Dark matter is estimated to make up 27% of the universe and is defined as matter that does not interact with light but has gravitational effects. While dark matter cannot be seen, evidence for its existence comes from observations of gravitational effects and the cosmic microwave background. Dark matter is thought to be made up of either WIMPs (Weakly Interacting Massive Particles) such as neutrinos or axions, or MACHOs (Massive Compact Halo Objects) which could be black holes, neutron stars, or brown dwarfs.

1. DARK MATTER
Presentation by: Ernesto Jiménez, Irene
Mengibar and Irene Wbanet

2. Introduction
• Everything we can see is made of atoms.
• Ordinary matter is just a 5% of the
universe.
• Evidence for dark matter (95%):
1.Cosmic Microwave Background.
2.The need of more matter than the visible
one to explain some gravitational effects.

4. Definition of dark matter
• Dark matter is a 27% of the universe.
• It is not reactant to light.
• It is important because of its gravitational
effects in the universe’s structure.

5. 1st type: Cosmological constant
• It is spread all around the universe,
homogeneously.
• It is the simplest for of dark energy
because it is constant in space and time.
• It is the type which causes the expansion
of the universe.

6. 2nd type: Scalar fields
• Is dynamic, so constant over space but
changes over time.
• Can change over space also but these
ones are very similar to cosmological
constant.

7. String Theory
1. Macroscopic level:
Matter
2. Molecular level
3. Atomic level: Protons,
neutrons, and electrons
4. Subatomic level:
Electron
5. Subatomic level: Quarks
6. String level

8. String Theory
• One string is the base of matter
• Each oscillation makes a sub-particle
• It makes up their properties
• It also explains particle interaction

9. Sub-particles

10. Supersymmetry
• Relates fermions with bosons
• Haven’t been observed yet.
• Suggest a
common origin

11. Superpartner examples:
 Leptons  Leptons
 Squarks  Quarks
 Photon  Photino
 Neutralino  ?

12. What is dark matter?
• Dark matter is not in the form of stars and
planets that we can see.
• It is not in the form of dark clouds of
normal matter, otherwise we could detect
the baryonic clouds which forms this
matter
• Dark matter is not antimatter, because we
can’t see the gamma rays

13. Composition
There are two different possibilities:
•The WIMPS (Weakly interacting Massive
Particles)
•The MACHOs (Massive Compact Halo
Objects)

14. WIMPs
• They are subatomic particles which are
not made up of ordinary matter.
• They include neutrinos, axions and
neutralinos

15. MACHOs
• They are objects ranging in size from
small stars to super massive black holes.
• They are made up of ordinary matter (like
protons, neutrons and electrons)
• They may be black holes, neutron stars or
brown dwarfs.

16. Pandora’s Cluster
• A complex collision of at least four galaxy
clusters
• Strange effects that have never been seen
together before
• It has apparently been produced because of this
smash-up.
• Dubbed "Pandora's Cluster" because of all of
the different structures found.
• Officially known as Abell 2744
• Located about 3.5 billion light years from Earth.

17. PANDORA’S CLUSTER

18. Pandora’s Visions
XRAY VISION OPTICAL VISION LMAP VISION

19. NOW PREPARE YOURSELF
FOR…
A TEST
Only one answer is valid…

20. Test
• What does not react to electromagnetic
waves in any significant form?
A: Dark energy
B: Dark matter
C: Cosmic Microwave Background.

21. Test
• What does not react to electromagnetic
waves in any significant form?
A: Dark energy
B: Dark matter
C: Cosmic Microwave Background.

22. Test
• What is the value of the energy density
of the vacuum of space?
A: Dark energy
B: Black holes
C: Cosmological constant

23. Test
• What is the value of the energy density
of the vacuum of space?
A: Dark energy
B: Black holes
C: Cosmological constant

24. Test
• How would the supersymmetrical
partner of an up quark be called?
A: Down quark
B: Antiup quark
C: Up squark
D: Up quark hasn’t got any
supersymmetrical partner

25. Test
• How would the supersymmetrical
partner of an up quark be called?
A: Down quark
B: Antiup quark
C: Up squark
D: Up quark hasn’t got any
supersymmetrical partner

26. Test
• How many sub-atomic particles are
there in the standard model?
A: 15
B: 18
C: 17

27. Test
• How many sub-atomic particles are
there in the standard model?
A: 15
B: 18
C: 17

28. Test
• Can you name the three particles
included in WIMPs?
A: Protons, neutrons and neutralinos
B: Neutrinos, axions and electrons
C: Neutrinos, axions and neutralinos
D: Neutrinos, neutrons and neutralinos

29. Test
• Can you name the three particles
included in WIMPs?
A: Protons, neutrons and neutralinos
B: Neutrinos, axions and electrons
C: Neutrinos, axions and neutralinos
D: Neutrinos, neutrons and neutralinos

30. Test
• What are MACHOs?
A: They are subatomic particles which are
not made up of ordinary matter.
B: They are very small objects made up of
neutrinos, axions and neutralinos
C: They are subatomic particles not made
from ordinary matter
D: They are objects ranging in size from
small to massive black holes

31. Test
• What are MACHOs?
A: They are subatomic particles which are
not made up of ordinary matter.
B: They are very small objects made up of
neutrinos, axions and neutralinos
C: They are subatomic particles not made
from ordinary matter
D: They are objects ranging in size from
small to massive black holes

32. Test
• WIMPs are…
A: Weakly Interacting Massive Particles
B: Weakly Interesting Massive Particles
C: White Infrared Massive Pieces
D: Widely Interacting Massive Particles

33. Test
• WIMPs are…
A: Weakly Interacting Massive Particles
B: Weakly Interesting Massive Particles
C: White Infrared Massive Pieces
D: Widely Interacting Massive Particles

34. HOPE YOU LIKED IT!!
Be careful with black holes….