Black holes continue to interest scientists, and the most recent Nobel Prize for Physics went to Roger Penrose ‘for the discovery that black hole formation is a robust prediction of the general theory of relativity’ together with Reinhard Genzel and Andrea Ghez ‘for the discovery of a supermassive compact object at the centre of our galaxy.’
The level of scientific appreciation for these super-dense objects continues, as new research continues to be published. This week’s Essential Science looks at three recent research papers that explore the mysteries of black holes.
Black holes and spacetime
Black holes are regions of spacetime, objects where gravity is so strong that nothing, no particles or any form of electromagnetic radiation ike light, can escape. Black holes form when a sufficiently compact mass develops that can deform spacetime.
By spacetime, this is the fusing together of the three dimensions of space and the one dimension of time into a single four-dimensional concept. This concept can explain, for example, why different people, located in different areas but viewing the same event may perceive differently where the event happened and even when the event happened.
Too close for comfort?
The Earth has moved seven kilometres per second faster and some 2000 light-years closer to the supermassive black hole that is located in the center of the Milky Way Galaxy. This does not present any immediate concern, at least not for a few million years.
Back in 1985, the galactic center was established as being 27700 light-years away from Earth. The new finding revises this to 25800 light-years from Earth. What this finding means is that it enables astronomers to construct an improved model of the Milky Way Galaxy, drawing upon new observation data. The data has been revealed through the Japanese radio astronomy project VERA. This is an acronym for a rather long string of words. The ‘V’ represents VLBI, which is turn represents Very Long Baseline Interferometry. The remaining letter – ERA are for ‘Exploration of Radio Astrometry’.
The research appears in Publications of the Astronomical Society of Japan, with the paper headed “The First VERA Astrometry Catalog.”
Dark matter
A theoretical paper proposes that supermassive black holes could be created from dark matter. This is different to the established formation scenarios for black holes, which involve ‘normal’ matter. The theoretical model runs that supermassive black holes may form directly from dark matter located within high density regions at the centres of galaxies. If this was to be established, it could change our understanding of the cosmology of the early Universe. This is because the formation of these types of black holes may not have required prior star formation or needed seed black holes to come together.
Observational evidence indicates that almost every large galaxy has a supermassive black hole at the galaxy’s center. This includes our own galaxy, the Milky Way. These large black holes have a mass that is on the order of millions to billions of times the mass of the Sun.
The research appears in Monthly Notices of the Royal Astronomical Society, where the research paper is titled “On the formation and stability of fermionic dark matter haloes in a cosmological framework.”
Star killer
Through a series of remarkable observations, astronomers have detected a hitherto unseen blast of light, which comes from a star being ripped apart by a supermassive black hole. This is called a tidal disruption event. The latest observation is the closest such flare recorded to date, positioned at around 215 million light-years from Earth.
The Hubble picture reveals a huge ultraviolet atmosphere with a mysterious hot spot on the stellar behemoth’s surface. The enormous bright spot is at least 2,000 kelvins hotter than the star’s surface.
A star subjected to this process undergoes what is referred to as ‘spaghettification’ as it is sucked in by a black hole. By this term it means the extreme gravitational pull of the black hole shreds the star into thin streams of material, as is it is pulled in. This causes bright flares to be released. The finding will build on the body of knowledge of what happens to matter in the extreme gravity environments around supermassive black holes.
The discovery appears in Monthly Notices of the Royal Astronomical Society, in research called “An outflow powers the optical rise of the nearby, fast-evolving tidal disruption event AT2019qiz.”
Essential Science
This article forms part of Digital Journal’s long running Essential Science series. Each week we take a more detailed look at an important and topical science subject.
Last week we looked at autonomous cars and the latest developments with both autonomous car technology, such as LiDAR, and with electric powering systems.
The week before we posed the question of whether a cat’s natural hunting instincts can be tamed through good food and interactive play? A new study appears to be confirm that the wilder site of cats can indeed be tamed through diet and exercise.
