Sunday, October 31, 2010

Spectral Classification of Stars Lab

1. Briefly describe the spectra.
PANEL 1: Mostly short wavelengths- a very hot star, with the peak of the curve around the violet-blue area. There are absorption lines to the longer wavelengths side.
PANEL 2: Max temperature at the far end of the spectrum on the short side, with many absorption lines to the right, near the longer wavelengths again. This looks like its a very very hot star as well. The curve is not really a bell-shaped one because it just stars at the highest point and goes down.
PANEL 3: A LOT of absorption lines at the longer-wavelength side, lots of dips, peaks around 4000, so it's pretty hot again... and will glow blue. XD
PANEL 4: Steep slope peaking at 4000, will glow blueish, some absorption lines at the longer wavelength side.
PANEL 5: Somewhat of a peak around 6000, some absorption lines in the longer wavelength side, lots of irregularity in the curve.. hard to tell exactly where the peak is at.
PANEL 6: Very high temperatures for the top star, peak around 4500, absorption lines to the right near the longer wavelength side.

OVERALL: the lines vary in depth and proximity, but all of the graphs have absorption gaps/lines to the longer-wavelength side of the spectrum. They usually peak before 6000, and some start lower and go higher, or start from higher and just go down in a curve.

2. A: 4 B: 3 F: 1 K: 6 M: 2 O: 5

3. PANEL 1: 4200 apprx | PANEL 2: 3600 apprx | PANEL 3: 4100 apprx | PANEL 4: 3950 apprx | PANEL 5: 5950 apprx | PANEL 6: 4500 apprx.

4. Hottest: Panel 2 | Coolest: Panel 5 (or 1.)

Panel 2, panel 3, panel 6, panel 4, panel 1, panel 5.

5. Nope, they are not the same. M, B, K, A, F, O. (Not sure if I understand what they're asking here.)

Sunday, October 24, 2010

Sky Journal Week 5

I didn't get a chance to record anything. : ( Maybe I'll do two entries this week to make up for the lack of brain stimulation.

Apollo 13 EC Notes

This is my makeshift Cornell notes.

1. Why was this Jim Lovell's last mission?
2. What went wrong BEFORE the launch?
3. What went wrong at the beginning the flight to the moon?
4. What happened because of that?
5. Did anything bad happen to the crew members physically?
6. What type of filter breaks?
7. Because of the lack of energy able to be used, what did the crew have to do to get back to earth?
8. What did the left-behind crew member do to help them get back to earth?
9. Did they get back safely? Describe.
10. What was the media attention to all of this?
11. How did Lovell's family react?

1. He wanted his last mission to be where he could stand on the moon.
2. A lab report came back reporting that the main pilot had measles and was unfit to go into space because the worst and feverish part of it would come in transit to the moon and could possibly inhibit brain functioning, impairing the mission. Some other foreshadowing with practicing simulations with the substitute member occur as well.
3. When a routine checkup was performed, a coil blew and caused an entire tank of oxygen to combust - this limited the air supply even further.
4. The energy supply and oxygen supply are depleted so greatly that the crew has to switch to the machine intended for the descent to moon.
5. No physical injuries are obtained, but one crew member is nearly frozen because they have to conserve enough energy to get back to Earth.
6. A carbon filter breaks and causes the levels to rise a lot. Since there is no replacement filter, the people back at Houston have to come up with a makeshift filter for them out of only stuff found on the ship. They succeed, and the crew on the Odyssey makes it in time.
7. The crew has to use the moon's gravity to swing them back into the direction of earth. Houston also has to develop a sequence to start the ship meant to land on the moon (which only had enough energy and oxygen for 2 people and a simple trip from the moon back to the main ship) back up that uses as little of energy as possible and leaves enough left for the crew to steer the ship in the right direction in order to enter the atmosphere again and to deploy the parachutes.
8. He helps develop the sequence with which to turn the ship back on with the least amount of energy used, and probably boosts a little morale.
9. Yes, they returned safely. They landed pretty much in target and made it through the atmosphere, deployed the parachutes, and didn't obtain any more physical damage beyond scratches and bruises from the impact. They landed in a body of water and were rescued immediately with a helicopter.
10. At the beginning, there wasn't that much media attention- just the routine stuff, like "They're going into space again, to the moon..", and the guys in the spaceship at the beginning send a "broadcast" describing what its like in space that doesn't actually get aired. Later, the media jumps all over it and tries to keep up with all of the technical difficulties and the statistics of what has failed and the probability of them getting back, etc.
11. There was plenty of nail biting and worriedness, especially when they were due to get through the atmosphere. There was a supposed "3 minute" time limit, and Apollo 13 went over by a minute or two, which caused a LOT of panic and pain for the family. But when they came through and were visible, it was like a huge sigh of relief.

