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On 8/22/2019 at 12:57 AM, tkdguy said:

 

The August 24, 2019 issue of The Economist also has a good article about the black hole-neutron star detection. Astronomers especially want to observe such an event in other ways, too, because it might give a glimpse of what's inside a neutron star. Astrophysicists have theories -- including blobs, threads and sheets of neutronium they've dubbed "nuclear pasta" -- but without some way to probe inside a neutron star, they can never test the theories. A black hole, however, can rip a neutron star apart so its insides become briefly visible.

 

(According to Jack Vance, this is where ioun stones come from. See, IIRC, the short story "Morreion" in the "Dying Earth" cycle.)

 

Dean Shomshak

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I saw the neutron star episode of Discovery Science's How The Universe Works yesterday. Fascinating subject and knowledgeable expert interviewees, but oh so American -- unnecessarily upping the drama, unnecessarily repeating bullet points every ten minutes, and a narrator that sounded stoned.

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9 hours ago, DShomshak said:

 

 

(According to Jack Vance, this is where ioun stones come from. See, IIRC, the short story "Morreion" in the "Dying Earth" cycle.)

 

Dean Shomshak

 

Sort of. They were found in the cores of stars (I don't recall that he specrified neutron stars) and were exposed when a star brushed against the physical edge of the universe, beyond which was "Nothing."  The part of the star that would have extended beyond that black border of the cosmos simply ceased to exist, leaving the core temporarily exposed.

 

Lucius Alexander

 

The palindromedary reassures me that Nothing Threatens Morreion.

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On 9/3/2019 at 4:38 AM, Lucius said:

Sort of. They were found in the cores of stars (I don't recall that he specrified neutron stars) and were exposed when a star brushed against the physical edge of the universe, beyond which was "Nothing."  The part of the star that would have extended beyond that black border of the cosmos simply ceased to exist, leaving the core temporarily exposed.

 

Lucius Alexander

 

The palindromedary reassures me that Nothing Threatens Morreion.

"...Occasionally we saw the corpses of dwarf stars,glistening balls of stuff so heavy that a speck outweighs an Earthly mountain. I saw such objects no more than ten miles across, containing the matter of a sun like vast Kerkaju. Inside these dead stars, the archveults told me, were to be found the IOUN stones."

--"Morreion," in Rhialto the Marvellous, p. 207

 

Sounds like a neutron star to me. But yes, it was sloppy not to include that in the story the stones were obtained by other means than a black hole. Having a neutron star ripped apart by a black hole presumably would also work, but would likely be even more dangerous to collect.

 

Dean Shomshak

 

I'd trust what your palindromedary says. It may be two-faced, but it's still more trustworthy than an archveult.

 

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5 minutes ago, DShomshak said:

"...Occasionally we saw the corpses of dwarf stars,glistening balls of stuff so heavy that a speck outweighs an Earthly mountain. I saw such objects no more than ten miles across, containing the matter of a sun like vast Kerkaju. Inside these dead stars, the archveults told me, were to be found the IOUN stones."

--"Morreion," in Rhialto the Marvellous, p. 207

 

Sounds like a neutron star to me.

 

To me too, now you've quoted the original text at me. I apologize; I did not remember the story as well as I thought I did.

 

Lucius Alexander

 

5 minutes ago, DShomshak said:

I'd trust what your palindromedary says. It may be two-faced, but it's still more trustworthy than an archveult.

 

 

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On September 2, 2019 at 7:08 PM, DShomshak said:

 

The August 24, 2019 issue of The Economist also has a good article about the black hole-neutron star detection. Astronomers especially want to observe such an event in other ways, too, because it might give a glimpse of what's inside a neutron star. Astrophysicists have theories -- including blobs, threads and sheets of neutronium they've dubbed "nuclear pasta" -- but without some way to probe inside a neutron star, they can never test the theories. A black hole, however, can rip a neutron star apart so its insides become briefly visible.

 

(According to Jack Vance, this is where ioun stones come from. See, IIRC, the short story "Morreion" in the "Dying Earth" cycle.)

 

Dean Shomshak

 

The equation of state (the relationship between pressure, density, temperature, etc.) for cold nuclear matter is not known very well.  What particle accelerators give you is data on hot nuclear matter.  ("Cold" means the kinetic energy of the particles is small compared to the mass-energy of the particles; "hot" means the kinetic energy is approaching or exceeding the mass energy.)  Neutron stars are big globs of gravity-confined cold nuclear matter.  Heck, even getting a well-measured diameter and mass for a neutron star would be a big, big win.

 

Knowledge of that EqOfSt is so poor that macroscopic considerations are important constraints.  In the graph of pressure vs density for nuclear matter -- a graph that is really badly known -- you can exclude big swaths on the basis of "unstable" (the pressure would not be high enough to prevent neutron stars and even atomic nuclei from collapsing to zero radius under their own gravity or nuclear binding force), and other big swaths on the basis of "acausal" -- that is, sound waves would travel faster than light, which is impossible.  That core collapse supernovae explode tells you that nuclear matter is really stiff (i.e. it takes enormous pressure to compress nuclear matter), but that's nothing like the details you'd like to know.

