Astronomy Exam 3 (Sun and Moon)

If the moon is a full moon when it rises in the evening, which of the phases will it be when it sets?

full moon

Spring Tide

highest tide (when moon and sun both pull)

In which phase will the Moon be up most of the day?

new moon

Where (in the southern sky, on the eastern horizon, on the western horizon, high in the sky) would you look to see the new moon, if it were visible, when it starts to rise? what time of the day would this happen?

the new moon would rise in the east at 6 pm

Flares

-sudden and violent eruptions, usually associated with sunspots big

Thickness of Atmosphere?

Edge of Atmosphere about 100km (Karman Line) 1cm = 500km xcm = 100km x=.2cm = 2 mm

when the moon is between the sun and the earth, the moon is a. new b. full c. first quarter d. last quarter

a. new

Solar Ecplise

Shadow of Moon on Earth Always at New Moon

Why do sunspots appear dark?

Magnetic fields block the convection making the sunspot cooler

Sunspot groups

- always paired -sunspots are bigger than earth

Inferior Structure: Theoretical Models

- inferior structure is deduced from theoretical models of equations incorporating principles of - hydrostatic equilibrium between all layers -thermal equilibrium between all layers - relationships between pressure, temperature and density sun is an equilibrium is assumption, can balance affect of gravity (balance between nuclear pressure (fusion) and gravity) - in end gravity always wins crushes down to black hole (sun - 9 billion years life balance) more pressure--> denser --> hotter

Inferior Structure: Radiative Zone

-gas is too dense to move around -photons are the main movers of energy -are absorbed and re-emitted; energy takes 1 million years to reach the surface

Inferior Structure: Convection Zone

-hot gas rises -gives up (radiates) energy as it moves across the solar surface (mainly how energy moves) -cools down and sinks back...seen as granules -granules on sun, surface tells you how deep these zones are

Energy Production: Neutrino Problem

-neutrinos are virtually unstoppable -occasional encounters with particles in large volumes of fluid produce detectable flashes -only one third the expected flux is detected -???Neutrinos changing to alternate types? - confirms core actually is 15 million degrees

When the moon is between the sun and the earth, the moon is a. up all day b. up all night c. up half the day, then half the night d. up half the night, then half the day

a. up all day

Which of the following pairs of objects would make a good scale model of Earth and the Moon? a. a basketball and a soccer ball b. a basketball and a baseball (or softball) c. a basketball and a ping pong ball d. a basketball and a pea e. a basketball and a grain of sand

b. a basketball and a baseball (or softball)

When the Earth is between the sun and the moon, the moon is a. new b. full c. first quarter d. last quarter

b. full

About how many years elapse between times of maximum solar activity? a. 3 b. 5 c. 11 d.33 e.105

c. 11

A friend comments to you that there was a beautiful, thin silver of a moon visible in the early morning just before sunrise. which phase of the moon would this be, and in what direction would you look to see the moon (in the southern sky, on the eastern horizon , no the western horizon, high in the sky, etc)?

waning crescent on the Eastern Horizon

Where (in the southern sky, on the eastern horizon, on the western horizon, high in the sky) would you look to see the sun when the full moon starts to rise?

when the full moon rises, the sun will be setting in the west

How many moons would fit across the diameter of the sun?

About 400 moons

What are the photosphere, chromosphere, and corona?

Photosphere - visible surface Chromosphere- region of atmosphere directly above the photosphere corona- upper atmosphere

What holds the sun together?

Pressure from the nuclear reactions in the Sun's core balance the force of gravity

Why doesn't the Sun collapse?

Pressure from the nuclear reactions in the Sun's core balance the force of gravity

Solar Prominences

Prominences: huge arches of glowing gas, rising from sunspots clear shape whereas flares don't

How does energy get to the sun's surface from its core?

Radiation and Convection

Super moon/Micro moon

Super Moon - Full moon and closest to Earth Micro Moon - Full moon and farthest from Earth

As you observed the Earth's phases, look at the positions of the Moon in its orbit and think about what phases of the Moon would be seen from the Earth at the same times. Are they the same as the Earth's phases seen from the Moon or different?

