Презентация, доклад Астрономия Билингвальный урок

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Early Astronomy ◆ Astronomy is the science that studies the universe. It includes the observation and interpretation of celestial bodies and phenomena.◆. The Greeks used philosophical arguments to explain natural phenomena◆ The Greeks also used

Слайд 1
Origin of Modern Astronomy

Origin of Modern Astronomy

Слайд 2Early Astronomy
◆ Astronomy is the science that studies the

universe. It includes the observation and interpretation of celestial bodies and phenomena.

◆. The Greeks used philosophical arguments to explain natural phenomena

◆ The Greeks also used some observational data.

Early Astronomy ◆ Astronomy is the science that studies the universe. It includes the observation and

Слайд 3Early Astronomy
◆ Geocentric Model = Ptolemy Greek Astronomer
• In

the ancient Greeks’ geocentric model, the moon, sun, and the known planets—Mercury, Venus, Mars, and Jupiter—orbit Earth.

◆ Heliocentric Model = Nicolaus Copernicus

• In the heliocentric model, Earth and the other planets orbit the sun.

Early Astronomy ◆ Geocentric Model = Ptolemy Greek Astronomer• In the ancient Greeks’ geocentric model, the

Слайд 4Early Astronomy
◆ Ptolemaic System
• Ptolemy created a model of

the universe that accounted for the movement of the planets.

• Retrograde motion is the apparent westward motion of the planets with respect to the stars.

Early Astronomy ◆ Ptolemaic System• Ptolemy created a model of the universe that accounted for the

Слайд 6Retrograde Motion

Retrograde Motion

Слайд 799 Years of Astronomy

99 Years of Astronomy

Слайд 8Early Astronomy
◆ Nicolaus Copernicus
• Copernicus concluded that Earth is

a planet. He proposed a model of the solar system with the sun at the center. Heliocentric Model

This model explained the retrograde motion of planets better than the geocentric model.

Early Astronomy ◆ Nicolaus Copernicus• Copernicus concluded that Earth is a planet. He proposed a model

Слайд 9Early Astronomy
◆ Tycho Brahe
• Tycho Brahe designed and built

instruments to measure the locations of the heavenly bodies. Brahe’s observations, especially of Mars, were far more precise than any made previously.

◆ Johannes Kepler

• Kepler discovered three laws of planetary motion:
1. Orbits of the planets are elliptical.
2. Planets revolve around the sun at varying speed.
3. There is a proportional relationship between a planet’s orbital period and its distance to the sun.



Early Astronomy ◆ Tycho Brahe• Tycho Brahe designed and built instruments to measure the locations of

Слайд 10Early Astronomy
German astronomer
Johannes Kepler
(1571-1630) helped establish the

era of modern astronomy by deriving three laws of planetary motion.
Early Astronomy German astronomer Johannes Kepler (1571-1630) helped establish the era of modern astronomy by deriving

Слайд 11Johannes Kepler
1599 – Kepler hired by Tycho Brahe
Work on

the orbit of Mars
1609 – Kepler’s 1st and 2nd Laws
Planets move on ellipses with the Sun at one focus
The radius vector sweeps out equal areas in equal times
1618 – Kepler’s 3rd Law
The square of a planet’s orbital period P is proportional to the cube of its semi-major axis R.
Johannes Kepler 1599 – Kepler hired by Tycho Brahe Work on the orbit of Mars 1609

Слайд 12Early Astronomy
Johannes Kepler used Tycho Brahe’s data to develop three laws

that explained the motions of the planets.
Early AstronomyJohannes Kepler used Tycho Brahe’s data to develop three laws that explained the motions of the

Слайд 13Early Astronomy
Faster
Slower
Equal areas law
KEPLER’S EQUAL AREA LAW states that a line

connecting Earth to the sun will pass over equal areas of space in equal times. Because Earth’s orbit is elliptical, Earth moves faster when it is nearer to the sun.
Early AstronomyFasterSlowerEqual areas lawKEPLER’S EQUAL AREA LAW states that a line connecting Earth to the sun will

Слайд 14Early Astronomy
◆ Galileo Galilei
Italian scientist
Galileo Galilei (1564—1642) used

a new invention, the telescope, to observe the Sun, Moon, and planets in more detail than ever before.
Early Astronomy ◆ Galileo GalileiItalian scientist Galileo Galilei (1564—1642) used a new invention, the telescope, to

Слайд 15Early Astronomy
◆ Galileo Galilei
• Galileo’s most important contributions were

his descriptions of the behavior of moving objects.

