Formation of Solar System
~ 4.6 billion years ago huge cloud of gas and dust
started collapsing gravitationally
• As it collapsed it spun faster (conservation of
angular momentum)
• No (or little) spin in the perpendicular plane
• Local clusters of dust and gas condensed - protosun
formed first
• As material cooled, it condensed but never stopped
rotating (rotates still since there’s nothing to stop
it)
• Cores probably formed first, then attracted
neighboring materials to form: planetesimal,
protoplanet
• Probably not a unique system - there is increasing
evidence for the existence of many other planetary
systems
• Still an evolving theory
• All planets revoluve around the sun in the same
direction, but 3 have different directions of rotation
(relative to the rest and to the direction of solar
system motion) - Uranus, Venus, Pluto
The Terrestrial Planets: Mercury, Venus, Earth, and
Mars
Relative Characteristics:
Planet Distance Period Radius Mass
Mercury 0.4 0.24 0.38 0.055
Venus 0.7 0.62 0.95 0.82
Earth 1 1 1 1
Mars 1.5 1.88 0.53 0.11
The Jovian Planets (gas giants)
Jupiter 5.2 11.9 11.2 318
Saturn 9.5 29.5 9.3 95
Uranus 19 84 4.0 14.6
Neptune 30 165 3.9 17.2
Tuesday, June 25, 2013
Thursday, June 20, 2013
The Analemma
http://en.wikipedia.org/wiki/Analemma
1. The Earth is tilted on its axis 23.5° in relation to the plane of its orbit around the sun.
2. The Earth does not orbit the sun in a circle, but in an ellipse.
It is simply the sum of these two effects that causes the analemma - an apparent path of the Sun, looking at it at the same time every day (or every few days).
Do a Google image search for analemma and you'll see how the inclination of the analemma depends on latitude.
http://www.perseus.gr/Astro-Solar-Analemma.htm
1. The Earth is tilted on its axis 23.5° in relation to the plane of its orbit around the sun.
2. The Earth does not orbit the sun in a circle, but in an ellipse.
It is simply the sum of these two effects that causes the analemma - an apparent path of the Sun, looking at it at the same time every day (or every few days).
Do a Google image search for analemma and you'll see how the inclination of the analemma depends on latitude.
http://www.perseus.gr/Astro-Solar-Analemma.htm
Phases of the Moon
http://astro.unl.edu/naap/lps/animations/lps.html
http://www.astro.wisc.edu/~dolan/java/MoonPhase.html
http://www.moonconnection.com/moon_phases.phtml
http://www.astro.wisc.edu/~dolan/java/MoonPhase.html
http://www.moonconnection.com/moon_phases.phtml
The Doppler Effect
See this simple, but effective applet:
http://lectureonline.cl.msu.edu/~mmp/applist/doppler/d.htm
In this simulation, v/vs is the ratio of your speed to the speed of sound; e.g., 0.5 is you, or the blue dot, traveling at half the speed of sound. Note how the waves experienced on one side "pile up" (giving an observer a greater detected frequency, or BLUE SHIFT); on the other side, the waves are "stretched apart" (giving an observer a lower detected frequency, or RED SHIFT).
Play with this for a bit, though it's a little less obvious:
http://falstad.com/ripple/
In astronomy, the red shift is very important historically: Edwin Hubble found that light from distant galaxies (as measured in their spectra) was red shifted, meaning that distant galaxies were moving away from us (everywhere we looked). The conclusion was obvious (and startling): The universe is expanding. Last year, local astrophysicist Adam Riess discovered that the rate of expansion was accelerating.
http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/
It's worth noting that the effect also works in reverse. If you (the detector) move toward a sound-emitter, you'll detect a higher frequency. If you move away from a detector move away from a sound-emitter, you'll detect a lower frequency.
Mind you, these Doppler effects only happen WHILE there is relative motion between source and detector (you).
