NASA Films 'Dirty Snowball' Comet Plunging Into Sun

NASA has captured images of a comet disintegrating as it passed too close to the sun.

Instruments onboard the Solar and Heliospheric Observatory (SOHO)—a spacecraft jointly operated by NASA and the European Space Agency—observed the comet heading toward our star on August 6.

One day later, more images captured by SOHO showed the comet disappearing as it flew too close to the sun.

"The dirty snowball evaporated," spaceweather.com reported in an alert.

Comets are objects that consist of frozen gases, rock and dust that orbit the sun. The nuclei of these objects can reach tens of miles across, although many are much smaller.

As comets approach closer to the sun, they are blasted with increasing quantities of radiation. This causes the comet to heat up, leading to a release of gas and dust, which creates a temporary atmosphere known as a coma that forms around the nucleus of the object. Comet comas can be significantly larger than the Earth.

A comet in space
NASA has captured images of a comet disintegrating as it passed too close to the sun. Above, an artist's illustration of a comet. iStock

In addition, comets also form two tails as they approach closer to the sun—the gas tail and the dust tail, which can measure million of miles in length.

The gas tail appears due to the effect of the solar wind—charged particles emitted by the sun—on electrically charged gas particles released by the comet. Meanwhile, interactions between photons—particles of light—emitted by the sun, the solar wind, and vaporized dust in the comet's coma lead to the formation of the dust tail.

Comets are leftovers from the formation of the solar system 4.6 billion years ago. According to the International Astronomical Union's Minor Planet Center, more than 4,000 comets have been discovered to date, although this likely represents only a tiny fraction of the ones that actually exist in the Solar System.

Some comets pass very close to the sun, and various terms can be used describe these objects, according to one study published in 2017.

"Sunskirters" are defined as comets that pass within 33 solar radii of the sun's center in the study. Meanwhile, "sungrazers" pass even closer, coming within around three solar radii. And finally, "sundivers" are those that actually intersect with the sun's photosphere—the lowest layer of the star's atmosphere.

According to spaceweather.com, the comet that recently disintegrated as it passed too close to the sun was almost certainly part of the Kreutz family of comets.

This group of comets, named after the 19th-century German astronomer who studied them, Heinrich Kreutz, are thought to have originated from the breakup of a single, giant comet hundreds of years ago.

Fragments of this huge object orbit the sun, and frequently pass close to our star, with many evaporating and disintegrating.