Presented July 9th, 2013
To showcase a research presentation for astronomy class at TCC.
Astronomy
Tidewater Community College
FVCproductions
https://fvcproductions.com
7. Dark Matter
Dominant form of mass in Universe
Besides shape of galactic rotation curves, dark matter has not been detected or
identified by any other means
Possible origins: MACHOs, black holes, WIMPS, neutrinos
Dark Energy
unidentified form of energy that caused Universe to increase expansion rate with time
(accelerating universe)
8. Evidence in Our Spiral Galaxy
(Milky Way)
Our galaxy rotates
Based on matter we can detect within our galaxy, there's not enough
mass to keep our galaxy from flying apart because of that rotation....
Unless there's some other form of undetectable matter present to
hold it together
9. Evidence in Galaxy
Clusters
Motions of galaxies in clusters
Gravitationally confined hot gas in clusters
Without dark matter, gravity of cluster would be too weak to
contain hot gas and it would evaporate
Gravitational lensing
Dark matter will distort image of a star or galaxy behind it
10. •2 kinds of dark matter: baryonic kind, like you and
me, and exotic, dominant, non-baryonic kind
•baryonic MACHOs (MAssive Compact Halo Objects)
•nonbaryonic WIMPs (Weakly Interacting Massive
Particles)
COMPOSITION
11. • MACHOs, like their human counterparts, are fairly
mundane: large planetoids, bigger than Jupiter but
smaller than a star, that drift untethered through
space.
• Astronomers have recently detected MACHOs
since their gravity momentarily bends light of
distant stars.
• WIMPs are exotic manifestation of an abstruse and
difficult mathematical theory called supersymmetry
whose existence is barely supported
• WIMPs may be Silent Majority in universe
• So search for WIMPs goes on in huge
accelerators and cold, quiet detectors
COMPOSITION
12. Does Dark Matter really exist?
All evidence for dark matter rests on understanding of gravity.
Possible that theory of gravity is wrong on cosmological
scales?
Maybe, but if you try to explain dark matter with any other
theory of gravity, it doesn’t coincide with masses in solar
system.
So until something comes up that rejects all we’ve known so
far about gravity, dark matter should be taken seriously.
13. The Vitality
Problem: Source of gravity of all stars we can see is
not strong enough to hold them all together so that
mean there must be some invisible rope that lets them
hold on dark matter
15. Food For Thought
There is a Nobel
Prize waiting for anyone
who cares to explain the
actual origin of dark
matter using a convincing
and an experimentally
verified method.
darkBECAUSE we are literally in the
when it comes to dark matter.