Awww! The sun's sad face emoji

A National Aeronautics and Space Administration spacecraft has captured a giant solar filament which appears as a dark line snaked across the lower half of the sun and is longer than 67 earths lined up in a row.

An image captured by the NASA's Solar Dynamics Observatory on February 10 shows the filament of solar material hovering above the sun's surface.

The SDO shows colder material as dark and hotter material as light, so the line is, in fact, an enormous swatch of colder material hovering in the sun's atmosphere, the corona.

If stretched out, that line - or solar filament as scientists call it - could be more than 857,780 km long. That is longer than 67 earths lined up in a row, NASA said.

Filaments can float sedately for days before disappearing. Sometimes they also erupt out into space, releasing solar material in a shower that either rains back down or escapes out into space, becoming a moving cloud known as a coronal mass ejection, or CME.

The SDO captured images of the filament in numerous wavelengths, each of which helps highlight material of different temperatures on the sun.

By looking at such features in different wavelengths and temperatures, scientists learn more about what causes these structures, as well as what catalyses their occasional eruptions.

Launched on February 11, 2010, the SDO is designed to study the causes of solar variability and its impacts on earth.

The spacecraft's long-term measurements give solar scientists in-depth information to help characterise the interior of the sun, its magnetic field, the hot plasma of the solar corona, and the density of radiation that creates the ionosphere of the planets.

All images: NASA