The Violent Universe


I can imagine the astonishment and terror of the astronomers of 400 years ago if they could have seen how the Universe is really made.

First Kepler and then Newton showed us how the dance of the spheres works. It seemed that the Universe was a silent celestial metronome, and indeed it was on this that celestial mechanics was built, one of the most beautiful mathematics ever invented. On parallel side astrometry was carried out using 3-D trigonometry – spherical trigonometry based on a spherical triangle of 270 ° – which allowed us to calculate with extreme precision the birth and sunset of the stars. Apart from the concept of “central force” finally discovered by Newton, the sky seemed to be only a mere orbital dance, where the planets and stars walk according to perfect mathematics. This is absolutely true: we can verify this from how we manage to send circumterrestrial and interplanetary probes into orbit.

We had to wait another 200 years to be able to verify, using William Herschel’s telescope and Father Angelo Secchi’s spectrograph, that looking at billions of billions of times farther away, the Universe is not actually limited to a mathematical dance of the spheres but produces occasionally events of unimaginable violence. We could find out this when mathematical astronomy became physics at all effects (with the mathematics always subject to it). Then we discovered that the Universe is, on a scale of infinitely larger energies, like our planet: quiet, but occasionally overwhelmed by lightning, volcanoes, hurricanes, earthquakes, tsunamis. On a cosmic scale this manifests itself through a truly diverse zoology of celestial objects, which includes mainly:

1. Nova stars and narrow cataclysmic binaries whose surface explode in a recurring mode without being destroyed, when a hyper-dense star such as a white dwarf orbits around a red giant star, sucking up matter from the second. Accumulating matter that is then heated to tens of millions of degrees in an accretion disk that matter is then literally “vomited” through violent events due to the overcoming of the famous Eddington limit for brightness in thermodynamically and hydrostatically stable systems.

2. Newborn stars (FU Orionis-like), which are only 50,000 years old, still resting in dark cocoons (a bit like a butterfly that has yet to fly) and which gradually form an accretion disk born of the gravitational sucking of gas and dust from the primeval interstellar cloud (idea already intuited two centuries ago by Kant and Laplace), until at a certain point, as in the previous case, the Eddington limit is exceeded and an explosion similar to that of a nova takes place. We will have to wait another 100,000 years to finally have a stabilized star (with no more disc of matter around) that can last from 0.5 to 10 billion years thermonuclearly burning first hydrogen, then helium, then carbon, then oxygen and so on, and then finish their life, in the case of solar-type stars, in the shape of wonderful and multicolored concentric arabesques such as planetary nebulae.

3. Massive red supergiant stars (10 solar masses) that at the end of their life explode as supernovae with an energy that equates the integrated brightness of a whole galaxy containing 100 billion stars, and that after a few hundred years will form filamentary arabesques in the sky and sometimes in the form of veils, extended up to 100 light years.

4. Blue supergiant stars with masses equal to 100 times that of the Sun which at the end of their life explode like hypernovae generating a stream of energy in the gamma rays with temperatures of billions of Kelvin degrees.

The beauty here is that the shock waves produced by 3 and 4 work as a trigger for the birth of 2, compressing the interstellar medium, after having enriched it with heavy chemical elements, and bringing it to situations of autogravitation and collapse.

5. Ultra-dense neutron stars as small as the island of Manhattan, produced by 3 which, in the most extreme cases, magnetized in a paroxysmal way behave like “magnetars” and rotate 1000 times a second like a pulsar; sometimes they are subjected to huge nucleoquakes generating the emission of gamma rays, the most violent existing eruptive events in the universe.

6. Binary neutron stars in very narrow orbits (with a period of a few hours, and not 365 days like the Earth around the Sun) that after having transformed their orbit into a spiral eventually merge to form a black hole, and consequently shaking the fabric of spacetime generating gravitational waves, as Albert Einstein had already predicted.
7. Massive blue giant stars (Be stars) that rotate so fast that they constantly eject matter from the equatorial zone until they form a disk around them looking like giant blue and bright Saturns. And when they are accompanied by a neutron star in a narrow and very eccentric orbit, they have the matter of the equatorial disk being sucked away by the neutron star, which in turn forms an accretion disk from the stolen material from which then periodic explosions arise in X-rays at each passage to the periastron.

8. Mammoth explosions generated by the nuclei of active galaxies (AGN: Active Galactic Nuclei), in the form of a magneto-collimated tube extended 10,000 light-years, which occur due to a central black hole of a billion solar masses, whose accretion disk, derived from sucked matter (gas, dust and disrupted stars) equals to our solar system in diameter, and ejects material and high-energy particles outwards to heat the intergalactic medium to millions Kelvin degrees over distances of hundreds of thousands light-years.

9. Mysterious and very brief explosions in radio waves (FRB: Fast Radio Bursts) that originate from mechanisms that are still unknown with preference in dwarf galaxies at cosmological distance.

10. The most gigantic of explosions, accompanied by the birth of space and time, which occurred from a fluctuation of the quantum void 13.5 billion years ago, and which gave rise to our Universe and therefore to the orbital harmonies coexisting with the violent events that we continue to observe.

The Universe is therefore not the tranquil starry vault contemplated by a couple of lovers or some romantic poet, but it is a continuous schrapnel, where the generated dynamics helps to shape the forms like a chisel in marble, to give birth to new stars, to create beautiful metals such as Gold or very hard metals such as Scandium, but also radioactive elements such as Cobalt, to illuminate by exciting the darkness of gas and interstellar dust by lighting them like Christmas trees for hundreds millions of years.

I don’t know if it’s better to think of the poetics of an immutable starry sky or of the cosmic violence that actually happens at distances from us that only super-telescopes can reach.

If a couple is lying on a lawn looking at the sky, they could catch its poetry using their eyes and its violence using their mind, perhaps unleashing the senses as well as the emotions. Then wake up in the morning to see the rising sun, a stable star that burns hydrogen in its nucleus. A star that appears to be immutable both in its light and in its shape, if it were not that if looked at close range it sometimes shows huge plasma ejections that in periods of increased activity escape from the Sun.

The point remains that everything appears serene and unchanging to human eyes. But the facts are quite different.