The orbits of the nearest stars orbiting the Milky Way’s central black hole are impossible to predict

The uncertainty of science: Using a computer program developed in 2018 that can predict with accuracy the orbits of more than three interacting objects, scientists have found that the orbits of the 27 nearest stars orbiting the Milky Way’s central black hole, Sagittarius A* (pronounced A-star) are impossible to predict after only a very short time.

“Already after 462 years, we cannot predict the orbits with confidence. That is astonishingly short,” says astronomer Simon Portegies Zwart (Leiden University, the Netherlands). He compares it to our solar system, which is no longer predictable with confidence after 12 million years. “So, the vicinity of the black hole is 30,000 times more chaotic than ours, and we didn’t expect that at all. Of course, the solar system is about 20,000 times smaller, contains millions of times less mass, and has only eight relatively light objects instead of 27 massive ones, but, if you had asked me beforehand, that shouldn’t have mattered so much.”

According to the researchers, the chaos emerges each time in roughly the same way. There are always two or three stars that approach each other closely. This causes a mutual pushing and pulling among the stars. This in turn leads to slightly different stellar orbits. The black hole around which those stars orbit is then slightly pushed away, which in turn is felt by all the stars. In this way, a small interaction between two stars affects all 27 stars in the central cluster. [emphasis mine]

To my mind, the quote by the scientist above should be considered the most absurd statement by a scientist ever spoken, except that nowadays scientists make such idiotic statements all the time. To think that such different conditions wouldn’t produce different results suggests a hubris that is astonishing for a person supposedly trained in the scientific method.

Regardless, these results suggest that acquiring an understanding of the dynamics that created these stars is going to be very difficult, if not impossible. The conditions change so rapidly, and in an unpredictable manner, that any theory proposed will be simply guessing.

99.9% of all mass at center of Milky Way is found in central black hole

New measurements of the orbits of several stars circling the Milky Way’s central supermassive black hole, Sagittarius A* (pronounced A-star), have confirmed that 99.9% of all mass at the galaxy’s center is concentrated in that black hole.

Astronomers have measured more precisely than ever before the position and velocity of four stars in the immediate vicinity of the supermassive black hole that lurks at the center of the Milky Way, known as Sagittarius A* (Sgr A*) [1]. These stars — called S2, S29, S38, and S55 — were found to be moving in a way that shows that the mass in the center of the Milky Way is almost entirely due to the Sgr A* black hole, leaving very little room for anything else.

The measurements, which further refine the mass of Sagittarius A* as 4.3 million times the mass of the Sun, show that very little of this mass is found in the surrounding space as gas or dark matter. It is all in the black hole, which might also help explain why the Milky Way’s central black hole is so quiescent. It has very little gas or other stars to feed it and thus produce emissions.

Astronomers discover first periodic erupting supermassive black hole

Astronomers observing a galaxy 570 million light years away have discovered that the periodic energetic flares that occur there every 114 days are not supernovae but eruptions from the supermassive black hole at the center of the galaxy, caused each time an orbiting star gets too close during its perihelion and has material stripped away from it.

ASASSN-14ko was first detected by the All-Sky Automated Survey for Supernovae (ASAS-SN), a global network of 20 robotic telescopes headquartered at The Ohio State University (OSU) in Columbus. When Payne examined all the ASAS-SN data on the phenomenon, she noticed a series of 17 regularly spaced flares.

Based on this discovery, the astronomers predicted that the galaxy would experience another burst on May 17 of last year and coordinated ground- and space-based facilities to make observations. They have since successfully predicted and witnessed flares on September 7 and December 26.

Though the press release tries to sell itself by saying these flares were initially mistaken for supernovae, a close reading suggests the astronomers thought this for only a very short time. As soon as they took their first close look and noticed the regularly space events, they abandoned the supernovae idea immediately.

Most supermassive black holes at the center of galaxies are active, emitting large amounts of energy in bursts or in a steady stream. That is why astronomers label them Active Galactic Nuclei, or AGNs. This is the first to do so in a periodic manner.

That most are active illustrates the mystery of the supermassive black hole in the center of the Milky Way. Sagittarius A* (pronounced A-star) is not active, even though it really should be.

G2 survives fly-by of Milky Way’s supermassive black hole

The uncertainty of science: The mysterious object G2, thought by astronomers to be either a cloud or a star, has survived its close fly-by of Sagittarius A* (pronounced A-star), the supermassive black hole at the center of the Milky Way, without telling scientists whether it is a cloud or a star.

Not only do astronomers still not know clearly what G2 is, the Milky Way’s supermassive black hole continues to behave in ways that baffle them.

Part of the gas cloud being ripped apart by the supermassive black hole at the center of the Milky Way have already swung past the black hole.

Part of a gas cloud, being ripped apart by the super massive black hole at the center of the Milky Way, has already swung past the black hole.

“The ionised gas at the head of the cloud is now stretched over more than 150 light-hours (about 160 billion kilometres) at the pericentre of the orbit around the black hole, with the closest approach being about 25 light-hours (or a bit more than 25 billion kilometres)”, explains Stefan Gillessen from MPE, who led the observing team. “The pericentre approach however is not a singular event but rather a process that will be stretching over a period of at least one year.”

The black hole, dubbed Sagittarius A* (pronounced A-star), is more than 4 billion times the mass of our Sun, but emits very little energy for its size. (Most super massive black holes emit energy as they swallow the mass around them.) Astronomers are hoping that they will see some action when it eats this cloud sometime next year.

The supermassive black hole in the center of the Milky Way is about to get a snack.

The supermassive black hole in the center of the Milky Way is about to get a snack.

Update: The recently launched NuStar telescope in July detected its first flare from the central black hole (which by the way is called Sagittarius A* and is pronounced Sagittarius A-star). If the gas cloud produces any fireworks as it whips past the black hole in the coming year then NuStar should see it.