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In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo

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In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo  [#permalink]

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New post Updated on: 25 Sep 2019, 03:38
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In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Boornazian, a mathematician in Boston, concluded that the sun is contracting at a considerable rate, based on daily measurements of the sun’s image. They estimated the reduction of the sun’s horizontal diameter to be about two seconds of arc, or about 0.1 percent, per century. These findings sparked renewed debate over solar measurement and the possibility that our sun may be shrinking.

Heliologists contend that the brilliance of the sun’s disk, and the imperfect and variable transparency of the earth’s atmosphere, make observations from the earth’s surface unreliable. A better source of data regarding solar shrinkage is the duration of total solar eclipses, while a second statistically independent check is provided by the time the planet Mercury is visible against the solar disk. These observations allow a monitoring of changes in the sun’s diameter at reasonably regular intervals back to about the start of the 18th century, or roughly twice the number of years covered by the data used by Eddy and Boornazian.

When the observations of total solar eclipses over the past three centuries are analyzed in conjunction with the evidence of the transits of Mercury, the data indicate only a negligible change in the sun’s diameter. The percentage of decrease per century has been calculated to be only 0.007, with a 0.0008 percent margin of error.

1. The author argues that Eddy and Boornazian have

a. misrepresented experimental results in order to gain support for their conclusions

b. incorrectly surmised that the sun's diameter is independent of Mercury's orbit

c. probably drawn an incorrect conclusion due to their reliance on unreliable data

d. made several noteworthy breakthroughs in the field of solar measurement

e. wilfully ignored the existence of data pertaining to the duration of solar eclipses



2. According to the author, evidence that the sun is shrinking only at a negligible rate is based on

I. measurement of the length of solar eclipses
II. measurement of the time during which Mercury can be observed crossing the sun's path
III. daily measurements of the sun's image

a. I only
b. II only
c. III only
d. I and II only
e. I, II and III



3. It can be inferred from the passage that all of the following cast doubt on Eddy and Boornazian's conclusion EXCEPT

a. the non-uniformity of atmospheric clarity

b. the calculations used to determine the sun's horizontal diameter

c. atmospheric distortion even during periods of clear skies

d. the sheer intensity of the sun's radiance

e. the comparatively brief period of time their study covers



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Originally posted by AkshdeepS on 15 Jul 2017, 00:53.
Last edited by SajjadAhmad on 25 Sep 2019, 03:38, edited 2 times in total.
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Re: In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo  [#permalink]

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New post 15 Jul 2017, 03:33
1
1. The author argues that Eddy and Boornazian have

a. misrepresented experimental results in order to gain support for their conclusions
b. incorrectly surmised that the sun's diameter is independent of Mercury's orbit
c. probably drawn an incorrect conclusion due to their reliance on unreliable data
d. made several noteworthy breakthroughs in the field of solar measurement
e. wilfully ignored the existence of data pertaining to the duration of solar eclipses


2. According to the author, evidence that the sun is shrinking only at a negligible rate is based on

I. measurement of the length of solar eclipses
II. measurement of the time during which Mercury can be observed crossing the sun's path
III. daily measurements of the sun's image


a. I only
b. II only
c. III only
e. I and II only
f. I, II and III
Only I and II is used to support that sun is shrinking at a negligible rate

3. It can be inferred from the passage that all of the following cast doubt on Eddy and Boornazian's conclusion EXCEPT

a. the non-uniformity of atmospheric clarity
b. the calculations used to determine the sun's horizontal diameter
c. atmospheric distortion even during periods of clear skies
d. the sheer intensity of the sun's radiance
e. the comparatively brief period of time their study covers
Author never questioned calculations, but input data of those calculations.
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Re: In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo  [#permalink]

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New post 08 Oct 2018, 02:17
can anyone explain how to eliminate Option D in the 3rd question.
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Re: In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo  [#permalink]

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New post 08 Oct 2018, 06:30
2
P1 - a theory is given by 2 guys.
P2 - a flaw in theory and how to improve.
P3 - final verdict far less then estimation.

