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# Before the 1920s, there was a long-standing debate about the nebulae

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Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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Updated on: 09 Sep 2019, 04:56
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New Project RC Butler 2019 - Practice 2 RC Passages Everyday
Passage # 219, Date : 21-Jul-2019
This post is a part of New Project RC Butler 2019. Click here for Details

Before the 1920s, there was a long-standing debate about the nebulae that are visible between galaxies. When viewed from a terrestrial telescope, they appear to be gas and dust emissions. In 1927, however, the team of Edwin Hubble theorized that these nebulae are actually star systems.

The bulk of Hubble’s evidence came from the analysis of gamma rays in the range of invisible light called 10^19 Hz. Hubble theorized that the arrival of these rays onto the earth’s surface was consistent with the most up-to-date knowledge about the collapse of a distant star system called 7.8ART. Existing data reveals that 7.8ART went Supernova roughly 27 billion years ago. Hubble’s team argued that the arrival of gamma rays in the 10^19 Hz spectrum are consistent with star materials having been ejected from the region of 7.8ART at a corresponding time in galactic history.

There continues to be some doubt surrounding Hubble’s theory, however. Some scientists point out that the origins of gamma rays landing on earth today are not easily determined, because the expanding nature of the universe means that the radiation has traveled farther than Hubble’s calculations suggest. However, Hubble’s team did provide an answer to that objection by stating that the expanding universe theory applies mainly to its edges, and not within its center, which is the previous home of 7.8ART.

The skeptics’ most powerful objection to Hubble’s hypothesis is the argument that had the rays traveled for 27 billion years, it is unlikely that their trajectory would have been linear, due to the curvature of the known universe. Hubble’s team, however, pointed out that the curvature of the universe has no measurable effect on the path taken by gamma rays, because they are not affected by the gravitational pull of star systems in the same way as are celestial bodies.
1. The primary purpose of the passage is to

a. propose new methods for studying the ages of ancient star systems
b. rewrite a hypothesis regarding the trajectory of gamma rays
c. reconcile competing hypotheses regarding the expansion of the universe
d. evaluate a new hypothesis regarding the life cycle of 7.8ART
e. describe a controversy surrounding 7.8ART and its origins

2. The passage suggests that Hubble’s team would agree with which of the following regarding the gamma rays that land on earth today?

a. These rays are not likely to have originated on 7.8ART.
b. These rays have probably been on earth for more than 27 billion years.
c. These gamma rays are unlikely to have been produced during a Supernova.
d. It is impossible to determine the precise distance traveled by gamma rays that originate at the edge of the universe.
e. These gamma rays are likely to accelerate as they approach the center of the universe.

3. The passage asserts which of the following about the claim that 7.8ART went Supernova roughly 27 billion years ago?

a. It was initially hypothesized by Edwin Hubble.
b. It is not widely disputed.
c. It has been questioned by some of Hubble’s critics.
d. It has been refuted thanks to recent work on gamma rays.
e. It is incompatible with the fact that the earth is now receiving gamma rays in the 1019 Hz frequency spectrum.

Originally posted by TheFlash on 09 May 2019, 06:29.
Last edited by SajjadAhmad on 09 Sep 2019, 04:56, edited 3 times in total.
Updated - Complete topic (473).
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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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23 Jul 2019, 20:30
I have taken 6 minutes (3 minutes to read the passage and 3 minutes for 3 questions), got last question wrong, i didn't understand the logic behind the correct answer choice. generis please gave us your precious time to explain this passage.

Thanks and regards
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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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23 Jul 2019, 20:59
2

The answer to question#3 can be given after reading the 2nd para closely.

Quote:
The bulk of Hubble’s evidence came from the analysis of gamma rays in the range of invisible light called 10^19 Hz. Hubble theorized that the arrival of these rays onto the earth’s surface was consistent with the most up-to-date knowledge about the collapse of a distant star system called 7.8ART. Existing data reveals that 7.8ART went Supernova roughly 27 billion years ago. Hubble’s team argued that the arrival of gamma rays in the 10^19 Hz spectrum are consistent with star materials having been ejected from the region of 7.8ART at a corresponding time in galactic history.

question#3

Quote:
3. The passage asserts which of the following about the claim that 7.8ART went Supernova roughly 27 billion years ago?

