Over 100 years ago, they discovered a strange radiation. Finally, the mystery was solved.

The latest breakthrough in this extraordinary research comes from observations of the globular cluster Terzan 5. This part of the Milky Way galaxy is located about 22,500 light-years from Earth. Sweeping through our galaxy at incredible speeds, Terzan 5 has captured the attention of astronomers for nearly sixty years.

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Based on their analysis, they were able to solve the great mystery associated with this object. As the authors of the research they wrote about explained: Natural astronomyThey were able to measure how quickly the direction of high-energy particles changed due to fluctuations in the magnetic fields between the stars.

The great unknown to scientists was why the protons and electrons that make up cosmic rays are accelerated to speeds close to the speed of light in an unknown way. In this way, they move through interstellar space and can reach the upper layers of our planet’s atmosphere. This was confirmed in 1912 by Victor Hess, who used a balloon to measure the amount of radiation at certain altitudes.

Cosmic radiation was first identified in 1912.

But where exactly do these particles come from? This is a more difficult task because their direction of motion changes when they interact with magnetic fields. From the perspective of Earth, we might have the impression that this radiation arrives from all directions equally. Moreover, it is not, or indeed has not been clear, where the magnetic fluctuations come from.

Perhaps the breakthrough was played by the Terzan 5 cluster and the astronomers who study it. The large number of dense stars with strong magnetic fields that make up this cluster accelerates cosmic rays to very high values. Even if they don’t reach Earth directly, you can still see signs of their interaction, creating gamma rays.

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The latter behave in a similar way, although they differ from the cosmic ones in at least one respect: they are not deflected by magnetic fields, so they reach Earth. In the case of Terzan 5, for reasons that are not explained, the gamma rays do not match the positions of its stars: the offset is about 30 light-years. The authors of the new research may have explained the source of this anomaly.

In their view, cosmic rays from the cluster first travel along its “tail.” Since the latter is not directed toward Earth, no gamma rays are visible. At some point, magnetic fluctuations come into play, causing changes in the direction of the cosmic rays. When they line up in the right configuration relative to our planet, gamma rays begin to form, although it takes about 30 years for this to happen. This explains the large shift between the expected and actual source of these signals.