Reading Comprehension

PT121 · S2 · P3 · Q19 Neutrinos

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According to the theory of gravitation, every particle of matter in the universe attracts every other particle with a force that increases as either the mass of the particles increases, or their proximity to one another increases, or both.

(Written summary below video)

Topic

Neutrinos and the Dark Matter mystery

Frameworks

Problem / Solution Answer a Question

Main Point

Question / Problem The observable matter in the universe only adds up to about 10% of the mass that would be needed for gravity to account for the observable structures in the universe. So given that we believe in gravity, and we believe we're correctly observing structures, where is the other 90% of the universe's mass?

Answer / Solution Neutrinos seem to account for about 20% of it, but more broadly the discovery that a tiny particle's crazy small mass might still add up to something significant (because of how numerous that type of particle is) is making scientists think that maybe the tiny masses of elementary particles is a big part of the missing mass.

Summary

P1 - Background on gravity, introduction to Curious Problem

After briefly summarizing what gravity means, this paragraph establishes the 90% missing matter conundrum, and says that cosmologists have postulated something called 'dark matter', which seems to just be a placeholder name.

P2 - A potential Solution that seemed non-viable

This paragraph introduces neutrinos as one possible answer/solution that cosmologists had considered, but ultimately rejected since they assumed that neutrinos had no mass.

P3 - New research brings back hope to possible Solution

This paragraph presents new research that suggests that neutrinos do have mass, so they're back as a contender for this dark matter problem we're trying to solve.

P5 - Implications of New research

The author's take on where we're at usually comes in the final paragraph of Science passages. Here, it sounds like neutrinos are promising as a Partial Solution, and they're also opening up new lines of inquiry that are potentially an encouraging step forward in the process of trying to find the Whole Solution.

Topic

The search for "dark matter" and the possible role of neutrinos in accounting for missing mass in the universe.

19.

The passage states each of the following EXCEPT:

  1. Correct

    There are more neutrinos in

    Why this is right

    In the middle of the 2nd paragraph, the author says that neutrinos "are by far the most numerous kind of particle in the universe". We could say that "Christian is by far the most common religious affiliation in the U.S.", but that doesn't mean that "Christians outnumber Non-Christians". When you add up atheists, Muslims, Hindus, Jews, etc., they might still be a bigger number than Christians. In order for there to be more X's than non-X's, we have to know that X's are more than 50% of the total. We were never told that "neutrinos are more than 50% of the particles in the universe".

    Skill tested: Locate Detail · how this choice captures the passage's function is the move to repeat next time.

    77% picked this

  2. Observable matter cannot exert enough

    Stated

    Halfway through the 1st paragraph, we're quoted the 90% and then right after that colon it says "the total amount of observable matter does not contain enough mass to explain why the universe is organized in the shape of galaxies and clusters".

    7% picked this

  3. Scientific experiments support the theory

    Stated

    The beginning of the 3rd paragraph (second sentence) says that "research findings supporting the existence of a long-theorized but never observed phenomenon called oscillation"

    4% picked this

  4. Neutrinos likely cannot account for

    Stated

    The second sentence of the last paragraph says "Still neutrinos could only account for about 20% of the 'missing' mass".

    4% picked this

  5. Dark matter may account for

    Stated (kind of)

    This one's being a little loose with the question stem's notion that this idea was "stated", because this claim is more something we can infer by bringing together two parts of the first paragraph. Since (last line of P1) cosmologists hypothesize that "dark matter" provides the gravitational force necessary to make the huge structures cohere, and since we know that dark matter is filling in the missing 90% (large portion), we can infer this idea.

    9% picked this

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