It’s one of the most baffling problems in astrophysics. If the solar surface is 5,500℃, how can the solar atmosphere (the corona) be between 1 million and 10 million degrees C?
For the first time, scientists have observed nanojets, bright thin lights traveling perpendicular to the magnetic field lines of the Sun that are the telltale signature of nanoflares: localized, rapid heating events of the corona.
The issue of coronal heating was first identified by astrophysicists in the 1940s. Since then, numerous hypotheses have been put forth to explain how the Sun’s atmosphere is many times hotter than its surface.
One such hypothesis put forward by Peter Gold and developed by Eugene Parker (for whom the Parker Solar Probe is named) is nanoflares, periodic small-scale heating events of the corona.
But a fundamental problem with this hypothesis — and others — was not being able to directly observe the complex physical processes at work in the corona.
Despite lacking a way to see the event, scientific models showed that a faint, hot emission from a nanoflare would be detectable and measurable.
To help study the corona in more detail, NASA developed the Interface Region Imaging Spectrograph (IRIS) spacecraft to ...