Amaterasu. If you are an anime fan, you would recognise the term from Naruto. That is the name of the goddess of the Sun in Japanese mythology. It is also the name scientists gave to a mysterious high-energy particle that hit Earth, seemingly coming from nowhere. While you are thinking about that, also, whose job is it to kill the International Space Station? Toshihiro Fujii, an astronomer at the Osaka Metropolitan University in Japan, was doing a routine data check at the Telescope Array Project in Utah. That is when he discovered some peculiar signals on May 27, 2021. On that day, the massive telescope array in the desert detected what turned out to be the second-highest extreme-energy cosmic ray ever recorded in history. But when researchers tried to find where it came from, they drew a blank. “The particles are so high energy, they shouldn’t be affected by galactic and extra-galactic magnetic fields. You should be able to point to where they come from in the sky. But in the case of the Oh-My-God particle and this new particle, you trace its trajectory to its source and there’s nothing high enough energy to have produced it. That’s the mystery of this—what the heck is going on?,” said John Matthews, Telescope Array co-spokesperson and co-author of a study published in the journal Nature, in a press statement. To produce particles like Amaterasu, you need something really powerful. Usually, that means, an exploding star (a supernova) or a supermassive black hole. But the researchers looked in the direction where the cosmic ray should have come from, and they discovered nothing there. There are three possible explanations for this—one, the source could be something that we are yet to detect and identify. Two, there might be something wrong with the models used by scientists to find the source location of high-energy particles. Three—there is a need to rewrite high-energy particle physics. While high-energy particle physicists are stumped by that, some at NASA have a difficult task to contend with much closer to home. It will soon be time to kill the International Space Station. (ISS) How will we do it? NASA, the Canadian Space Agency and the European Space Agency have committed to operating the space station till 2030. The Russians might leave much earlier since Roscosmos only committed till 2028. So, in all likelihood, the ISS will be little more than space junk after 2030. The problem here is that, unlike most space junk, the 109-metre wide space station is too big to completely vapourise in Earth’s atmosphere upon reentry. That is why NASA has plans to send a spacecraft to tug the space station and deorbit in such a way that whatever remains will enter over the sparsely populated South Pacific Ocean. Right now, the American space agency thinks it will spend $1 billion doing that. Even though it is supported by Canada, Japan, and Europe, the space station is mainly the creation of the United States and Russia. Interestingly, it's one of the few areas where the two countries continued to cooperate even when their relations deteriorated. Until recently, NASA was planning on using multiple Russian Progress spacecraft to deorbit the space station. But that plan was already quite ambitious because of how difficult it will be to coordinate multiple spacecraft for the deorbiting manoeuvre. That would have been difficult even if the United States and Russia were on cordial terms. But not enough water has flowed under the bridge since the latter invaded Ukraine. The relations between the United States and Russia are arguably at its worst since the Cold War. In fact, that is already straining their cooperation on the International Space Station. This, combined with the fact that Russia’s space capabilities have seemingly declined, means that NASA is looking elsewhere for solutions.
