Dark matter is invisible matter that accounts for approximately 27% of the mass-energy in the universe. Although it cannot be directly observed, astronomers deduce its existence through its gravitational effects, such as the anomalous rotation curves of galaxies. Dark matter is classified as cold, warm, or hot depending on the size of protogalaxies, and may consist of either baryonic matter like protons and neutrons or nonbaryonic particles like axions. It plays a prominent role in science fiction works but descriptions are often inconsistent with scientific understanding.

1. DARK MATTER
NOELIA ALONSO
AND
ALBA MUÑOZ

2. INDEX
• CONCEPT
• ASTRONOMERS WHO SUGGESTED
EXISTENCE OF DARK MATTER
• OBSERVATIONAL EVIDENCE
• ALTERNATIVE THEORIES
• BARYONIC VS NON-BARYONIC
MATTER
• CLASSIFICATION
• POPULAR CULTURE

3. Concept
• CORRESPONDS TO THE 27% OF THE MASS AND ENERGY IN THE UNIVERSE.
• IT DOES NOT EMIT OR INTERACT WITH ELECTROMAGNETIC RADIATION.
• IT HAS NOT BEEN DIRECTLY OBSERVED, BUT ITS EXISTENCE IS DEDUCED FROM ITS
GRAVITATIONAL EFFECTS
• IS TRANSPARENT TO ELECTROMAGNETIC RADIATION AND IS SO DENSE AND SMALL THAT IT
CAN’T EMIT ENOUGH RADIATION TO BE DETECTABLE WITH OUR TECHNOLOGY.
• THE TOTAL MASS-ENERGY OF THE UNIVERSE CONTAINS 4.9% ORDINARY MATTER, 26.8%
DARK MATTER AND 68.3% DARK ENERGY.

4. ASTRONOMERS WHO SUGGESTED DARK MATTER

5. Observational evidence
• Much of the evidence comes from the motions of galaxies. Galactic rotation curves,
illustrate the velocity of rotation versus the distance from the galactic center,
showing the "excess" velocity.
• Diffusse galaxies (galaxies with brightness lower than night sky) have an uncommon
low ratio of visible dark matter. Gravitational observations of galaxy clusters allow
direct estimates of the gravitational mass based on its effect on light coming from
other galaxies.

6. ALTERNATIVE THEORIES
• MASS IN EXTRA
DIMENSIONS
• TOPOLOGICAL DEFECTS
• MODIFIED GRAVITY

7. BARYONIC VS. NON-
BARYONIC MATTER
● Baryonic matter is made of protons and neutrons that make up
stars and planets.
● Nonbaryonic dark matter are hypothetical particles such as
axions particles.

8. CLASSIFICATION
● Dark matter can be divided into cold, warm and hot categories.
● The categories are set with respect to the size of a protogalaxy. Dark
matter particles are classified according as their Free Streaming
Length:
● much smaller than a protogalaxy (cold)
● similar to a protogalaxy (warm)
● or much larger than a protogalaxy (hot)

9. POPULAR CULTURE
• IT IS COMMONLY USE IN SCI-FI WORKS (SERIES, BOOKS…)
• USUALLY ATTRIBUTED TO EXTRAORDINARY PHYSICAL OR MAGICAL
PROPERTIES.
• DESCRIPTIONS ARE OFTEN INCONSISTENT

10. Videos
• https://youtu.be/9y3i2tJwl1w - FRITZ ZWICKY
• https://youtu.be/5HjhUiHZue0
• https://youtu.be/kaGRvkVQIDM - Vera Rubin’s observation

11. BIBLIOGRAPHY
•HTTPS://ES.WIKIPEDIA.ORG/WIKI/DARK_MATTER
•HTTPS://ES.WIKIPEDIA.ORG/WIKI/MATERIA_OSCURA
•HTTPS://SCIENCE.NASA.GOV/ASTROPHYSICS/FOCUS-AREAS/WHAT-IS-DARK-ENERGY
•HTTP://SCIENCE.NATIONALGEOGRAPHIC.COM/SCIENCE/SPACE/DARK-MATTER/
•HTTP://WWW.SPACE.COM/20930-DARK-MATTER.HTML
•OUR SCIENTIFIC CULTURE BOOK!

12. THE END!
WE HOPE YOU LIKED IT.
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