A routine mission with the unlucky name of "Apollo 13" begins to go awry 3 months before departure with several kinks and foreshadowing in the film. The launch goes fine, until about a day in- things start going wrong right and left, with tanks exploding, energy leaking, and all sorts of things. The crew ends up getting back safely, but only barely. The movie is based off the book by one of the surviving astronauts, Jim Lovell.

Weekly Reflection 5

I don't think I ready for the next test quite yet. I know how to use the equations and such, but I have difficulty actually finding what needs to go into the equation. I think I finally figured out how to use the appendices in the back to find the surface gravity and such, but other than that... ack.

Problem areas:
1) The homework. The logic behind the homework. Where the heck do some of the numbers come from? What data from the appendices are you supposed to use?
2) The tides are still a little shifty - I have the basic concepts, but not stuff with the CALCULATING the tide/weight/etc problems.

Homework Ch 4, 5, and 9

Chapter 4:
p. 130: #3, 8, and 9

3) 3 kg on Ceres.
8)128 planetesimals. (127.56 to be more exact), probably more in order to get the correct density... not sure about this one.
9) 2,500 comets per year over 500 million years.

Chapter 5:
p. 158m: #2,4

2) 1/5 of the weight. (30kg on moon vs. 150kg on earth).

Solar Spectra Lab Reflection

I didn't have much difficulty with this - in the beginning, just knowing what to do initially was a little confusing, but once I got going it was rather simple. The questions weren't particularly taxing, either, except for number 3. I can think of a more complex step to insure that the lines A and B are caused by the earth's atmosphere, but a simple one didn't come to mind, so I don't now if I got that one right or not. XD

It applies to the current unit because of chapter 9, which is all about the sun. It mentions the elements in the sun, and this lab has many similarities to that. It also gives an idea of what elements block what wavelengths, etc.

Solar Spectra Lab

PART A and B
< --------

1) The image isn't set up to do that- there are margins on the image that should be taken into account.
2) It looks like most of the light came from hydrogen, but a lot of it came from heavier elements like iron and sodium. So, no, not really dependent on this composition, unless there are some mistakes.
3) Well, a not-so-simple step could be to check what the spectra sensors say in space, outside of the atmosphere, about the solar spectra and compare it to the spectra sensor on earth.
4) The thicker lines means that there is more of that gas blocking the light, so in a sense, it is "stronger" because it's absorbing more.
5) Of course! The discrepancy ranged from 5-30 or so nanometers away.
6) I'm sure that each element has a range of wavelengths it emits, since we don't have 500 or more elements to each have its own specific wavelength. The wavelength measurements were hard to get because the image was small enough that one could not be very specific in the clicking to find the coordinates. One must consider whether to click on the edge of the line or the middle of the line, and that sort of thing. The scale factor was determined to be very close to 0.30, so there wasn't a huge percent error in that calculation. These factors didn't have a very large affect on the calculated results- the calculated results were off because each element has a wavelength set of light that it could emit.

