federica bianco PRO
astro | data science | data for good
gravity
Instructor: Dr. Bianco
TAs: Joey Betz; Lily Padlow
University of Delaware - Spring 2021
back to uniform circular motion
circular orbits
back to uniform circular motion
circular orbits
back to uniform circular motion
circular orbits
back to uniform circular motion
circular orbits
back to uniform circular motion
circular orbits
back to uniform circular motion
circular orbits
how about F = mg?
back to uniform circular motion
circular orbits
circular orbits
R
circular orbits
R
circular orbits
R
circular orbits
R
if the orbit is circular
circular orbits
R
circular orbits
R
circular orbits
R
circular orbits
R
only depends on the
mass and radius of the earth!
circular orbits
R
only depends on the
mass and radius of the earth!
1 - the orbit (of planets) are ellipses
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
the wedges are triangles after all
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
the wedges are triangles after all
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
the wedges are triangles after all
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
the wedges are triangles after all
1 - the orbit (of planets) are ellipses
2 - equal areas of the ellipse (wedges) are spanned in equal time
3 -
the wedges are triangles after all
dA/dt constant means conservation of angular momentum
how far is Neptune?
d = 4,568,488,662 kilometers
c = 299,792 km/s
how much longer is the period of its orbit?
how far is Neptune?
d = 4,568,488,662 kilometers
c = 299,792 km/s
how much longer is the period of its orbit?
parabolic
Because the velocity does not depend on the mass of the orbiting star, but only on the mass the body around which the star orbits, we can detect invisible masses by studying orbits!
The mass of the Black Hole at the center of our own Galaxy was measured
Because the velocity does not depend on the mass of the orbiting star, but only on the mass the body around which the star orbits, we can detect invisible masses by studying orbits!
The mass of the Black Hole at the center of our own Galaxy was measured
Andrea Ghez is the fourth woman to win a Nobel Prize in physics (2020).
Donna Strickland won for the discovery that led to short-pulse high-intensity lasers (2018)
Maria Goeppert Mayer discoveries concerning nuclear shell structure (1963)
Marie Curie studies of the spontaneous radiation (1903)
schwarzschild radius:
c is the speed of light, and nothing can go faster!!
so nothing can escape!
schwarzschild radius:
c is the speed of light, and nothing can go faster!!
so nothing can escape!
really this is a "dark star"
to describe a black hole we need general relativity
gravity = field
gravity is not force acting at a distance but a deformation of spacetime
schwarzschild radius:
c is the speed of light, and nothing can go faster!!
so nothing can escape!
time slows to infinity!
schwarzschild radius:
c is the speed of light, and nothing can go faster!!
so nothing can escape!
time slows to infinity!
the sun turned into a black whole??
Hydrostatic Equilibrium
Hydrostatic Equilibrium
Gravity is pushing in
Nuclear reaction push out
Gravity is pushing in
H->He->C->N->O->…Fe
Hydrostatic Equilibrium
Nuclear reactions push the star outward
Nuclear reactions push the star outward
Elements up to iron are forged in star cores.
Iron is so tightly bound that it absorbs energy instead of generating it in fusion : temperature drops instead of rising, gravitational pressure wins
I. we are made of star dust
high initial mass
8-100 MSun
live fast and die in spectacular explosions
lives of stars
….. live to be old and die peacefully by slowly cooling down
low initial mass
0.1-8 MSun
lives of stars
What is the radius of a BH the mass of the Sun?
you can derive it from the escape velocity formula and c=3x10^8 m/s
the sun turned into a black whole??
By federica bianco
gravity