Events & Promotions
|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Nov 2007:30 AM PST
-08:30 AM PST
Learn what truly sets the UC Riverside MBA apart and how it helps in your professional growth
Nov 2001:30 PM EST
-02:30 PM IST
Learn how Kamakshi achieved a GMAT 675 with an impressive 96th %ile in Data Insights. Discover the unique methods and exam strategies that helped her excel in DI along with other sections for a balanced and high score.
Nov 1912:30 PM EST
-01:30 PM EST
Learn how Keshav, a Chartered Accountant, scored an impressive 705 on GMAT in just 30 days with GMATWhiz's expert guidance. In this video, he shares preparation tips and strategies that worked for him, including the mock, time management, and more
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2407:00 PM PST
-08:00 PM PST
Full-length FE mock with insightful analytics, weakness diagnosis, and video explanations!
Nov 2510:00 AM EST
-11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.
16 Apr 2011, 21:14
Kudos
Bookmarks
While popular science tends to favor extragalactic astronomical research that emphasizes current challenges to physics, such ass the existence of dark matter, dark energy, and Cosmic inflation, significant research continues to take place in the field of planetary astronomy on the formation of our own solar system. In early attempts to explain this phenomenon, astronomers believed in the encounter, or"rogue star", hypothesis, which suggests that matter was tidally stripped away from our sun as a larger star passed within a gravitationally-significant distance some billions of years ago. The encounter hypothesis postulates that after being stripped away, the matter cooled as it spun father from the sun, and formed planets with their own centers of gravity. This hypothesis conveniently accounts for the fact that all planets in the solar system revolve in the same direction around the sun; it is also consistent with the denser planets remaining closer to the sun, and the more gaseous planets traveling further away.
The encounter hypothesis explained the phenomenon sufficiently enough that it allowed scientists to focus on more immediately rewarding topics in physics and astronomy for most of the first half of the 20th century. Closer investigation, however, found several significant problems with the encounter hypothesis, most notably that the hot gas pulled from the sun would not condense to form dense planets, but rather would expand in the absence of a central, gravitational force. Furthermore, the statistical unlikelihood of a star passing in the (astronomically speaking) short time of the sun's existence required scientists to abandon the encounter hypothesis in search of a new explanation. Soon after astronomers formed a second theory, the nebular hypothesis, which submits that the solar system began as large cloud of gas containing the matter that would form the sun and its orbiting planets. The nebular hypothesis suggests that angular momentum would have morphed the nebular into a protoplanetary disc, with a dense center that generated intense heat and pressure, and a cooler, thinner mass that revolved around it. The central mass would have continued to build in density and heat, forming the sun, while the centrifugal force around the disc's edge kept smaller masses from being pulled in to the sun; those masses, upon cooling, would break off to become planets held in orbit by the competing gravitational force of the sun and centrifugal force of their orbital inertia.
The nebular hypothesis, however well it explained the sun's formation, remained problematic in its ability to account for the formation of several planets with differing physical and chemical properties. Encouraged by their advance toward a provable hypothesis for the solar system, scientists have recently come to adopt a third hypothesis, the protoplanet hypothesis. This currently accepted theory holds that the gaseous cloud that would form the solar system was composed of particles so cold that even the heat of the forming sun could not significantly impact the temperature of the outer reaches of the cloud. Gas in the inner region, within what scientists refer to as the frost line, was quickly either burned or dispersed, leaving a small amount of metallic matter, such as nickel and iron, to form the inner planets. Such matter would need to have an extremely high melting point to avoid becoming liquefied, ensuring that Mercury, Venus, Earth, and Mars would remain small and dense. Outside the frost line, however, gas was kept cool enough to remain in solid, icy states. Over time, planets such as Jupiter and Saturn would amass large quantities of frozen gas, enough to grow to hundreds of times the size of the Earth.
1. Which of the following discoveries, if true, would best support the protoplanet hypothesis that the temperature difference is responsible for the different sizes of planets on either side of the frost line?
A. The core of Saturn and the core of Mercury are found to be 98% composed of the same materials.
B. The cores of Saturn and Jupiter are found to each contain at least five chemical elements not found in the other.
C. The core of the Earth and the core of Mars are found to be comprised of the same mix of chemical elements.
D. A nearby star is found to be orbited by six planets, and the size of each is inversely proportional to its distance form the star.
