Cosmic dust

Porous chondrite interplanetary dust particle.

Cosmic dust, also called extraterrestrial dust or space dust, is dust which exists in outer space, as well as all over planet Earth.[1][2] Most cosmic dust particles are between a few molecules to 0.1 µm in size. A smaller fraction of all dust in space consists of larger refractory minerals that condensed as matter left by stars. It is called "stardust" and is included in a separate section below. The dust density falling to Earth is approximately 10−6/m3 with each grain having a mass between 10−16kg (0.1 pg) and 10−4 kg (100 mg).[3][4]

Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust (such as in the zodiacal cloud) and circumplanetary dust (such as in a planetary ring). In the Solar System, interplanetary dust causes the zodiacal light. Sources of Solar System dust include comet dust, asteroidal dust, dust from the Kuiper belt, and interstellar dust passing through the Solar System. The terminology has no specific application for describing materials found on the planet Earth except for dust that has demonstrably fallen to Earth. By one estimate, as much as 40,000 tons of cosmic dust reaches the Earth's surface every year.[3] In October 2011, scientists reported that cosmic dust contains complex organic matter (amorphous organic solids with a mixed aromaticaliphatic structure) that could be created naturally, and rapidly, by stars.[5][6][7]

In August 2014, scientists announced the collection of possible interstellar dust particles from the Stardust spacecraft since returning to Earth in 2006.[8][9][10][11] In March 2017, scientists reported that extraterrestrial dust particles have been identified all over planet Earth.[2] According to one of the researchers, “Once I knew what to look for, I found them everywhere.”[1]

Study and importance

Artist’s impression of dust formation around a supernova explosion.[12]

Cosmic dust was once solely an annoyance to astronomers, as it obscures objects they wish to observe. When infrared astronomy began, the dust particles were observed to be significant and vital components of astrophysical processes. Their analysis can reveal information about phenomena like the formation of the Solar System.[13] For example, cosmic dust can drive the mass loss when a star is nearing the end of its life, play a part in the early stages of star formation, and form planets. In the Solar System, dust plays a major role in the zodiacal light, Saturn's B Ring spokes, the outer diffuse planetary rings at Jupiter, Saturn, Uranus and Neptune, and comets.

Zodiacal light caused by cosmic dust.[14]

The study of dust is a largely researched topic that brings together different scientific fields: physics (solid-state, electromagnetic theory, surface physics, statistical physics, thermal physics), fractal mathematics, chemistry (chemical reactions on grain surfaces), meteoritics, as well as every branch of astronomy and astrophysics.[15] These disparate research areas can be linked by the following theme: the cosmic dust particles evolve cyclically; chemically, physically and dynamically. The evolution of dust traces out paths in which the Universe recycles material, in processes analogous to the daily recycling steps with which many people are familiar: production, storage, processing, collection, consumption, and discarding. Observations and measurements of cosmic dust in different regions provide an important insight into the Universe's recycling processes; in the clouds of the diffuse interstellar medium, in molecular clouds, in the circumstellar dust of young stellar objects, and in planetary systems such as the Solar System, where astronomers consider dust as in its most recycled state. The astronomers accumulate observational ‘snapshots’ of dust at different stages of its life and, over time, form a more complete movie of the Universe's complicated recycling steps.

Parameters such as the particle's initial motion, material properties, intervening plasma and magnetic field determined the dust particle's arrival at the dust detector. Slightly changing any of these parameters can give significantly different dust dynamical behavior. Therefore, one can learn about where that object came from, and what is (in) the intervening medium.

Other Languages
Afrikaans: Ruimtestof
العربية: غبار كوني
asturianu: Polvu cósmico
azərbaycanca: Kosmik toz
башҡортса: Космос саңы
беларуская: Касмічны пыл
беларуская (тарашкевіца)‎: Касьмічны пыл
български: Космически прах
català: Pols còsmica
čeština: Kosmický prach
Ελληνικά: Κοσμική σκόνη
español: Polvo cósmico
Esperanto: Kosma polvo
euskara: Hauts kosmiko
한국어: 우주진
हिन्दी: खगोलीय धूल
къарачай-малкъар: Алам букъу
Bahasa Melayu: Debu kosmos
Nederlands: Kosmisch stof
日本語: 宇宙塵
ਪੰਜਾਬੀ: ਖਗੋਲੀ ਧੂਲ
română: Praf cosmic
Simple English: Cosmic dust
српски / srpski: Космичка прашина
svenska: Rymdstoft
Türkçe: Kozmik toz
українська: Космічний пил
Tiếng Việt: Bụi vũ trụ
中文: 宇宙塵