any scenario of intelligent life evolution. The probability of the development of the exact microscopic and macroscopic scenario that is capable of supporting intelligent life or any other type of life in any planet is vanishingly small. Thus, the present analysis suggests that mankind, as an extremely statistically uncommon occurrence, is unique and alone in the Universe.
      International Journal of Astrobiology 10/2015; DOI:10.1017/S1473550415000415
  • Victor Christianto added an answer:
    Is there global gravitational potential associated with local galactic cluster and beyond?

    In an old paper, Dr. D.V. Ahluwalia suggests that the Great Attractor embeds us in gravitational potential at the order of -3x10^(-5).

    Interestingly, one of my colleague (Michael Peck) also suggestes that there could be global gravitaional potential affecting the entire Universe. So what di you think?

    Victor Christianto

    Dear Dr. Ostrovskii:
    Thanks, yesterday i just downloaded your paper on PFO theory, will find time to read it.

    Btw, you can find my recent question here:

  • Andrew W. Beckwith added an answer:
    Is Hubble's Constant really a constant? Or just a parameter?
    Hubble's constant gives the expansion rate of the universe and the universe is accelerating. So does it mean that the Hubble's constant itself is changing? Why call it a constant then?
    Andrew W. Beckwith

    Its a parameter. If one looks at inflation, the rate of expansion of the universe has been changing all along

  • Mike Mcculloch added an answer:
    Does anyone know if measures were performed on the Doppler shifts of the probe that reached Pluto (type Pioneer effect)?

    There has never been a satisfactory answer to this effect. Finally, due to lack of good explanation, it has been considered as an 'experimental' error or material problem (but observed at least on two probes i think, may be three)

    I wonder if this effect was observed on recent 'far space' probes.

    Thank you for any information.

    Mike Mcculloch

    I asked NASA about this a while ago. New Horizons was not tracked, a great shame because standard physics is consistently having trouble in predicting this particular acceleration regime (eg: Pioneer anomaly, Ulysses anomaly, galaxy rotation, cosmic acceleration, all showing the same anomalous acceleration by the way) and in my opinion overly-complex and different solutions are being proposed to explain them (dark matter, dark energy, thermal effects). A great opportunity has been missed to track something in this very regime, but they can always start to do it, with the Voyager probes too, since they are now free-flying.

  • Volker Maiwald added an answer:
    Oort cloud in binary star systems?

    Does anyone know if there has been a study on Oort Cloud formation in binary star systems?

    Volker Maiwald

    I am not too familiar with current research on Oort Cloud formation, but what I know about the Oort Cloud means it is remnants for the solar system formation, partly remaining there and partly pushed outward to this region by gravitational perturbations due to planetary formation and migration. Unless we assume that these mechanisms differ greatly in a binary star system - which would be new to me - why would there no Oort Cloud form for a multi-star system? Do you have any research (papers, articles, etc.) available, which states that an Oort Cloud could not have formed in a multi-star system?

    Given the possible "extra source" of gravitaionyl perturbations in a multi-star system, I would rather assume that the chances for an Oort Cloud are even larger there.

  • Jan Gunneweg added an answer:
    When the Big-Bang exploded in a millisecond, what created the space in which primordial matter traveled?
    Did a certain type of space exist before the explosion took place? Even when the explosion itself created the space by its own strength, there had to be something that existed before the Big-Bang, or was there?
    Jan Gunneweg

    Dear Arghya, I am happy that at least the question about the pre-Big Bang was an intelligent question in spite of the first answer I got.  With all my due respect to Einstein, one cannot use his knowledge in claiming that the pre-Bi Bang state is not important. Thanks. 

  • Arghya Ray added an answer:
    What is the astrophysical nature of the observed cosmological redshift?
    In recent astrophysical literature there are splashs of acute discussions on the interpretation of the observed cosmological redshift: is it space expansion, the Doppler effect of receeding galaxies or the gravitational effect of cosmologically distributed matter. The question is how to distinctly observe these different interpretations of observed properties of cosmological redshift.
    The problem was formulated by H.Bondi (1947) and also by E. Harrison in his book “Cosmology”, Cambridge Univ. Press, 1981 (second ed. 2000). Now there are more than ten papers which argue the different possibilities. Abramowicz et al.(2007; 2008) demonstrate that only space expansion can be used for understanding the cosmological redshift within general relativity, while Chodorowski (2007; 2011), Bunn & Hogg (2009), Melia (2012) insists on the interpretation as the sum of the Doppler effect plus the gravitational effect.
    In general relativity space / space-time itself has the same level of existence as matter (Einstein equation joins them) so the space can be curved, stretch, spread (as gravitational waves) and so on. And this also can be considered as an argument in favor of the expanding space interpretation, though the problem is still open.
    Arghya Ray

    @ Matts Roos 

    The question was:

    "What is the astrophysical nature of the observed cosmological redshift?"