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The article also suggests that observing a third class of event means gravitational astronomy has come of age as its own branch of science, rather than just an oddball technique for detecting one or two very specific types of events. But the real prize will be when gravitational astronomers detect some event that can't be mapped onto any known entity. Primordial gravitational waves from the Big Bang? Cosmic strings cracking the whop? Something even the wildest theories have not yet imagined? Gravitational astronomy might also enable testing of general relativity under conditions far more extreme than can be achieved on Earth. Heady stuff, at least for science nerds.

 

Dean Shomshak

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The article also suggests that observing a third class of event means gravitational astronomy has come of age as its own branch of science, rather than just an oddball technique for detecting one or two very specific types of events. But the real prize will be when gravitational astronomers detect some event that can't be mapped onto any known entity. Primordial gravitational waves from the Big Bang? Cosmic strings cracking the whop? Something even the wildest theories have not yet imagined? Gravitational astronomy might also enable testing of general relativity under conditions far more extreme than can be achieved on Earth. Heady stuff, at least for science nerds.

 

Dean Shomshak

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On 9/3/2019 at 11:53 AM, archer said:

 

Corporate mergers are bad enough. If celestial bodies start merging on a regular basis as well, I'm out of here!

 

Now I'm really curious as to where you expect to go "out" to where there are no celestial bodies.

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Water vapor claimed detection for an 8-earth-mass planet orbiting a M2.5V star

 

Planet's in a 33-day orbit; this is a star from the extended Kepler mission (from which it was a habitable zone candidate) with subsequent observation & analysis from other sources.

 

That link is to the arXiv preprint so it'll be a thick read, but it shows the transit lightcurve as a function of wavelength and the reconstruction of the planet spectrum.

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Very briefly, the presence of a cloud deck means the path length of the light through the atmosphere is less than the full geometric depth of the atmosphere, which can alter the strength of the absorption features in the observed spectrum.  Also, a cloud deck can alter the broadband color of the atmosphere, depending on the size (but not composition) of the particles making the clouds; wavelengths much smaller than the size of the cloud particles are scattered differently than wavelengths longer than the cloud particle size (see "Rayleigh scattering").

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On September 2, 2019 at 11:38 PM, L. Marcus said:

I saw the neutron star episode of Discovery Science's How The Universe Works yesterday. Fascinating subject and knowledgeable expert interviewees, but oh so American -- unnecessarily upping the drama, unnecessarily repeating bullet points every ten minutes, and a narrator that sounded stoned.

 

 

It's not so much about building the drama as it is keeping the modern American's three-minute attention span.

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12 minutes ago, L. Marcus said:

But what about the narrator? "I am stoned. I ought not be stoned, so as to not sound stoned I must enounce every word verrry clearly, stonedly."

 

 

The tragical truth about the Discovery channel is that it hasn't been educational for _years_.  That's why the stuff with actual interesting tidbits comes on at odd hours and utilizes the services of narrators guaranteed to cure your insomnia.

 

 

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I'm reading The Planets by Andrew Cohen "with" Professor Brian Cox (the cover includes is title), the companion book to the BBC/Nova series. Very interesting and almost as pretty as the TV series. Good to get some of the science behind the visuals. Professor Cox's chapter on Mars seems the best so far, going into more detail about things like how to estimate the age of Martian topography. Andrew Cohen, however, could have used another editorial pass to deal with redundant sentences. Cohen's too-frequent use of the word "vast" also became obtrusive for me. Yes, much of the Solar System is very big, but there are other words.

 

Dean Shomshak

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On 9/12/2019 at 5:45 AM, Cancer said:

Water vapor claimed detection for an 8-earth-mass planet orbiting a M2.5V star

 

Planet's in a 33-day orbit; this is a star from the extended Kepler mission (from which it was a habitable zone candidate) with subsequent observation & analysis from other sources.

 

That link is to the arXiv preprint so it'll be a thick read, but it shows the transit lightcurve as a function of wavelength and the reconstruction of the planet spectrum.

 

And it’s only 124 light years away. Road trip anyone?

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1 hour ago, DShomshak said:

I'm reading The Planets by Andrew Cohen "with" Professor Brian Cox (the cover includes is title), the companion book to the BBC/Nova series. Very interesting and almost as pretty as the TV series. Good to get some of the science behind the visuals. Professor Cox's chapter on Mars seems the best so far, going into more detail about things like how to estimate the age of Martian topography. Andrew Cohen, however, could have used another editorial pass to deal with redundant sentences. Cohen's too-frequent use of the word "vast" also became obtrusive for me. Yes, much of the Solar System is very big, but there are other words.

 

Dean Shomshak

 

So you're saying the writers could have vastly benefited from a more vast vocabulary?

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5 hours ago, DShomshak said:

I Cohen's too-frequent use of the word "vast" also became obtrusive for me. Yes, much of the Solar System is very big, but there are other words.

 

Dean Shomshak

 

 

I understand your pain so very well.

 

I have sworn to throat-stab anyone who, in my presence, uses the word "space" more than twice when describing home decor or floor plans.

 

 

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