DARK MATTERNOELIA ALONSO

AND ALBA MUÑOZ

INDEX• CONCEPT• ASTRONOMERS WHO

SUGGESTED EXISTENCE OF DARK MATTER

• OBSERVATIONAL EVIDENCE• ALTERNATIVE THEORIES• BARYONIC VS NON-BARYONIC

MATTER• CLASSIFICATION• POPULAR CULTURE

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. 

ASTRONOMERS WHO SUGGESTED DARK MATTER

• THE FIRST TO SUGGEST THE EXISTENCE OF DARK MATTER WAS  JACOBUS KAPTEYN IN 1922.

• JAN OORT HYPOTHESIZED EXISTENCE OF DARK MATTER IN 1932.

• IN 1933, FRITZ ZWICKY APPLIED THE VIRIAL THEOREM TO THE COMA GALAXY CLUSTER.

• IN 1939, BABCOCK REPORTED THE ROTATION CURVE FOR THE ANDROMEDA NEBULA, WHICH SUGGESTED THAT THE MASS-TO-LUMINOSITY RATIO INCREASES.

• VERA RUBIN AND KENT FORD  IN THE 1960S–1970S PROVIDED STRONG EVIDENCE, ALSO USING GALAXY ROTATION CURVES. 

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.

ALTERNATIVE THEORIES

• MASS IN EXTRA DIMENSIONS

• TOPOLOGICAL DEFECTS

• MODIFIED GRAVITY

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.

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)

POPULAR CULTURE• IT IS COMMONLY USE IN SCI-FI WORKS (SERIES,

BOOKS…) • USUALLY ATTRIBUTED TO EXTRAORDINARY PHYSICAL

OR MAGICAL PROPERTIES.• DESCRIPTIONS ARE OFTEN INCONSISTENT

Videos

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

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!

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