Reflection for Properties of the Sun Lab

It was quite interesting seeing how the calculations could be made. Although we were just using pixels and such and don't REALLY know the true width of the sun using the lab (aka we didn't do fancy angle measurements and stuff), it was still rather fun to see what we could figure out about the rotation of the sun and the height of those gigantic prominences. It was especially interesting to see how FAST stuff around the sun moves! It makes it look like it's moving slowly, but since it's so huge, it's actually incredibly fast (just like the earth- its moving hundreds of miles per day, yet it seems like we're stationary). Anyway, I came to the conclusion that the sun is gigantic and very hot, and has lots of interesting things on its surface that move in a very quick manner.

Friday, October 22, 2010

Properties of the Sun Lab

1. They move to the east, indicating that the sun rotates counter clockwise.

They both rotate counterclockwise. The earth rotates counterclockwise in a counterclockwise orbit around the sun, which also rotates counterclockwise.
A possible reason could be that the sun and earth came from the same original source, but developed differently.

3. Image scale: 1.4mil/424px, or 3301.89 km/pixel.
4. It moved 49 pixels.
5. 162,321 km. (plug and chug, huhuhuhu.)
6. P (days)/1 day = 2pi7mil/162,321 = 27 P (days).
7. 49 pixels within about 4 pixels... 4/49 = 8% error.
8. 27 days, +/- 2 days. (0.08 x 27 = 2.16)


1. Done.
2. Image scale: 14,737 km per px. (1.4 mil/95px)
3. 16 pixels, or 235,792 km
4. 18.7 pixels, or 275,582 km
5. 275,582 - 235,792 = 39,790 km change in height.
6. 14 hours and 53 minutes. : )
7. 1672 mph. (39,790km/893 mins ====> 44.56km/1 min ====> 2673.6 km/1 hour.
2673.6 km = 1671 mi, so 1672 mph.) It's really fast.. at least 4 times greater than a commercial jet, and at least 2 times the speed of sound.


Solar Research (Question #2)

Solar win, earth’s magnetosphere, and electron transitions work together to create something that many people only see in pictures: an aurora. Earth can usually see two auroras, positioned at the north and south poles, called “aurora borealis” and “aurora australis” respectively. Auroras are caused by the fluctuation and motion of the sun’s solar wind, a constant stream of particle extending from the sun’s magnetic field, and the earth’s magnetosphere, the protective shield produced from the magnetic pulls of the earth and centered around the north and south poles. The solar wind moves at a rate of 250 miles per second away from the sun, fast enough to break free of the magnetic field and continue towards earth. As shown in the picture below, the shape of the magnetic field from earth would be less squashed on the side closest to the sun if it weren’t for the solar wind. When the earth’s magnetic field and the sun’s solar wind interact, an aurora can be seen only at the north and south poles, where the magnetic pull of the magnetosphere are most apparent and originate.

When this interaction occurs, electrons and protons from the atmospheric gases smash together, and a display of lights occurs in patterns in the sky between 60-155 miles above the earth. When an atom becomes excited and begins to promote and demote electrons, a light is emitted at various frequencies according to the element. For example, oxygen gives of a greenish yellow light, nitrogen gives off violet-blue light, and at lower altitudes the two gases together give off a bright red. When the three are combined, they create the colors we see in auroras most commonly.

Aurora and meteor

APOD Photo #2

August 13, 2009

This is a picture taken from the probe on Mars' surface. The rock in the center was oddly out of place in the vast landscape of flatness, and upon further analyzation of chemical/density/all that, it was identified as a fallen meteorite. It was called "Block Island" and was made of mostly iron and nickel. You could say it fits into the nebular theory, seeing as the foreign materials from the meteorite could have been a fragment from the nebula. Seeing as it was a meteorite, it fits in with the meteorite lab (as one can observe, there isn't much of an impact area around the meteorite, suggesting that the surface of mars is incredibly solid, or the object didn't have much velocity).

Monday, October 18, 2010

Weekly Reflection 4

Sorry it's a bit late... I've been so busy lately. XD All of my courses have a lot of homework all of a sudden.

