From visible light to radio waves, our Milky Way can be observed in a variety of ways. In a new image, we’re seeing our galaxy through a completely different lens: neutrinos.
The universe is full of elusive neutrinos. These uncharged subatomic elementary particles hardly interact with other matter. For this reason, they are also referred to as “ghost particles”. The fact that the universe is full of them pushed scientists out IceCube Neutrino Observatory – that hunts down neutrinos, or “ghost particles” – an ambitious idea. Because in a new study they have created an image of the Milky Way using neutrinos for the first time.
More about neutrinos
We know that neutrinos occur in large quantities and usually pass through Earth undetected. In fact, they are currently traveling through your body in the billions without you even noticing. This is because they are fundamental particles, but they hardly care about other particles. Strange particles were first seen in 1956. Meanwhile, we know that the mysterious neutrino is the most abundant particle in the universe and plays an important role in the process that makes stars shine. As far as we know now, these neutrinos come in three “flavors”: you have the muon, the electron, and the tau neutrinos. It is known that neutrinos can switch to a different flavor as they travel. For example, in 2013 it was shown for the first time that the muon neutrino had changed into an electron neutrino.
From visible light to radio waves, the Milky Way can be observed in a variety of ways due to the different frequencies of electromagnetic radiation it emits. But now scientists are going one step further. For the first time, they have created a completely unique picture of our galaxy. By determining the galactic origin of thousands of neutrinos. The neutrino-based image of the Milky Way is the first of its kind: an image of a galaxy made of particles of matter rather than electromagnetic energy.
Below you can enjoy the new image of the Milky Way. The top image shows the Milky Way as you’ve seen it before, in visible light. The bottom one is the first ever recorded with neutrinos. “I remember saying, at this point in human history, we are the first to see our galaxy in something other than light,” said physicist Naoko Kurahashi-Nelson.
High-energy neutrinos – thinking at energies millions to billions of times higher than those produced by the fusion reactions that power stars – have been discovered by IceCube Neutrino Observatory, a neutrino detector at the South Pole, near the Amundsen-Scott South Pole Station. The massive observatory detects subtle signs of high-energy neutrinos using thousands of sensors buried deep within a cubic kilometer of pure, crystal clear ice. IceCube searches for signs of high-energy neutrinos emanating from our galaxy and beyond, to the far reaches of the universe.
A new view of our galaxy
Thanks to this detector, researchers have now painted a whole new picture of the galaxy we live in. said Dennis Caldwell, director Physics Division affiliate National Science Foundation. “The highly sensitive IceCube detector, combined with new data analysis tools, has now given us a whole new perspective of our galaxy. In the future, this image will be refined and refined at a higher resolution. This may reveal hidden features of our galaxy that humanity has not seen before.”
In addition to the scientists’ already impressive ability to spot elusive ghost particles, they’ve also succeeded in achieving the more ambitious goal of pinpointing their source. When neutrino interactions occur with the ice beneath the IceCube, those rare encounters produce fuzzy light patterns, which the IceCube can detect. And some patterns of light clearly point to a specific part of the sky, helping researchers pinpoint the source of the neutrinos. However, other interactions are much less clear. That’s why the researchers developed one machine learning algorithm. It took them more than two years to carefully test and verify the algorithm using synthetic data that simulates neutrino detections. When they finally fed real data provided by IceCube into the algorithm, an image emerged with bright spots corresponding to locations in the Milky Way that they are suspected of emitting neutrinos.
Over many decades, scientists have made countless astronomical discoveries, thanks to new methods of observing the universe. For example, radio astronomy and infrared astronomy were once revolutionary developments. Then new phenomena joined them, such as gravitational waves and now neutrinos. According to Nilsson, the new neutrino-based image of the Milky Way is another important and pioneering step forward that will eventually lead to new discoveries of hitherto unknown aspects of the universe. “It’s a big step that we are observing our own galaxy for the first time using particles instead of light,” she says. “As neutrino astronomy develops, we will be able to observe the universe through new glasses. That is why we do what we do: to see something no one has seen before, and to understand things we have not yet understood.”
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