    The main part of my answer is: 

    "I think creation of more conjectures can help at the initial stages of assessing redshift as an astrophysical process at the best and illusion at the worst."

    Of course my answer is not completely dependable, but I am trying to hint toward more conjectures that we will have to face in near future.

  • Oliver Manuel added an answer:
    What empirical evidence is there that the expansion of the universe is accelerating at the present time, T_0?
    SN-1a data [Reiss et al., Perlmutter et al.] indicates that there is a deviation from a linear Hubble curve for data points at large distances, > 3-4 Gly. Theoretical fits are then made, based on Friedmann equations, that include a “dark energy” term, Lambda. From this fit it is shown that the rate of the expansion of the universe will lead to an accelerating universe. It is often stated that the universe is accelerating at the present time, T_0. But if one looks at the Hubble curve for only the past 2-3 billion years the Hubble curve can be fit nearly perfectly with a straight line. This indicates to me that there is no empirical evidence that the expansion of the universe is accelerating at the present time. In other words, the Lambda -fit curve _suggests_ that the expansion is accelerating at the present time but this acceleration is, in fact, presently _not_ observed to any degree of certainty over the past few billion years.
  • Madhu KASHYAP Jagadeesh added an answer:
    Is GJ 581 g undetected because it's too close to GJ 581 d?
    In the detection of exoplanets usually the (RV)-(radial velocity method) is used. However, there is dispute according to some scientists that Gliese 581 g in its (HZ) does not exist because it could not be detected with either the HARPS and or HIRES data sets because of red noise etc. However, the discoverer of the proposed GJ 581 g exoplanet mentions that both HIRES and HARPS data sets were needed in order to detect this exoplanet. My point is that what has never been thought about-(which I bring out in this new paper), that to detect an exoplanet successfully takes many years and attempts to detect an exoplanet certain number of time successfully. My point is:"That in the Gliese 581 star system it is proposed that Gliese 581 g and Gliese 581 d are in the narow banded (HZ) habitable zone. If so, than if they are relatively close together, it could be a situation where sometimes Gliese 581 g is truly detected. However, other times Gliese 581 d is detected as well. But, if the exoplanets are relatively close together sometimes the (RV) amplitude detection signal could be picking up either exoplanet. making it appear that Gliese 581 g does not exist. Please read the paper it goes into much more detail than this and provides new formidable evidence to help determine if Gliese 581 g exists or not.
    • [Show abstract] [Hide abstract]
      ABSTRACT: Since 2007 to 2013 GJ-581d and GJ-581g have been two of the most controversial exoplanets known. In 2009 and in 2011 data was revised on GJ-581d and it was estimated to be warmer than previously thought, and likely had one or more oceans upon its surface. However, in 2012 the existence of GJ-581d came into question, and the existence of especially GJ-581g was considered to be just an illusion and new claims proposed that GJ-581g did not exist. The aims are to re-examine some of the current known data on GJ-581d and GJ-581g and provide new data and evidence regarding not only regarding GJ-581d, but to also help determine if GJ-581g exists or not.
    Madhu KASHYAP Jagadeesh

    Is this not verified by transit method ? 

  • Nainan Varghese added an answer:
    What is the gravitational force? How does it exist?
    Is anyone have an explanation? Thank you =)
    Nainan Varghese

    Dear Palmer,

    Thank you very much for the feedback. As the said article is a very small part of an elaborate concept, it would not give detailed explanations on spatial dimensions or their implications. Your deductions about spatial dimensions are correct. I also believe the same; that all real entities exist in all available spatial dimensions. Only such existence can provide them with positive existence and objective reality.

