How do we see the invisible glue of our universe?
In short: Dark matter doesn't emit, reflect, or absorb light, making it completely invisible to traditional telescopes. Yet, scientists are certain it exists because they can watch it pull on everything else. By observing how galaxies behave, we can map a substance that makes up the majority of our cosmos.
The existence of dark matter was first proposed in 1933 by Swiss-born astronomer Fritz Zwicky. While studying the Coma Cluster—a large group of galaxies—Zwicky noticed a profound discrepancy: the galaxies were moving far too quickly to be held together by the gravity of their visible contents. Based on the amount of ordinary matter he could see, these galaxies should have flown apart. He concluded there must be an invisible form of matter providing extra gravitational pull, which he called "dunkle Materie."
Today, we understand that dark matter acts as a cosmic scaffold. It makes up about 27% of the universe's total composition, while ordinary matter—the stuff that forms stars, planets, and humans—accounts for only about 5%. Because dark matter interacts with ordinary matter through gravity but ignores the electromagnetic spectrum entirely, we cannot detect it directly. Instead, astronomers use tools like X-ray astronomy to study its effects on galaxy clusters and other astronomical settings.
This cosmic struggle defines our reality: while dark matter acts as a gravitational glue pulling things together, a different mystery called dark energy drives the universe apart. Understanding these two components is essential because they determine the ultimate fate of the cosmos. While we can see only about 4% of the universe's contents with our eyes and telescopes, the remaining 96% remains a frontier where general relativity and quantum mechanics continue to clash.
Opens the Intellect+ feed with this card first. Swipe up for the next one.
Sources
- Summary by Intellect · source: How do we know how much dark matter there is in the Universe?
- Also: Dark Matter - NASA Science
- Also: chandra.harvard.edu — The Dark Universe
To cite this card, link to https://intellectplus.co.uk/app/space-how-do-we-know-how-much-dark-matter-there-is-in-the-universe.
How we source, check and correct cards: Editorial standards.
General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.
Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?
Related
More in Dark matter · More in Space · Latest · A–Z · All topics