And of course, they also work for light. That's why we care about them. In fact, the terms red shift and blue shift refer mainly to light (or other electromagnetic) phenomena.
http://lectureonline.cl.msu.edu/~mmp/applist/doppler/d.htm
In this simulation, v/vs is the ratio of your speed to the speed of sound; e.g., 0.5 is you, or the blue dot, traveling at half the speed of sound. Note how the waves experienced on one side "pile up" (giving an observer a greater detected frequency, or BLUE SHIFT); on the other side, the waves are "stretched apart" (giving an observer a lower detected frequency, or RED SHIFT).
Play with this for a bit, though it's a little less obvious:
http://falstad.com/ripple/
In astronomy, the red shift is very important historically: Edwin Hubble found that light from distant galaxies (as measured in their spectra) was red shifted, meaning that distant galaxies were moving away from us (everywhere we looked). The conclusion was obvious (and startling): The universe is expanding. Last year, local astrophysicist Adam Riess discovered that the rate of expansion was accelerating.
http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/
It's worth noting that the effect also works in reverse. If you (the detector) move toward a sound-emitter, you'll detect a higher frequency. If you move away from a detector move away from a sound-emitter, you'll detect a lower frequency.
Mind you, these Doppler effects only happen WHILE there is relative motion between source and detector (you).
And of course, they also work for light. That's why we care about them. In fact, the terms red shift and blue shift refer mainly to light (or other electromagnetic) phenomena.
Alternate lab #2 - Planet quest
Planet "lab"
A Tour of the Planets
Please determine many interesting tidbits of trivia about our solar neighbors. You may like the following website:
http://nineplanets.org/
Please answer the following questions, based on your reading and web discovery. Some questions might have several answers, while the answer to others might be "none of them."
Please determine many interesting tidbits of trivia about our solar neighbors. You may like the following website:
http://nineplanets.org/
Please answer the following questions, based on your reading and web discovery. Some questions might have several answers, while the answer to others might be "none of them."
Which planet(s):
1. Rotates backwards?
2. Revolves backwards?
3. Rotates nearly on its side?
4. Have more than 10 moons?
5. Have only one moon?
6. Has an orbit with the greatest inclination to the ecliptic?
7. Is the furthest planet known to the ancients?
8. Has a largely methane atmosphere?
9. Has a nondescript, pale greenish color?
10. Has a blemish known as the great dark spot?
11. Has a fine iron oxide regolith?
12. Is most similar to Earth in its surface gravity?
13. Has the greatest mass?
14. Has the smallest diameter?
15. Have been visited by humans?
16. Has the strongest magnetic field?
17. Has rings?
18. Has sulfuric acid clouds?
19. Has the tallest mountain in the Solar System (and what is it)?
20. Has a day longer than its year?
21. Has been landed on most recently by spacecraft?
22. Experiences global dust storms?
23. Has a moon that rotates retrograde (and what is it)?
24. May be an escaped Kuiper object?
25. Was once thought to be a failed star?
26. Is heavily cratered?
27. Has moons which are likely candidates for life?
28. Was hit by a large comet in the last several years?
29. Is most oblate?
30. Has a central pressure 100 million times Earth's atmospheric pressure?
Now for the minor bodies.
