dark matter

noun

a hypothetical form of matter invisible to electromagnetic radiation, postulated to account for gravitational forces observed in the universe.

Origin of dark matter

First recorded in 1985–90

Words Nearby dark matter

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use dark matter in a sentence

For Baillet, the aperiodic signals in the brain are a bit like dark matter, the invisible scaffolding of the universe that interacts with normal matter only through gravity.
Brain’s ‘Background Noise’ May Hold Clues to Persistent Mysteries | Elizabeth Landau | February 8, 2021 | Quanta Magazine
That dark matter is probably some new kind of new particle is almost universally accepted, too.
A Prodigy Who Cracked Open the Cosmos | Claudia Dreifus | January 12, 2021 | Quanta Magazine
It’s sort of like the dark matter of the economy and society, it matters very greatly and yet we don’t seem to focus on it very much.
Trust Me (Ep. 266 Rebroadcast) | Stephen J. Dubner | December 31, 2020 | Freakonomics
Some describe the many that remain unknown as “nutritional dark matter.”
How technology rewrites your diet | Amy Nordrum | December 18, 2020 | MIT Technology Review
Beyond that disk lies a broad stretch of gas surrounded by a vast halo of invisible dark matter.
From Elvis worms to the Milky Way’s edge, these science stories sparked joy in 2020 | Erika Engelhaupt | December 17, 2020 | Science News

Instead, dark matter is its own antimatter, so any pair of particles that meet will destroy each other.
Still No Dark Matter from Space Station Experiment | Matthew R. Francis | September 21, 2014 | THE DAILY BEAST
The Universe is filled with the mysterious invisible substance we call dark matter.
Still No Dark Matter from Space Station Experiment | Matthew R. Francis | September 21, 2014 | THE DAILY BEAST
Nearly everything we know about dark matter so far comes from astronomy.
Still No Dark Matter from Space Station Experiment | Matthew R. Francis | September 21, 2014 | THE DAILY BEAST
Not only that, they are a rich environment for galaxies, hot plasma, and dark matter.
The Care and Feeding of Baby Giant Galaxies | Matthew R. Francis | May 25, 2014 | THE DAILY BEAST
For one thing, it sounds like it has to do “dark matter,” but they are almost complete opposites.
Using Black Holes to Measure Dark Energy, Like a BOSS | Matthew R. Francis | April 13, 2014 | THE DAILY BEAST
But how reconcile that with what we have said above on the absence of a noteworthy proportion of dark matter?
The Foundations of Science: Science and Hypothesis, The Value of Science, Science and Method | Henri Poincar
When I stooped over him he was in convulsions, and dark matter was oozing out of his mouth.
Stories by English Authors: Africa | Various
Showing a great projection of "dark matter" cutting off the light from behind.
The Outline of Science, Vol. 1 (of 4) | J. Arthur Thomson
Then she turned to Neville, and said, solemnly, "You wish to know the truth in this dark matter: for dark it is in very sooth."
The Atlantic Monthly, Volume 18, No. 107, September, 1866 | Various
In a dark matter like this, where we know so little, it behoves us to provide for every chance.
Wulf the Saxon | G. A. Henty

British Dictionary definitions for dark matter

dark matter

noun

astronomy matter known to make up perhaps 90% of the mass of the universe, but not detectable by its absorption or emission of electromagnetic radiation

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for dark matter

dark matter

Matter that emits little or no detectable radiation. Gravitational forces observed on many astronomical objects suggest the significant presence of such matter in the universe, accounting for approximately 23 percent of the total mass and energy of the universe. Its exact nature is not well understood, but it may be largely composed of varieties of subatomic particles that have not yet been discovered, as well as the mass of black holes and of stars too dim to observe. Also called missing mass

a closer look

What is the universe made of? We know that galaxies consist of planets, stars, and huge gas and dust clouds-all of these objects are observable by the radiation they give off, such as radio, infrared, optical, ultraviolet, x-ray, or gamma-ray radiation, and all can be observed using various kinds of telescopes. But there are reasons to suspect the existence of far more matter than this, matter that is not directly observable. Evidence for such dark matter comes from observations of certain gravitational effects. For example, astronomers have found that galaxies rotate much faster than they would be expected to rotate based solely on their observable mass-in fact, they should be flying apart. One explanation for this apparent anomaly is to assume that the galaxies have much more mass than we can see, and this invisible mass holds them together gravitationally. Various theories of the composition of this invisible dark matter have been proposed, from exotic yet-to-be discovered particles to planet-sized objects made of ordinary matter that are too small or far away to be detected by present-day instruments. But none of these theories are entirely satisfactory, and the fundamental question of what makes up most of the universe remains unanswered.

Cultural definitions for dark matter

dark matter

Unseen matter that may make up more than ninety percent of the universe. As the name implies, dark matter does not interact with light or other electromagnetic radiation, so it cannot be seen directly, but it can be detected by measuring its gravitational effects. It is believed that dark matter was instrumental in forming galaxies early in the Big Bang.

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