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Dark energy

(Last edited: Sunday, 17 September 2023, 9:55 PM)



Dark energy (not to be mistaken with dark matter) makes up approximately 68% of the universe, and it is distributed evenly not only in space, but also in time (therefore it has a global effect on the universe as a whole). This is a repulsive force, that accelerates the expansion of the universe. The rate of expansion and its acceleration can be measured by observations based on the Hubble law. The existence of dark energy is proven and its role in the universe can be described thanks to Albert Einstein’s theory of general relativity. 

Example Sentence(s):

"Dark energy is generally accepted as contributing to the increased acceleration of the expanding universe, so understanding this relationship will help to refine how physicists and astrophysicists understand it."

"And there are still no final answers to the questions surrounding dark energy."

  • French: L'énergie sombre
  • German: Dunkle Energie
  • Polish: Ciemna energia
  • Russian: тёмная энергия 
  • Swedish: Mörk energi

Links to Videos/Articles:

Dark matter

(Last edited: Sunday, 17 September 2023, 9:56 PM)



Dark matter (not to be mistaken with dark energy) makes up about 27% of the universe. Unlike normal matter, dark matter does not interact with electromagnetic forces. This means it does not absorb, reflect or emit light, therefore it can't be seen, but researchers can detect it and map it by measuring gravitational lensing. Because of these properties, it works like an attractive force, holding the universe together. 

In the 1930s, astronomer Fritz Zwicky studied images of around 1,000 galaxies that make up the Coma Cluster and speculated that some kind of matter must be keeping them together. Astronomers Vera Rubin and Kent Ford found a similar phenomenon when they studied the rotation rates of individual galaxies, with even more evidence of the features mentioned above.

The existence of dark matter is so widely accepted that it’s part of the "standard model of cosmology", although there is no solid evidence that it is real. There are many theories suggesting that physics beyond the Standard Model, such as supersymmetry and extra dimensions, exist. If other parallel universes exist, then physical features of each universe would be different, therefore the amount of dark matter in each universe would be different. Dark matter helps scientists gain a better understanding of the composition of our universe and how galaxies are held together. 

Sample Sentence(s):

"You can see the galaxy clusters that Professor Zwicky studied to discover Dark Matter."

"Dr. Shepherd's work enhances our profile in the area of Dark Matter exploration significantly."

  • French: Matière Noire
  • German: Dunkle Materie
  • Polish: Ciemna materia
  • Russian: тёмная материя
  • Swedish: Mörk materia

Links to Videos/Articles:

Dark Nebula

(Last edited: Tuesday, 29 August 2023, 5:39 PM)

Short Definition

A dark nebula, also known as an absorption nebula, is a form of interstellar cloud. It is so thick that it obscures visible wavelengths of light from things behind it, such as reflection nebulae or background stars and emission. Interstellar dust grains in molecular clouds' coldest, densest portions produce light extinction.

Detailed Definition

Sometimes the light from the background stars or reflection nebulas can be obscured by an interstellar cloud composed of gas, plasma and galaxy dust, creating irregular shapes without defined boundaries. This results in the formation of a black nebula or absorption nebula. The naked eye has seen large dark nebulas, often seen as shadows falling from the sky.

The development of stars and meteors is crucial in the black nebula. Because of the difference in density, it is impossible to form stars during condensation. Enormous molecular clouds often surround the black nebulas, while the small ones can be called Bok globulos. Half of the world's famous Bang globules have been discovered to contain new stars.


mid-15c., nebule "a cloud, mist," from Latin nebula, plural nebulae, "mist, vapor, fog, smoke, exhalation," figuratively "darkness, obscurity," from PIE root *nebh- "cloud."

Sample Sentence(s)

1.    Later, when I looked to my left, there was a black nebula. It had initially been an implacable cloud.

2.    In general, the detections best suited the concept of a collision between a star and an interstellar nebula.

3.    We've seen enough evidence to believe our solar system began with a cold black nebula spinning in slow motion.

Translations of Terms/Concepts into Partner Languages

French:nébuleuse sombre

German: dunkler Nebel

Italian: nebulosa oscura

Polish: ciemna mgławica

Swedish: mörk nebulosa

Links to videos or articles:
1. Kurzgesagt - In a Nutwchell. 2017. The Last Light Before Eternal Darkness – White Dwarfs & Black Dwarfs. Retrieved on June 6, 2023 from
2. Encyclopedia Britannica Contributors. February 23. 2023. Nebula. Retrieved June 15, 2023 from

DART Mission

(Last edited: Sunday, 17 September 2023, 10:27 PM)



A mission planned by NASA to test a method of planetary defense by redirecting an asteroid, which could hypothetically pose a threat to Earth, by means of the DART spacecraft deliberately crashing itself into this asteroid.