• He developed his own telescope and made important discoveries:

1. Four satellites, or moons, orbit Jupiter.

2. Planets are circular disks, not just points of light.

3. Venus has phases just like the moon.

4. The moon’s surface is not smooth.

5. The sun has sunspots, or dark regions.

Early Astronomy ◆ Galileo Galilei• Galileo’s most important contributions were his descriptions of the behavior of

Слайд 17Early Astronomy
◆ Sir Isaac Newton
English scientist
Sir Isaac Newton

(1642—1727) explained gravity as the force that holds planets in orbit around the Sun.
Early Astronomy ◆ Sir Isaac NewtonEnglish scientist Sir Isaac Newton (1642—1727) explained gravity as the force

Слайд 18Early Astronomy
◆ Sir Isaac Newton
• Although others had theorized

the existence of gravitational force, Newton was the first to formulate and test the law of universal gravitation. The universal law of gravitation, helped explain the motions of planets in the solar system.

◆ Universal Gravitation

• Gravitational force decreases with distance.

• The greater the mass of an object, the greater is its gravitational force.

Early Astronomy ◆ Sir Isaac Newton• Although others had theorized the existence of gravitational force, Newton

Слайд 19Gravity’s Influence on Orbits

Gravity’s Influence on Orbits

Слайд 20Newton’s Laws of Motion
1st Law
A body at rest, or in uniform

motion, will remain so unless acted upon by an unbalanced force.
2nd Law
The change in motion (acceleration) is proportional to the unbalanced force
3rd Law
For every action there is an equal and opposite reaction

Newton’s Laws of Motion1st LawA body at rest, or in uniform motion, will remain so unless acted

Слайд 21Gravity
Gravity is the force that
holds us to the Earth
causes a rock

to fall towards the ground
causes the Earth to go around the Sun
causes the Sun to be pulled towards the center of the Milky Way galaxy
Gravity acts between any two objects even if they are far apart.
“action at a distance”
GravityGravity is the force thatholds us to the Earthcauses a rock to fall towards the groundcauses the

Слайд 22The Movements of Planets and Stars
B. Ptolemy’s Geocentric Model
C. Copernicus’s Heliocentric

Model
D. Tycho, Kepler, and Planetary Motion
E. Isaac Newton and the Law of Gravitation




VOCABULARY

Observing the Solar System: A History

geocentric

heliocentric

gravitation

retrograde

The Movements of Planets and StarsB. Ptolemy’s Geocentric ModelC. Copernicus’s Heliocentric ModelD. Tycho, Kepler, and Planetary MotionE.

Слайд 23Summary
Kepler’s and Galileo’s Laws provided Newton with important clues that helped

him formulate his laws of motion
Newton arrived at 3 laws that govern the motion of objects
The law of inertia
The law of force
The law of action and reaction
Newton also arrived at a law of gravity
But it seemed to require action at a distance!
SummaryKepler’s and Galileo’s Laws provided Newton with important clues that helped him formulate his laws of motion

Слайд 24 Light and Astronomical Observations
Earth Science

Light and Astronomical ObservationsEarth Science

Слайд 25• An ellipse is an oval-shaped path.
An astronomical unit (AU) is

the average distance between
Earth and the sun; it is about 150 million kilometers.

Light-year The distance that light travels in one year, about 9.5 trillion kilometers.

Parsec: A unit of measurement used to describe distances between celestial objects, equal to 3.258 light-years.

Important Astronomical Measurements

• An ellipse is an oval-shaped path.An astronomical unit (AU) is the average distance betweenEarth and the

Слайд 26Electromagnetic radiation
Visible light is only one small part of

an array of energy
Electromagnetic radiation includes
Gamma rays
X-rays
Ultraviolet light
Visible light
Infrared light
Radio waves

The study of light

*Energy radiated in the form of a wave, resulting from the motion of electric charges and the magnetic fields they produce.

