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Astrophysics/Questions

SubjectDate AskedExpert
Experimental evidence for Universe Expansion12/10/2016Philip A. Stahl
  Q: I have heard about red-shift experiments that show that most stellar objects are receding from each ...
  A: First, it is incorrect to refer to "most stellar objects” receding from each other in the context of ...
superfluidity12/1/2016Dr. Stephen O. Nelson
  Q: what is superfluidity actually ?
  A: Superfluidity is a state where a fluid can flow with no viscosity, like liquid helium below 4 ...
Inflation & the multiverse10/25/2016Philip A. Stahl
  Q: I've been following popular science all my life, incl. aspects of cosmology, but recent news casting ...
  A: and thanks for your question. First, let me point out that the "multiverse" remains a reasonably ...
big bang9/24/2016Dr. Stephen O. Nelson
  Q: could the big bang be caused by one singularity being matter and another singularity being ...
  A: The word "singularity" implies that the laws of physics break down and we don't know what that ...
Earth obrit7/9/2016Dr. Stephen O. Nelson
  Q: I am not in the subject of physics, but keen to know about univers. Could I know that the earth ...
  A: The Earth is moving around the Sun due to the curvature of space. The planets are slowly moving ...
help6/27/2016Philip A. Stahl
  Q: Sir here is my question is related to matter. Sir why scientist have named everything around us as ...
  A: Empirical science is concerned with inquiry at every level, and in physics at the most fundamental ...
Shape of earth6/1/2016Philip A. Stahl
  Q: Why is our earth spherical like most other planets and stars? Couldn't it be flat or cubic? I may ...
  A: First, planets and stars acquire spherical shapes by different processes. Stars form from the ...
Habitable planets within 260000 light years5/7/2016James Gort
  Q: There's 260000 stars within 250 light years of us. So out of these 260000 stars how many are of the ...
  A: A recent study published in the "Monthly Notices of the Royal Astronomical Society" ...
gravity5/4/2016James Gort
  Q: How does gravity affects time? Expression of relation between time and gravityi
  A: The answer to your question can be very involved, and I'm not sure how mathematical you'd like the ...
Curious3/30/2016Philip A. Stahl
  Q: it is said that if - hypothetically - a space craft moved almost at the speed of light the space ...
  A: Actually in terms of special relativity it is the mass that is critical not the size. (Which is more ...
Dark matter3/24/2016Philip A. Stahl
  Q: Scientists know that there must be more mass than what is visible in galaxies as they manage to hold ...
  A: The conception of dark matter planets or solar systems for that matter is dependent on how well we ...
Red shift and expanding space....1/14/2016Dr. Stephen O. Nelson
  Q: One more question....As curved space curves light,does expanding space make light wavelenght longer ...
  A: Well, it should transition the wavelength of light. I'll have to look into the math to be sure, but ...
How much energy would be needed to generate a wormhole?1/12/2016Dr. Stephen O. Nelson
  Q: How much energy would be needed to generate a wormhole? I am not talking about specific numbers, ...
  A: You would need something on the order of the energy of an evaporating, spinning, massive black hole. ...
How much old the universe really is?....1/10/2016Dr. Stephen O. Nelson
  Q: If We look at the farthest objects in the observable universe We see quasars how they were 13.7 ...
  A: Your thinking about this problem will probably be eased with the addition of understanding that the ...
gravity and light1/7/2016Dr. Stephen O. Nelson
  Q: Please can You answer does gravity bend al frequencies of em-waves in the same way or not and why?
  A: The simple answer is that for all practical purposes, it does. It doesn't really "bend the light," ...
Black Hole Experiment12/22/2015Dr. Stephen O. Nelson
  Q: Dr. Nelson, I have tried now with multiple pumps and various types of tubing; however, the intake ...
  A: Wow, that doesn't seem possible. In fact, that result itself might be very interesting science and ...
Lagrange points12/3/2015Philip A. Stahl
  Q: What way would an object at L1 progress if pushed, say, directly towards earth? I figure it's period ...
  A: You say you 'can't work it out'. What exactly are you trying to work out? Velocity, acceleration, ...
Cosmic rays11/13/2015Dr. Stephen O. Nelson
  Q: How astronauts are protected from the cosmic rays in the space?
  A: They're generally still within the Earth's magnetic field when they're in orbit for long periods. ...
Climate11/8/2015Dr. Stephen O. Nelson
  Q: Do you have any idea why the weather changes?
  A: There are hundreds of factors causing the weather to change. On a day-to-day basis, the weather ...
Equation of motion for the radius of the universe10/31/2015Philip A. Stahl
  Q: I found that the formula of equation of motion for the radius of the universe is : R" = ...
  A: And thanks for your question. In answer to your question (1), the reason we have the second ...
AP Theory10/29/2015Dr. Stephen O. Nelson
  Q: I read your thoughts (answers), and agree with you, regarding the fact that due to weight of ...