The phases at the same time would be opposite. From the Earth, the moon would be in a full phase and from the moon the earth would be in a new phase.

Neap Tide

a tide just after the first or third quarters of the moon when there is the least difference between high and low water.

Which month is longer? a. synodic b. sidereal c. they are the same

a. synodic

How is solar energy generated?

The extreme temperatures are required for the fusion of hydrogen to helium

Length of sidereal month

24.5 days

Atmosphere: Chromosphere

- surrounds photosphere - thin cool layer - temp increases with altitude -spicules form and vanish in minutes -300,000 visible at any time - thin jets of has shooting at 20 km/s - rise to 10,000 km - form around super granules (30,000 km) - due to magnetic effects, red stuff, how fast gas is moving due to magnetic field -pinkish color due to emission lines - hydrogen alpha line -red spikes due to hydrogen gas (can see with eclipse)

Inferior Structure: Core

- the region of energy production - T= 15.5 million K -Density = 150 gm/cm^3 - High enough to fuse, temp needs to be 15 million, temp is higher so core must be dense -takes a long time to get to

Energy Production: Nucleosynthesis

-conversion of hydrogen to hellium -625 million tons of H disappears per second -621 million tons of He formed per second -4 million tons converted to energy per second -making other nuclei -energy that powers the sun: converting hydrogen to helium--> makes sunlight

How big is the sun compared to the Earth?

100 Earths fit across the Sun's surface. Sun's mass = 2 X 10^30 kg. Earth's mass= 6 X 10^24. About 33000 X!

What is the period between maximum sunspot numbers? How does this differ from the period of the full solar cycle?

11 years generally for min to max for sunspots, 22 years for full solar cycle (sunspots return to original polarity)

Approximately how many times could the moon's orbital diameter fit between the Earth and the sun?

150,000,000/ 384000= ? 200 Moons

How many Earths fit across the Sun?

Diameter of Sun - 1.4 X 10^6 km Diameter of Earth - 12,756 km 1.4 X 10^6 km/12,756 km = 100 How many Earth's fit inside the sun? v=4/3pi*r^2 (100)^3 = 1,000,000

How big is the Sun?

Diameter of Sun = 1.4 X 10^6 km 1cm = 500km x cm = 1.4 X 10^6 x=2800cm = 28 m (4 rooms)

Eclipses

Does not happen every month because moons orbit is tilted with respect to the plane of earths orbit Moon misses earths shadow by being either above or below it. Moons shadow misses earth for the same reason. Moons orbit precesses once every 18.6 years (can predict eclipses) Eclipse seasons shift forward about 20 days each year.

Earth and Moon scaling (Diameter)

Earths Diameter - 12,756 km Moon's Diameter - 3476 km Ratio - 12,756/3476 = 3.67:1 (4:1) Basketball vs Tennis Ball

In which phase will the Moon be up most of the night?

Full moon

What visible evidence do we have that the sun has a convection zone?

Granulation on the sun's surface

The diameter of the Moon's orbit around earth is about 769,000 km across. So, the ratio of the Sun's diameter to the Moon's orbital diameter is roughly 2 (1,392,000/769,000)=2 Does this mean that two suns placed side by side would fit inside the moon's orbit around the earth, or that two moon orbits placed side by side would fit across the sun?

It would mean that two moon orbits side by side would fit across the sun Drawing in handout sun size

If we used a basketball to represent the sun and a ping pong ball to represent earth, and separated them by the distance you answered in question 6 (62), would we have an accurate scale model of the Sun - Earth system?