Electromagnetic radiation Visible light is only one small part of an array of energyElectromagnetic radiation includesGamma

Слайд 27The study of light
Electromagnetic radiation
All forms of radiation

travel at 300,000 kilometers (186,000 miles) per second

Light (electromagnetic radiation) can be described in two ways
Wave model
Wavelengths of radiation vary
Radio waves measure up to several kilometers long
Gamma ray waves are less than a billionth of a centimeter long
White light consists of several wavelengths corresponding to the colors of the rainbow

A continuum depicting the range of electromagnetic radiation, with the longest wavelength at one end and the shortest at the other.

The study of light Electromagnetic radiation All forms of radiation travel at 300,000 kilometers (186,000 miles)

Слайд 28Light (electromagnetic radiation) can be described in two ways
Particle model


Particles called photons
Exert a pressure, called radiation pressure, on matter
Shorter wavelengths correspond to more energetic photons
Light (electromagnetic radiation) can be described in two ways Particle model Particles called photonsExert a pressure, called

Слайд 29Spectroscopy
The study of the properties of light that depend on wavelength
The

light pattern produced by passing light through a prism, which spreads out the various wavelengths, is called a spectrum (plural: spectra)

The study of light

SpectroscopyThe study of the properties of light that depend on wavelengthThe light pattern produced by passing light

Слайд 30A spectrum is produced when white light passes through a prism
The

study of light
A spectrum is produced when white light passes through a prismThe study of light

Слайд 31Spectroscopy

The study of light
Types of spectra
Continuous spectrum: A spectrum

that contains all colors or wavelengths.
Produced by an incandescent solid, liquid, or high pressure gas

Uninterrupted band of color
Dark-line (absorption) spectrum
Produced when white light is passed through a comparatively cool, low pressure gas
Appears as a continuous spectrum but with dark lines running through it

SpectroscopyThe study of light Types of spectra Continuous spectrum: A spectrum that contains all colors or wavelengths.Produced

Слайд 32Formation of the three types of spectra

Formation of the three types of spectra

Слайд 33A spectrum consisting of individual lines at characteristic wavelengths produced when

light passes through an incandescent gas; a bright-line spectrum.

Emission Spectrum

A continuous spectrum crossed by dark lines produced when light passes through a nonincandescent gas.

Absorption Spectrum

A spectrum consisting of individual lines at characteristic wavelengths produced when light passes through an incandescent gas;

Слайд 34Doppler effect
The apparent change in wavelength of radiation caused by the

relative motions of the source and observer
Used to determine
Direction of motion
Increasing distance – wavelength is longer ("stretches")
Decreasing distance – makes wavelength shorter ("compresses")
Velocity – larger Doppler shifts indicate higher velocities

The study of light

Doppler effectThe apparent change in wavelength of radiation caused by the relative motions of the source and

Слайд 35The Doppler effect
Originally discovered by the Austrian mathematician and physicist, Christian

Doppler (1803-53), this change in pitch results from a shift in the frequency of the sound waves.
The Doppler effectOriginally discovered by the Austrian mathematician and physicist, Christian Doppler (1803-53), this change in pitch

Слайд 36
Redshift, a phenomenon of electromagnetic waves such as light in which

spectral lines are shifted to the red end of the spectrum.


The electromagnetic radiation emitted by a moving object also exhibits the Doppler effect.

The Doppler effect

Redshift, a phenomenon of electromagnetic waves such as light in which spectral lines are shifted to the

Слайд 37The radiation emitted by an object moving toward an observer is

squeezed; its frequency appears to increase and is therefore said to be blueshifted. In contrast, the radiation emitted by an object moving away is stretched or redshifted. Blueshifts and redshifts exhibited by stars, galaxies and gas clouds also indicate their motions with respect to the observer.