Anyway, I've learned QUITE a bit from the lecture today, so I am much more confident in satellite motion. I still haven't done the meteorite lab.. still no time. I'm probably going to do it tomorrow, but if I don't find time even then, I'll just send an e-mail and ask if I can do it sometime when I have access to all the materials and before the next test.

The labs have been only slightly useful in demonstrating the concepts behind satellite motion. The real stuff that helped me understand were the lab QUESTIONS. Having to reason through them and figure out how the laws pertain to motion in the universe is really interesting and gratifying when I finally understand how everything meshes together. I learn best through memorization of concepts, not memorization of phrases and such. I think that I still have brain overload because this is my first time through anything related to physics, but I'm slowly getting it. : )

Sky Journal Week 4

Not a lot has changed other than the phase of the moon (it's a waxing gibbus right now) I saw a man-made satellite and am proud to know that I know how that little thing is staying in orbit. : )

Looking at Google Sky, I can see that Polaris has changed slightly from last week, too... we're getting closer and closer to winter. From where I'm sitting, it's up at about 80 degrees to the left of me.

Not sure what else to say this week.. the skies are getting cloudy again. Google Sky is my hero once again.

Sunday, October 17, 2010

Satellite Motion Lab POST LAB Questions

1. An object becomes a satellite when it orbits an object with a larger mass/gravitational pull.

2. The earth is curved, and an object has to be moving at a very fast rate in order to drop that distance and not actually fall into the planet - they say that the measurement for the curve of earth is that for every 8000km, the horizon drops about 5 meters, so the object is actually orbiting the earth instead of "dropping".

3. Inside the atmosphere, an object would have to maintain constant motion itself (like using energy like a jet engine or something similar) than just using gravity and the curve of earth to stay in orbit. The orbital path would eventually "decay" because the ratio of dropping to speed would change in short periods of time, and would slow down enough not to maintain the orbit. (Newton's 1st law - the object would have stayed in motion unless earth's gravity hadn't have interefered too much to inhibit the orbit.) The slowing is caused by the friction of the atmosphere.

4. Gravity is constant, and there is no friction in outer space. The gravity continuously pulls the satellite to the center of mass, but inertia keeps it moving around. This is only true in circular orbits. In elliptical orbits, the speed of the satellite changes depending on the speed initially and its relative position to the center of mass.

5. Kepler: Using Kepler's second law of planetary motion, the area covered by the arc of motion and the lines connecting the two bodies are equal to all other areas covered in the same amount of time. Using this, one must determine that the speed of the orbit changes in order to maintain the same amount of area covered in the same amount of time. Since this applies to ellipses, the satellite isn't the same distance away from the center of mass the entire orbit, like in a circle, so the speed HAS to change in order to keep Kepler's second law.

Newton: Using the law of inertia, one can explain why the speed of an elliptical orbit changes. Since the center of mass and the satellite are not the same distance from each other throughout the orbit, the centrifugal/centripetal forces will react with each other in a different way. The farther away the satellite is from the center of the centripetal force, the less that force affects the satellite's orbit. The close the satellite is, the greater the effect of the force, and the greater the speed of the satellite is. When the satellite is closest to the center of mass, it moves the fastest.

These are true in all elliptical cases... however, the speed of a circular orbit never changes.

Using the equation, one can see that the greater the distance between the center of mass and the satellite, the less the velocity (or speed). Therefore, the smaller the distance, the greater the velocity.

Some really helpful sites that may be useful for other students as well:

6. When the satellite slows, it is merely using less energy to move than if it were closer to the center of mass. When it is closer, the satellite gains energy from moving (kinetic), then turns into potential energy as it slows down. The potential is then used to get back closer to the center of mass. The total amount of energy, whether it is kinetic or potential, never changes though.

7. The "escape speed" is the amount of velocity required to free an object from the surface gravity of the launching site. In earth's case, 11km/sec is required to get away from earth and not get pulled back because of gravity. The distance, the mass of both bodies, and the amount of friction in the atmosphere all affect the success.

