The largest and smallest Black Holes

[John Clark]

In the last month astronomers have broken records, they have found both the largest and the smallest Black Holes in the universe, at least so far. The largest Black Hole is 40 billion solar masses plus or minus 800 million.

A 40-BILLION SOLAR MASS BLACK HOLE IN THE CENTRAL GALAXY OF ABELL 85

Even more interesting is the discovery of the smallest Black Hole, it's probably 3.3 solar masses although it could be as large as 6.1 or as small as 2.6.

A low-mass black hole–giant star binary system

There are theoretical reasons to think a non-rotating Neutron Star can't get any more massive than 2.16 solar masses before it collapses into a Black Hole (unless Quark Stars made of Strange Matter exist), although they might be as massive as 2.7 solar masses if they're spinning close to the speed of light. But If a Neutron Star were spinning that fast it would have a huge magnetic field which would slow it down so it couldn't keep that rate of spin for long, astronomically speaking.  Magnetars might be Neutron Stars of that sort, and short lifetime might be why they're so rare, only 23 have ever been discovered. The most massive Neutron Star ever observed is 2.14 solar masses, very close to the theoretical limit.

John K Clark

[Lawrence Crowell]

I don't know what happens in this gap between 2.2 and 3.4 solar masses. It is possibly a domain for quark stars and related exotic hadronic stars.

LC

[John Clark]

On Thu, Dec 5, 2019 at 4:44 PM Lawrence Crowell <goldenfield...@gmail.com> wrote:

> I don't know what happens in this gap between 2.2 and 3.4 solar masses. It is possibly a domain for quark stars and related exotic hadronic stars.

If they exist Quark Stars could be the most dangerous objects in the universe. The stuff they're made of, Strange Matter, would be even denser than neutronium and unlike neutron star stuff it would be stable at earthly pressure; in fact it would be more stable than ordinary matter so one microscopic speck of it would convert the entire planet into a ball of Strange Matter about a foot in diameter. 

  John K Clark 

 

[Bruno Marchal]

I read that some believe that all neutron star could have a core made of quark condensation. Not sure if this would necessarily be strange matter, but perhaps I am wrong. It is denser than neutronium, to be sure.

I read a paper a long time ago describing some exotic quark condensate exploiting a sort of quantum games to assure persistence. 

Bruno

  John K Clark 

 

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[Lawrence Crowell]

Strangelets are a baryon state (d,u,s) where this has a lower energy state than a proton state (d,u,u). There is a large potential barrier obstructing a flavor changing weak interaction u --> s + e + nu_ e-bar. However, this is not so much for s + u --> s + s + e + nu_ e-bar. So this is self catalysing interaction. If there is enough "seed" strangelets this could run away.

If a neutron star has a strange core and it collides with another this stuff could slash out and covert more matter to strangelets. However, I suspect this is no more a threat than that of a black hole coming through the solar system and gravitationally flinging planets and Earth around.

[Bruno Marchal]

> On 6 Dec 2019, at 16:38, Lawrence Crowell <goldenfield...@gmail.com> wrote:
>
> Strangelets are a baryon state (d,u,s) where this has a lower energy state than a proton state (d,u,u). There is a large potential barrier obstructing a flavor changing weak interaction u --> s + e + nu_ e-bar. However, this is not so much for s + u --> s + s + e + nu_ e-bar. So this is self catalysing interaction. If there is enough "seed" strangelets this could run away.
>
> If a neutron star has a strange core and it collides with another this stuff could slash out and covert more matter to strangelets. However, I suspect this is no more a threat than that of a black hole coming through the solar system and gravitationally flinging planets and Earth around.

Thanks for the precisions. I guess I fear less the neutron stars and the black holes than an asteroid. Apparently there is one coming at us which might collide with Earth in 175 years. We can hope we will manage to deflect its path. It looks also that a rapid star might go through the solar system in 19000 years. He might provoke some havoc in it, but again, we can hope to solve this problem during those 19,000 years to come …
Neutron stars are still a very fascinating topic though. Some exotic matter might inspire some generation of quantum computing, and vice versa, I think.

Bruno

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[Lawrence Crowell]

Astronomical objects and events are nothing to fear. The probabilities are small. Earth has been here 4.6 billion years and so far no black hole event or strangelet wipeout. Even large asteroids are a one in ten million year event. Only one person has been documented to be hit by a small meteor.

[Bruno Marchal]

> On 10 Dec 2019, at 15:58, Lawrence Crowell <goldenfield...@gmail.com> wrote:
>
> Astronomical objects and events are nothing to fear. The probabilities are small. Earth has been here 4.6 billion years and so far no black hole event or strangelet wipeout. Even large asteroids are a one in ten million year event. Only one person has been documented to be hit by a small meteor.

I guess solar flare might be more dangerous, with all the electronically equipment surrounding us. Life has always survived the many catastrophic events which already occurred, but a complex civilisation might be more fragile.
Volcanoes can be rather destructive too. A guy made a thesis that the last very big eruption led to Islam! (I have no opinion on the seriousness of that idea, but he presented well its point).

The humans themselves remain the biggest threat to humanity or to humanity’s quality of life.
It seems that the more we have neurons, the more we have tricks and means to deny evidences and truth, and to build our own misery.

Bruno




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[John Clark]

On Wed, Dec 11, 2019 at 10:33 AM Bruno Marchal <mar...@ulb.ac.be> wrote:

> I guess solar flare might be more dangerous, with all the electronically equipment surrounding us

Just before noon on September 1 1859 at Kew Observatory in England astronomers witnessed a HUGE solar flare called the "Carrington Event"; 17 hours and 36 minutes later when the Coronal Mass Ejection from the sun hit the Earth it just knocked out newfangled telegraph lines and caused beautiful northern light displays that could be seen as far south as Cuba, but if something that big happened today it would devastate the world economy.

 John K Clark