Astr nomy Part 1 Earth in the Universe

Astr nomy Part 1 – Earth in the Universe

The Big Bang Video

• The universe started with a concentrated area of matter and energy. • 15 -20 billion years ago. • Then, it exploded and has been expanding ever since.

• Matter began to clump together forming stars and galaxies. • The universe continued to expand is still expanding today.

Our Expanding Universe Video

Regents Question Which celestial feature is largest in actual size? (1) the Moon (2) the Sun (3) Jupiter (4) the Milky Way Answer is… 4

• How do we know the universe is expanding? • Pg. 14 in the ESRT shows the electromagnetic spectrum. • Notice that in the visible spectrum there all the colors of the rainbow.

Please answer the questions on the Electromagnetic spectrum ½ sheet.

• When looking at the visible spectrum wavelengths are shifted either to the blue end (shorter wave) or the red end (longer wave). • This shift in wavelengths is called the Doppler Effect. • If they are shifted towards red, they are moving away from you. • If they are shifted toward blue, they are coming towards you.

• When scientists look at the universe, they see a red shift. This proves it is moving away from us, thus, expanding!

A Quick look at the Doppler Affect Using a police car

Another look at the Doppler Affect using sound

Earth Science Light from galaxies moving away Rocks Notice the shift towards red

Earth Science Light from galaxies moving toward us Rocks Notice the shift towards blue.

• A galaxy is a collection of billions of stars and gas and dust. • Our solar system is part of the Milky Way Galaxy. • The Milky Way is a spiral-shaped galaxy.

Regents Question The Milky Way Galaxy is best described as (1) elliptical (2) circular (3) irregular (4) Spiral Answer is… 4

Earth Science Rock • A star is usually a large ball of gas held together by gravity. • Energy is produced by nuclear fusion – combination of nuclei of smaller elements to form nuclei of larger elements.

Regents Question Which star color indicates the hottest star surface temperature? (1) blue (2) yellow (3) white (4) Red

The good news!! This is all for free on pg. 15 of the ESRT!

Regents Question Which star color indicates the hottest star surface temperature? (1) blue (2) yellow (3) white (4) Red Answer is… 1

Regents Question In the main sequence, compared to the surface temperature and luminosity of massive stars, the smaller stars are (1) hotter and less luminous (2) hotter and more luminous (3) cooler and less luminous (4) cooler and more luminous Answer is… 3

Life and Death of a Star Video Clip

Take out ESRT- Page 15

1. What is the most massive star on the chart? DENEB ________________ 2. What is the temperature and luminosity 5, 600 ºK of the Sun? _________ and Luminosity = 1 ________ 3. What group is a star in during a late stage? White Dwarfs ________________

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4. What is the temperature and luminosity of 3300ºK Betelguese? __________ and 200, 000 __________ 5. What color would a star be if it was 15, 000ºK? Blue White ________________ 6. What group of star is Albebaran in? Giants ________________

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7. What temperature and color is Proxima Centauri? 2800ºK Red _________ and _________ 8. Massive stars are (more / less) luminous. (Circle one) Procyon B or Eridani B 9. Name a White Dwarf star. _________ 10. What stage are Main Sequence stars in? _______ Early

• The solar system is the sun and all objects that orbit the sun under its gravitational influence. • Our solar system has 1 sun and 8 planets.

Regents Question The Sun’s position in space is best described as the approximate center of (1) a constellation (2) the universe (3) the Milky Way galaxy (4) our solar system Answer is… 4

Regents Question Compared to Earth’s solar system, the universe is inferred to be (1) younger and larger (2) older and larger (3) younger and smaller (4) older and smaller Answer is… 2

Pluto? New Chart in your ESRT… Sorry Pluto…

Using the data table on page 15 of your ESRT, answer the following questions. 1. What is the period of rotation of Mercury? _______________ 59 d 2. What is a year on Mars? _____________________ 687 d 3. Which planet has the most eccentric orbit? ______________ Mercury 4. Which has the least eccentric orbit? ______________ Venus 5. What is the diameter of Jupiter? _____________ 142, 984 km 6. What is a day on Saturn? _____________________ 10 h 14 min

Venus Jupiter 7. Which planet has the longest period of rotation? _____The shortest? _____ Earth Saturn 8. Which planet is the most dense? _______The least? ______ 108. 2 million km 9. How far from the sun is Venus? _________ 0. 386 million km 10. How far from Earth is our Moon? ___________________ 4, 498. 3 million km 11. What is the mass of Neptune ? __________ 60, 268 km 12. What is the radius of Saturn? ________________

Regents Question Which event takes the most time? (1) one revolution of Earth around the Sun (2) one revolution of Venus around the Sun (3) one rotation of the Moon on its axis (4) one rotation of Venus on its axis Answer is… 1

• An ellipse is an oval shape. • Earth’s orbit around the sun is an ellipse. • Within an ellipse, there are two fixed points called foci. • In our solar system, the sun is ALWAYS ONE of those foci.

• The degree of flatness or “ovalness” of an ellipse is measured by eccentricity. • This formula is on page 1 of your ESRT!

• The more oval the orbit is, the more eccentric it is, or the higher the eccentricity. Increasing Eccentricity

• Calculating Eccentricity: Major Axis X Foci 1 X Foci 2

An ellipse is an example of a “conic section”. Circles and hyperbolas are others. All are possible forms for orbits. You can make an ellipse with 2 tacks and a string. The tacks are the “foci”, and if you put them further apart, the ellipse is more “eccentric” (one tack makes a circle).

• Calculating Eccentricity: • When you measure those 2 distances and calculate them, you will NEVER get higher than 1!! • The closer to 1 you are the MORE oval or eccentric the orbit. • The closer to 0 you are the LESS oval or eccentric the orbit.

Regents Question Which planet’s orbit around the Sun is most nearly circular? (ESRT 15) (1) Mercury (2) Pluto (3) Neptune (4) Venus Answer is… 4 No More Pluto

• The closer 2 objects are to each other, the greater the gravitational pull between them. • Therefore, during the perihelion – when Earth is closer to the sun, there is a greater gravitational pull between it and the sun. • This makes the Earth speed up a bit in its orbit around the sun during that time.

Earth Science Rocks Perihelion Aphelion

Planets move What do you noticequicker about the planets orbital velocity? the closer they are to the Sun Aphelion Perihelion

Kepler’s Second Law

Regents Question Compared to Neptune, Mercury moves more rapidly in its orbit because Mercury (1) is larger (2) is more dense (3) is closer to the Sun (4) has a more elliptical orbit Answer is… 3

Distance between foci length of Major Axis X X Write the formula for eccentricity below: Page 1 of ESRT’s Calculate the eccentricity of the ellipse. 6. 4 cm Distance between foci: _______ 8. 8 cm Length of major axis: _______. 72 Eccentricity= _______

Distance between foci Length of Major Axis X X Calculate the eccentricity of the ellipse. 1. 3 cm Distance between foci: _______ 5. 4 cm Length of major axis: _______. 24 Eccentricity= _______

What is the minimum value that eccentricity 0 can be? ____ The more eccentric Doesn’t a circle look the more stretched like a zero? ? out until you get a straight line What is the maximum value that. 99 eccentricity can be? _______ Look the # one.