Read the lines colored in blue. It says that existing data reveals that 7.8ART went Supernova roughly 27 billion years ago.
Now in the whole paragraph and even in the subsequent paragraphs their is no mention to counter this statement.

Quote:
a. It was initially hypothesized by Edwin Hubble.

No it was not hypothesized by him. He gathered existing data.

Quote:
b. It is not widely disputed.

Yes, this is something true because no counter has been made to the existing data in para#2.

Quote:
c. It has been questioned by some of Hubble’s critics.

NO, they did not question this but used this to tell about gamma rays.

Quote:
d. It has been refuted thanks to recent work on gamma rays.

Not refuted. Incorrect choice.

Quote:
e. It is incompatible with the fact that the earth is now receiving gamma rays in the 1019 Hz frequency spectrum.

Wrong choice . It is not incompatible.

IMO B.
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24 Jul 2019, 08:37
Why C is the correct answer for Q1?

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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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24 Jul 2019, 09:21
1
Explanation

1. The primary purpose of the passage is to

Difficulty Level: 750

Explanation

POE is useful in this question. Take a look at answer choices

(A) is wrong because there is no new method has been purposed or discussed in the passage

(B) is wrong because hypothesis are discussed but not rewriting is available

(C) is correct because first para provide one hypothesis second para provide another hypothesis and in subsequent paragraphs these hypothesis compete with each other and reconciled in the last paragraph so this answer choice truly click the main purpose

(D) This information has been discussed in the passage but in fraction. It didn't click the main purpose of the passage

(E) Same as D It didn't click the main purpose of the passage

Hope it helps

Srija221 wrote:
Why C is the correct answer for Q1?

Posted from my mobile device

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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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24 Jul 2019, 20:59
Can anyone please explain the passage map of this passage?

My passage map- 1st para- Introduction of Hubble's theory
2nd para- Evidence given by the Hubble's team against possible counter argument.
3rd para-same as 2nd para
4th para-same as 2nd para

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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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24 Jul 2019, 22:54
2
I have taken 6 minutes (3 minutes to read the passage and 3 minutes for 3 questions), got last question wrong, i didn't understand the logic behind the correct answer choice. generis please gave us your precious time to explain this passage.

Thanks and regards

I don't take notes in RC the way most people do.
I don't summarize paragraphs, though I did so here in "paragraph summaries" section.
I make a map, a flowchart.

I have provided both paragraph summary and my map in this post.
Questions 1, 2, and 3 follow.

You know, someone needs to figure out how to make these questions easier to answer. Formatting? /end rant
Speaking of rants, I don't rant enough. /almost end rant

I don't write sentences. I don't summarize paragraphs.
I make maps that resemble . . . flow charts.
I make boxes and circles. I draw arrows.

I use many fewer words than you see here. I use abbreviations.

Hope this analysis helps.
************************************************************
PASSAGE - paragraph summaries
P1 -- Visible clouds between galaxies seem to be composed of gas and dust [emissions?].
-- 1927: Hubble, theory: no. Nebulae are star systems

P 2 Most of Hubble's evidence:
Arrival time (age) of gamma rays on Earth is consistent with time of Supernova BART collapse. It exploded and ejected star material.

P 3 People doubt Hubble: gamma rays’ origins? Hard to know→ Expanding universe = Distance traveled is uncertain.
Hubble’s answer: “expanding universe” theory applies to edges of universe. BART was in center

P 4 Strongest objection to Hubble theory: gamma rays’ trajectory probably was not linear. Spacetime is curved. Age may not be 27 billion years.
Hubble’s answer: curved universe and gravity do not affect gamma rays.

*************************
MAPPING THE NEBULAE PASSAGE
My version of taking notes in RC.
If summarizing paragraphs works for you, do not change.

ROUGHLY: Paragraphs 1 and 2 are in blue, in the upper half of the page.

