Starship Asterisk*

I think the determining factors will ultimately be determined by physics. I think testable physical differences between fogbows and glories should decide this. Does anyone know of anything definitive that would clearly decide between the two possibilities in this case? Rob, I'd like to share my tho...

These are links to the only two articles I could find on cloud droplet size distribution. http://ramanlidar.gsfc.nasa.gov/activities/publications/data/cloudliqwateretc.pdf http://langley.atmos.colostate.edu/publications/Documents_1978/Stephens_JAS_I_1978.pdf Is it possible that the fogbow and glory...

This is NOT a glory. The title and caption are incorrect. It is a fogbow. A fogbow is similar to a rainbow but produced by small mist and fog droplets rather than raindrops. Significant diffraction occurs in the small droplets causing the bow to be diffuse, with weak color and multiple supernumerar...

The phenomenon has a counterpart in astronomy, where looking out from planet Earth in the direction opposite the Sun yields a bright spot called the gegenschein . I like the photo, and I don't mean to quibble, but the gegenschein is far from a "bright spot". I believe a reasonable brightn...

Thank you very much, alter-ego. If the impact angle, theta, were less than zero, I could simply substract E(k) from the energy conservation equation to obtain the resulting angular velocity. Of course, the solution for w(1) would necessarily be different. Is this correct ? Also, if the primary body...

yes my sentence was wrong. what i meant was that the 7times/sec pulses may not be necessarily because of the rotation around the axis of rotation; they may be the result of another motion like Precession . could it be? In principle, I suppose a very newly created pulsar might precess, and if its em...

O what big eyes! Even bigger eyes (this is a dragonfly I imaged when it landed on me...) Not many bugs are considered "cute", but I think this little fellow qualifies. That's a really great shot! It looks like it took a liking to you. Even if your camera wasn't handy (was it??), the bug p...

The more I look, the more it looks to me like this guy belongs there. Those dark glasses look nothing like what people wear today. Anybody trying to be a little cool wouldn't be caught dead in that sweater. The "modern" appearance is very superficial, and amplified by the very traditional...

Pretty nice batch of galaxies. In the Coma cluster, I once counted at least 30 galaxies in the FOV of a 6" Newtonian. It was likely this same area. The field of view is ~35', just a little more than a full moon. Here is the star chart for the uncropped picture : http://www.jburnell.com/AGC1656...

Pretty nice batch of galaxies. In the Coma cluster, I once counted at least 30 galaxies in the FOV of a 6" Newtonian. It was likely this same area. The field of view is ~35', just a little more than a full moon. Here is the star chart for the uncropped picture: http://www.jburnell.com/AGC1656Co...

Is the number of members and topics correlated? I doubt it. Now that I submitted this topic, a new member has to join.

There are more details to be defined before a single-equation solution can had. The densities and post-collision distribution of the masses are needed. A simpler, tractable model could be: 1. The smaller colliding mass hits on the equator (equatorial plane perpendicular to the rotation axis). 2. Th...

There are more details to be defined before a single-equation solution can had. The densities and post-collision distribution of the masses are needed. A simpler, tractable model could be: 1. The smaller colliding mass hits on the equator (equatorial plane perpendicular to the rotation axis). 2. The...

Yes. Magnetic breaking is considered a fundamental mechanism for transferring angular momentum in single and (close) multiple star systems. We don't really know the Sun's formation enviroment, but growth in a cluster can play a role too. http://iopscience.iop.org/0004-637X/599/1/516/pdf/0004-637X_59...

...however, my concern here is that if c is used to calculate 2.5GHz value, then we are not actually measuring anything. Ditto. As mentioned, microwaves are designed to prevent standing waves, certainly fundamental ones, which are what you want to measure. My guess is the hot spots will only be sli...

... But I'm often surprised by the clever ways people come up with to extract what would seem like impossible to know information. Chris, I think this is one of those times. There are really two questions posed that I think I understand better, and are now reasonably answered: 1. The posted radial ...

...If you don't know the axial tilt of the star, or the stellar latitude that the planet is crossing, how can you convert the observed wavelength shift to a velocity or period that applies to the star at its equator (the usual reference for stellar rotation)? You are absolutely right, and I am remi...

In fact, identifying anomolous radial velocity spectra is the method by which the retrograde orbiting exoplanets were discovered. For the retrograde orbit, the red-shifted planet perturbs the blue-shifted stellar limb. Both retrograde an prograde orbits have a distinct signiture on the radial veloc...

Can the rotational velocities of nearby single stars be measured using the Doppler affect if its alignment with Earth is appropriate? Of course, I know neutron stars or pulsar rotations are measured. Interferometric techniques are probably good enough now that a handful of stars might have their ro...

Hello hstarbuck, Thank you for the clarification on neutrino oscillation. I was in left field and a decade behind! I still thought there was a still solar deficit of neutrino production, so you helped me learn something new. I was actually not asking if gravity had mass, but if all gravity was tied ...

Generally speaking, I'm for any process that promotes astronomy to the public. I don't understand all the resource requirments to employ what you suggest, but even if it's low-level, low-maintainence web site, BB or whatever, ANY effort is worthwhile. Start easy and build on it if successful, BUT fo...

hstarbuck, It's funny, for some reason every time I see you post, I think of coffee... Anyway, you've asked several questions, and details abound. All great questions! First of all, everything has a wavelength whose value depends on energy. Quantum Mechanics dictates that only at Absolute Zero Tempe...

RJN, Excuse my ignorance, but what constitutes a problem, e.g. copyright violation? It seems like Twitter is based on "following". I didn't think one could start posting APODs or forum posts as a part of Twitter, but if I have a Twitter account, people decide to follow me, I can link to wh...

What makes up nuclear matter is one of the LHC experiments. Your point? There's is nothing in the discussion of dark matter about "nuclear matter". You are using a term that has no single definition, and which you haven't defined for us. What is "nuclear matter"? The term is usu...

It is interesting that the formation of a dipole was found, indicating a possible origin from the centre of a cluster of galaxies. Hi harry, I believe your statement is a bit misleading, and I apologize if I interpreted you wrong. The dipole Kashlinsky et al wrote about was determined to be statist...