Term
| Define the following terms, as they relate to the topic of time: sequence, duration, rate, cyclicity. |
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Definition
| Sequence: the order in which events happen. Duration: the amount of time that passes during or between events. Rate: how many cycles of a periodic behavior occur within a given time frame. Cyclicity: the characteristic of repetition. |
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Term
| What two characteristics must be possessed by any object or process that can be used as a clock? |
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Definition
| It must be based on a rate constant process, and the number of “ticks” must be recorded somehow. |
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Term
| What is a rate constant process? |
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Definition
| A cyclic process where the duration of time between the beginning of successive cycles is constant. |
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Term
| What are the three major scales of nature? |
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Definition
| Atomic/subatomic, scale of everyday, scale of cosmos. |
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Term
| “Your...intuition is unavoidably based on _____________________________.” |
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Definition
Your personal
experiences in the scale of the everyday.
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Term
| What does the term “deep time” refer to? |
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Definition
The vast expanses of time that have elapsed since the formation of the Earth
and/or the formation of the universe.
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Term
| Describe Albert Einstein's formal educational experience. |
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Definition
He was, to put it lightly, a somewhat less-than-ideal
student.
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Term
Complete the phrase: “the special theory of relativity states that at speeds approaching the speed of light,
_________.”
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Definition
| Both space and time contract. |
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Term
| Why does relativity seem strange to us? |
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Definition
Because we do not experience speeds close to the speed of light in our
everyday life. In other words, we haven't developed the intuition!
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Term
Complete the phrase: “The only way to truly understand [electrons] is to account for both their ________ and
_______ properties.”Complete the phrase:
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Definition
| both particle and wave-like |
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Term
If we used a football field (100 yards) to represent the entire 4.6 billion year history of the Earth, where would we
find the dinosaurs?
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Definition
| About 2-4 yards from the present day. |
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Term
How long does it take light to travel 100 light years?
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Definition
100 years, because one light year is, by definition, the distance
light will travel through empty space in one year. |
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Term
| If a star 50 light years from the Earth were to explode today, how soon would we know about it? |
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Definition
| 50 years from now, because it takes light 50 years to travel the distance between the start and the Earth. |
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Term
| “all celestial bodies that are observable with the naked eye appear to move ________________.” |
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Definition
| In circles around the Earth. |
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Term
| The geocentric model is also known as what? |
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Definition
| The Earth-centered model. |
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Term
What is retrograde motion? |
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Definition
The way that the planets appear to occasionally reverse direction and move backwards
relative to the background of stars. |
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Term
| Retrograde motion was accounted for in the geocentric model by adding what to the model? |
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Definition
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Term
| Galileo observed the phases of what planet? |
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Definition
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Term
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Definition
The planet's (or other object's) position relative to the source of light (the Sun) and the observer
(people on the Earth). |
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Term
| Was the observation of these phases consistent with the geocentric model? |
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Definition
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Term
| The model proposed by Nicolaus Copernicus was called what? |
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Definition
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Term
| What two major ideas that surfaced in the early 20th century completely changed the way we view nature? |
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Definition
| Relativity and quantum mechanics. |
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Term
| Complete the phrase “...experiment after experiment indicates that relativity is ______________.” |
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Definition
| A valid description of the way nature works. |
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Term
| What is the Doppler shift? |
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Definition
| The way that the pitch of a sound (or the color of light) varies when the observer is moving with respect to the source (or vice versa). |
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Term
| Why do we not observe the Doppler shifting of light in our everyday experience? |
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Definition
| Because everyday speeds are so very, very small compared to the speed of light. |
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Term
| Complete the phrase: “This set of wavelengths, called the emission spectrum, is like ______________.” |
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Definition
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Term
| How many of the galaxies we have observed have light that is shifted to the red? |
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Definition
| Practically all of them. The only exceptions are the very nearby galaxies in our local cluster, which are being drawn together by gravity. |
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Term
| How does the redshift of nearby galaxies compare to that of distant galaxies? |
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Definition
| The more distant the galaxy, the greater the redshift. |
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Term
| The further away a galaxy is from us, the ________________ it is moving away from us. |
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Definition
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Term
What is the cosmic microwave background, and how is it explained in the Big Bang theory? |
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Definition
Everywhere we look in space, beyond the most distant galaxies, we find microwaves. This is the cosmic microwave background. According to
the big bang theory, these microwaves (which are very far away, and therefore existed long ago) are radiation from just before the moment that the universe became transparent to visible light. This radiation would have been gamma rays, but the space those waves occupy has been expanding for 13.7 billion years, effectively stretching them out into microwaves. |
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Term
| The visible universe is composed primarily of which element? |
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Definition
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Term
| As the universe expands, what happens to its temperature? |
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Definition
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Term
3. The planets, as observed from the Earth, exhibit retrograde motion.
4. The Moon exhibits a full set of phases.
5. The planet Venus exhibits a full set of phases.
6. The Sun is at the center of the solar system.
7. The Earth is at the center of the Universe.
8. Things that look like other galaxies exist.
9. There are microwaves arriving at the Earth from space.
10. Distant galaxies have a greater red-shift than nearby galaxies.
11. Nearby stars exhibit parallax motion.
12. The universe is predominantly made of hydrogen and helium.
13. The universe is expanding.
14. The cosmic microwave background is leftover heat from the early universe.
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Definition
3) O
4) O
5) O
6) I
7) I
8) O
9) O
10) O
11) O
12) I
13) I
14) I |
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Term
| Complete the phrase: “A fraction of a second after the beginning, the universe was a hot, formless soup of ________.” |
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Definition
| The most elementary particles: quarks and leptons. |
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Term
| Complete the phrase: “As cosmologists imagine rewinding the clock, the universe becomes ______, _______, ______ and ________.” |
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Definition
| Denser, hotter, more extreme, and simpler. |
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Term
| What celestial bodies preceded the existence of the first galaxies? |
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Definition
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Term
Compared to our Sun (which has a mass of one solar mass), how large were the first stars? |
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Definition
About 100 times larger
(100 solar masses). |
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Term
| How long after the big bang did the first atomic nuclei form? |
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Definition
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Term
| How long after the big bang did the first atoms form? |
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Definition
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Term
What percent of the total energy density of the universe is ordinary matter, according to our current model? |
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Definition
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Term
What two independent observations are used as the primary basis for this conclusion? |
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Definition
Abundance of deuterium and
the analysis of the cosmic microwave background. |
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Term
What do scientists believe the universe was composed of earlier than a microsecond after the big bang? |
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Definition
Quarks,
leptons, and force carriers. |
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Term
Complete the phrase: “The identity of dark matter remains _________, but its existence is ____________.” |
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Definition
Unclear;
very well established. |
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Term
| Name the two dark matter candidates from particle physics. |
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Definition
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Term
| How much antimatter is there in the universe today? |
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Definition
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Term
Complete the phrase: “As cosmologists try to go even further to understand the beginning of the universe itself, our
ideas become _______________.”
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Definition
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Term
Which two major theories in contemporary physics are inconsistent with each other? |
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Definition
General relativity and quantum
mechanics. |
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Term
What, according to the article, are two of the biggest questions in all of science? |
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Definition
What happened before the big bang?
Why are the laws of physics as they are? |
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Term
Complete the phrase: “If the disconnected subuniverses are truly incommunicado, we _________________.” |
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Definition
Cannot
hope to test their existance. |
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Term
| According to the reading, the universe is approximately how old? |
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Definition
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