Paragraphs 3 and 4 are in two sets of statements in RED and GREEN, lower half of the page.
CRITICS:
HUBBLE

Attachment:

RC - nebulae - hubble - july 2019.jpg [ 64.96 KiB | Viewed 1503 times ]
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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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24 Jul 2019, 22:55
1
Question 1 The primary purpose of the passage is to

A). propose new methods for studying the ages of ancient star systems
B) rewrite a hypothesis regarding the trajectory of gamma rays
C) reconcile competing hypotheses regarding the expansion of the universe
D) evaluate a new hypothesis regarding the life cycle of 7.8ART
E) describe a controversy surrounding 7.8ART and its origins

Srija221 - here is an explanation for Q 1.
• see my map. Basic outline:
Subject → background
→→→Hubble theory and evidence
Objection
Objection

• look at the verbs

This passage does not
A) propose new methods or
B) rewrite a hypothesis
Eliminate A and B

• look at subject matter

D) evaluate a new hypothesis - no new hypothesis mentioned
E) describe a controversy surrounding 7.8ART and its origins -
-- no new hypothesis mentioned. Eliminate D
-- controversy, yes, but not about BART and its origins.
The controversy is about nebulae and whether BART gamma rays could have reached Earth (and created star systems?).
BART's origin is not at issue.

• By POE, the answer is C: reconcile competing hypotheses regarding the expansion of the universe

Hmm. That answer does not look great initially.
-- This passage does seem to be reconciling two views
-- but initially I was not happy with "expansion of the universe." I dug a little deeper. Expansion of the universe may or may not be the central topic, but the author does spend a lot of time talking about two views of exactly that.

The main clash of viewpoints does not seem to be about the expansion of the universe.
The central quarrel, though, does involve the expansion of the universe.

Passage?
Objection to Hubble, #1: Hubble's evidentiary gamma rays traveled farther than 27 billion years b/c of expanding universe
Hubble's answer to #1: Expansion of universe applies to edges of universe. BART was in the center.

Objection to Hubble, #2: 27 billion years is not accurate. Spacetime is curved. Gamma rays did not travel in linear fashion.
Hubble's answer to #2: Curvature of spacetime and gravitational have no measurable effect on gamma rays

Option (C) is better than I thought and quite a bit better than the other options.
There IS an argument about the expansion of the universe going on, albeit in the context of a debate about the composition of nebulae between galaxies, about which we do not hear much more.

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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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24 Jul 2019, 22:55
2
2. The passage suggests that Hubble’s team would agree with which of the following regarding the gamma rays that land on earth today?

Quote:
A. These rays are not likely to have originated on 7.8ART.

Opposite. Hubble team would DISAGREE:
7.BART is precisely where the gamma rays originated according to Hubble's team.

Passage: ... 7.8ART went Supernova roughly 27 billion years ago. Hubble’s team argued that the arrival of gamma rays in the 10^19 Hz spectrum are IS consistent with star materials having been ejected from the region of 7.8ART at a corresponding time in galactic history.

Quote:
B. These rays have probably been on earth for more than 27 billion years.

No. Hubble team would DISAGREE.
Hubble team, as just mentioned in para 2, says that gamma rays' age is consistent with BART going Supernova 27 B years ago.
Critics say that rays are probably older because of expanding universe and curved spacetime. Hubble has an answer for both.

Quote:
C. These gamma rays are unlikely to have been produced during a Supernova.

Opposite: Hubble team theorized that the gamma rays on Earth matched the time of . . . the explosion of a Supernova.

Passage: Existing data reveals that 7.8ART went Supernova roughly 27 billion years ago. Hubble’s team argued that the arrival of gamma rays in the 10^19 Hz spectrum are consistent with star materials having been ejected from the region of 7.8ART at a corresponding time in galactic history.

Quote:
D. It is impossible to determine the precise distance traveled by gamma rays that originate at the edge of the universe.

