Astrophysics/Questions
| Subject | Date Asked | Expert |
| speed of light | 2/9/2012 | Steve Nelson |
| Q: Some of the kids in my calculus class that are also in physics asked the whole class a seemingly ... A: You're invoking impossibility, traveling at the speed of light when you have mass and that would ... | ||
| Astonomy / Physics | 1/31/2012 | Philip A. Stahl |
| Q: 1. An asteroids closest approach to the Sun (perihelion) is 2AU and farthest distance from the sun ... A: Okay, let's make it more concrete using the problem below - with the accompanying diagram as a ... | ||
| Astonomy / Physics | 1/31/2012 | Philip A. Stahl |
| Q: 1. An asteroids closest approach to the Sun (perihelion) is 2AU and farthest distance from the sun ... A: This sounds suspiciously like a homework problem which I don't do. However, I can provide some ... | ||
| Time dilation and expansion of the universe | 1/27/2012 | Philip A. Stahl |
| Q: Why don´t the time dilation neutralize the effect of a universe which seems to expand in an ... A: You raise an intriguing question and one which, certainly at first glance, appears to have or ... | ||
| Ric Ross questioin -infinite gravitational force | 1/12/2012 | Philip A. Stahl |
| Q: Having to do with infinite gravitational force. Black holes have infinite gravitational force. ... A: "Infinite gravitational force" is kind of a poor description of what's going on. Also, the new ... | ||
| Auroral magnetic bottle problem | 1/4/2012 | Philip A. Stahl |
| Q: Your assistance in the previous self-study problem I had was so much appreciated, I wondered if you ... A: Okay, like the previous solution I provided for your self-study this is fairly straightforward. You ... | ||
| Plasma orbit theory & magnetosphere | 1/2/2012 | Philip A. Stahl |
| Q: I am very interested in the aurora but want to get beyond the pretty pictures to the physics. I have ... A: It is nice to see someone doing self study in basic plasma physics, especially as it can help to ... | ||
| Black Hole - Holographic Principle | 12/23/2011 | James Gort |
| Q: The holographic black hole principle sounds like a record or dvd full of information but when ... A: I'm afraid I don't agree or disagree with the Holographic Principle. I just don't know, and from ... | ||
| comets and Jupiter | 12/20/2011 | James Gort |
| Q: James, I've heard many times about the high percentage of comets that have not hit the earth due to ... A: The main compelling evidence for the asteroid theory seems to be the widespread bombardment at the ... | ||
| comets and Jupiter | 12/19/2011 | James Gort |
| Q: James, I've heard many times about the high percentage of comets that have not hit the earth due to ... A: Very interesting question! But until recently, little research was done to back up the claim that ... | ||
| Expanding universe | 12/9/2011 | James Gort |
| Q: I know that the universe is expanding at an accelerating rate. Will the speed of the expansion ever ... A: First, I know some Nobel Prizes were awarded for the "discovery" of the accelerating universe. So I ... | ||
| deep-space exploration | 12/7/2011 | Steve Nelson |
| Q: I wonder why they continue to launch deep space missions from the earth's surface when the vehicle ... A: You should be concerned about energy expenditures, they're the primary consideration in spaceflight. ... | ||
| deep-space exploration | 12/6/2011 | Steve Nelson |
| Q: I wonder why they continue to launch deep space missions from the earth's surface when the vehicle ... A: You still have to get the materials up to orbit to build the vehicle out of. That takes more energy ... | ||
| venus | 12/5/2011 | James Gort |
| Q: I have read that in the craters of venus ice has been detected. Is this true? A: No, there's no liquid water or ice. The surface temperature is several hundred degrees. Some ... | ||
| orbital bodies | 12/4/2011 | Steve Nelson |
| Q: Steve, I hope you can help me get a grasp on something rather basic. I know that bodies with ... A: You'll be at higher speed if you do it instantaneously you'll enter an elliptical orbit which will ... | ||
| physics | 12/3/2011 | James Gort |
| Q: sir why the value of g gets changed when it suddenly stops spinning?and sir by any mean can the ... A: An object which is spinning is in an accelerating reference frame. "g" is the "gravitational ... | ||
| black holes | 11/28/2011 | Steve Nelson |
| Q: i was wondering if it was possible to see into a black hole.lets say we had the worlds most powerful ... A: No, it's not possible. Wireless cameras broacast via light (radio waves are light) and light can't ... | ||
| microgravity | 11/26/2011 | Steve Nelson |
| Q: Sir,what do you mean by microgravity please explain? & sir what type of experiments can be performed ... A: I didn't coin the term, so it's kind of improper to ask me what *I* mean by it. Experiments in ... | ||
| matter/dark matter ratio | 11/23/2011 | Steve Nelson |
| Q: I am just wondering; do we know whether the ratio between matter and dark matter is constant? Does ... A: I'll say it this way: 1) People in physics are ABSOLUTELY obsessed with dark matter and come up ... | ||
| Maxwell and the Speed of LIght | 11/4/2011 | Philip A. Stahl |
| Q: Did James Maxwell's calculation of the speed of light state that light's speed would vary inversely ... A: Bear in mind that the density of interstellar gas in a black hole’s vicinity is likely to be ... | ||
| Maxwell and the Speed of LIght | 11/4/2011 | Philip A. Stahl |
| Q: Did James Maxwell's calculation of the speed of light state that light's speed would vary inversely ... A: Maxwell's key wave equations actually say nothing about light propagating with a velocity that will ... | ||
| Gliese 581 | 10/30/2011 | James Gort |