8. The escape velocity for earth is 11km/sec at LEAST. It is not the same for all planets because they all have different amounts of gravity. The moon requires a lesser amount of speed to defy its gravity than the earth.

Escape velocity of the moon: 2.4 km/sec
Escape velocity of Jupiter: 59 km/sec
(both calculated on paper)

9. The surface gravity for all planets are different. Their masses are all different, so the gravity is different. It is calculated using the gravity constant x the mass of the object all divided by the radius of the object squared.

10. Moon: 1.627m/s^2, yes, I calculated 1.63m/s^2.
Jupiter: 24.79m/s^2, calculated 24.8m/s^2.

I used the masses/radii/gravity constant found on Google.

11. For a satellite's orbit to decay, there must be friction occurring that slows the satellite down enough to the point where it cannot orbit anymore and instead falls into the gravitational pull of the center of mass.

Satellite Motion Lab


1. Gravity keeps the satellite from leaving orbit.
2. If an object goes into orbit around something larger or something that has a larger gravitational force (usually something larger/with more mass)
3. A circular satellite orbits in a circle, while an elliptical satellite goes in a more oblong motion.
4. Centripetal force is the force that causes the satellite to move towards the center, while centrifugal force is basically inertia.
5. Centrifugal force keeps the object wanting to go in a straight line, but the centripetal force causes it to orbit. They work together to obtain a consistent orbit using inward and outward/straight motion playing against each other.


Change of radius: 62.6 cm - 1.66 rotations per second | 76.2 cm - 1.58 rotations per second | 84.6 cm - 1.46 rotations per second. MASS: 200g for all radii.

Change of mass: 150 g - 2.17 rotations per second | 200 g - 1.88 rotations per second | 250 g - 1.79 rotations per second RADIUS: 51 cm for all masses.

CONCLUSION: Based on the graphs, one can conclude that as the radius goes up, the rotations per second goes down - as well as the amount traveled in one second (aka, the larger the radius, the faster the object moves). As the mass goes up, the satellite slows in its rotation.

Measured mass of stopper: 28.9 g
Calculated AVERAGE mass of stopper: 26.4 g

An example of the procedure.
v = d/t ||| (2π x 0.51m) / .578 (average number of rotations per second) = 5.54 m/sec
a = v^2/r ||| 5.54^2 / 0.51m = 60.18
f = m x a ||| mass (unknown) = 1.96 /60.18 = .033, or 33 grams
.2kg (mass of 200g) into newtons = 1.96 newtons.

1. Mass 1: 33 g (200g, 51cm)
2. Mass 2: 37 g (250g, 51cm)
3. Mass 3: 16 g (150g, 51cm)
4. Mass 4: 21.5 g (200g, 76cm)
5. Mass 5: 27 g (200g, 63cm)
6. Mass 6: 24 g (200g, 85cm)

Average mass: 26.4 g

Monday, October 11, 2010

Weekly Reflection 3

Test week went pretty well. I'm not sure if I really understood some of the concepts going into it, but I definitely got better at determining certain things after going over the test today. I hope to be able to understand the material well enough to have a good base for chapters to come.

Concepts I'm still partially struggling with:
the spectra stuff (I know the basics)
some of the mathematics (like the gravity things - what measurement can we use for the distance between mars/sun, earth/sun, etc?)
other logic-based things like the position of stars at certain times of day/year

I think that by the end of the quarter I will be able to understand these things better just by spending more time with them. : )

Spectra Lab Reflection

This lab really helped to solidify the concepts.. seeing the difference between emission and continuous spectra and being able to see first hand actual emission lines was really interesting. I hope I understood the material well enough to answer the lab correctly... I had to look up many of the answers on the internet, but oh well. That's what the internet is for half of the time anyway. I still don't understand some things, but I think I will be able to get it better when I spend more time with the material.

