Does this rule out cosmic natural selection? (1.97 solar neutron star)

[marcus]

A letter in the current issue of Nature:
==quote==
A two-solar-mass neutron star measured using Shapiro delay

P. B. Demorest1, T. Pennucci2, S. M. Ransom1, M. S. E. Roberts3 & J. W. T. Hessels4,5

National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, Virginia 22093, USA
Astronomy Department, University of Virginia, Charlottesville, Virginia 22094-4325, USA
Eureka Scientific, Inc., Oakland, California 94602, USA
Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo, The Netherlands
Astronomical Institute “Anton Pannekoek”, University of Amsterdam, 1098 SJ Amsterdam, The Netherlands

Abstract
Neutron stars are composed of the densest form of matter known to exist in our Universe, the composition and properties of which are still theoretically uncertain. Measurements of the masses or radii of these objects can strongly constrain the neutron star matter equation of state and rule out theoretical models of their composition1, 2. The observed range of neutron star masses, however, has hitherto been too narrow to rule out many predictions of ‘exotic’ non-nucleonic components3, 4, 5, 6. The Shapiro delay is a general-relativistic increase in light travel time through the curved space-time near a massive body7. For highly inclined (nearly edge-on) binary millisecond radio pulsar systems, this effect allows us to infer the masses of both the neutron star and its binary companion to high precision8, 9. Here we present radio timing observations of the binary millisecond pulsar J1614-223010, 11 that show a strong Shapiro delay signature. We calculate the pulsar mass to be (1.97 ± 0.04)M⊙, which rules out almost all currently proposed2, 3, 4, 5 hyperon or boson condensate equations of state (M⊙, solar mass). Quark matter can support a star this massive only if the quarks are strongly interacting and are therefore not ‘free’ quarks12.
==endquote==
http://www.nature.com/nature/journal/v467/n7319/full/nature09466.html

 

[marcus]

I seem to recall that when Lee Smolin proposed his CNS hypothesis (some 15 or more years ago) he said it would be falsified if a neutron star was found with mass exceeding 1.6 solar*.

If I am not misremembering the number, the idea was that if fundamental particle masses were adjusted perfectly to produce abundant black holes, then a neutron star with mass exceeding 1.6 solar would be able to collapse and form a black hole.

The fact that one observes a neutron star with mass 1.97 seems to indicate that Nature is not perfectly adjusted to produce as many black holes as possible.

I may be mistaken. In any case we should be hearing more about this. The discovery of such a massive neutron star is exciting and will have a lot of theoretical consequences. A lot else besides CNS (cosmic natural selection) is involved.
===============

Yes, look on page 8 of
http://arxiv.org/pdf/hep-th/0612185

The only proposed multiverse hypothesis that was directly falsifiable by today's observational means has finally, after 15 years, been falsified.

So let's see, maybe the understanding of what is inside neutron stars has changed and the new understanding of matter at extreme density will permit a new formulation of CNS. We await developments.

 

[Max™]

Very interesting, I didn't catch that he said CNS would be falsified by a 1.6+ Solar Mass observation. I DID notice the story though.

 

[bcrowell]

It's interesting because it kills off a ton of neutron star models. The Bethe-Brown scenario is dead, and probably any model that involves exotic matter.

 

[Chronos]

There are a handful of other suspected high mass neutron stars that appear to defy the Smolin conjecture. Another candidate is PSR J0751+1807 [http://www.arxiv.org/abs/astro-ph/0508050] , which looks fairly convincing. I am, however, hit with a tinge of skepticism by the very tight error bar claimed for J1614-2230.