Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit.

Astronomers more precisely estimate the diameter of neutron stars

Using several different techniques, astronomers now estimate that the typical neutron star will have a diameter of 11 kilometers, or about 7 miles.

What is significant about this new estimate is that if that neutron star happens to be orbiting a black hole and get pulled into it, it will be swallowed whole instead of being ripped apart.

Their results, which appeared in Nature Astronomy today, are more stringent by a factor of two than previous limits and show that a typical neutron star has a radius close to 11 kilometers. They also find that neutron stars merging with black holes are in most cases likely to be swallowed whole, unless the black hole is small and/or rapidly rotating. This means that while such mergers might be observable as gravitational-wave sources, they would be invisible in the electromagnetic spectrum.

In other words, such cataclysmic events would be largely invisible to observers.

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  • MDN

    Interesting. Since most black holes have an accretion disk around them is it likely that the neutron star will simply sweep all that up as it spirals in? Or will it amass an accretion disk of it’s own on the way, which would then be the source for an electromagnetic signature of a merger event, as presumably that would get heated up and radiate pretty impressively as natural part of the process.

    As you like to say Bob, the uncertainty of science : )

  • If I understand correctly, the paper argues that rather than lose atmosphere over time, as in the case of a white dwarf orbiting a supergiant, the neutron star is taken entire into the black hole’s accretion disk, and then *fwoop*, a star is gone.

    It seems that the neutron star could not form an accretion disk, as it would have to capture material from the black hole’s disk. For that to happen, would not the gravitational attraction of the neutron star have to exceed the radial velocity of the black hole’s disk?

  • wayne

    tangentially related….

    “Galaxy surveys and the possible breakdown of the standard model of cosmology”
    Paris Astrophysics Institute
    September 2019

  • Col Beausabre23

    Black hole, “Burp”

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