1. Which body is an asteroid with its own orbiting asteroid?
2. Which moon has erupting volcanoes?
3. Which body is the largest asteroid?
4. Approximately how many known asteroids are there?
5. Approximately how many known Kuiper objects are there? What is the Kuiper belt?
6. How large is the Oort Cloud? What is the Oort Cloud?
7. Which moon was the first discovered after the Galilean satellites?
1. Rotates backwards?
2. Revolves backwards?
3. Rotates nearly on its side?
4. Have more than 10 moons?
5. Have only one moon?
6. Has an orbit with the greatest inclination to the ecliptic?
7. Is the furthest planet known to the ancients?
8. Has a largely methane atmosphere?
9. Has a nondescript, pale greenish color?
10. Has a blemish known as the great dark spot?
11. Has a fine iron oxide regolith?
12. Is most similar to Earth in its surface gravity?
13. Has the greatest mass?
14. Has the smallest diameter?
15. Have been visited by humans?
16. Has the strongest magnetic field?
17. Has rings?
18. Has sulfuric acid clouds?
19. Has the tallest mountain in the Solar System (and what is it)?
20. Has a day longer than its year?
21. Has been landed on most recently by spacecraft?
22. Experiences global dust storms?
23. Has a moon that rotates retrograde (and what is it)?
24. May be an escaped Kuiper object?
25. Was once thought to be a failed star?
26. Is heavily cratered?
27. Has moons which are likely candidates for life?
28. Was hit by a large comet in the last several years?
29. Is most oblate?
30. Has a central pressure 100 million times Earth's atmospheric pressure?
Now for the minor bodies.
1. Which body is an asteroid with its own orbiting asteroid?
2. Which moon has erupting volcanoes?
3. Which body is the largest asteroid?
4. Approximately how many known asteroids are there?
5. Approximately how many known Kuiper objects are there? What is the Kuiper belt?
6. How large is the Oort Cloud? What is the Oort Cloud?
7. Which moon was the first discovered after the Galilean satellites?
8. How many "extrasolar" planets are there? Which was the first discovered?
9. What is the status of Pluto and why was is "demoted" from planet status?
Additional - list anything you found interesting in your hunt. Or multiple things.
Tuesday, June 18, 2013
For next class
Quiz topics:
1. electromagnetic spectrum
2. the connection between speed, frequency and wavelength
3. the parts of a wave
4. the basics of how a lens works
5. the meaning of "spectrum" and what you viewed when looking through the diffraction glasses at the gas tubes
Things to consider for your brief planet presentation:
1. Origin of name
2. Comparison to Earth (mass, diameter, gravitation)
3. Does it have moons? Is there something interesting about its moons?
4. Period/time for one orbit
5. Distance (a) from Sun
6. Atmosphere?
7. What is the primary make-up of the planet?
8. Interesting features that can be seen on the planet
9. What you find particularly interesting or compelling about the planet
10. Anything really strange about your planet?
Please email me your notes before class. I can provide images and will post your notes to the blog.
1. electromagnetic spectrum
2. the connection between speed, frequency and wavelength
3. the parts of a wave
4. the basics of how a lens works
5. the meaning of "spectrum" and what you viewed when looking through the diffraction glasses at the gas tubes
Things to consider for your brief planet presentation:
1. Origin of name
2. Comparison to Earth (mass, diameter, gravitation)
3. Does it have moons? Is there something interesting about its moons?
4. Period/time for one orbit
5. Distance (a) from Sun
6. Atmosphere?
7. What is the primary make-up of the planet?
8. Interesting features that can be seen on the planet
9. What you find particularly interesting or compelling about the planet
10. Anything really strange about your planet?
Please email me your notes before class. I can provide images and will post your notes to the blog.
Wave notes
NOTES - THERE ARE 3 COMPLETE WAVES IN THE IMAGE ABOVE.
Frequency (f) - number of waves per second (in hertz, Hz)
Wavelength (l - this should really be lambda, the Greek symbol) - the length of one wave. It can also be thought of as the distance between 2 crests, 2 troughs or the distance from the start to finish of ONE wave.
Speed (v) - literally (in m/s), how fast one wave is traveling (relative to some background)
These 3 variables are related by this equation:
v = f l
That is, speed equals frequency times wavelength. With light waves, the speed is constant - it's the speed of light in a vacuum (3 x 10^8 m/s, or 186,000 miles/second).
Since the speed is constant, as the wavelength goes UP, the frequency goes DOWN. Or the other way around, if the frequency goes UP, the wavelength goes DOWN.
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