The Doppler effect

The radiation emitted by an object moving toward an observer is squeezed; its frequency appears to increase

Слайд 38Optical (visible light) telescopes
Two basic types (1) Refracting telescope
Uses

a lens (called the objective) to bend (refract) the light to produce an image
Light converges at an area called the focus
Distance between the lens and the focus is called the focal length
The eyepiece is a second lens used to examine the image directly
Have an optical defect called chromatic aberration (color distortion)

Astronomical tools

Optical (visible light) telescopes Two basic types (1) Refracting telescope Uses a lens (called the objective) to

Слайд 39A simple refracting telescope

A simple refracting telescope

Слайд 40
Optical (visible light) telescopes
Two basic types (2) Reflecting telescope

Uses

a concave mirror to gather the light
No color distortion
Nearly all large telescopes are of this type

Astronomical tools

Optical (visible light) telescopes Two basic types (2) Reflecting telescope Uses a concave mirror to gather the

Слайд 41A prime focus reflecting telescope

A prime focus reflecting telescope

Слайд 42Cassegrain focus reflecting telescope

Cassegrain focus reflecting telescope

Слайд 43Newtonian focus reflecting telescope

Newtonian focus reflecting telescope

Слайд 44The 200" (5m) Hale Reflector of Palomar Observatory is shown above.

Until recently it was the world's largest optical/infrared telescope.

The 200

Слайд 45
Optical (visible light) telescopes
Properties of optical telescopes
Light-gathering power
Larger

lens (or mirror) intercepts more light
Determines the brightness
Resolving power
The ability to separate close objects
Allows for a sharper image and finer detail

Astronomical tools

Optical (visible light) telescopes Properties of optical telescopes Light-gathering power Larger lens (or mirror) intercepts more lightDetermines

Слайд 46Optical (visible light) telescopes
Properties of optical telescopes
Magnifying power
The ability

to make an image larger
Calculated by dividing the focal length of the objective by the focal length of the eyepiece
Can be changed by changing the eyepiece
Limited by atmospheric conditions and the resolving power of the telescope
Even with the largest telescopes, stars (other than the Sun) appear only as points of light

Astronomical tools

Optical (visible light) telescopes Properties of optical telescopes Magnifying powerThe ability to make an image largerCalculated by

Слайд 47
Detecting invisible radiation
Radio radiation
Gathered by "big dishes" called radio telescopes


Large because radio waves are about 100,000 times longer than visible radiation
Often made of a wire mesh
Have rather poor resolution
Can be wired together into a network called a radio interferometer

Astronomical tools

Detecting invisible radiationRadio radiation Gathered by

Слайд 48A steerable radio telescope at Green Bank, West Virginia
Radio Telescope

A steerable radio telescope at Green Bank, West VirginiaRadio Telescope

Слайд 49Detecting invisible radiation
Radio radiation
Gathered by "big dishes" called radio telescopes


Advantages over optical telescopes
Less affected by weather
Less expensive
Can be used 24 hours a day
Detects material that does not emit visible radiation
Can "see" through interstellar dust clouds

Astronomical tools

Detecting invisible radiationRadio radiation Gathered by

Слайд 50The 300-meter radio telescope at Arecibo, Puerto Rico
Radio Telescope

The 300-meter radio telescope at Arecibo, Puerto RicoRadio Telescope

Слайд 51The theory holding that the universe originated from the instant expansion

of an extremely small agglomeration of matter of extremely high density and temperature.

The Big Bang Theory

The theory holding that the universe originated from the instant expansion of an extremely small agglomeration of

Слайд 52Photons converted into particle-antiparticle pairs and vice-versa

E = mc2

Early universe

was full of particles and radiation because of its high temperature

Photons converted into particle-antiparticle pairs and vice-versa E = mc2Early universe was full of particles and radiation

Слайд 54The Big Band Theory
Evidence for Big Bang
This is the theory of

the universe’s earliest moments.
It presumes that the universe began from a tiny, hot, and dense collection of matter and radiation.
It describes how expansion and cooling of particles could have led to the present universe of stars and galaxies.
It explains several aspects of today’s universe with a very good accuracy.



The Big Band TheoryEvidence for Big BangThis is the theory of the universe’s earliest moments.It presumes that

Слайд 55The Big Band Theory
The Big Bang theory is a model, which

explains some facts (observations).

