Do neutrinos transfer in straight traces? | Scientists reply | Science | EUROtoday

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In reply to the query, sure, let’s imagine that neutrinos journey in a straight line from the supply wherein they have been produced. In truth, it’s what makes them engaging, amongst different issues, for astrophysics. That they don’t deviate from the place the place they have been generated offers us details about the place the supply is situated. If we’re in a position to detect the neutrinos produced throughout a supernova explosion, we might know the place that supernova occurred. This can be the quick reply, however it’s needed to clarify it intimately as a result of it’s not that easy.

Neutrinos are basic particles, with out electrical cost and really small—so small that for a time it was thought that they’d no mass—so that they work together weakly with matter. During nuclear reactions inside stars, completely different particles corresponding to photons or neutrinos are produced. Unlike photons—which, though they don’t have any cost or mass, behave as in the event that they did when interacting with matter—neutrinos escape following a rectilinear path with out interacting with it.

That occurs inside a star, however what occurs within the universe? In the cosmos, neutrinos transfer the identical. As they don’t have any cost, they don’t work together with electromagnetic fields that might divert them from their path, and it’s also not possible that they are going to work together with matter attributable to their low mass. That is why we are saying that neutrinos journey in straight traces, as a result of they don’t work together with the remainder of the matter within the universe. This does occur to different particles, corresponding to cosmic rays, which work together with electromagnetic fields or photons.

Neutrinos might work together with matter via the pressure of gravity. However, though they’ve mass, it’s so small that even within the occasion that you simply encounter a really huge object that considerably curves space-time, corresponding to a supermassive black gap, the likelihood of interplay is virtually negligible.

However, we should make clear that they transfer in a straight line as a result of the space-time of the universe is just not flat, however curved because of the matter it incorporates. Taking this curvature into consideration, neutrinos truly transfer alongside geodesic traces (that are the shortest path becoming a member of two factors on a given floor). It is one thing analogous to what occurs with the trajectory of airplanes on the floor of the Earth: they don’t observe straight traces between, for instance, Madrid and New York, however they historically deviate in the direction of the north when crossing the Atlantic Ocean because of the curvature of the Earth. Of course, if we restrict ourselves to a small area of the universe with out massive lots, what is called Minkowski area, the curvature is minimal and the geodesic line coincides with a rectilinear path.

In abstract, to reply this query, I might say that neutrinos transfer alongside geodesic traces, which within the absence of huge lots that considerably curve space-time, corresponding to supermassive black holes, coincide with straight-line trajectories.

And this straight-line motion of neutrinos is exactly one of many properties that makes them so attention-grabbing for astronomy. That and they’re very quick particles. They are believed to journey at speeds very near that of sunshine. In truth, some research argued that they may overcome it, though the outcomes have been extremely disputed. Because they’re so quick and there may be nothing to deflect them, they attain Earth earlier than the photons. And that, for instance, detecting a supernova explosion is essential. The individuals who do analysis with neutrino detectors—corresponding to Super-Kamiokande, situated in Japan and the place I work—are ready in order that, within the occasion of a supernova explosion, they’ll launch an alert in a matter of seconds. It is just essential to detect the neutrinos and inform the telescopes, each terrestrial and area, the place they need to level to watch the phenomenon from the start of the explosion.

Nataly Ospina Escobar She is a researcher within the Department of Theoretical Physics of the Autonomous University of Madrid.

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