Question 180·Hard·Transitions
Many astronomers once believed that all gamma-ray bursts originated from within the Milky Way galaxy. ______ observations from the Compton Gamma Ray Observatory in the 1990s demonstrated that these energetic flashes are distributed uniformly across the sky and thus occur at cosmological distances.
Which choice completes the text with the most logical transition?
For transition questions, first ignore the answer choices and read the surrounding sentences to decide the relationship between the ideas: are they similar, contrasting, cause–effect, or a restatement? Once you’ve labeled the relationship in your own words, eliminate any choices that signal the wrong type of connection, then plug the remaining option(s) back into the sentence to confirm that both the logic and the tone fit smoothly.
Hints
Read both sentences together
Ignore the blank at first and read the two sentences as one connected thought. Focus on how the second sentence relates to the first.
Compare the old belief and the new observations
Ask yourself: Do the new observations support the old belief about gamma-ray bursts, explain it more clearly, or show that it was wrong?
Think about the type of connection each option makes
Each choice signals a different relationship: similarity, cause–effect, or restatement. Decide which kind of connection fits the way the new observations relate to the old belief.
Test options in the sentence
Read the sentence with each transition in place and ask: Does this word match the logical relationship I see between the old belief and the new evidence?
Step-by-step Explanation
Understand the first sentence
The first sentence says that many astronomers once believed all gamma-ray bursts came from within the Milky Way galaxy. This sets up an older, now outdated view.
Understand the second sentence
The second sentence explains that observations from the Compton Gamma Ray Observatory showed gamma-ray bursts are uniformly distributed across the sky and occur at cosmological distances (very far away, outside our galaxy). This means the newer observations disagree with the earlier belief that they were all in the Milky Way.
Decide the logical relationship
Compare the ideas: the old belief (bursts from within the Milky Way) versus the new evidence (bursts from all over the sky at huge distances). The new information challenges or contradicts the earlier belief; it does not support it, restate it, or result from it in a simple cause–effect way.
Match the relationship to the correct transition
Now check each option: "Similarly," shows similarity, "Therefore," shows cause–effect, and "In other words," restates the same idea. None of these fit a contrast between an old belief and new, conflicting evidence. Only "However," correctly signals this contradiction, so the best answer is D) However,.