    However, a plane that we consider as 2D object is considered to have zero thickness. An object that has zero thickness cannot have positive existence in space. Nevertheless, great many number of parallel planes in contact may occupy volumetric space (making it a 3D object). Here, ‘zero thickness’ can only mean that the thickness is so small that it is intangible by using any of the standards, we use. It is in this sense I use 1D and 2D spatial dimensions. A 1D entity has positive existence in all spatial dimensions. However, its existence in single spatial dimension is tangible and in any higher spatial dimension, its existences are intangible and hence zero. For more details, kindly refer Chapter 2 (available at of my book ‘MATTER (Re-examined)’.

    We deal only with structured matter bodies, which have tendency (under gravitational collapse) to grow into all available spatial dimensions. Thus, they tend to become spherical in shape. Contrary to this, unstructured matter has tendency to reduce its existence into minimum number of spatial dimensions. A 3D lump of unstructured matter tends to become 2D / 1D object (with intangible measurements in one or two spatial dimensions). For brief description, see: . This phenomenon is the basis of creation, existence and destruction of universe and its contents, as we observe. Logical explanations to all physical phenomena (including gravitation and gravitational attraction) can be derived from this strange behaviour of unstructured matter.


  • George Stoica added an answer:
    Can fracture mechanics predict when the whole Universe will fracture?
    This question is open for chemists, metallurgists, physicists and astrophysicists:
    Check out this diagram which has been released today on Universe inflation. It describes how the universe has been expanding with time. It says that the Universe, around 2 billion years after the Big Bang inflated at a rate of 1% every 44 million years. The expansion decelerated under the influence of dark matter before the expansion continued under the influence of dark energy.

    Now Let's look at another [quite similar] diagram, called creep diagram:
    The diagram describes the elongation of a structure under a static load with time, across three stages before fracture.

    It happens that a certain concept in a scientific field can be used to describe (and predict) a phenomenon in a seemingly (and sometimes totally) different scientific field.

    Can these two diagrams help make the case, one day?
    George Stoica

    Fracture mechanics cannot predict anything, it's an exact science, with answers in black and white. And I do not know of any attempts of mixing fracture mechanics with probability theory or quantum mechanics. 

  • Frank Kahle added an answer:
    Can anyone help me find the formula of the precision of differential photometry of one dataset?

    Hi, I am trying to find out the formula to calculate the precision of differential photometry. IRAF or SExtractor can give magnitude errors, but these errors are usually given as instrumental errors, therefore ignoring the errors introduced by the different extinction behaviors of comparison star of unknown spectral type. The possible intrinsic variation of the comparison star is usually not addressed. Besides, bias frame and dark current and flat field calibration error also exists. However, there is still not a unified formula to calculate these potential error for the time being. I've been puzzled by above problems and would greatly appreciate your comments and suggestions.

    Frank Kahle

    See Broeg et al for computing an optimum artificial comparison star:

    CH. BROEG, M. FERNANDEZ, and R. NEUHAUSER. "A new algorithm for differential photometry: computing an optimum artificial comparison star". Astron. Nachr. / AN 326, No. 2, 134–142 (2005) / DOI 10.1002/asna.200410350

  • Victor Ostrovskii added an answer:
    Can the initial singularity be removed from cosmology models?

    In a rather old paper, Michael Heller argues that in certain cases it is possible to remove the initial singularity from cosmology models. He discusses b-boubdary and noncommutative geometry. So what do yo think?

    Victor Ostrovskii

    The PFO-CFO Theory contains no singularity (see my and Elena Kadyshevich ResearchGate pages). 

  • Raul Simon added an answer:
    What is really serious about "Oort's Cloud"?

    Can we see something like this around any other star?

    The Oort's idea was surely born upon his correct consideration that Nature "don't accept nothingness". The difference between the traditionally considered distances to the (then) last planet Pluto and to the nearest next star (alpha Centauri group) was too large a space containing "Nothing", so this space has been imagined to be filled out with myriads of cometary bodies. But today we know much more about the interstellar space. We know, there is no vacuum there outside. Why do we still need the concept of the "Oort's Cloud" at all?

    Raul Simon

    Thank you, James and Dr. Neslusan.

  • Maxim Eingorn added an answer:
    An old question that is still fresh: Is gravity a Newtonian force or Einstein space-time curvature?
    No gravitational wave was measured yet, no graviton was detected accordingly. On the other hand no space- time curvature was observable. There is no successful experiment to validate the current theories. What is the nature of the mysterious gravity? What is the velocity of this effect ?
  • Nicolai Herrmann added an answer:
    Who will assist me in developing a new theoretical concept on our oceans' formation - ?