Spectra Lab

HELIUM | emission | one of each color except cyan/green
HYDROGEN | emission | one of red, cyan, indigo, violet.
INCANDESCENT | continuous | all visible
FLUORESCENT | continuous | all visible
MYSTERY LAMP | emission | one of red, cyan, indigo, violet
SOLAR | continuous | all visible

1. The mystery gas was hydrogen.
2. Mercury vapor.
3. Red filter: We saw all the colors still, but you're only supposed to see red (it blocks out all other colors except red) | Blue filter: Same. We saw all, only supposed to be blue. | Green: We couldn't find a green filter, but one would assume the results would be similar.
4. Neon lights of different colors do not contain neon: true neon glows red, but often neon lights are made with other gases that either glow different colors or tint the glass a different color with a white glowing gas.
5. Every wavelength has some absorption lines, but they're small pieces- one must consider that the light is travelling through millions of miles as well as the atmosphere.

Absorption lines are the tiny lines that are missing when a continuous light source is shone through the cold gas. Emission lines are the lines corresponding to the missing places that are shown when the gas itself is heated and emits light.


Emission is when the electrons fall to a lower energy level- they emit photons, causing the glowing-ness we see.

Absorption is when the electrons are promoted to a higher energy level, usually caused by an outside source of energy, like heat.

8. Emission lines are discreet and specific wavelengths of light are emitted- in continuum radiation, the light source emits light at all wavelengths.

Helium - only certain wavelengths show up.
Sunlight (many, many gases, etc) - all wavelengths show up.

I made all of these little examples myself in Sai, a painting program I use. : ) I didn't just find them on the internet.

Wednesday, October 6, 2010

Telescope Research

The Hubble Telescope was named after Edwin Hubble, an astronomer in the 1920's who discovered many important foundations for astronomers today. The telescope, which weighs 25,000 pounds, has been in orbit around Earth for over 20 years and has had several missions to repair it. It is one of the only in-space telescopes and can take clear pictures billions of light years away - a near unfathomable distance. The telescope was sent up in 1990 and since then has sent numerous images that have been claimed as astronomic classics - pictures easily recognizable in any science textbook. Its purpose was to see what was beyond on our galaxy, and it accomplished that and beyond- we now know how many billions and trillions of galaxies are out there.

It's 7 feet 10 inches in diameter and has 48 square feet of collecting area. The focal length is 189 feet. It has an infrared camera/spectrometer, a nearly failed optical survey camera, and several other types of spectrometers and cameras.
It functions with a mirror, classifying it as a "reflector" telescope (optical).

To see an interactive (ish) diagram of how Hubble works, click here.
The telescope itself:

Some stunning images taken by Hubble:

This Hubble photo is of a small portion of one of the largest-seen star-birth regions in the galaxy, the Carina Nebula. Towers of cool hydrogen laced with dust rise from the wall of the nebula.
The Carina nebula, a birthplace of galaxies, sometimes referred to as a "nursery".

Hubble Maps Dark Matter in Galaxy Cluster
An gigantic cluster of galaxies located over 2 billion light years away.

Colliding Galaxies

Neat Video to Watch:

All information was found on the official NASA Hubble site. (Wikipedia was used for the dimensions, which I assume were found on the official site as well).

Monday, October 4, 2010

Sky Journal Week 3

My mom came in from the hot tub a few minutes ago and asked if I had any assignments that required me to view the night sky. I told her about the sky journal and she showed me what she thought was Venus.. good guess, but upon using GoogleSky, I found that it was Jupiter! At about 150 azimuth and 30 altitude, it was extremely bright and more "round" than the stars. Apparently Uranus is almost directly in line with Jupiter as well, but obviously not viewable by the naked eye.

I also saw many constellations- my mother pointed out Cassiopeia and I also saw the little dipper and some other stuff. Most likely, if it weren't for that handy dandy app on the droid, I wouldn't have been able to actually identify most of what I saw.. eventually, as I continue to observe the sky, I will be able to navigate around it successfully without the aide of an electronic device.

