Contrabang! #32 Beyond The Superficial

Sorry Science Fans, Discovering A 70-Solar-Mass Black Hole Is Routine, Not Impossible (link)

Late last month, this blog ran the post Scientists Find "Impossible" Black Hole, which was based on this ScienceAlert article by a similar title. Now, Mr. Siegle has interjected to tell us all why we're actually wrong.

Did you hear that astronomers had recently discovered a stellar mass black hole that was so heavy, it shouldn’t exist? At 70 solar masses and closer to the galactic center than we are, it’s certainly an interesting system to discover, entirely worthy of its publication in Nature last week. It ranks, at the moment, as the heaviest stellar mass (as opposed to supermassive) black hole ever discovered through optical techniques.

But on the theory side, claiming that this object shouldn’t exist is not only foolish, it requires that you ignore a number of basic facts about astronomy and the Universe. We’ve already discovered a handful of comparably massed black holes through gravitational waves, and have a very good idea of how they form and why. Here’s the science of these heavy black holes that goes beyond the superficial.

His assertion that our analysis was superficial is not only smug, but it is extraordinarily ironic because his own arguments are demonstrably superficial. In his haste to prognosticate on his chosen savior of cosmology - LIGO - Ethan has completely missed the crux of the issue. He counters that black holes of such size from direct collapse are theoretically possible, and that while no stellar black holes of such mass have ever been observed before by conventional means, they have already been seen by LIGO as the result of black hole mergers.

As black holes orbit other black holes, they radiate energy away in the form of gravitational waves, causing the two masses to inspiral and merge. During the first two science runs of LIGO and Virgo, a total of 11 events were seen, with 10 of them resulting from black hole-black hole mergers.

In the study itself, the authors note that this 70 solar mass black hole was found because it’s in a binary orbit with another massive star: a B-class star, which is short-lived and massive itself, a candidate for going supernova and creating a black hole on its own. But this is exactly where you’d expect to find a 70 solar mass black hole! There’s one simple reason for this that most astronomers rarely reference: star systems don’t just come in singlets and binaries, but that three-or-more stars are often found in the same system, and could easily lead to massive black holes that merge together while still having remaining stellar companions.

The original article did not call the black hole find "impossible" and itself referenced the LIGO results. It stated,

The LIGO/Virgo experiments have revealed black holes with masses of several tens of solar masses17,18, much higher than previously known Galactic black holes. The discovery of a 70M☉ black hole in LB-1 would confirm their existence in our Milky Way.

Thus, Ethan's complaint is not with the study, but with the reporting. It is eminently clear that Ethan did not read those. From the science article in which we first saw this story.

The star, around 35 million years old and clocking in at around eight times the mass of the Sun, is orbiting the black hole every 79 days on what the researchers called a "surprisingly circular" orbit.

There has been another black hole of a similar mass range detected, clocking in at around 62 solar masses - it was created as a result of a collision between two black holes in a binary pair - GW150914, the first direct detection of gravitational waves ever made by humans. It's not in the Milky Way, but it does offer one way such a black hole can form.

But the newly discovered LB-1 still has its binary companion. One scenario could be that LB-1 formed from the collision of two black holes and then captured the star later - but the circular orbit of its companion causes a problem here. A capture would produce a highly eccentric, elliptical orbit. Time could smooth this orbit out, but it would take longer than the star's age.

One possibility, however, could be a fallback supernova, in which material ejected from the dying star falls immediately back into it, resulting in the direct formation of a black hole. This is theoretically possible under certain conditions, but no direct evidence for it currently exists.

The reporting also acknowledges the LIGO results, and that the most likely scenario for the observed black hole - if it really exists - is from black hole mergers in a multi-body system. It also acknowledges the theoretical possibility of direct collapse, but states that the evidences does not support that scenario. Oddly, the "superficial" reporting already contains all the analysis that Ethan made, but more. Their opposition to the merger scenario is that observed binary system is too circular. The initial capture would have had to have been on a highly elliptical orbit, and over time smoothed out by tidal forces. Thus, the observed orbit puts the capture so far back that there isn't enough time for a black-hole merger event to have preceded it. Ethan ignores this aspect of the argument entirely. No where does he mention the actual core argument being made. Superficial indeed.