It would represent a small model of Earth and Sun because Earth is accurately represented by a golf ball

The Sun: Vital Statistics

Mean Distance: 1 AU: cannot triangulate to get distance of the sun cause it is too far, once you know distance to venus you can. Radius: 696,000 km Mass: 2 x 10 ^30 kg Density: 1.41 gm/cm^3: not very dense, made up of light material (He and H) earth's density: 5.5 (rock and iron- all fusion stops with iron) Surface Temp: 5800K: color gives off green light wien's law Central Temp: 15,000,000 K Power Output = 3.9 x 10^26: wattage (how much energy per second) sun is powered by fusion 75% H; 24% He; 1% other elements

Earth and Moon scaling (Distance)

Moon is 384,400 km from the Earth Moon is 30 Earth Diameters away from the Earth

Can any of these combinations of the following items be used to make an accurate scale model of the earth and the sun? if so what two and why? -basketball -soccer ball -baseball -pingpong ball -pea -grain of sand

Soccer ball is 22 cm and grain of sand is .2 cm this the soccer ball and sand have the same ratio compared to the Earth and Sun

If the moon is a full moon tonight, will the moon be waxing or waning one week later? which side of the moon (right or left) will appear illuminated at this time?

Waning and Left

A first quarter moon is seen highest in the sky at a. noon b. midnight c. sunset d. sunrise

c. sunset

Tides

Moon pulls on Earth 2 high tides a day 2 low tides a day

Keeping in mind the same side of the moon always faces the earth, do you think that the Earth would cycle through rising and setting times when viewed from the moon in a similar way as the moon does when viewed from the earth?

No, the earth never sets on the moon. The moon spins at the same rate that it rotates the earth, so the same side of the moon is always facing the earth.

Lunar Ecplise

Shadow of Earth on Moon Always at Full Moon

Collision Ejection Theory

(Currently Accepted Theory) -A young Earth (or even proto-Earth) was hit by a large, Mars sized astroid (mass - 10% of Earth Mass) -Explains why no water - water would be evaporated by collision -Glancing Collision; tore off material from the surface. (explains why not much iron) -Gravity collected ejected mass into Moon by, and orbited Earth due to initial angular momentum -Differentiation had left Earth's outer regions devoid or iron. Heat caused by the collision depleted the ejected material volatiles. -Orbiting Debris rained down on the young Moon, creating crating -Accounts for the orbital plane of the moon being close to the ecliptic -May have been responsible for the tilt of the Earth's equator to the ecliptic. (Mercury and Venus do not have such tilts) -Can only have 1 moon - 2 moon's would wipe each other out.

Fission Theory

(Old Theory) -Spun off from a young, molten, rapidly - rotating Earth -Being close, got into orbit around the Earth. Would have to be spinning really fast. -It's composition would be similar to Earth's crust, from which its material mostly came -But, this does not explain the lack of volatile (react with water) elements (sodium, potassium) and water.

Twin (Co-Creation) Theory

(Old Theory) Formed at the same time as the Earth, in the same neighborhood. Being close, got into orbit around the Earth. Its composition would be similar to, but not necessarily same as that of Earth. Could also not explain the lack of volatile (react with water) elements (sodium, potassium) and water.

Capture Theory

(Old Theory) Was a small planet orbiting the Sun. Approached too close to Earth and was captured. Would have had to get within 50,000 km of Earth with *just the right speed and direction*. Its composition might have been quite dissimilar to that of Earth, unless we invoke yet another set of fortunate coincidences. the moons rocks are similar to Earths - only outer layer but density is less than Earth's

Sun's Parts

- Corona -Chromosphere -Photosphere -Convection Zone -Core Sunspots Prominence

Atmosphere: Corona

- thin gas, extremely hot -surrounds chromosphere -very hot and tenuous layer -once get up to the corona very hot because of magnetic field -extends many million km -heated by the action of solar magnetic fields accelerating charged particles -magnetic field acts like a whip particles go really fast and gives off high temp -emits X-rays because of high temperatures -coronal hole - escape -see and study through X-rays -continues into solar wind- a continuous stream of charged particles blowing away

Atmosphere: Photosphere

- visible surface on the sun - looks dimmer near edges; sharply defined boundary (does not have defined smooth edge as it appears to us) -Has granules that form and vanish in minutes (granules tell you how deep convection layers go) - hot gas rising, cooling, and falling back - typically larger than texas + oklahoma - Temp is 5800K - Upper parts at 4000K Sunspots and prominences are features on surface

Problems with these Theories:

-Oxygen Isotopes differ considerably between Earth, Mars and the different meteorite groups, but not between the Earth and the Moon -This implies that the Moon is comprised of the silicate part of the earth at the time of the impact -Problem - Computer simulations indicate that the Moon should actually be comprised of the silicate part of the impactor, not the Earth.