It should be able to make predictions that can be verified through observations or experiments.

Two important predictions:

Cosmic microwave background radiation.
2. Fusion of original hydrogen into helium.

The Big Band TheoryThe Big Bang theory is a model, which explains some facts (observations).It should be

Слайд 56Evidence for the Big Bang
The Cosmic Background Radiation (Microwaves)
Penzias & Wilson

(1962) discovered an isotropic background microwave signal during testing a microwave antenna at Bell Labs in 1965. The noise was found to be coming from every direction.

At the same time, physicists from Princeton calculated the expected radiation from the initially hot universe.They suggested that this radiation could be detected with a microwave antenna.

The result was a Nobel Prize in physics for 1978.

Evidence for the Big BangThe Cosmic Background Radiation (Microwaves)Penzias & Wilson (1962) discovered an isotropic background microwave

Слайд 57The Cosmic Microwave Background

The Cosmic Microwave Background

Слайд 58The Cosmic Background Radiation (Microwaves)
Background radiation from Big Bang has been

freely streaming across universe since atoms formed at temperature ~ 3,000 K: visible/IR
The Cosmic Background Radiation (Microwaves)Background radiation from Big Bang has been freely streaming across universe since atoms

Слайд 59The Cosmic Microwave Background
The background consists of photons (radiation) arriving at

Earth directly from the end of the era of nuclei (when the Universe was about 380,000 years old).
Neutral atoms captured most of the electrons.
Photons were released and have flown freely through the universe ever since.

This background radiation can be detected with a small TV antenna as part (1%) of static “snow”. The redshifted spectrum of the background radiation has now a temperature of 2.73 K.

The Cosmic Microwave BackgroundThe background consists of photons (radiation) arriving at Earth directly from the end of

Слайд 60
Cosmic Background Explorer

The first satelliteThe first satellite built dedicated to

cosmologyThe first satellite built dedicated to cosmology. Its goals were to investigate the cosmic microwave background radiationThe first satellite built dedicated to cosmology. Its goals were to investigate the cosmic microwave background radiation (CMB) of the universe and provide measurements that would help shape our understanding of the cosmos.

Cosmic Background Explorer The first satelliteThe first satellite built dedicated to cosmologyThe first satellite built dedicated to

Слайд 61This work helped cement the big-bangThis work helped cement the big-bang

theory of the universe. According to the Nobel Prize committee, "the COBE-project can also be regarded as the starting point for cosmologyThis work helped cement the big-bang theory of the universe. According to the Nobel Prize committee, "the COBE-project can also be regarded as the starting point for cosmology as a precision science". Two of COBE's principal investigators, George SmootThis work helped cement the big-bang theory of the universe. According to the Nobel Prize committee, "the COBE-project can also be regarded as the starting point for cosmology as a precision science". Two of COBE's principal investigators, George Smoot and John MatherThis work helped cement the big-bang theory of the universe. According to the Nobel Prize committee, "the COBE-project can also be regarded as the starting point for cosmology as a precision science". Two of COBE's principal investigators, George Smoot and John Mather, received the Nobel Prize in Physics in 2006.

Cosmic Background Explorer

This work helped cement the big-bangThis work helped cement the big-bang theory of the universe. According to

Слайд 62Cosmic Background Explorer

Cosmic Background Explorer

Слайд 63The "famous" map of the CMB anisotropy formed from data taken

by the COBE spacecraft.

Cosmic Background Explorer

The

Слайд 64In 1927, the Belgian priest Georges Lemaître was the first to

propose that the universe began with the explosion of a primeval atom.

Evidence for the Big Bang

In 1927, the Belgian priest Georges Lemaître was the first to propose that the universe began with

Слайд 65Evidence for the Big Bang
Edwin Hubble found experimental evidence to help

justify Lemaître's theory. He found that distant galaxies in every direction are going away from us with speeds proportional to their distance (the redshift).

The big bang was initially suggested because it explains why distant galaxies are traveling away from us at great speeds. The theory also predicts the existence of cosmic background radiation (the glow left over from the explosion itself). The Big Bang Theory received its strongest confirmation when this radiation was discovered in 1964 by Arno Penzias and Robert Wilson, who later won the Nobel Prize for this discovery.

