The X-ray image above shows one of the neighbors of the Milky Way, the Great Magellanic Cloud. In this image you can see vague gas emissions, stars, distant galactic nuclei and in the center the remains of a supernova discovered for the first time 32 years ago, all orbiting our galaxy 158,200 light years away. But to be able to observe all this from Earth it took decades of work, and some dramatic failures.
Scientists at the Max Planck Institute have just released the first images of the eROSITA telescope, taken from space over the last two weeks. Over time, they hope to use the eROSITA telescope and the ART-XC telescope, both launched as part of the Spectrum-Roentgen-Gamma (SRG) mission last summer, to map the sky using X-rays and thus better understand the structure itself of the universe. This mission, especially that of the eROSITA, carries the ghosts of the ABRIXAS telescope, which had an unfortunate end shortly after its launch in 1999.
Scientists have been waiting for a device with which to measure high energy X-rays for decades. Soviet scientists proposed one of those missions in 1987, but died after the collapse of the Soviet Union. X-ray astronomy studies some of the most important questions about our universe by probing its densest and hottest regions: those of black holes, clusters of galaxies or remnants of supernovae. Knowing how galaxy clusters work is especially important to understand the large-scale structure and evolution of the universe. Powerful X-ray telescopes such as the Chandra X-ray Observatory and the XMM-Newton are used to observe smaller regions of the universe and individual objects.
But scientists need a reconnaissance telescope, one that maps the entire sky into X-ray wavelengths to answer broader questions about the universe and that serves to know where to point those other more sophisticated X-ray telescopes. eROSITA is the culmination of those efforts . The telescope will take X-ray images of the entire sky, revealing information never before seen about the night sky and perhaps up to 100,000 new galaxy clusters. These new clusters of galaxies will help scientists better understand the behavior of dark matter – that kind of invisible element that seems to make up most of the mass of the universe – and dark energy, whose presence seems to cause an increase in the expansion rate of the universe.
Individual galaxies collide, merge and evolve, but cannot provide as much information about the history of the universe itself. However, the images that eROSITA and ART-XC will get “are like a fossil record of the large-scale structure of the universe,” said Grant Tremblay, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. “They become nodes of a cosmic network. It’s like trying to map a web, we can’t see the real filaments, but we can see the nodes that connect them. We can still discern at least a large part of the structure of the network itself.”
The first X-ray satellite in the sky, ROSAT, was launched in 1990. That telescope conducted the first X-ray study of the entire sky at low-energy X-ray wavelengths , and made thousands of observations . But a great deal of data seemed to hide beyond ROSAT’s reach at those wavelengths of higher energy. German scientists then thought of a successor to ROSAT, which was baptized as ABRIXAS.
ABRIXAS combined seven smaller telescopes in a compact and powerful satellite , which used the same technology as the XMM-Newton telescope. It took only three years to develop it with a relatively small budget of $ 20 million, and I was ready to show the part of the universe that ROSAT could not see . But only three days after its launch, the disaster occurred: its main battery failed, and it would never make any observations .
The loss was “tragic , ” he told Gizmodo Jonathan Grindlay, professor of astronomy d and the University of Harvard. Since then, they have not been able to study the high-energy X-rays of the sky , Gizmodo Tesla Jeltema, a professor at the University of California , told Gizmodo .
The scientists asked for a replacement that could show the clusters of galaxies and other objects of greater energy that ABRIXAS was going to study. To this day, “everyone is still using the ROSAT telescope data,” said Jeltema.
The German institutes behind ABRIXAS proposed a replacement in 2002, an almost identical mission that would be coupled to the ISS, but they realized that there was not enough space in the ISS . Later , in 2005, Peter Predehl, who worked at ABRIXAS (and now at eROSITA) took a flight with the then director of the high-energy group of the Max Planck Institute , Günther Hasinger. The two talked about creating a telescope five times larger than ABRIXAS and using similar technology, and made some calculations . When they landed, they asked a classmate to prepare a presentationto introduce her to her Russian counterparts the next day. Thus was born the eROSITA telescope . Finally, it became the first high-energy X-ray telescope , and its mission was to observe what the universe was like nine billion years ago.
Without ABRIXAS ‘failure, “we would never have had the eROSITA,” Predehl told Gizmodo. “It’s much bigger and much better than ABRIXAS would have been.”
The failure of ABRIXAS gave scientists time to incorporate better software software to the satellite, as well as improvements in the hardware of their mirrors . The Max-Planck Society and the DLR secured the funds for the eROSITA in 2009, and the mission was scheduled to leave next to the Russian X-ray telescope, ART-XC, making the dream of Soviet scientists come true decades before. After the typical delays associated with large projects of this type , Roscosmos launched the mission last summer.
These telescopes also have a value beyond serving other X-ray missions, Jeltema explained. If optical or radio wave telescopes find something strange, these telescopes may obtain additional information to illustrate another series of findings.
eROSITA and ART-XC will be an important tool in the future. Scientists continue to dream of newer and more powerful X-ray telescopes , such as the Lynx X-ray Observatory , one of the four new missions that the National Academy of Sciences could propose for the next decade .
“Lynx will be ready to continue the immense space of discoveries that eROSITA has just opened ,” Tremblay said.