8/10/2019 NATSCI 2014.pptx

1/42

Motion in the SolarSystem

Chapter 2

8/10/2019 NATSCI 2014.pptx

2/42

We could imagine that the earth is at thecenter of a large sphere, called the celestialsphere.

The Earth is rotating from the west to east. The circumpolar starts near the north

celestial pole never set. One of the

circumpolar stars, called Polaris, is specialbecause it is very near to the northcelestial pole. Thus it appears to bestationary.

The Motion of the Heavenly Bodies

8/10/2019 NATSCI 2014.pptx

3/42

elestial Sphere

8/10/2019 NATSCI 2014.pptx

4/42

Stars do not move on the celestialsphere. Thus , if the earth is notrotating, stars are stationary.

Some stars do move on the celestialsphere which is referred as the propermotion of stars.

The path that the sun traces out on thecelestial sphere is called ecliptic.

Motion of stars

8/10/2019 NATSCI 2014.pptx

5/42

Twelve constellation that the sun goesthrough are the zodiac.

Ecliptic does also go through theConstellation Ophiuchus, but due tohistorical reason, it is not included inthe zodiac

The sun does not spend equal time oneach ecliptic constellation.

The Constellation

8/10/2019 NATSCI 2014.pptx

6/42

8/10/2019 NATSCI 2014.pptx

7/42

Due to revolution of the earth, a solarday is longer than a sidereal day.

Solar day- a year has 365. Sidereal days- a year ha 366. It will take about 365.25 days for the

earth to complete its revolution aroundthe sun which is referred to as thesidereal year.

Rotation and Revolution

8/10/2019 NATSCI 2014.pptx

8/42

Solar and Sidereal days

8/10/2019 NATSCI 2014.pptx

9/42

The time between successive full Moonsis the synodic Month which is completedevery 29.5 days while the number of the

days required for the moon to completeits revolution around the earth 27.5 daysreferred to as sidereal month.

8/10/2019 NATSCI 2014.pptx

10/42

Planet in the solar system are classifiedas terrestrial and Jovian. From the eight planets, Mercury and

Venus are classified as inferior planets. Mars, Jupiter, Saturn, Uranus andNeptune are called superior planets.

Motion from west to east called progrademotion .

Motion from east to west calledretrograde motion .

Motion of Planet

8/10/2019 NATSCI 2014.pptx

11/42

8/10/2019 NATSCI 2014.pptx

12/42

THE RENAISSANCE AND

THE HELIOCENTRICSYSTEMIt was during the renaissance period

that the helio centric system wasproposed and found tobe scientificallytrue.The idea that the earth revolvesaround the sun had been proposed as

during the 3rd century BC by Aristarchus of samos but was not

supported by other greekphilosophers.

8/10/2019 NATSCI 2014.pptx

13/42

8/10/2019 NATSCI 2014.pptx

14/42

8/10/2019 NATSCI 2014.pptx

15/42

The Earth's axis is tilted fromperpendicular to the plane of the eclipticby 23.45. This tilting is what gives usthe four seasons of the year - spring,summer, autumn (fall) and winter. Sincethe axis is tilted, different parts of theglobe are oriented towards the Sun at

different times of the year.

8/10/2019 NATSCI 2014.pptx

16/42

The solstices are days when the Sunreaches its farthest northern andsouthern declinations. The winter

solstice occurs on December 21 or 22 andmarks the beginning of winter (this isthe shortest day of the year). The

summer solstice occurs on June 21 andmarks the beginning of summer (this isthe longest day of the year).

Solstices

8/10/2019 NATSCI 2014.pptx

17/42

Equinoxes are days in which day andnight are of equal duration. The twoyearly equinoxes occur when the Suncrosses the celestial equator.

The moon as the natural satellite of theearth also exhibits motion on its axis(rotation) and its revolution around theearth which causes tides.

Equinoxes

8/10/2019 NATSCI 2014.pptx

18/42

8/10/2019 NATSCI 2014.pptx

19/42

Karl Schwarzschild 1906 Karl

Schwarzschildmodelled the solaratmosphere fromtheory ofthermodynamic

equilibrium where R.Emden published histheory of gaseousspheres.

Modern Astronomy

8/10/2019 NATSCI 2014.pptx

20/42

Ejnar Hertzsprung 1906-1912 the

investigation ontemperature-luminosity relationof starsdiscovered

(Hertzsprung-Russell diagram).

8/10/2019 NATSCI 2014.pptx

21/42

temperature-luminosity

8/10/2019 NATSCI 2014.pptx

22/42

Arthur StanleyEddington

ChristopherHarrison

1925-1930 intensive studies on stellaratmospheres were pioneered by C.H. Paynewhile stellar structure was investigated by

A.S. Eddington the following year.

