Which Technique Has NOT Provided a Means by Which Astronomers

question 337

Multiple Choice

Which technique has NOT provided a means by which astronomers can infer the presence of dark matter in the universe?

• A) measurement of the orbital speeds of stars near possible supermassive black holes at the centers of galaxies
• B) measurement of the orbital speeds of stars in the outer regions of galaxies
• C) observation of the bending of light (gravitational lensing) from remote galaxies as it passes through intervening clusters of galaxies
• D) measurement of the line-of-sight speeds of individual galaxies in clusters of galaxies

---

Definitions:

Existential Instantiation

A rule of inference used in logic to deduce that if there exists an element in a domain with a certain property, one can infer the existence of a specific example of that element.

Universal Instantiation

A logical rule that allows for the conclusion that what is true of all members of a class is true for any specific member.

Quantifier Negation

The logical operation of negating the quantifiers within a statement, which often changes the scope or meaning of the statement.

Existential Generalization

A logical inference rule stating that if an assertion is true for some member of a domain, then there exists an element in that domain for which the assertion holds.