    Hello and thank you for welcoming me here.

    I am thrilled to announce that I seem to have developed an in itself seemingly "water-proof" raw theory on the formation of our (and any) planet's oceans. (Please check the attached file for a short rough concept paper).

    So far, noone I know was able to refute it - so I now seem to need some mathematical and educated assistance/peer review for further development into a proper scientific paper (lacking the skill set in mathematics and detailed education).

    The job would be, to discuss/"bombard" my ideas from a professional point of view, to assess and futher expand my source material for my upcoming long form of the attached, at this point still source-bare concept paper, and to do some math, where necessary. My goal (or you might call it "dream") would be an accepted article in a renowned science magazine.

    If there is anyone out there, willing to partner up - please let me know. I would offer a full equal partnership in this brand-new theory (already documented in different locations on the web, in its raw colloquial form). Even one single trained helper might suffice, as of now. It would literally mean "the world" to me :-) – and maybe to all of us, if you agree in the validity of the thoughts conveyed. Not a small thing, is it?

    Nicolai Herrmann

    Nicolai Herrmann

    Thank you very much for this crucial input - so there is much of my thoughts in this, to be sure (minus the link to theia). Very interesting. I initially just was irritated by the lack of alternate information i could obtain through established channels. The wish of not taking short-cuts by the way can be seen as the cause of this post, so none intended. :-) But I deeply appreciate you taking your time, still. Thanks. We will see, how this further develops. :-)

  • Gengis Kanhg Toledo added an answer:
    What are essential and nice features to have in a telescope control system?
    I am currently writing software to control a small refractor (125 mm). Drive motors are brushed DC, encoders are 10 000 ppr mounted on the motors, gearbox has 1:8000 ratio. The German equatorial mount is well built and solid. The observer's software has a GUI and writes directly to Excel spreadsheet using dynamic data exchange (DDE). Another program communicates with the servo drives, and receives pointing information and other instructions from the GUI, via Excel spreadsheet. So both the GUI and servo control software can exchange data via DDE and both can read and write to Excel spreadsheets, allowing data plots, simple statistics etc. Currently the software has a fair number of GUI accessible functions. What would you expect a telescope control program to have as a must, and what would you like if you could choose features?
    Gengis Kanhg Toledo

    I support the ideas of Nicolas Produit in order to design and develop using standards and do not inventing the wheel, instead of that, cooperation using the free software model in order to improve TCS. For many large grounded based telescopes it is used Linux/CentOS, and VxWorks for such critical RT functions. Interoperability, maintenance, upgrade-ability and long lifespan should be attended in such developments.

  • Ingila Rahim added an answer:
    How can we calculate the depth of convective zone of sun like stars or envelope of stars?

    I want to know when the convective zone of any star start to begin and what is the thickness of convective envelope. 

    Ingila Rahim

    Thank you sir Ken and madam E Nihal.

  • Amrit Sorli added an answer:
    Could Planck constant be a function of the gravitational potential?
    Kentosh and Mohageg looked through a year’s worth of GPS data and found that the corrections depended in an unexpected way on a satellite’s distance above the Earth. This small discrepancy could be due to atmospheric effects or random errors, but it could also arise from a position-dependent Planck’s constant.
    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Based on several assumptions to deduce a cosmological model with three fundamental constants along with the dimensionless electroweak coupling constant turned into functions of the gravitational potential. Initial research of this model has indicated solutions to avoid the singularity in both special relativity and general relativity.
    Amrit Sorli

    they both depend on density of quantum vacuum

  • Ingo H Leubner added an answer:
    Is dark energy merely an illusion?

    According to a report by Carlo Iorio and Timothy Clifton, dark energy may be an illusion. And LTb model or variations of it can be promising candidates to get rid of it. What do you think?

    Ingo H Leubner

    Dark Energy and dark Matter were introduced in cosmology when observations were made that did not agree with Newton’s models and other observations.

    Mainly, rotational behavior of galaxies were observed that could not be explained with ‘earth’ physics. Once the concepts of dark matter and energy were established, they became the daily tool of astronomers on large telescopes. I could solve many of observed astronomical enigmas (un-solvable puzzles) using standard ‘earth’ physics.  For instance, see my publication at Researchgate about ‘Why and When a Wet Mars?’. It changed -3.6 Byrs ago, and was concurrently derived from observations on Mars. Thank you for your interesting questions! Ingo

  • O. M. Guilera added an answer:
    Does anyone know about planet migration and outcomes?