8/10/2019 NATSCI 2014.pptx

23/42

1934 W. Baade and F. Zwicky proposedthe neutron stars hypothesis.

1938 H B h d C F W i k

8/10/2019 NATSCI 2014.pptx

24/42

1938 H. Bethe and C.F. Weitzsackerproposed that nuclear reactions are stellar

energy sources. Hans Bethe

Carl FriedrichWeitzsacker

8/10/2019 NATSCI 2014.pptx

25/42

1950 the carbon formation reaction alsoknown as Triple alpha process was

investigated by Opik and Salpeter. Salpeter Opik

8/10/2019 NATSCI 2014.pptx

26/42

8/10/2019 NATSCI 2014.pptx

27/42

1955 thecomputermodelling ofstellar structureand evolution wasintroduced bySchwarzschildand Hoyle.

O S A O S

8/10/2019 NATSCI 2014.pptx

28/42

1800 William Herschel

discovered theinfrared radiation.

OBSERVATIONS IN THEINVISIBLE LIGHT AND SPACE

ASTRONOMY

8/10/2019 NATSCI 2014.pptx

29/42

Johann Wilhelm

Ritter discoveredthe UV radiationthroughdemonstrationshowing some ofits chemicaleffects.

8/10/2019 NATSCI 2014.pptx

30/42

1931 Karl Guthe

Jansky discoveredradio radiationfrom the MilkyWay.

8/10/2019 NATSCI 2014.pptx

31/42

1939

Grote Rebermade a follow upin the year 1939showing that thisradiatation isconcentratedwithin the galacticplane and towardthe galacticcenter.

8/10/2019 NATSCI 2014.pptx

32/42

1942 J.S. Hey and J.

Southward foundthe firstextragalacticradio radiation.

8/10/2019 NATSCI 2014.pptx

33/42

8/10/2019 NATSCI 2014.pptx

34/42

1963

Radioastronomersdiscovered thefirst quasar.(Maarten.Schmidt)

8/10/2019 NATSCI 2014.pptx

35/42

1965

E.T. Byram, H.Friedman andT.A. Chubb discovered thefirst cosmic x-rays.

8/10/2019 NATSCI 2014.pptx

36/42

1967 J. Bell and A.

Hewish discoveredthe first pulsar.

8/10/2019 NATSCI 2014.pptx

37/42

1970

U.S. satelliteUhuru discovered160 x-ray sources.

8/10/2019 NATSCI 2014.pptx

38/42

October 4, 1957:1 st Artificial Satellite

The Soviet Union ushers in a newera the space age with the launchof Sputnik 1 . Atechnological feat,

the beach ball-size satellite weighs184 pounds (84 kilograms) andtakes 98 minutes to orbit Earth

SPACE EXPLORATION

8/10/2019 NATSCI 2014.pptx

39/42

November 3, 1957:First Animal in Orbit

Having stunned the world with the firstorbital space launch, Sputnik 1, less thana month before, the Soviet Union tries fora second coup by launching a dog namedLaika on a one-way journey on a hastilycompleted follow-up mission, Sputnik 2.The dog survives the launch, but Soviet

secrecy masks her ultimate fate for manyyears. It now appears that even thoughshe had a week's supply of food,Laika

8/10/2019 NATSCI 2014.pptx

40/42

July 20, 1969 :1 st Manned Moon Landing

The lunar module of Apollo 11,nicknamed the Eagle, touches down onthe moon, with 30 seconds' worth of fuel

to spare. Neil Armstrong and Edwin"Buzz" Aldrin, Jr., descend to the

surface. "That's one small step for [a]man, one giant leap for mankind,"

Armstrong says. "Beautiful. Beautiful.Magnificent desolation," Aldrin adds.

8/10/2019 NATSCI 2014.pptx

41/42

July 20, 1976:First U.S. Mars Landing Viking 1 soft-lands on Mars. Pictures showa stark, rocky landscape much like someEarthly deserts, and chemical testsdesigned to search for life show anomaliesin the soil that have yet to be fullyexplained.

August September, 1977: Voyagers 1 and 2Launched

NASA launches two spacecraft, Voyager 1and Voyager 2, on a grand tour of the solarsystem.

8/10/2019 NATSCI 2014.pptx

42/42

April 25, 1990:Hubble Space TelescopeDeplo A day after launching, the space

shuttle Discovery opens its cargo baydoors to deploy a unique cargo: the12-ton Hubble Space Telescope