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:
Jan 13, 2016
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.