Stardust

Read the following two details.

1.Stardust that formed more than 5 billion years ago, long before the birth of the Earth and the sun, has been discovered in a meteorite that crashed down in Australia, making it the oldest known solid material on the planet.

2."We have more young grains that we expected," said Heck. "Our hypothesis is that the majority of those grains, which are 4.6 billion to 4.9 billion years old, formed in an episode of enhanced star formation when about 50 percent more stars than normal were forming."

Select the answer choice that BEST explains how these details develop a central idea of the article.

• Both details describe recent discoveries that will help scientists to better understand our galaxy.

• Both details describe the period when the majority of stars formed in the Milky Way.

• Both details illustrate the rarity of direct physical evidence of star formation in the early Milky Way.

• Both details illustrate the difficulty of estimating the ages of stars in the distant cosmos.

Tags

CCSS.RL.8.1

CCSS.RI.8.2

CCSS.RI.7.2

CCSS.RL.7.1

CCSS.RL.7.2

Read the following two summaries of the article.

Option 1: Scientists discovered stardust from a meteorite impact that they've dated to billions of years ago using advanced techniques that measure the decay of a sample's composite materials due to cosmic rays over time.

Option 2: Scientists recently discovered the oldest known solid material on the planet, stardust billions of years old that will provide new evidence for understanding how and when the stars in our galaxy formed.

Which option provides an objective, accurate summary of the article, and why?

• Option 1; it briefly explains the a recent discovery and the scientific technique used to analyze it.

• Option 2; it clearly describes what scientists want to know about the Milky Way.

• Option 1; it clearly describes the effect of cosmic rays on materials in the cosmos.

• Option 2; it briefly explains the source and implications of the recent scientific discovery.

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CCSS.RL.8.2

CCSS.RI.8.2

CCSS.RL.9-10.2

CCSS.RI.7.2

CCSS.RL.7.2

Which of the following did the author develop the LEAST in this article about scientists' research into star formation?

• the implications of recent research on 5-billion-year-old stardust

• the use of statistical models of star and galaxy formation

• the process of determining the age of the stardust sample through decay measurements

• the reasons for an apparent increase in star formation about 4.7 billion years ago

Tags

CCSS.RL.8.1

CCSS.RI.8.2

CCSS.RI.7.2

CCSS.RL.9-10.2

CCSS.RL.7.2

Which of the following accurately summarizes HOW different scientists feel about the recent research on the Murchison meteorite's stardust?

• They are skeptical about the recent findings, which do not align with other research about star formation using alternate research methods.

• They are excited to have direct evidence of star formation and encouraged that it will help develop models of galaxy formation.

• They are eager to do similar tests on other samples to verify and corroborate the initial findings from Philipp Heck's research team.

• They are doubtful about the recent findings, since earlier experiments on similar samples produced much different results.

Tags

CCSS.RL.8.2

CCSS.RI.8.2

CCSS.RL.7.2

CCSS.RI. 9-10.2

CCSS.RI.7.2