  A: There are dozens and dozens of such science crackpots online. This isn't even the biggest one, and ...
Science Fair Help10/18/2015Dr. Stephen O. Nelson
  Q: Nelson, My name is Jonathan. I am in the 11th grade at my high school. Science Fair is fast ...
  A: In the 11th grade, I assume you want something more impressive than a 5th grader would do. ...
Does habitable planet mean a planet with life on them?10/1/2015Philip A. Stahl
  Q: I just read that Milky Way has a minimum of a billion and a maximum of a hundred billion habitable ...
  A: No, a "habitable planet" does not mean a planet bearing actual life, only potentially. It means the ...
Question about Venus' temperature.9/14/2015Dr. Stephen O. Nelson
  Q: How much would Venus cool down if it had rotated around itself as fast as the Earth does?
  A: Due to Venus's very thick carbon dioxide atmosphere, its temperature is actually largely due to the ...
How close to confirmed it is that our galaxy is 50% larger?9/13/2015Dr. Stephen O. Nelson
  Q: Greetings! On this year there where news about our galaxy being fifty percent larger than we had ...
  A: I'm going to preface this by saying that this is not in my direct research area of expertise. ...
Our galaxy cluster?8/19/2015Philip A. Stahl
  Q: I know we belong to the local group of galaxies and Virgo supercluster off galaxies but to which ...
  A: Actually, the Virgo supercluster is *also* called the Local supercluster and our local group belongs ...
Are planets around red dwarf stars habitable?8/12/2015Philip A. Stahl
  Q: Do red dwarf type stars have any chances of harboring life bearing planets on their orbits? Because ...
  A: Given red dwarf stars exhibit much lower surface temperature (4,000 F vs. 11,000 F for Sun) one ...
Photos from vacuum7/29/2015Philip A. Stahl
  Q: Good day. If we were placed in a vacuum to the electromagnetic field of high performance and ...
  A: I am not quite sure of the meaning of your question. Is it possible for you to rephrase it, to make ...
How many stars in this area?7/26/2015Philip A. Stahl
  Q: Greetings, Mr. Stahl. I am working on a fanfic of a science fiction franchise I am fond of. So ...
  A: First, let's change the units to parsecs instead of light years. Currently, the star density near ...
connection between blackholes and suns7/22/2015Philip A. Stahl
  Q: Is it possible that a blackhole and a sun act in tandem as a from of combustion engine. Where the ...
  A: You come up with an interesting proposition, but alas, it's a non-starter. For one thing there is no ...
Hubbles red shift6/2/2015Dr. Stephen O. Nelson
  Q: I was looking at some of your answers in astrophysics related question--- like Red shift. It appears ...
  A: Expansion of the universe (Hubble) gives us velocities for distant objects. This causes the Doppler ...
Quantum5/25/2015Philip A. Stahl
  Q: Can quantum fluctuation create something from "nothing" (a vacuum)? In quantum cannot electrons and ...
  A: Charles First, 'nothing' in physics terms is generally taken to refer to a negative energy quantum ...
Appearance of the MCs before gravitational distortion?5/17/2015James Gort
  Q: So the Milky Way pretty much destroyed the appearance of Magellanic Clouds with its gravitational ...
  A: Almost but not quite. Many speculate that the Magellanic Clouds were barred spirals before being ...
Zeeman effect in sunspots5/17/2015Philip A. Stahl
  Q: Can you give me a quantitative example of how the Zeeman effect can be used to find the magnetic ...
  A: The classic Zeeman effect occurs in "triplet" form and can be quantified as George Ellery Hale ...
Size of the universe through the ages5/15/2015James Gort
  Q: there is a diagram where i can see the dimension of universe in function of time ? I know that the ...
  A: This is a very difficult question to answer, for three main reasons: 1) We don't know the current ...
Size of the universe5/6/2015James Gort
  Q: Galaxy EGS-zs8-1 was recently discovered and is said to be the oldest galaxy we know of. It is said ...
  A: This question requires a lengthy answer. But the confusion lies, I think, in the published ...
How many habitable planets are in the Milky Way?4/10/2015James Gort
  Q: So I am working on worldbuilding a science fiction story and I need some consultation on how many ...
  A: I can give you a wild guess based on my estimates of total number of stars in the Milky Way (more ...
How many stars are in our local galaxy group?4/7/2015Philip A. Stahl
  Q: How many stars have been estimated to be in our local galaxy group?
  A: By "local galaxy group" I presume you mean the Milky Way galaxy. However, the estimate is not a ...
How far are these places in this picture?3/31/2015Philip A. Stahl
  Q: I am a fan of Mass Effect video game series (as my email name might suggest :D ) and in the game ...
  A: Unfortunately, there isn't enough information given to make such a distance determination. While the ...
The appearance of dwarf galaxies.3/30/2015James Gort
  Q: Why are the dwarf galaxies so much different looking than the bigger ones like the one we live in? ...
  A: This question is one of much current research. It seems that galaxy formation is a very complicated ...

