Dark Matter: An Opportunity for Discovery

By: Francisco Gonzalez, Veronica Hernandez, Fernanda Torres, and Israel

Vega

Instructors: Julie A. Rolla, Nathan Earnest,  and Arran Phipps

Primary Investigator:  Bernard Sadoulet

Overview:

What is Dark Matter?•  A theory to answer the

question of what is the universe made of?

Types of forces• Weak Force• Strong Force• Electromagnetic• GravityRadiation         

• TypesoAlphaoBetaoGamma

•  DetectorsoPhotomultiplier Tubes oGe and Si detectors

The Cloud Chamber:• Temperature Gradient• Condensation trails 

What is Dark Matter?• A theory of what may be in the space between stars,

planets, galaxies etc.        • Discovered by Fritz Zwiky in the 1930s• Thought to be composed of WIMPs (Weakly

Interacting Massive Particles)• Five times as heavy as stars, planets, asteroids and all

other known matter

Unknown Universe- 75% Known Universe- 5% Dark Matter (only a theory)- 20%

Weak Force:Is like electromagnetism, but much weaker.

Strong Force:It binds the nucleus                together.

Electromagnetism:When two charges attract or repel each other.

Gravity:It causes two particles to            pull together. 

Forces:

http://www.particlephysics.ac.uk/explore/the-standard-model.html

Interactions/Proof: Dark Matter has not been directly detected, but many scientists can tell when dark matter is in a certain place because it affects the movement of galaxies, stars, etc. • Spiral galaxies should be expandig

    but something is keeping them    together

• It has gravity • Dark Matter bends light, 

      making it seem as if there is           a galaxy in two different places,      but there is only one • "Bullet Cluster"- Dark Matter went right

through each other because there is no electromagnetism, but regular matter collided.

http://www.learner.org/courses/physics/unit/text.html?unit=10&secNum=4

http://www.phdcomics.com/comics.php?f=1430

http://chandra.harvard.edu/photo/2006/1e0657/

Radiation:Alpha Radiation- these are fast moving helium nuclei• Large mass, high energy • Are stopped by a few inches of air or a piece 

      of paper  Beta Radiation- these are fast moving electrons• Less massive than helium atoms• Can penetrate through several feet of air or millimeters of plastic/light

metal  Gamma Radiation- these are photons.• Typically higher energy than visible light• Depending on energy level, they can be stopped by a thin piece of

aluminum foil or a few inches of lead

http://www.deq.idaho.gov/inl-oversight/radiation.aspx

Radiation Detectors:• Photomultiplier Tubes

o Super sensitive tubes that detect light 

o They re-produce the light they detect by as much as 100 million times

• Germanium or Silicon Detectorso Absorb light into E-tubes o The detectors are semiconductors-

that means that it only conducts in perfect conditions. (the colder the working environment the better the conductor.

http://en.wikipedia.org/wiki/Photomultiplier

Cloud Chamber:Cloud chambers- • Original method of detecting invisible particles going through the

atmosphere. • It can't detect WIMPS.

o WIMPs make up dark matter. • A heat gradient from the top of the chamber to the bottom of the chamber

causes the alcohol in the chamber to be super saturated. o Gradient- Change of something over a distance.o Cloud Condensation Nuclei (CCN)

• Gas molecule want something to condense onto.• An invisible particle enters (Cloud Condensation Nuclei).

o A trail of condense vapor is formed, following the particle.

ConclusionDark matter does not interact through any forces but can be detected using other methods.• Types of forces 

o Weak Forceo Strong Forceo Electromagnetismo Gravity

• There are a a few ways in which scientists have proven the existence of dark matter. Some of these ways are:o "Bullet Cluster"

Two galaxies collided into each other and the normal matter slammed into each other, but the dark matter passed right through each other. 

o Gravity's affect on light When dark matter interferes with the light, the dark matter bends it. 

o Things don't Spin the way they should Stars are being held together even though they are spinning super fast

In addition to dark matter, there is still much more out there waiting to be discovered.