As is typical, he ends his piece with an air of intellectual superiority.

Astronomers aren’t perplexed by this object (or similar ones to it) at all, but rather are fascinated with uncovering the details of how they formed and how common they truly are. The mystery isn’t why these objects exist at all, but rather how the Universe makes them in the abundances we observe. We don’t falsely generate excitement by spreading misinformation that diminishes our knowledge and ideas prior to this discovery.

Fortunately, he says, astronomers are't perplexed by the misinformation that diminishes our knowledge. Apparently the astronomers who made the discovery don't count as astronomers.

"Black holes of such mass should not even exist in our Galaxy, according to most of the current models of stellar evolution," said Prof. LIU. "We thought that very massive stars with the chemical composition typical of our Galaxy must shed most of their gas in powerful stellar winds, as they approach the end of their life. Therefore, they should not leave behind such a massive remnant. LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation."

If they're non-astronomers, then why is Ethan linking to their paper at all? Other (non)astronomers  with rebuttals are here, here, and here. Don't let the titles of the authors fool you: they aren't really astronomers, because astronomers are not actually perplexed by such misinformation.

The icing on this irony cake is that Ethan has completely missed the arguments being made in his zeal to point to LIGO as the golden goose that solves all astronomical puzzles. His mistake is to assume that he is informed of the cutting edge research being performed there, and the rest of the world is slow in catching up. Thus, it is quite interesting to see the director of LIGO chime in on the matter.

"This discovery forces us to re-examine our models of how stellar-mass black holes form," said LIGO Director David Reitze of the University of Florida, who was not involved in the research.

"This remarkable result along with the LIGO-Virgo detections of binary black hole collisions during the past four years really points towards a renaissance in our understanding of black hole astrophysics."

Ethan says the findings are routine and points to LIGO as proof, yet the director of LIGO finds the results "remarkable" and contradictory to the current models. So either Ethan is right that the LIGO director is not an astronomer - thus invalidating his frequent invocations of LIGO results - or he is wrong on the subject and this article should be corrected or retracted entirely.

This Is Why Scientists Will Never Exactly Solve General Relativity (link)

It’s difficult to appreciate how revolutionary of a transformation it is to consider the Universe from Einstein’s, rather than Newton’s, point of view. According to Newtonian mechanics and Newtonian gravity, the Universe is a perfectly deterministic system. If you were to give a scientist who understood the masses, positions, and momenta of each and every particle in the Universe, they could determine for you where any particle would be and what it would be doing at any point in the future.

In theory, Einstein’s equations are deterministic as well, so you can imagine something similar would occur: if you could only know the mass, position, and momentum of each particle in the Universe, you could compute anything as far into the future as you were willing to look. But whereas you can write down the equations that would govern how these particles would behave in a Newtonian Universe, we can’t practically achieve even that step in a Universe governed by General Relativity. Here’s why.

There are two reasons why this isn't practically so, and they have to do with two of the biggest scientific advancements made in the last century.

First is quantum mechanics. Heisenberg's Uncertainty Principle states that we can never have complete knowledge of any real system, no matter how small. For instance, we can't know with perfect precision both the location and the velocity of any particle. Thus, the example given of knowing the exact state of the universe to calculate all future states is only a hypothetical. Such information can never be known.

Second is chaos theory. The gist of this article is that Newtonian dynamics are described in closed-form expressions, while general relativity is a set of differential equations. Ethan makes this out to be a profound difference, but most real-world systems are similar. A differential equation is any function that depends on a derivative of the variables. That is, the inputs are a function of the outputs. One example is the flight dynamics of an airplane. A stable airplane tend to return to level flight. Thus, a high angle of attack (AOA) will tend to cause the plane to have a highly negative rate of AOA change. An unstable airframe will tend to have a highly positive rate change for the same AOA. So the rate of AOA depends on the current value, and that value changes with the current rate. Each measure influences the other.

