New type of matter demonstrated

Post #35,049 by ben_tilly 4/10/02 9:54:37 PM Reply	New type of matter demonstrated [link\|http://www.cnn.com/2002/TECH/space/04/10/new.matter/index.html\|Story]. Note that they are thinking a quark version of a neutron star. Personally I am curious whether this is in line with what the Yilmaz theory would predict when a neutron star gets too big to stay stable... Cheers, Ben "... I couldn't see how anyone could be educated by this self-propagating system in which people pass exams, teach others to pass exams, but nobody knows anything." --Richard Feynman
Post #35,073 by Ashton 4/11/02 12:17:09 AM Reply	"11.3 km" diameter? 1% accuracy ?? Other than the detail of suspiciously high precision.. I have no mathematical or physical idea of what 'quark-matter' might behave like - not enough info ('course he kinda said that). I suspect though, that accelerator physics won't be the method of next resort... Ashton
Post #35,084 by ben_tilly 4/11/02 6:23:27 AM Reply	I suspect that precision is reporter stupidity They just translated from one unit system to another and put in extra decimal places. The same way that we all have branded on our memories that human body temperature is 98.6F when it varies by a couple of degrees from person to person and through the day. Truth is it was measured as 37C and then people converted that exactly. That said, I am wondering how they produced a diameter... Cheers, Ben "... I couldn't see how anyone could be educated by this self-propagating system in which people pass exams, teach others to pass exams, but nobody knows anything." --Richard Feynman
Post #35,217 by a6l6e6x 4/11/02 9:35:27 PM Reply	Yep, probably originally stated as 7 miles. Alex "Never express yourself more clearly than you think." -- Neils Bohr (1885-1962)
Post #35,103 by boxley 4/11/02 11:10:44 AM Reply	Maybe I missed something "At least, until astronomers using the Chandra X-ray Observatory spied two presumed neutron stars, RXJ1856 and 3C58. Based on the known laws of physics, the former appeared much smaller and the latter much colder than they should" if one is smaller and the other colder, then different burn rates would indicate different materials or processes? thanx, bill TAM ARIS QUAM ARMIPOTENS
Post #36,001 by scoenye 4/19/02 1:01:58 PM Reply	No more burning There is no fuel to burn. These are giant cinders radiating their left-over heat into the vacuum of space. Bottom line is that all their properties are determined by their mass (through gravitation.) The mass of a neutron star is constrained on the high end by gravity and on the low end by the minimum it takes to allow a star to go supernova. Based on the understanding of all the forces in play, if you can estimate the mass, you can calculate its size. So when you find one that is significantly smaller/larger than expected, either the mass estimate is wrong, your measurements are wrong, or the thing isn't made up of neutrons. I suspect a similar line of reasoning for the colder object based on specific rates of heat radiation for neutron matter.
Post #36,079 by ben_tilly 4/21/02 4:06:55 PM Reply	My guess Keep in mind that this is just a guess. They determined the temperature by comparing with the well-known [link\|http://www.phys.virginia.edu/CLASSES/252/black_body_radiation.html\|black body spectrum] to find the temperature. Once they find a temperature, assuming that they have an estimate of the distance (probably done by estimating the distance to the nebula associated with the supernova), they can then look at how bright it is and figure out how big it's cross-sectional area is. Which leads me to wonder how they ruled out any number of options. For instance with the dim one, what if there is just a dust cloud between us and it? (Say, there happened to be a bulge in the nebula between us and it. For a sideways picture of what that might look like go [link\|http://www.cosmiverse.com/reflib/Image_Gallery/messier/messier7.html\|here].) As for the cold one, suppose that neutron stars can go through a phase transition of some sort (much like freezing in regular materials), then it could have cooled off rather suddenly from currently unknown internal dynamics. Rather more prosaic than claiming a new form of matter, but both seem like plausible options to me. (Note that a lot of astronomy rests on very long chains of assumptions. What they are trying to find out is very hard to verify.) Cheers, Ben "... I couldn't see how anyone could be educated by this self-propagating system in which people pass exams, teach others to pass exams, but nobody knows anything." --Richard Feynman
Post #35,104 by neelk 4/11/02 11:21:12 AM Reply	Re: New type of matter demonstrated That's pretty cool. I remember speculating about them with one of my professors -- he thought it was unlikely, that the whole thing would collapse into a black hole before you could get anything else. It's good to know that the universe still has a few surprises in it. :)

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