    It has been shown (in 2010) that planets which undergo Type I migration usually migrate towards a point in the disk called as "planet trap".

    I am curious what will be the result if many planets in the disk migrate towards the same planet trap. Will they collide causing fragmentation or forming bigger planets? Or maybe they wont collide and start orbiting around their center of mass?


    O. M. Guilera

    Dear Antranik,

    here there are some references about your concern:

  • Hitesh Changela added an answer:
    Are there any "Triple Planets"?

    Double planets- two planetary mass objects orbiting each other- have already been detected.

    My question is whether or not "triple planets" exist? In fact, are there any detections? If there are no detections, what are the reasons which prevent triple planets to exist? I even see that it is not classified as planet type in the link below.

    I really appreciate all the answers.

    Hitesh Changela

    That's cool! I guess I was trying to get at some conditions for a planet to be a planet in the first place. Let's take our favorite Pluto. Pluto and Charon don't have the barycentre in their volumes, correct? So is that a binary system of dwarf planets? Then think of Mars, clearly it has 2 moons. In that system of Phobos, Deimos and Mars can it be justified to have that as a system of 3 planets rather than exclusively a planet and 2 moons? I'm just shooting the breeze here, but great Q & A!

  • Ivan Grosz added an answer:
    How significant is the discovery of Kepler-186f, an earth-sized habitable zone planet?
    Kepler-186f is the first earth-sized planet located in the habitable zone of another star that has been discovered. With this discovery, the search for life on other planets has entered into a new zone of discovery.
    Ivan Grosz

    No objection, but my calculations give an overview of all possible galactic habitability scenarios based on non-controversial mathematical principles.  My few basic assumptions try to help identify the high probability scenarios. The conclusion is straightforward. Existence of a substantial number of habitable planets with advanced civilizations most likely distributed over the Galaxy's habitable time span.

  • Igor Urusovskii added an answer:
    How do cosmologists determine the curvature of the universe based on astronomical data?

    Almost all cosmologists agree that the curvature of the universe is “flat” (k=0). Obviously this conclusion is based on solid astronomical observations - data. My question then is: Is there direct observational evidence that shows the universe is flat or is this conclusion solely a model-dependant parameter?

    Igor Urusovskii

    I. A. Urusovskii, Multidimensional   Treatment of the Expanding Universe,

     Physical Science International Journal, 4(8): 1110-1144, 2014

  • Reed Schmell added an answer:
    Does anyone know of any commercial high-reflectance (>98% in 300-400 nm) mirror film (thin flexible film)?
    I am looking for reflective mirror film (specular flexible film) which has high reflectance (>98%) in the UV region (300 - 400 nm) in order to use it in our astrophysics project. There are some products in the market (e.g. ESR by 3M), but all of them do not have high reflectance for wavelengths below 400 nm. It is technically possible to make such film if multi-layer coating is used, but a custom order will be very expensive.

    I would very appreciate it if you could tell me any nice products.
    Reed Schmell

    You can coat Mylar or Upliex with an Enhanced Al coating using reactive DC magnetron sputtering.

  • G. Bothun added an answer:
    How does the chemistry of the secondary MS star change before and after the CE phase?

    I am trying the understand the chemical evolution of the secondary MS star of a pair of close MS binary. When the primary star evolved and had the envelope ejected, C/N/O would be accreted by the secondary hence there would be enrichments (Marks & Sarna 1998). However, what happens to the heavier elements, do we assume the primary and secondary MS stars have the same, for example, [Fe/H] throughout the evolution?

    G. Bothun

    well that changes the situation considerably so yes, both stars should have the same Fe/H as there is no ability for local enhancement.  Only accretion of heavy elements from the ISM would change the surface Fe/H on the WD but that WD would have had to have been exposed to the ISM for a few Gyrs for any effect to occur.

  • Douglas Frederick Drye added an answer:
    How do we know Earth's precession period is 26,000 years?
    How do we get this measurement since man has not yet measured a full cycle of precession. In 26,000 years (or whatever the exact time is) will Polaris be in the exact same position, or is there likely to be some kind of variation?
    Douglas Frederick Drye

    This paper will probably tell you more than you could ever want to know about the question: 

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