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According to most scientists, the universe began approximat

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According to most scientists, the universe began approximat [#permalink] New post 27 May 2017, 08:17
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71% (06:26) correct 28% (10:06) wrong based on 7 sessions


According to most scientists, the universe began approximately 10 to 15 billion years ago and has been expanding ever since. This theory, known as the Big Bang theory, is the fairly direct result of Hubble’s law, which states that objects farther away from Earth are receding faster than those closer. This expansion implies a singular point which all matter is expanding from.

Complicating the scientific explanation is that the Big Bang cannot be thought of as an explosion from some identifiable source—rather, space and time were created in the Big Bang. Furthermore, the relationship between distance and speed is not precisely linear. So, if one were to think of galaxies as particles created in a big bang, these galaxies have both a local component of motion, as well as playing a role in the overall expansion of the universe.

A further complication is that galactic distances are so great that galactic motion, even if the galaxies are moving at incredible speeds, is difficult to observe. Scientists must, therefore, rely on a “standard candle,” an object of known brightness within the galaxy they wish to observe. Using the inverse square law, scientists can then measure how far that galaxy is away from our own. For instance, suppose a supernova in galaxy A appears one hundred times as bright as one in galaxy B. By the inverse square law, galaxy B is ten times farther away than galaxy A, assuming, of course, that distance is the only factor affecting brightness.
It can be inferred from the sentence highlighted in the passage that a standard candle is useful to scientists for which of the following reasons?

A) Standard candles do not have their own locus of motion.
B) Standard candles more reliably adhere to the law of inverse squares than do other supernovas.
C) Only standard candles provide a known measure of brightness.
D) Knowledge of an object’s brightness allows scientists to measure the speed at which the object is moving toward Earth.
E) Knowledge of an object’s brightness allows scientists to accurately measure its distance from Earth.

[Reveal] Spoiler: OA
E


Consider each of the choices separately and select all that apply.


According to the passage, if two astronomical objects of differing distances from Earth were observed, which of the following would be true of the object closer to Earth?

❑ It would not be as bright as the object farther from Earth.

❑ It would be younger than the object farther from Earth.

❑ It would be traveling away from the Earth more slowly than the farther object.

[Reveal] Spoiler: OA
C


It can be inferred from the passage that a standard candle may not provide an accurate measure of distance if

A) the galaxy being measured is moving too quickly
B) interstellar dust makes the object measured appear dimmer than it really is
C) if the galaxy being measured has a local component of measurement
D) the particles being measured do not completely accord with a linear motion
E) the galaxies being measured move at different speeds

[Reveal] Spoiler: OA
B


According to the passage, if two supernovas are observed and one of those supernovas is brighter than the other, scientists can conclude that

A) the brighter supernova is moving closer to our galaxy at a higher speed
B) the precise location of the supernova is measurable
C) the brighter supernova may be closer to our own galaxy
D) the brighter supernova is farther away from Earth by a distance that is roughly inversely proportional to the dim supernova
E) the distance between the supernovas and our own galaxy is inversely proportional

[Reveal] Spoiler: OA
C


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Re: According to most scientists, the universe began approximat [#permalink] New post 19 Jan 2019, 20:27
Any explanation please?
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Re: According to most scientists, the universe began approximat [#permalink] New post 22 Jan 2019, 23:34
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1) The author mentions the “Prozac lag” primarily in order to:

The author introduces a new theory neurogenesis in first paragraph.He also said that the new theory could be used for research in new applications. In second paragraph he goes on to describe a new specific application where neurogenesis could be used to describe Prozac lag. Hence option B serves as best answer for this question.

2) In the second paragraph, select the sentence in which the author describes an unexpected observation.
" However, patients suffering from depression only begin to experience mood elevation weeks after beginning treatment."
The author says that after antidepressant there should be instant mood elevation. However this does not happen and then describes what happens otherwise. This sentence with however is thus unexpected and is our answer for this question.
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Re: According to most scientists, the universe began approximat [#permalink] New post 23 Jan 2019, 19:14
Could someone please provide an explanation for the third question?

It can be inferred from the passage that a standard candle may not provide an accurate measure of distance if

A) the galaxy being measured is moving too quickly
B) interstellar dust makes the object measured appear dimmer than it really is
C) if the galaxy being measured has a local component of measurement
D) the particles being measured do not completely accord with a linear motion
E) the galaxies being measured move at different speeds
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Re: According to most scientists, the universe began approximat [#permalink] New post 29 Jan 2019, 19:52
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Explanation For Question 3)

It can be inferred from the passage that a standard candle may not provide an accurate measure of distance if

A) the galaxy being measured is moving too quickly
B) interstellar dust makes the object measured appear dimmer than it really is
C) if the galaxy being measured has a local component of measurement
D) the particles being measured do not completely accord with a linear motion
E) the galaxies being measured move at different speeds

Last line says "...assuming, of course, that distance is the only factor affecting brightness."
In other words, if ANYTHING other than distance is affecting the brightness then you wouldn't get an accurate measurement.
The only answer choice which suggests brightness is the second one.
Re: According to most scientists, the universe began approximat   [#permalink] 29 Jan 2019, 19:52
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According to most scientists, the universe began approximat

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