Term
What is the cause of the most basic and obvious changes in the appearance of celestial objects? |
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Definition
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Term
What is the celestial sphere, what are its features, and why is it useful? |
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Definition
Where the stars and constellation lie on this, which surround earth. Features: North Celestial Pole, South Celestial Pole, Celestial Equator, and Ecliptic(path sun follows). It allows us to map the sky as seen from Earth. |
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Term
Why do we see different stars at night at different times of the year? |
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Definition
The constellations you see depend on your latitude. The Sun's apparent location along the ecliptic determines which constellations we see at night. |
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Term
What causes the Earth's seasons? |
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Definition
Earth's rational tilt relative to the Sun. The tilt of the Earth's axis causes sunlight to fall directly on Earth at different times of the year. |
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Term
Why does the amount of daylight change throughout the year? |
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Definition
The steeper sunlight angle formed as Earth rotates means the Sun follows a longer and higher path through the sky, giving that hemisphere longer daylight. |
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Term
What are solstices and equinoxes? |
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Definition
Solstices-two point at which sunlight becomes most extreme for the two hemispheres. Equinoxes- two points at which the hemispheres are equally illuminated. |
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Term
What are the four solstices and equinoxes? When do they occur? |
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Definition
Summer Solstice- June, Winter Solstice- December, Spring Equinox- March, Fall Equinox- September |
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Term
What is precision and what are its effects? |
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Definition
A gradual wobble that changes the orientation of Earth's axis in space. Takes about 26,000 years, gradually changing where the axis points in space. |
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Term
What causes the Moon to appear in phases? |
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Definition
The phase of the moon depends on its position relative to the sun as it orbits Earth. |
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Term
How much of the moon can we see from Earth? |
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Definition
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Term
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Definition
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Term
When are tides strongest and weakest? |
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Definition
Strongest- In the spring (sun, moon reinforce) Weakest- neap (sun, moon interfere) |
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Term
What are tides on Earth doing to the Earth's rotation and to the Moon's orbit around us? |
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Definition
Causes Earth's rotation to slow, friction of water mixed with faster rotation Earth causes the tides to lead the moon. |
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Term
Which of our largest time divisions is not "natural", that is, not based on some orbital/rotational characteristic? |
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Definition
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Term
Why do planets sometimes appear to have retrograde motion? |
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Definition
When planets temporarily revers their apparent motion through the stars |
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Term
If the Earth's rotation was not tilted relative to the Sun, what would be the consequences? |
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Definition
Equal day and night all over, every day an equinox. No seasons. The sun would be overhead at noon only along the equator. |
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Term
How do sciences operate and evolve? |
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Definition
Interplay between theory and observations |
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Term
What is the most important characteristic of a scientific theory, distinguishing it from other kinds of theories? |
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Definition
Most valued theories make testable predictions |
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Term
What causes lunar and solar eclipses? |
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Definition
Lunar- occurs when Earth lies directly between the sun and the moon, so that Earth's shadow falls on the Moon. Solar- occurs when the Moon lies directly between the Sun & Earth, so that the Moon's shadow falls on Earth. |
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Term
What phase must the moon be in for a lunar eclipse to occur? for a solar eclipse? |
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Definition
lunar- full moon near node, solar- new moon near node |
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Term
Which kind of eclipses do we see most often? |
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Definition
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Term
Was Copernicus' heliocentric model of the Solar System more accurate than the contemporaneous descendant of Ptolemy's geocentric model? |
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Definition
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Term
How was Brahe able to compile the most accurate positions of astronomical objects? |
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Definition
Huge instruments, large lever arm |
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Term
Who used Brahe's accurate planetary positions to make a very accurate heliocentric model of the Solar System? |
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Definition
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Term
How did Galileo's Law of Inertia differ from Aristotle's? |
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Definition
Different masses fall at the same rate |
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Term
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Definition
an electromagnetic wave, but also comes in individual pieces(Photons). |
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Term
What are the wave-like behaviors of light? |
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Definition
Dual wave/particle nature. Reflection, refraction, diffraction, and interference |
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Term
What are the particle-like properties of light? |
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Definition
Photons (massless)- Individual pieces of light |
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Term
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Definition
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Term
What do E, m, c correspond to in E=mc^2? |
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Definition
E: the amount of potential energy, m: the mass of the object, c:speed of light |
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Term
What does E=mc^2 mean when applied to light? |
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Definition
The speed of lighht is about 300,00 km/s. All light travels through empty space at the same speed. |
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Term
What are the three kinds of light spectra? |
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Definition
1) Continuous Spectrum- the spectrum of an ordinary(incadescent) light bulb is a rainbow of color. Broad range with wavelength's without interruption. 2) Emission Line Spectrum- thing, low density cloud of gas emits light only at specific wavelengths that depends on its composition and temperature. Bright emission lines against a black background. 3) Absorption Line Spectrum- cloud of gas lies between us and the light bulb. Cloud absorbs lights of specific wavelength's, so the spectrum shows dark absorption lines over rainbow background. |
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Term
Why do astronomers want telescopes to be large? There are two main reasons. |
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Definition
They collect more light, so can see fainter and deeper. They can resolve angular structures. |
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Term
What is the difference between refracting and reflecting telescopes? |
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Definition
Reflecting use mirrors and refracting use lenses. |
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Term
Why are some telescopes sent into space as satellites? |
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Definition
Some telescopes need to be above the Earth's atmosphere: Our atmosphere absorbs many wavelengths of light, atmosphere turbulence blurs images from space |
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