Evidence for the Big BangEdwin Hubble found experimental evidence to help justify Lemaître's theory. He found that

Слайд 66Hubble’s Evidence
Doppler shifting - wavelength emitted by something moving away from

us is shifted to a lower frequency
Sound of a fire truck siren - pitch of the siren is higher as the fire truck moves towards you, and lower as it moves away from you
Visible wavelengths emitted by objects moving away from us are shifted towards the red part of the visible spectrum
The faster they move away from us, the more they are redshifted. Thus, redshift is a reasonable way to measure the speed of an object (this, by the way, is the principal by which radar guns measure the speed of a car or baseball)
When we observe the redshift of galaxies outside our local group, every galaxy appears to be moving away from us - universe is expanding.


Hubble’s EvidenceDoppler shifting - wavelength emitted by something moving away from us is shifted to a lower

Слайд 67Expansion of universe has redshifted thermal radiation from that time to

~1000 times longer wavelength: microwaves
Expansion of universe has redshifted thermal radiation from that time to ~1000 times longer wavelength: microwaves

Слайд 68Big Bang Theory - Evidence for the Theory What are the major

evidences which support the Big Bang theory?

Evidence for the Big Bang


First of all, we are reasonably certain that the universe had a beginning.
Second, galaxies appear to be moving away from us at speeds proportional to their distance. This is called "Hubble's Law," named after Edwin Hubble (1889-1953) who discovered this phenomenon in 1929. This observation supports the expansion of the universe and suggests that the universe was once compacted.

Big Bang Theory - Evidence for the Theory What are the major evidences which support the Big

Слайд 69Evidence for the Big Bang

Third, if the universe was initially very,

very hot as the Big Bang suggests, we should be able to find some remnant of this heat. In 1965, Radioastronomers Arno Penzias and Robert Wilson discovered a 2.725 degree Kelvin (-454.765 degree Fahrenheit, -270.425 degree Celsius) Cosmic Microwave Background radiation (CMB) which pervades the observable universe. This is thought to be the remnant which scientists were looking for. Penzias and Wilson shared in the 1978 Nobel Prize for Physics for their discovery.

Evidence for the Big BangThird, if the universe was initially very, very hot as the Big Bang

Слайд 70Evidence for the Big Bang

Finally, the abundance of the "light elements"

Hydrogen and Helium found in the observable universe are thought to support the Big Bang model of origins.

Evidence for the Big BangFinally, the abundance of the

Слайд 71Synthesis of Helium
The current CMB temperature tells us precisely how hot

the universe was when it appeared.

It tells us how much helium was initially produced.

A helium nucleus contains 2 protons and 2 neutrons.

At T > 1011 K, nuclear reactions converted protons into neutrons and back, keeping their numbers nearly equal.
Between 1010 and 1011 K, neutron – proton reactions favor protons, because neutrons are heavier than protons.

Synthesis of HeliumThe current CMB temperature tells us precisely how hot the universe was when it appeared.It

Слайд 72Energy is required to convert protons to neutrons.
At T < 1010

K, only neutrons can be changed into protons.
However, fusion continued to operate
and protons and neutrons combined into deuterium.
Then deuterium fused into helium.
During the early era of nucleosynthesis, helium nuclei were being destroyed by gamma-rays.
At ~1 minute, gamma-rays were gone and the proton – neutron ratio was set to 7:1.

Synthesis of Helium

Energy is required to convert protons to neutrons.At T < 1010 K, only neutrons can be changed

Слайд 73Big Bang theory prediction: 75% H, 25% He (by mass)

Matches

observations of nearly primordial gases

Synthesis of Helium

Big Bang theory prediction: 75% H, 25% He (by mass)Matches observations of nearly primordial gasesSynthesis of

Слайд 74Abundances of other light elements agree with Big Bang model having

4.4% normal matter – more evidence for WIMPS!

Synthesis of Helium

Abundances of other light elements agree with Big Bang model having 4.4% normal matter – more evidence

Слайд 76Nebular Hypothesis of Solar System Formation.

Nebular Hypothesis of Solar System Formation.
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