Sunday, October 3, 2010

Weekly Reflection 2

I haven't learned a ton of new material this week regarding math, because I've already done it in recent quarters. I still need to review the chapters again before the next test, but other than that, I'm not having any troubles. I downloaded GoogleSky for my droid this week, too, which is like having a planetarium in your pocket at all times. I can actually "look through" the earth at the stars that the souther hemisphere can see! If you ever get a droid, I reccomend it. I think you might be able to access it online as well.

I also really like the sky journals because it makes me actually look at the sky at night, and that can be really mind-blowing at times. The sky is so crazy and infinite and I'm really excited to learn more about the stars, nebulae, galaxies, and black holes.

Scientific Methods Lab

PART 1: Scientific Notation

A. 9.3 x 10^12
B. 7.7792 x 10^11
C. 6.1134 x 10^23

PART 2: Measurement Errors and Uncertainties

A. ----------
1) Blue: 420 nm, Yellow: 580 nm, Red: 650 nm
2) 0-20 nm off... not very accurate at all. All estimates with just eyeballing and no actual measuring.
3) By measuring the specific distances and how they relate to the 100nm markers.
4) Yellow/Blue: 2.5 cm +/- .05 cm | Yellow/Red: 1.8 cm, +/- 0.05 cm | Blue/Red: 5.3 cm, +/- 0.05 cm
5) Average: 0.426 scale factor (nm/mm)
6) Yes- they estimated their distances differently and used (possibly) different units, giving results that are mostly different.
C. ----------
Accurate: Like getting a bull's-eye. Right on target measurements, etc.. like a result being close or right on to the "pre-measured" and official result.
Precise: Getting the same sort of answer every time, but not neccessarily right on the official result. Consistent.

Galaxy Measurements, etc.
1. I used the thinnest part of the galaxy as the criteria for determining the diameter.
2. ------
a) Yes- if one measures the width one then the height for another galaxy, the sizes won't be similar and the supposed distance won't be able to be calculated.
b) No- as long as they were consistent and that eventual results were similar, it shouldn't matter, unless the galaxies aren't similar in shape.
3. I used a piece of paper and made marks on it then compared those measured marks to the other marks and determined the relative sizes/distances of the galaxies.
4. ------
a) Nearest: First one, Farthest: second one
b) About 6 times as far (using the criteria in the beginning)
c) One would have to assume that the original astronomer's postulate was true, and the photographs were taken from the same place/time on earth with the same amount of zoom on the telescope, etc.

Graphing Star Magnitude
1. I used my calculator to do this (I just took precalc so I know how to do it. : D)
2. y = -2.63x+5.6 (best fit line on calculator.. didn't hand calculate it)
3. -----
a) -2.63 = m
b) Yes. I use it a lot.
c) Yes, that makes sense.

PART 3: Significant Digits

A. ----
1) 2 sig figs
2) 5 sig figs
3) 1 sig fig
4) 3 sig figs

B. 78,801,312... 1 sig fig (from 4,000)... 8x10^4 or 80,000.

Homework Ch E and Ch 1

PART ONE Dimensional Analysis

1. 0.9375 mi (sig figs: 0.94 miles)
2. 245.12 km/h (s.f.: 245.1 km/h)
3. 9.89 ft/second
4. 1,008 minutes
5. 5,628 km/min (s.f.: 5,630 km/min)
6. 55.08 km/h (s.f.: 55.1 km/h)
7. 54.72 km (s.f.: 54.7 km)
8. 2.72 x 10^-5
9. 49.68 km/h (s.f.: 49.7 km/h)
10. 2.51 x 10^4
11. 5.76 km/h

Astronomy Problems using Dimensional Analysis

1. 4,444 m/s, 16,000 k/h
2. a) 4.134 x 10^13 km b) 1.34 parsecs c) 163,748.19 years at 8km/sec, or 1.6 x 10^5 years.

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