The black hole and what it means for Namibia
Following the first image of a black hole being captured, the next step is building a radio telescope in Namibia – the Africa Millimetre Telescope.
28 April 2019 | International
The photo shows the black hole at the centre of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole is 55 million light-years from earth and is 6.5 billion times the mass of the Sun.
Interlinking eight telescopes has resulted in unprecedented sensitivity and resolution. Time after time, independent observations with the EHT, using different imaging techniques, have revealed a circular-type structure, with a dark area in the middle, a shadow of the black hole in M87.
“Scientists from all over the world worked together,” said Prof Anton Zensus of the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn and chair of the EHT management.
The director of the EHT Project, Sheperd Doeleman of the American Harvard/Smithsonian Centre for Astrophysics, said that this milestone in astronomy, was achieved thanks to a team of over 200 researchers from 18 countries.
In the beginning
Heino Falcke, Professor of Astroparticle Physics and Radio Astronomy at Radboud University, is the chair of the EHT Science Council and was there when the idea to photograph a black hole using a network of telescopes was first proposed.
“If the black hole exists in a bright area, such as a disc of glowing gas, we expect that it will create a very dark area, comparable to a shadow. We have also compared the photo with supercomputer simulations of different black-hole models. These simulations match up surprisingly well with the observations and make it possible to determine the characteristics of the black hole.”
The shadow is created by deflection of the light caused by the curvature of space and by the absorption of light in the so-called event horizon of the black hole. The horizon is the edge of the area from which nothing, not even light, can escape from the black hole.
Falcke: “Shape and size of the shadow perfectly match our expectations based on Einstein's general theory of relativity and the existence of an event horizon.”
Black holes are exotic cosmic objects which have enormous mass, but are small in size. A black hole exerts extreme influence on its environment. It curves spacetime and heats surrounding matter to super-high temperatures.
“The size of the shadow is related to the mass of a black hole and we managed to actually measure the enormous mass of the black hole in M87,” says Sera Markoff, professor of Astrophysics in Amsterdam.
With the EHT, scientists have a new instrument to study the most extreme objects in the universe, which were predicted by Einstein. The result comes exactly 100 years after the experiment that first proved Einstein's theory.
Falcke is looking forward to achieving clearer imaging after upgrades in the network. “It is the beginning of a new era in which the ultimate limit of space and time is no longer an abstract concept, but a measurable reality. To increase the sensitivity, we want to expand the EHT network and build a millimetre telescope in Africa. We are fortunate to already have the first supports in place, from different parties and even businesses.”
The Africa Millimetre Telescope
The mentioned Africa Millimetre Telescope (AMT) project is co-led by two teams at the Radboud University Nijmegen and the University of Namibia and aims at realising a 15m single-dish radio telescope on the Gamsberg in Namibia.
The AMT will be the only radio telescope in the mm-wavelength regime in Africa, and as such provides unique science opportunities for Namibia. The AMT project is envisioned as a highly visible and unique enabler of science, education & outreach, capacity enriching, sustainable energy and social-economic development in Namibia.
The explanation to the question why this extra telescope in Africa is needed is three-fold: quantity, location and connection.
The effectiveness of the EHT network depends on the length and orientation of the lines connecting each possible pair of telescopes: The more connections the better the image quality, the longer the separation, the better the resolution. The number of connections increases almost quadratically with the number of telescopes; hence even a single new telescope adds many new connections and improves the image quality by a critical margin.
A telescope placed in southern Africa will have additional benefits.
First of all, the centre of the Milky Way is right overhead at that location, providing the longest and least disturbed view of the black hole. In addition, it is centrally located between the big telescopes in Europe, Latin America and America and hence is of great importance for the entire experiment.
The AMT requires skilled personnel for the installation, maintenance and operations of the telescope and associated facilities. It is the goal of the AMT project to involve local industry partners for this, in combination with both Namibian Universities. This way, the AMT project can serve as a showcase for expertise of Namibian industry and the training and education of engineering capacity.
Furthermore, astronomy is one of the most extreme examples of Big Data, and is thus the ideal showcase for the Namibian ICT industry to present their expertise, paired with training opportunities at the local universities.
Beyond the actual project, the AMT team is developing an education and outreach programme. The goals are to motivate and inspire young students to pursue a career in science or engineering, and to make the general audience aware and proud of their Namibian scientists and engineers.
The AMT is currently in its telescope and infrastructure design phase. Next, the preliminary technical design of the AMT will be worked out, studies for the access to the site, on environmental impact and local infrastructure will be conducted as well as funds for the project shall be raised.
Only after this has been accomplished, the actual building and later commissioning and science phases can begin.
However, if all goes well, the AMT could be observing the supermassive black hole in the centre of our Milky Way as part of the EHT as of 2021.