(1) The document discusses the history of gravitational theory from Newton to Einstein.
(2) Newton conceived of gravity as an attractive force between objects and derived the inverse-square law. This allowed him to explain Kepler's laws of planetary motion.
(3) Einstein later proposed general relativity, which holds that gravity is a distortion of spacetime caused by mass-energy. General relativity made several novel predictions that have since been confirmed, such as gravitational waves, black holes, and the expanding universe.
It is always amazing to see the interaction of planets, Sun, Stars, and other celestial objects in space which leads to astronomical events. In this chapter we will learn certain laws of physics which explains gravitation between celestial objects, free fall of body, mass and weight of the objects.
Law Of Gravitation PPT For All The Students | With Modern Animations and Info...Jay Butani
Law Of Gravitation PPT For All The Students | With Modern Animations and Infographics
All the Students od Class 1,2,3,4,5,6,7,8,9,10,11,12 and all the students of engineering, medical, CBSE, GSEB, U.P from beginner to Top and high level can get used. All The informtion are gathered to help you all the people.
All colleges and School students can use it.
All the people can reuse it by downloading by giving credits.
Copyright @ Jay Butani 2019
DISCLAIMER :- ALL THE INFORMARION ARE NOT EXACT OR 100% CORRECT THERE MAY BE MISTAKE. WE ARE NOT RESPONSIBLE OVER THAT.
It is always amazing to see the interaction of planets, Sun, Stars, and other celestial objects in space which leads to astronomical events. In this chapter we will learn certain laws of physics which explains gravitation between celestial objects, free fall of body, mass and weight of the objects.
Law Of Gravitation PPT For All The Students | With Modern Animations and Info...Jay Butani
Law Of Gravitation PPT For All The Students | With Modern Animations and Infographics
All the Students od Class 1,2,3,4,5,6,7,8,9,10,11,12 and all the students of engineering, medical, CBSE, GSEB, U.P from beginner to Top and high level can get used. All The informtion are gathered to help you all the people.
All colleges and School students can use it.
All the people can reuse it by downloading by giving credits.
Copyright @ Jay Butani 2019
DISCLAIMER :- ALL THE INFORMARION ARE NOT EXACT OR 100% CORRECT THERE MAY BE MISTAKE. WE ARE NOT RESPONSIBLE OVER THAT.
Newton's Universal Law of Gravitation and some simple consequences, thereof. Introduction to satellite motion. Discussion of apparent weightlessness in free fall.
Newton's Universal Law of Gravitation and some simple consequences, thereof. Introduction to satellite motion. Discussion of apparent weightlessness in free fall.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
2. Gravity(万有引⼒)
Newton’s idea:
Any object having mass always have an attractive
gravitational force on all other massive objects.
Consider baseball. When we throw up ball on the
earth, the ball is pulled continuously downward(arrow)
by the gravity. The ball moves in a parabolic motion.
3. Gravity(万有引⼒)
The gravity between two objects can be expressed by
F =
GM1M2
r2
The gravity becomes stronger when…
(1) The mass of objects is heavier.
(2) The distance between two objects is closer.
(ex) If the distance between two objects becomes
1m from 2m, then the gravity becomes 4 times
larger
G = 6.67 × 10−11
m3
kg−1
s−2
5. F =
GM1M2
r2
(Answer)
G = 6.67 × 10−11
m3
kg−1
s−2
If your weight is M kg, then
F =
6.67 × 10−11
[m3
kg−1
s−2
] × 75[kg] × M[kg]
32[m2]
= 5.56 × 10−10
M[N]
Electrostatic force(静电⼒)
F ∼ 10−3
[N]
[N] = [kg ⋅ m/s2
]
F ∼ 102
N
Someone slaps you (average force)
6. F =
GM1M2
r2
(Answer)
G = 6.67 × 10−11
m3
kg−1
s−2
If your weight is M kg, then
F =
6.67 × 10−11
[m3
kg−1
s−2
] × 75[kg] × M[kg]
32[m2]
= 5.56 × 10−10
M[N]
Gravity is very weak at
human level !!
Electrostatic force(静电⼒)
F ∼ 10−3
[N]
[N] = [kg ⋅ m/s2
]
F ∼ 102
N
Someone slaps you (average force)
7. gravity
centrifugal force
(离⼼⼒)
The motion of planet
The earth is pulled by sun’s gravity. Not only gravity, the earth feels centrifugal force(离⼼⼒)
due to its accelerating motion
Consider the motion of earth around the sun.
