5 Impossible-Sounding Solar and Plasma Events on the Sun That Science Has Confirmed Are Real

The Sun's visible surface, the photosphere, sits at roughly 5,500 degrees Celsius. Step away from it into the corona, the wispy outer atmosphere that becomes visible during a total solar eclipse, and the temperature jumps to somewhere between one and three million degrees Celsius. Moving away from a heat source and getting hotter violates every intuition about how heat works. Scientists call this the coronal heating problem, and it has been one of the most stubborn open questions in solar physics for over eighty years. The leading explanation involves magnetic waves called Alfvén waves, which carry energy from the Sun's churning interior outward into the corona and dissipate it as heat. NASA's Parker Solar Probe, which has made multiple close passes of the Sun since its 2018 launch, is gathering data on exactly this mechanism by flying through the corona itself, the first spacecraft ever to do so. India's Aditya-L1, launched by ISRO from Sriharikota in September 2023, is positioned at the L1 Lagrange point between Earth and the Sun, studying the corona continuously without the interruption of Earth's shadow. The mystery is not solved. But the measurement is exact: the corona is hotter, and we are watching it happen in real time.

The Sun vibrates. Not metaphorically. Pressure waves generated by convection in the solar interior bounce around inside the star, producing oscillations at the surface that have been measured precisely. The dominant mode has a period of about five minutes. The field that studies these oscillations is called helioseismology, and it works on the same principle as seismology on Earth: by analysing the waves, scientists can map the interior of an object they cannot directly observe. Helioseismology has revealed the Sun's internal rotation rate, shown that the core rotates faster than the outer layers, and helped locate where the solar dynamo, the engine that generates the magnetic field, operates. The Global Oscillation Network Group, a ring of six ground-based telescopes positioned around the world to give uninterrupted solar observation, has been running since 1995. The Sun does not make sound in the vacuum of space. But inside itself, it is producing pressure waves in the range of infrasound, frequencies below human hearing, that carry detailed information about everything happening beneath the surface we can see.

Solar prominences are arcs of plasma that lift off the photosphere and follow magnetic field lines into the corona. Some of these structures are stable for weeks. Others erupt. The largest prominences on record have extended hundreds of thousands of kilometres into space, the Earth's diameter is about 12,742 kilometres, which means a single prominence can be twenty or thirty times that length. The plasma in these loops reaches temperatures of tens of thousands of degrees Celsius. When a prominence becomes unstable and erupts, it can release a coronal mass ejection, a billion-tonne cloud of magnetised plasma travelling at speeds between 250 and 3,000 kilometres per second. A large coronal mass ejection aimed at Earth compresses the magnetosphere, drives geomagnetic storms, and can disrupt satellite communications, GPS systems, and power grids. The 1989 Quebec blackout, which left six million people without power for nine hours, was caused by a geomagnetic storm triggered by a solar eruption. ISRO's Aditya-L1 carries instruments specifically designed to monitor solar flares and coronal mass ejections, feeding early-warning data that matters to every satellite operator and power utility in the country.

The Sun's magnetic north and south poles swap positions on a roughly eleven-year cycle. The process is not sudden. Over the course of several years, the existing polar magnetic field weakens, reaches zero, and then rebuilds with opposite polarity. The solar maximum, the peak of sunspot activity and solar flares within each cycle, occurs near the midpoint of this reversal. The current cycle, Solar Cycle 25, reached its predicted maximum around 2024 and has produced some of the most intense solar flares recorded in two decades. The reversal is driven by differential rotation: the Sun does not rotate as a solid body. The equator completes one rotation in about 25 days; the poles take closer to 35 days. This difference winds and stretches the internal magnetic field until it becomes so tangled that the poles flip to release the stress. The full magnetic cycle, pole-to-pole and back again, takes about 22 years. Every 22 years, the Sun returns to the same magnetic configuration it started with. Earth's magnetic field also reverses, but on a timescale of hundreds of thousands of years. The Sun does it on a schedule you can track within a human lifetime.

The Sun continuously sheds a stream of charged particles, mostly electrons and protons, outward in all directions at speeds of 400 to 800 kilometres per second. This is the solar wind. At Earth's distance, roughly 150 million kilometres from the Sun, the solar wind arrives in about three to four days. At Mars, about 228 million kilometres away on average, it arrives in three to four days as well, depending on solar activity and the geometry of the planets' orbits at any given time. The solar wind is the reason Mars lost most of its atmosphere. Mars has no global magnetic field to deflect it, so the solar wind has been stripping away Martian atmospheric particles for billions of years. ISRO's Mangalyaan mission, which entered Mars orbit in 2014, carried a sensor called the Mars Exospheric Neutral Composition Analyser to study exactly this process. Earth is protected because the magnetosphere deflects the solar wind around the planet. Where the wind meets the magnetosphere at the poles, it creates the auroras. The solar wind is not a weather event. It is a permanent feature of the space environment, and every spacecraft operating beyond Earth's magnetosphere is flying through it continuously.The five phenomena described here look like separate curiosities, but they all trace back to the same engine: the Sun's magnetic field, generated by differential rotation, amplified by convection, and released in every form from a quiet five-minute oscillation to a billion-tonne plasma eruption. Aditya-L1 is not studying five different things. It is studying one system at different scales, and helioseismology, corona temperatures, flares, solar wind, and magnetic reversals are all its outputs.