The DART spacecraft was built by Johns Hopkins Applied Physics Laboratory and was launched on November 23, 2021 at Vandenberg Space Force Base in California. Its target is the binary near-Earth asteroid Didymos (780 m across) and its secondary body, or “moonlet”, Dimorphos (163 m across). This binary asteroid is situated roughly 11 million kilometers from the Earth and does not pose a threat to the planet, but corresponds to the size of a potentially hazardous celestial body (140 m or more in diameter). As a result of the planned collision at the end of September 2022, the orbit of Dimorphos will change, this change will be observed and measured using telescopes on Earth and the data will be used to predict effectiveness of kinetic impact for the purpose of asteroid deflection as a planetary defense method.



DART stands for “Double Asteroid Redirection Test”


  • French: Test de déviation d'un astéroïde double – [tɛst də de.vja.sjɔ̃ dœ̃ as.te.ʁɔ.id dubl]
  • German: Doppel-Asteroiden-Umleitungs-Test – [ˈdɔpl̩ asteʁoˈiːdn̩ ˈʊmˌlaɪ̯tʊŋs tɛst]
  • Polish: – Misja DART (test przekierowania podwójnej asteroidy)
  • Russian: испытания перенаправления двойного астероида – [ɪspɨˈtanʲɪjɐ pʲɪrʲɪnəprɐˈvlʲenʲɪɪ̯ɐ dvɐjˈnovə ɐsʲtʲɪˈroɪdə]
  • Swedish:– []

Links to Videos/Articles:

More detailed information on the project:


(Last edited: Sunday, 17 September 2023, 10:33 PM)


The smaller of the two natural satellites/moons of Mars situated farthest from the planet.


Named after Deimos, the Ancient Greek god of terror, twin brother of Phobos, son of Ares (the equivalent of the Ancient Roman god of war Mars).

  • English: Deimos    [ˈdaɪmɒs]
  • French: Déimos    [deimos]
  • German: Deimos (m)    []
  • Polish: Deimos, Dejmos
  • Russian: Деймос (m)    [ˈdejməs]
  • Swedish:

Links to Videos/Articles:

Dusty Vacuum Chamber (Dirty Vacuum Chamber)

(Last edited: Saturday, 30 September 2023, 6:00 PM)

Dwarf Galaxy

(Last edited: Tuesday, 29 August 2023, 5:40 PM)
Picture: Fornax Dwarf Galaxy Image/Video/Audio Source:

Picture: Fornax Dwarf Galaxy Image/Video/Audio Source:

Short Definition:

A dwarf galaxy is one that contains fewer stars than larger galaxies. A dwarf galaxy is a galaxy made up of material and dark matter ejected from larger galaxies by the force of gravity. Although a dwarf galaxy is defined by astronomers by the number of stars it contains, and hence its size, it is also defined as dwarf by its shape, content, and even appearance.

Detailed Definition:

Dwarf galaxies, formed from fragments of larger galaxies, are the most abundant type of galaxy in the universe. Dwarf galaxies are galaxies that break apart due to their relatively small size to their neighbors, causing stellar streams and galaxy mergers. However dynamic these relationships with neighboring galaxies may be, they are difficult to detect by astronomers due to their low light, mass and small size. The astronomical importance of these dwarf galaxies actually comes from their tendency to form from other large galaxies and merge again with larger galaxies. Their difference from the usual galaxy shape is that they have low metallicity and gas in abundance. This situation is used by astronomers as evidence to interpret the motion and evolution of galaxies. Dwarf galaxies are basically divided into three groups: Dwarf elliptical galaxies, dwarf spheroidal galaxies, and dwarf irregular galaxies.


From Old English Dweorg + From Latin Galaxias

Sample Sentence(s):

The most powerful space telescope currently operating has zoomed in on a lonely dwarf galaxy in our galactic neighborhood, imaging it in stunning detail.’’

(Lea, R. (2022, November 11). James Webb Space Telescope peers into lonely dwarf galaxy with sparkling results.

‘’This Living Collection starts with an introductory Comment and continues with a series of articles on the science of dwarf galaxies, their properties and their theoretical modelling and simulations.’’

(It’s time for some plane speaking. (2021, December 13). Nature. error=cookies_not_supported&code=03e197b7-7ba4-4db9-a0c7-ee3cf2730af7)

Translations of Terms/Concepts into Partner Languages:


Galaxie Naine




Galaktyka karłowata




Cüce Gökada

Links to Videos/Articles: