How Solar Prominences Defy Gravity and Float Above the Sun

New research from Germany’s Max Planck Institute for Solar System Research (MPS) has provided a detailed explanation of how solar prominences—massive arcs of plasma that hover above the Sun—remain stable despite extreme differences in temperature and density compared to their surroundings.

These structures are of particular interest to scientists studying space weather because they can act as potential triggers for solar eruptions. When these prominences break apart, they can drive charged solar particles into space, creating events that pose risks to Earth’s technological infrastructure, including communication systems and satellites.

The Physics of Solar Prominences

Solar prominences are characterized by a physical contradiction: they are significantly cooler and denser than the solar corona that surrounds them. While the corona exceeds a million degrees, prominences typically sit at approximately 10,000 degrees.

In addition to the temperature gap, these structures are about 100 times denser than the surrounding environment. Dr. Lisa-Marie Zessner, the lead author of the study, describes these features as cool and dynamic plasma clouds hovering in the hot solar atmosphere.

The disparity in density is so extreme that Zessner uses an analogy to illustrate the phenomenon’s unusual nature:

The density of the prominence material is typically two orders of magnitude higher than the density of the surrounding corona. A comparison to the typical density ratio might be a piece of wood (a bit dependent on the type of wood), so we could, for example, say that this is roughly like if a wooden ship were floating in Earth’s atmosphere (at least close to ground level).

Dr. Lisa-Marie Zessner

Despite their immense mass and the pull of gravity, these plasma structures can stretch for thousands of kilometers and remain stable for weeks or even months.

Magnetic Support and Stability

The research, published in Nature Astronomy, explains that these heavy plasma clouds are supported against gravity by magnetic fields. Specifically, solar prominences form in areas where magnetic field lines curve downward, creating dips that can trap and hold the dense plasma.

This magnetic architecture allows the prominences to exist in various shapes and sizes across the surface of the Sun. However, this stability is not permanent. The research indicates that these structures can either gradually fade away or suddenly erupt.

Implications for Earth’s Technology

The transition from a stable prominence to an eruption is a critical event for space weather monitoring. When a prominence becomes unstable and explodes, it releases a burst of charged particles into the solar system.

These eruptions can have direct consequences for human technology. The resulting streams of charged particles can interfere with the operation of satellites and disrupt global communication systems. Understanding the formation and evolution of these structures is essential for predicting when such eruptions might occur.

By decoding the dynamics of how these structures form and eventually fail, researchers at the Max Planck Institute aim to better understand the mechanisms that drive dangerous solar eruptions, providing a clearer picture of the risks posed to orbital and ground-based technology.