Can “Black Holes” or Pulsars Spin at Near the Speed of Light?
No, not even close — the mainstream is wrong, again.
Since All “Black Holes” Are Escapable, Even from Their Black Surfaces we should understand that “theoretical Black Holes” wrapped in “theoretical Event Horizon” do not exist: they exist only as “nearly Black Holes”, as heavy/dense non-ignited stars, like neutron stars, are wrapped in slow, but not stopped time.
And since Maximal Velocity on a Circular Orbit Is Less than 43% of the Speed of Light we should understand that speed on the equator of spinning pulsars cannot exceed 43% of c (c = 300,000 km/sec). Pulsars are neutron stars, the spin of which is measurable by astronomers (using their pulse).
1) Let’s put 43% limit to the test, at the surface of the fastest spinning pulsar PSR J1748−2446ad:
At its equator it is spinning at approximately 24% of the speed of light.
24% < 43%, end of test? Not yet. For us it appears spinning at 0.24c speed, BUT on the surface of the pulsar time runs slower than our time. Let’s denote by D time dilation factor, meaning for 1 second on that pulsar, D seconds pass for us, on the Earth; 1 second of our time happens in 1/D seconds of the pulsar time. The speed 0.24c is measured in 1 second of our time, which happens in 1/D seconds of the pulsar time, thus, the speed of rotation there is D times greater in the local-to-the-pulsar time: 0.24×D×c. Now, do we know actual D value? There are formulas from Einstein (though they are not precise, but good approximations), which astrophysicists use to estimate time dilation around celestial bodies. And usually they estimate not D, but so-called redshift Z, which are directly related to D by the formula D = 1+Z. For PSR J1748−2446ad they estimated Z ≈ 0.834:
=> D ≈ 1.834. Then the speed of that pulsar rotation is
0.24×D×c ≈ 0.24×1.834×c ≈ 0.44×c, which breaks 0.43×c limit, right?
Limit is broken because Einstein’s formulas are not precise (and because estimates of this pulsar mass and radius are not precise either). To understand the difference between real redshift and the predicted by Einstein’s formulas redshift (let’s call the latter “GR-redshift” — redshift by General Relativity formulas), we compare real redshift measurements vs. GR-redshift/prediction for well-known Sagittarius A* — central “Black Hole” in our Milky Way. Astronomers observed real redshift of starlight coming from star S2 orbiting Sagittarius A* by elongated elliptical orbit with the perigee very close to Sagittarius A*:
Real redshift ≈ 0.88 is lower than GR-redshift ≈ 1.0. Such a gap is already enough to explain 0.44 (coming from the same GR formulas, giving higher than real values) breaking the 43% limit in PSR J1748−2446ad case above.
2) Now, to “Black Holes” spinning at near-c speed claims. For example, astrophysicists claim that our Sagittarius A* spins at about 0.84c–0.96c. First of all, what does it even mean, if they cannot see “theoretical Black Holes” inside “theoretical Event Horizon”. They say, there are ways to estimate the projection of “Black Hole” rotation on “Event Horizon”, what!? So, it is not the rotation speed of the “Black Hole” per se, but projection of this rotation on the surrounding “Event Horizon”. Forget this nonsense (neither Black Holes nor Event Horizon exist). There are other real measurements: Gas bubble found going 30% speed of light around Milky Way’s supermassive black hole, which do not break 43% limit. And there are so-called accretion disks, which is matter spiraling down to “Black Holes”, check “Black Holes” section in my Science of Visibility and Invisibility, which gives a grip on what is going on there.
For trajectories other than circular (elliptical, parabolic, spiral), there is no .43c speed limit,
as I showed in All “Black Holes” Are Escapable, Even from Their Black Surfaces, velocities at perigee can come closer to c:
max(v) = c × sqrt[ 1-exp(-2GM/(Rc²)) ].
But still, exp(-2GM/(Rc²)) keeps v separated from c. Each star, by its individual mass M and radius R, restricts velocity of its satellites (from coming too close to c). That restriction does not apply to visitors passing nearby on hyperbolic orbit, neither it restricts a crashing-into-the-star object’s velocity.