1. The author argues that Eddy and Boornazian have

c. probably drawn an incorrect conclusion due to their reliance on unreliable data - yes

rest all the answer are too broad.
--------------------------------------------------
2. According to the author, evidence that the sun is shrinking only at a negligible rate is based on
P3
I. measurement of the length of solar eclipses - y
II. measurement of the time during which Mercury can be observed crossing the sun's path - y
III. daily measurements of the sun's image - not mentioned.

a. I only
b. II only
c. III only
d. I and II only
e. I, II and III
----------------------------------------------------
3. It can be inferred from the passage that all of the following cast doubt on Eddy and Boornazian's conclusion EXCEPT

a. the non-uniformity of atmospheric clarity - "the imperfect and variable transparency of the earth’s atmosphere"
b. the calculations used to determine the sun's horizontal diameter - not mentioned
c. atmospheric distortion even during periods of clear skies - "the imperfect and variable transparency of the earth’s atmosphere"
d. the sheer intensity of the sun's radiance - "the brilliance of the sun’s disk"
e. the comparatively brief period of time their study covers - as it mentioned in P2, they must observed for a longer duration.

MaheshDuggirala - i have tried to explain Q3, let me know if you need more clarity.
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Re: In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo  [#permalink]

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New post 08 Oct 2018, 06:47
3. It can be inferred from the passage that all of the following cast doubt on Eddy and Boornazian's conclusion EXCEPT

a. the non-uniformity of atmospheric clarity---the imperfect and variable transparency of the earth’s atmosphere Eliminated

b. the calculations used to determine the sun's horizontal diameter

c. atmospheric distortion even during periods of clear skies---the imperfect and variable transparency of the earth’s atmosphere Eliminated

d. the sheer intensity of the sun's radiance----- the brilliance of the sun’s disk (eliminated )

e. the comparatively brief period of time their study covers

stuck between B and E.Kindly anyone help me in eliminating Answer E
AkshdeepS,workout--help me
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Re: In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo  [#permalink]

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New post 08 Oct 2018, 06:56
1
teja@6091 wrote:
3. It can be inferred from the passage that all of the following cast doubt on Eddy and Boornazian's conclusion EXCEPT

a. the non-uniformity of atmospheric clarity---the imperfect and variable transparency of the earth’s atmosphere Eliminated

b. the calculations used to determine the sun's horizontal diameter

c. atmospheric distortion even during periods of clear skies---the imperfect and variable transparency of the earth’s atmosphere Eliminated

d. the sheer intensity of the sun's radiance----- the brilliance of the sun’s disk (eliminated )

e. the comparatively brief period of time their study covers

stuck between B and E.Kindly anyone help me in eliminating Answer E
AkshdeepS,workout--help me


Lets observe following lines.
last sentence of P2 - roughly twice the number of years covered by the data used by Eddy and Boornazian.
or 1st sentence of P3 - When the observations of total solar eclipses over the past three centuries are analyzed

we can term for a longer duration observation in final study. This way we can eliminate E. B is the best answer.
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“Once you’ve eliminated the impossible, whatever remains, however improbable, must be the truth.”

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Re: In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo  [#permalink]

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New post 08 Oct 2018, 14:15
MaheshDuggirala wrote:
can anyone explain how to eliminate Option D in the 3rd question.


You can eliminate choice D in question 3 by referring to the first sentence of the 2nd paragraph.


Heliologists contend that the brilliance of the sun’s disk, and the imperfect and variable transparency of the earth’s atmosphere, make observations from the earth’s surface unreliable.

"The brilliance of the sun's disk", refers to the intensity of the sun's radiance.
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Re: In 1979, John A. Eddy of the High Altitude Observatory and Aram A. Bo   [#permalink] 08 Oct 2018, 14:15
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