E. The Earth;s moon is found to have a vastly different composition from that of the moons of Jupiter.
The encounter hypothesis explained the phenomenon sufficiently enough that it allowed scientists to focus on more immediately rewarding topics in physics and astronomy for most of the first half of the 20th century. Closer investigation, however, found several significant problems with the encounter hypothesis, most notably that the hot gas pulled from the sun would not condense to form dense planets, but rather would expand in the absence of a central, gravitational force. Furthermore, the statistical unlikelihood of a star passing in the (astronomically speaking) short time of the sun's existence required scientists to abandon the encounter hypothesis in search of a new explanation. Soon after astronomers formed a second theory, the nebular hypothesis, which submits that the solar system began as large cloud of gas containing the matter that would form the sun and its orbiting planets. The nebular hypothesis suggests that angular momentum would have morphed the nebular into a protoplanetary disc, with a dense center that generated intense heat and pressure, and a cooler, thinner mass that revolved around it. The central mass would have continued to build in density and heat, forming the sun, while the centrifugal force around the disc's edge kept smaller masses from being pulled in to the sun; those masses, upon cooling, would break off to become planets held in orbit by the competing gravitational force of the sun and centrifugal force of their orbital inertia.
The nebular hypothesis, however well it explained the sun's formation, remained problematic in its ability to account for the formation of several planets with differing physical and chemical properties. Encouraged by their advance toward a provable hypothesis for the solar system, scientists have recently come to adopt a third hypothesis, the protoplanet hypothesis. This currently accepted theory holds that the gaseous cloud that would form the solar system was composed of particles so cold that even the heat of the forming sun could not significantly impact the temperature of the outer reaches of the cloud. Gas in the inner region, within what scientists refer to as the frost line, was quickly either burned or dispersed, leaving a small amount of metallic matter, such as nickel and iron, to form the inner planets. Such matter would need to have an extremely high melting point to avoid becoming liquefied, ensuring that Mercury, Venus, Earth, and Mars would remain small and dense. Outside the frost line, however, gas was kept cool enough to remain in solid, icy states. Over time, planets such as Jupiter and Saturn would amass large quantities of frozen gas, enough to grow to hundreds of times the size of the Earth.
1. Which of the following discoveries, if true, would best support the protoplanet hypothesis that the temperature difference is responsible for the different sizes of planets on either side of the frost line?
A. The core of Saturn and the core of Mercury are found to be 98% composed of the same materials.
B. The cores of Saturn and Jupiter are found to each contain at least five chemical elements not found in the other.
C. The core of the Earth and the core of Mars are found to be comprised of the same mix of chemical elements.
D. A nearby star is found to be orbited by six planets, and the size of each is inversely proportional to its distance form the star.
E. The Earth;s moon is found to have a vastly different composition from that of the moons of Jupiter.
OA is C
I first chose D, since I couldn't find any information about the component about the core of the Earth and the core of Mars are the same chemical elements from the passage. Please indicate. thanks!
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Reading Comprehension (RC) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
17 Apr 2011, 00:54
Kudos
Bookmarks
D suggests the "encounter hyp" - since the planets away from the centre will be less dense
This hypothesis conveniently accounts for the fact that all planets in the solar system revolve in the same direction around the sun; it is also consistent with the denser planets remaining closer to the sun, and the more gaseous planets traveling further away.
However C is a defender assumption since it precludes an alternate explanation for the difference in the size of the plants except for the frost line theory. i.e. the matter within the frost line is denser however the matter outside the frost line is thin and cold. That explains why the planets could have increased the size by amassing more frozen gas on the outside.
This hypothesis conveniently accounts for the fact that all planets in the solar system revolve in the same direction around the sun; it is also consistent with the denser planets remaining closer to the sun, and the more gaseous planets traveling further away.
However C is a defender assumption since it precludes an alternate explanation for the difference in the size of the plants except for the frost line theory. i.e. the matter within the frost line is denser however the matter outside the frost line is thin and cold. That explains why the planets could have increased the size by amassing more frozen gas on the outside.
17 Apr 2011, 14:54
Kudos
Bookmarks
gmat1220
Sorry, but I'm still confusing about "the same mix of chemical elements" from the answer C. For this question, I should look for information in the last paragraph,
Quote:
...From what I understood, this part mentions the relation between temperature and the planets, but it doesn't really mention the relation between temperature and the different sizes of planets.
So how can I answer this question by getting the correct information from the passage?
Thanks,