Because most differential equations don't have exact solutions, they are solved with approximate methods, thus the solutions are approximations. However, chaos theory showed that even linear systems are prone to chaotic behavior, because of slight nonlinearities of the real system that aren't reflected in the models. That is, the compact equations of Newton are themselves only approximations of reality.

You might notice that these solutions are also extraordinarily simple, and don’t include the most basic gravitational system we consider all the time: a Universe where two masses are gravitationally bound together. This problem — the two-body problem in General Relativity — cannot be solved exactly. There is no exact, analytical solution known for a spacetime with more than one mass in it, and it’s thought (but not, to my knowledge, proven) that no such solution is possible.

This is something I've wondered about the general relativity, where there is not an actual force of gravity. Instead, massive bodies distort spacetime, which the influences the motions of other bodies nearby. So what of a two-body system where both bodies are perfectly still? Intuition would tell us the two bodies should be gravitationally attracted and move towards each other, but if there is no initial motion, how would the theory of general relativity apply? From what I've seen, all examinations include initial movement, normally with the two bodies in binary orbits.

Ask Ethan: Do Ancient Galaxies Get Magnified By The Expanding Universe? (link)

If you want to know how large an object actually will appear in the expanding Universe, you need to know not only its physical size, but the physics of how the Universe expands over time. In the Universe we actually have — which is composed of 68% dark energy, 27% dark matter, 5% normal matter and about 0.01% radiation — you can determine that objects will appear smaller the farther away they get, but then the physics of the expanding Universe magnifies them once again the farther away you look.

It might surprise you to learn that the most distant galaxy we’ve ever observed, GN-z11, actually appears twice as large as a similarly sized galaxy that’s only half the distance away from us. The farther away we look, beyond a specific critical distance, objects actually appear larger the farther away they get. Even without gravitational lensing, the expanding Universe alone makes ultra-distant galaxies appear larger to our eyes.

This will become another magic bullet in the modern astronomy toolkit of contradiction avoidance. When galaxies appear too large and evolved for the Big Bang timeline. Anomalies will be explained away as an artifact of universal expansion, but when observations are as expected, then the expansion/enlargement effect will be ignored.

This Is How Quantum Physics Creates The Largest Cosmic Structures Of All (link)

Like so many aspects of astrophysics, quantum mechanics is on an à la carte menu: you take what you want whenever you need it. On its own, the Big Bang Theory offers nothing to explain the structure of the universe, which they openly admit.

If not for quantum physics, the Universe would have been born perfectly smooth, with every region of space having the exact same temperature and density as every other region.

The current reigning theory is that the cosmic web is a relic of quantum fluctuations that have been inflated to vast proportions by expansion, similar  to how lettering on a balloon grows when inflated, but on a scale of unimaginable proportions. They take some poetic joy in attributing the largest structure in the universe to the smallest, but that does little to inform us whether the theory is correct.

The problem is that the alleged quantum bubbles don't look like the observed universe, which is filamentary in appearance. Instead, he dwells on the clumpy CMB image, which looks more convincing. Thus, we must believe that the CMB captured a snapshot of the early universe, and the cosmic web has evolved from there. How the clumps with 1 part in 30,000 less matter opposed the unrelenting expansion of space to morph into huge abysses nearly devoid of any matter, and the clumps with 1 part in 30,000 more matter evolved into massive intergalactic filament networks reminiscent of neural maps, is left unanswered. While interjecting the CMB into the mix seems to offer a convenient transition point for the theorists, it amounts to one more assumption added to the stack. By my count, the major ones are:

1. That all redshifts are caused by relative motion
2. That Type 1A supernovae are standard candles (related to #1)
3. That redshifts imply a Big Bang event
4. That quantum fluctuations caused the slight variations seen in the CMB
5. That those slight variations evolved into the cosmic web over ~13 billion years

Adding to the Jenga tower of assumptions is a way to buy time, but brings with it increased likelihood of the whole thing toppling over in a glorious collapse.