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Philip A. Stahl

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Expertise

I specialize in stellar and solar astrophysics. Can answer questions pertaining to these areas, including: stellar structure and evolution, HR diagrams, binary systems, collapsars (black holes, neutron stars) stellar atmospheres and the spectroscopic analysis of stars – as well as the magnetohydrodynamics of sunspots and solar flares. Sorry – No homework problems done or research projects! I will provide hints on solutions. No nonsense questions accepted, i.e. pertaining to astrology, or 'UFOs' or overly speculative questions: 'traveling through or near black holes, worm holes, time travel etc. Absolutely NO questions based on the twaddle at this Canadian site: http://members.shaw.ca/warmbeach/FAQ.htm purporting to show a "new physics". Do not waste my time or yours by wasting bandwidith with reference to such bunkum.

Experience

Have constructed computerized stellar models; MHD research. Gave workshops in astrophysics (stellar spectroscopy, analysis) at Harry Bayley Observatory, Barbados. More than twenty years spent in solar physics research, including discovery of SID flares. Developed first ever consistent magnetic arcade model for solar flares incorporating energy dissipation and accumulation. Developed first ever loop-based solar flare model using double layers and incorporating cavity resonators. (Paper presented at Joint AGU/AAS Meeting in Baltimore, MD, May 1994)

Organizations
American Astronomical Society (Solar physics and Dynamical astronomy divisions), American Geophysical Union, American Mathematical Society, Intertel.

Publications
Papers appearing in Solar Physics, Journal of the Royal Astronomical Society of Canada, Journal of the Barbados Astronomical Society, Meudon Solar Flare Proceedings (Meudon, France). Books: 'Fundamentals of Solar Physics', 'Selected Analyses in Solar Flare Plasma Dynamics', 'Physics Notes for Advanced Level', 'Astronomy & Astrophysics: Notes, Problems and Solutions', 'Modern Physics: Notes, Problems and Solutions'

Education/Credentials
B.A. degree in Astronomy; M.Phil. degree in Physics - specializing in solar physics.

Awards and Honors
Postgraduate research award- Barbados government; Studentship Award in Solar Physics - American Astronomical Society. Barbados Astronomical Society award for service (1977-91) as Journal editor.

Past/Present Clients
Caribbean Examinations Council (as advisor, examiner), Barbados Astronomical Society (as Journal Editor 1977-91), Trinidad & Tobago Astronomical Society (as consultant on courses, methods of instruction, and guest speaker).

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