Length of synodic month

29.5 days

Which of these layers is hottest? How do we know this?

Corona- gives off x rays

What is the sun made of? How do we know this?

Hydrogen - 75% He- 24% Other - 1% know this from density determination and spectra

Sunspots

Spots; darker than surroundings -numbers increase and decrease: 11 year cycle - 11 year cycle: max to min -Strong magnetic fields at the spots; detected by Zeeman Effect (atoms in a magnetic field have lines in their spectra split into several closely spaced lines) -Magnetic polarity of spots --> different in different hemispheres --> reverses in each successive 11 year cycle; dull cycle length is therefore 22 years --> 22 year cycle polarity cycle: brings back to the same polarity they started

Why must the interior of the Sun be so hot?

The extreme temperatures are required for the fusion of hydrogen to helium

Where (in the southern sky, on the eastern horizon, on the western horizon, high in the sky) would you look to see the full moon when it starts to rise? what time of the day would this happen?

The full moon would rise in the East at around 6 pm

How can we measure the Sun's size, mass, and temp?

To get the size of the sun you need the distance the sun and size of earth. Distance to the sun is found using triangulation with nearby objects (venus for example, or the moon). Mass of the sun is found using keepers third law. Surface temperature is found using Wien's law. Internal temperature found by modeling.

Sunspots are dark because a. they are cool relative to the gas around them b. they contain 10 times as much iron as surrounding regions c. nuclear reactions occur in them more slowly than in the surrounding gas d. clouds in the cool corona block our view of the hot photosphere e. the gas within them is too hot to emit any light

a. they are cool relative to the gas around them

In which month is a blue moon (two full moons in one calendar month) impossible? a. October b. February c. May d. this is never possible

b. February

When a full moon is observed from earth, an observer on the moon would see a______ Earth. a. full b. new c. quarter d. crescent

b. new

When the earth is between the sun and the moon the moon is a. up all day b. up all night c. up half the day, then half the night d. up half the night, then half the day

b. up all night

Which month is observable from Earth a. synodic b. sidereal c. both are observable from earth

c. both are observable from earth

The diameter of the sun is about how large compared with the Earth's? a. twice as big b. one half as big c. 10 times as big d. 100 times as big e. 10,000 times as big

d. 100 times as big

The distance from Earth to the sun is about 150,000,000km. This makes the distance between the sun and earth about 110 time larger than the diameter of the sun. If you were to use a 1 foot basketball to represent the sun, how far would it have to be from earth to be accurate scale model? a. 1 foot b. 10 feet c. 30 feet d. 110 feet e. 300 feet

d. 110 feet 1 X 110= 110

Let's say you use a 1 foot (12 inch) basketball and a 3-inch orange as your Earth and Moon respectively. About how far apart mist they be placed to represent an accurate scale model of the Earth-Moon orbital system? a. 1 foot b. 4 feet c. 10 feet d. 30 feet e. 300 feet

d. 30 feet

The Sun produces its energy from a. fusion of neutrinos into helium b. fusion of positrons into hydrogen c. disintegration of helium into hydrogen d. fusion of hydrogen into helium e. electric currents generated in its core

d. fusion of hydrogen into helium

The sun is supported against the crushing force of its own gravity by a. magnetic forces b. its rapid rotation c. the force exerted by escaping neutrinos d. gas pressure e. the antigravity of its positrons

d. gas pressure

In which phase is the moon up half the night, then half the day? a. new b. full c. first quarter d. last quarter

d. last quarter

Surface Oscillations

seen by analyzing doppler shifts from different regions of the solar surface -most prominent is the 5 minute oscillation -reveals details about the layers deep below the surface -given rise to the field of helioseismology

At what time would you look to see a first quarter Moon at its highest position in the sky?

sunset

Why sunspots are dark

sunspots slightly low (cooler); magnetic field blocks the convection thus darker