| Q: Dr. Gort, Although I am not formally educated, I am, like many others, a fan of cosmology. I am ... A: Although your son may eventually be able to get there, please explain to him that we'll have to ... | ||
| Expansion of the universe trough diffusion | 10/20/2011 | Philip A. Stahl |
| Q: After viewing an episode of "trough the wormhole" I was left pondering about dark matter and dark ... A: The problem with comparing the diffusion of ink spreading through water with the accelerating cosmic ... | ||
| Polar Lights | 9/30/2011 | Steve Nelson |
| Q: I'm not sure if you're the right person to ask, but I didn't see anyone who seemed like a definite ... A: I somehow answered this and it never got posted. In a nutshell, there are no specific frequency ... | ||
| electromagnetic waves | 9/30/2011 | Philip A. Stahl |
| Q: sir pls tell why radio waves are non polarizing while light waves are A: I'm not sure where exactly you got the idea that radio waves are not polarized, but they are. For ... | ||
| Ref: question | 9/11/2011 | Philip A. Stahl |
| Q: Good day How does spectroscopic analysis work and how do we know what we know about the light from ... A: This is simply too vast an area to casually address in a forum like this, so I post several links ... | ||
| titans | 9/10/2011 | Philip A. Stahl |
| Q: Titan, one of Saturn's many moons, has an atmosphere, but our own Moon does not. What is the ... A: The bottom line is there's no easy explanation. ON the face of it, given Titan is about the same ... | ||
| speed of light | 9/6/2011 | James Gort |
| Q: It is said that nothing,even information,can exceed the speed of light in this universe.However if ... A: What you're missing is that no rod is truly "rigid". For instance, steel has a carbon and iron ... | ||
| waves | 9/6/2011 | Steve Nelson |
| Q: sir please tell me the difference and similarities between radio signals(waves) and light waves A: Radio waves are a form of electromagnetic waves, just like light waves. By light waves, I'll assume ... | ||
| Cosmological Expansion or Transition? | 8/19/2011 | James Gort |
| Q: Is the Hobble observation conclusive evidence that our universe is expanding? Would there be an ... A: Yes, I think there would be an observable difference, but let me go through your scenario: If a ... | ||
| scientific notation | 8/17/2011 | James Gort |
| Q: My basic question is if it okay to write scientific notstion without using superscripts. For example ... A: There are basically three ways that I know of. But there should be a footnote or other explanation ... | ||
| light | 6/21/2011 | Philip A. Stahl |
| Q: 1]Can the speed of light be increased? 2]Is it possible for light to move objects? ANSWER: ... A: This site is rich in information, more than I could ever give at one time, and also full of ... | ||
| light | 6/20/2011 | Philip A. Stahl |
| Q: 1]Can the speed of light be increased? 2]Is it possible for light to move objects? ANSWER: ... A: No one knows 'why' light moves 'so fast', but that is also because in science we give more emphasis ... | ||
| light | 6/20/2011 | Philip A. Stahl |
| Q: 1]Can the speed of light be increased? 2]Is it possible for light to move objects? A: Answers: 1) No, the speed of light can't be increased. But, an addendum and proviso. In a paper ... | ||
| Dark energy | 6/13/2011 | Philip A. Stahl |
| Q: Can dark energy/dark matter be created? How can we detect dark matter/dark energy? Are there ... A: Whether dark energy can be created will depend on exactly what its nature is. So far this is an open ... | ||
| universe | 5/27/2011 | Philip A. Stahl |
| Q: (could be a stupid question) scientist say they see an explosion 13 billion light years from earth, ... A: Okay first, true - in general when one looks out at objects in space, e.g. stars, star clusters, ... | ||
| Two fluid theory | 5/18/2011 | Philip A. Stahl |
| Q: I'm not a student but just interested in plasma physics and have done lots of work on it, mostly ... A: Classification of differing fluid regimes is far beyond the scope of this answer, but you can find ... | ||
| Alien spacecraft | 5/17/2011 | Steve Nelson |
| Q: Can astrophysics explain the possibility of their existence utilizing cold plasma, electromagnetism ... A: "Astro"physics is just a subspecializition of physics. Physics Today (the professional magazine we ... | ||
| Astronomy | 5/4/2011 | James Gort |
| Q: I want to know that what will happen if Two Neutron stars or Two Black holes or a Neutron star and a ... A: If two neutron stars, two black holes, or a neutron star and a black hole came close to each other ... | ||
| average mass per particle | 4/12/2011 | Steve Nelson |
| Q: This is a follow up question - when calculating the Jeans mass to determine when a cloud will ... A: I don't answer homework question, and this isn't a follow-up to any question I've been asked before, ... | ||
Philip A. Stahl
Top Expert on this page
Expertise
I specialize in stellar and solar astrophysics. Can answer any questions pertaining to these areas, the spectroscopic analysis of stars – as well as the magneto-hydrodynamics of sunspots and solar flares. Sorry – No homework problems done or research projects! I will provide hints on solutions.
Experience
Have published papers on the relationship between sunspot morphology and solar flares; discovery of SID flares related to this, constructed computerized stellar models; MHD research.
Organizations
American Astronomical Society (Solar physics and Dynamical astronomy divisions), American Geophysical Union, American Mathematical Society, Intertel.
Publications
Solar Physics, Journal of the Royal Astronomical Society of Canada, Journal of the Barbados Astronomical Society, Meudon Solar Flare Proceedings (Meudon, France)
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
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