We’ve long suspected that Israel punches far above its weight in fields of science and technological research – and now here’s concrete proof, with news that a group of astrophysicists from Tel Aviv University have contributed to the discovery of the most massive stellar black hole yet found.
Professor Tsevi Mazeh and Avi Shporer of TAU joined with researchers from the United States and Germany in analyzing data collected by the Chandra X-ray Observatory and Gemini telescope on the spiral galaxy Messier 33. Their results, published in Nature this week, point to the existence in Messier of what is known as a “stellar mass” black hole – almost sixteen times heavier than our own sun. Messier is about 3 million light years from Earth.
A stellar black hole is formed from the supernova and subsequent collapse of the core of a massive star at the end of its life, creating a region of searing gravitational force. The term “black hole” derives from the fact that even light rays are unable to escape this gravitational pull, rendering the phenomenon in itself invisible. As a result, scientists are able to study black holes only where they interact with outside matter – as in this case, where the black hole was locked in orbit with a massive companion star which eclipsed it every three and a half days, allowing the scientists to gather accurate data on the hole’s mass and motion.
Mazeh, director of the Sackler Institute for Astronomy, noted that the research was enabled by the international partnership which administers the Gemini observatory. “Giant telescopes make it possible for us to research space systems that seem to have come from a science fiction film,” he said. “We are able to study black holes whose existence we were able to imagine only thanks to Einstein’s General Theory of Relativity.”
The find is all the more significant for the fact that existing models for the production of black holes cannot account for the extreme mass of the binary pair. Traditionally, it has been thought that the parent star must have been heavier that its companion in order to have formed a black hole first. But such a massive star – perhaps 150 times heavier than our own sun – would have had a radius much larger than the present separation between the stars. “The discovery raises all sorts of questions about how such a big black hole could have been formed,” noted co-author Jerome Orosz of San Diego State University.
As Mazeh put it, such questions can only lead to wonder, both at the scale of the universe and the smallness of the Earth within it. “I hope these discoveries will lead scientists and even all of human society to a degree of modesty,” he said.