Yes, Hubble team would AGREE.
Critics: expanding universe means that radiation travels [gamma rays travel] farther than Hubble's calculations suggest.
Hubble: expanding universe theory applies [is true], but only at the edges of the universe. [Not at center. BART was at center.]
Hubble conceded the point about the expanding universe theory at the edges.
Expanding universe theory = hard to measure distance traveled. (The gamma ray is moving but space itself is expanding at the same time.)
Passage:
Some scientists point out that the origins of gamma rays landing on earth today arenot easily determined, because the expanding nature of the universe means that the radiation has traveled farther than Hubble’s calculations suggest.

Passage:Hubble’s team did provide an answer to that objection by stating that the expanding universe theory applies mainly to its edges.
Okay, so apply critics' observation to edges: universe expands as gamma rays travel, making distances hard to measure.
Quote:
E. These gamma rays are likely to accelerate as they approach the center of the universe.

Take one second to decide that this is a throwaway.
Not one mention of gamma rays traveling towards the center of the universe.
Hubble team says that expanding universe theory applies at edges, not at center.
(Things travel more slowly at the expanding edges. Counterpart: travel more swiftly at center?
Hubble: no. Expanding universe theory does not apply to center of universe.

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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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24 Jul 2019, 22:56
1
3. The passage asserts which of the following about the claim that 7.8ART went Supernova roughly 27 billion years ago?

Find the part of the passage that matters. Paragraph 2
[Hubble theorized that the arrival of these rays onto the earth’s surface] was consistent with the most up-to-date knowledge about the collapse of a distant star system called 7.8ART. Existing data reveals that 7.8ART went Supernova roughly 27 billion years ago. . . .

Quote:
A. It was initially hypothesized by Edwin Hubble.

No. Hubble theorized about gamma rays on Earth

Quote:
B. It is not widely disputed
.
Probably the answer. "Existing data" [as in, NOW] reveals that 7.BART went Supernova roughly 27 billion years ago.
Declarative statement.
No hedging. No qualifiers. No doubters.
Existing data reveals sounds conclusive and confident. Not disputed.

Quote:
c. It has been questioned by some of Hubble’s critics.

No. Hubble's critics question whether the gamma rays on Earth got here from BART. No more than that issue.

Quote:
d. It has been refuted thanks to recent work on gamma rays.

Two seconds to read: bye. No mention of recent work on gamma rays.
No refutation about when BART went Supernova. The objections are about the age of the gamma rays.

Quote:
e. It is incompatible with the fact that the earth is now receiving gamma rays in the 1019 Hz frequency spectrum.

REJECT. Simple maps are good. I leave off details such as this one.

1019 Hz frequency spectrum? (This sounds like some horrible new app for my phone.)

Think: No, this logic is exactly backwards. The critics think that the gamma rays are not necessarily consistent with BART's having gone Supernova.
The critics do not dispute the Supernova. They dispute whether and how gamma rays on earth can be explained by the explosion of BART.
No one objects to: BART went supernova 27 billion years ago. That fact is not "incompatible" with anything.

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Re: Before the 1920s, there was a long-standing debate about the nebulae  [#permalink]

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24 Jul 2019, 23:09
1
Srija221 wrote:
Can anyone please explain the passage map of this passage?

My passage map- 1st para- Introduction of Hubble's theory
2nd para- Evidence given by the Hubble's team against possible counter argument.
3rd para-same as 2nd para
4th para-same as 2nd para

Posted from my mobile device

Srija221 wrote:
Can anyone please explain the passage map of this passage?

My passage map- 1st para- Introduction of Hubble's theory
2nd para- Evidence given by the Hubble's team against possible counter argument.
3rd para-same as 2nd para
4th para-same as 2nd para

Posted from my mobile device

Srija221 , I mapped the passage in two ways in my post, HERE

I would recommend pasting the passage into a document and printing it as you read answers.
It is very difficult to keep a passage organized without being able to see it.

The third and fourth paragraphs are not the same as the second paragraph.
The third and fourth paragraphs are not the same as each other.

On my drawing (which is a slightly expanded version of what I actually wrote), paragraphs 3 and 4 are in RED and GREEN, lower left.

Hope that helps.
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Re: Before the 1920s, there was a long-standing debate about the nebulae   [#permalink] 24 Jul 2019, 23:09
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