dark matter mathematics
DESCRIPTION
Dark Matter Mathematics. Janet Moore NASA Educator Ambassador. Merry-Go-Round. Merry-Go-Round. Solar System. Solar System. Solar System. Solar System. In Summary - Solar System. Orbital speed depends on force of gravity Force of gravity depends on mass within the radius - PowerPoint PPT PresentationTRANSCRIPT
Dark Matter MathematicsDark Matter Mathematics
Janet MooreNASA Educator Ambassador
Janet MooreNASA Educator Ambassador
Merry-Go-RoundMerry-Go-Round
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Merry-Go-RoundMerry-Go-Round
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Solar SystemSolar System
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Solar SystemSolar System
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Velocity vs. Radius
Distance (r)
Velo
cit
y (
v)
Solar SystemSolar System
Mass vs. Radius
Distance (r)
Mass (
m)
Mass vs. Radius
Distance (r)
Mass (
m)
Solar SystemSolar System
Mass vs. Radius
Distance (r)
Mass (
m)
Mass vs. Radius
Distance (r)
Mass (
m)
In Summary - Solar System
In Summary - Solar System
Orbital speed depends on force of gravity
Force of gravity depends on mass within the radius
Therefore, orbital speed depends on mass within the radius
Orbital speed depends on force of gravity
Force of gravity depends on mass within the radius
Therefore, orbital speed depends on mass within the radius
What About Galaxies?What About Galaxies?
How would you expect stars to move around in a spiral galaxy?
What would you expect the mass distribution in a spiral galaxy to be?
How would you expect stars to move around in a spiral galaxy?
What would you expect the mass distribution in a spiral galaxy to be?
The Activity - NGC 2742
The Activity - NGC 2742
You will be given: Rotation Curve (velocity vs. radius)
Luminosity Curve (luminosity vs. radius)
Use the Data Chart to analyze the mass in the galaxy
G = 4.31 x 10-6
You will be given: Rotation Curve (velocity vs. radius)
Luminosity Curve (luminosity vs. radius)
Use the Data Chart to analyze the mass in the galaxy
G = 4.31 x 10-6
Sample Data ChartSample Data Chart
Radius
Rot. Vel.
Grav. Mass
Lum. Lum. Mass
Lum/Grav
1 80 1.5 e9
3 e8 6 e8 0.4
3 100 6.9 e9
1 e9 2 e9 0.29
5 120 1.7 e10
2 e9 4 e9 0.24
8 140 3.6 e10
3.5 e9
7 e9 0.19
Evidence for Dark Matter
Evidence for Dark Matter
Light (visible matter) drops off as you go farther out in a galaxy
BUT . . . Velocities do not drop off
Result: Dark Matter mass is about 10x Luminous Matter mass
Light (visible matter) drops off as you go farther out in a galaxy
BUT . . . Velocities do not drop off
Result: Dark Matter mass is about 10x Luminous Matter mass
What is Dark Matter?What is Dark Matter?Baryonic (Normal) Matter:
Low mass stars, brown dwarfs (likely), large planets, meteoroids, black holes, neutron stars, white dwarfs, hydrogen snowballs, clouds in halo.
Non-Baryonic (Exotic) Matter:Hot Dark Matter: fast-moving at time of galaxy formation, eg massive neutrinos
Cold Dark Matter: slow-moving at times of galaxy formation, eg WIMPs -- particle detector experiments looking for them
Baryonic (Normal) Matter:Low mass stars, brown dwarfs (likely), large planets, meteoroids, black holes, neutron stars, white dwarfs, hydrogen snowballs, clouds in halo.
Non-Baryonic (Exotic) Matter:Hot Dark Matter: fast-moving at time of galaxy formation, eg massive neutrinos
Cold Dark Matter: slow-moving at times of galaxy formation, eg WIMPs -- particle detector experiments looking for them
NASA’s Fermi MissionNASA’s Fermi Mission
Formerly known as the GLAST mission
Launched June 11, 2008Studying gamma ray sources in the universe
Studying potential sources of dark matter in the universe
Formerly known as the GLAST mission
Launched June 11, 2008Studying gamma ray sources in the universe
Studying potential sources of dark matter in the universe
Questions?Questions?
Janet [email protected]
epo.sonoma.edu
My Other Workshops:NEWTON’S LAWS 11:00 am - Room 207PI IN THE SKY 3:30 pm - Room
262
Janet [email protected]
epo.sonoma.edu
My Other Workshops:NEWTON’S LAWS 11:00 am - Room 207PI IN THE SKY 3:30 pm - Room
262