8. In order to keep that earth can orbit around the sun, gravity should be
equal to centrifugal force ( )
Fg = Fc
The motion of planet
9. m
v2
r
= G
Mm
r2
Mass of the Sun
M =
rv2
G
r = 1.5 × 108
km
The distance between
Sun and earth
The speed of the earth
v = 30km/s G = 6.67 × 10−20
km3
kg−1
s−2
M =
rv2
G
=
1.5 × 108
× 30 × 30
6.67 × 10−20
= 2 × 1030
kg
Fg = Fc can be expressed by
Mass of Sun
Thus, we can evaluate the mass of the sun
10. Kepler’s law and Newton gravity
Newton’s theory can explain
Kepler’s law perfectly!
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T2
/ R3
F = ma
Kepler's law
F =
GM1M2
r2
12. Derive Kepler’s 3rd law
r m
v2
r
= G
Mm
r2
Equation of motion
From equation of motion, we can get
T =
2πr
v
= 2πr
r
GM
In the case of circular motion, the orbital period is
T
Thus, we can derive
T2
r3
=
4π2
GM
= constant
Here we assume circular motion, we can also derive Kepler’s 3rd law in the case of elliptical
orbit.
v =
GM
r
13. Is Newton theory perfect?
Newton explained the motion of planets. So, that’s all? Did we understand gravity?
No! This is the beginning of the modern physics.
Newton’s theory has continued for 250 years! But, in 1905, Einstein suggested a new theory of
gravity, called theory of general relativity (⼴义相对论)
250 years
Albert Einstein
14. Einstein gravity
•In Newton's theory, he did not explain what gravity is. He just explained the how we calculate
the gravity.
Rμν −
1
2
gμνR + Λgμν =
8πG
c4
Tμν
Einstein equation
•However, Einstein explained “Gravity is a distortion of space-time(引⼒是时空的扭曲).”
时空的扭曲 物质(能量)
If there exists material (energy), it distorts space-time and then gravity arises.
15. What General relativity predicts ①
•General relativity predicts very massive objects called “blackhole(⿊洞)”
•After relatively massive stars die, they become blackhole.
•In 2019, EHT first observed the shadow of
super massive blackhole !
•There are two kinds of black holes.
1. Star-size black hole (~太阳质量)
2. Supermassive blakchole ( 太阳质量)
105
− 1010
16. What General relativity predicts②
引⼒波
• General relativity predicts “gravitational wave (引⼒
波)”
•When massive objects (black holes, neutron stars)
move, they generate gravitational wave.
•We had not observed the gravitational wave for 100 years after Einstein predicted it.
•In 2016, LIGO & Virgo finally detected the gravitational wave!
17. What General relativity predicts ③
Distortion of image (Weak lensing) Multiple images (strong lensing)
• General relativity predicts the gravitational lensing
effect(引⼒透镜)and this effect is already observed.
•If there are massive objects (galaxy, galaxy clusters)
between background source and us, the path of light is
distorted.
18. What General relativity predicts④
•General relativity predicts “expanding universe (膨胀宇宙)”
In 1929, Hubble discovered that galaxies are moving
away from earth at speeds proportion to their
distance.
V = Hr
The velocity of galaxy How long distance galaxy is away from us
•This is due to expansion of the universe.
Our universe is expanding !!
19. Scientific direction
In the case of Newton, Newton discovered his gravity theory from Kepler’s data.
In science, there are 2 approaches.
(1) Data (phenomenon) > Theory
You discover a rule from observational data (phenomenon). (e.g Newton)
(2) Theory > Data (phenomenon)
With guidance of mathematics, you first establish theory and predict phenomenon (e.g. Einstein)
⿊洞
引⼒波
20. (Question 1) : Let’s calculate the gravitational force between the sun and the earth.
Report task
F =
GM1M2
r2
G = 6.67 × 10−11
m3
kg−1
s−2
•The mass of sun :M1 = 2 × 1030
kg •The mass of the earth :M2 = 6.0 × 1024
kg
•The distance between the sun and the earth : r = 1.5 × 108
km
(Question 2) : Please explain how geocentric idea historically changed to heliocentric
idea.
(Question 3) : Please choose 1 topic below and report it.
1. Blackhole(⿊洞) 2. Gravitational lensing(引⼒透镜) 3. Gravitational wave(引⼒波)
21. •Please send your report to shimabukuro@ynu.edu.cn by PDF.
Report task
Please including following information
1. The tittle of your email is “现代天⽂学作业报告”
2. Your name (姓名)
3. Your student number(学号)
Deadline of the submission: 2023/3/27 (Monday)
I accept the report written by English or Chinese, but I recommend you to write the report by
English (and it is very helpful for me!). Even if your English is wrong, it does not affect your
score.
22. Summary
• Newton discovered the rule of gravity and established
mechanics. He successfully explained Kepler’s law.
• Their contributions opened modern astronomy.
• Einstein constructed a new gravity theory.