Difficulty: Medium
Correct Answer: A1689 B11
Explanation:
Introduction / Context:
Galaxies in the early universe provide important clues about how the large-scale structure of the cosmos formed and evolved. Discovering spiral galaxies at very great distances, corresponding to times billions of years in the past, helps astronomers understand when and how ordered spiral structures emerged. One such ancient spiral galaxy has been observed through gravitational lensing and detailed imaging, and it has a specific catalogue designation. This question checks whether you know the name associated with that distant spiral galaxy, thought to have existed about 11 billion years ago.
Given Data / Assumptions:
Concept / Approach:
The galaxy in question has been widely reported in astronomy news as one of the earliest known spiral galaxies, with its light passing through a cluster called Abell 1689, which acts as a gravitational lens. The magnified and distorted image allowed astronomers to study its spiral structure in detail. The designation given to this object is A1689B11. The other options are similar-looking catalogue names but do not correspond to this particular ancient spiral galaxy. Recognising the correct designation is largely a matter of recall from reading or studying astronomy reports.
Step-by-Step Solution:
Step 1: Identify that the question refers to a specific well-known ancient spiral galaxy observed through gravitational lensing.
Step 2: Recall that the galaxy was given the designation A1689B11 in scientific reports and news articles.
Step 3: Compare this with the options provided, noting that A1689 B11 matches the designation when written with a space.
Step 4: Recognise that A1689 B01, A1689 B10, and A1689 B20 are distractor options created by varying the last digits.
Step 5: Understand that only A1689 B11 corresponds to the famous ancient spiral galaxy described in the question.
Step 6: Select A1689 B11 as the correct answer.
Verification / Alternative check:
Popular science articles and astronomy press releases discussing this discovery describe A1689B11 as a spiral galaxy seen as it was roughly 11 billion years ago. The Abell 1689 cluster acts as a natural lens, bending and magnifying its light. Astronomers used high-resolution imaging and spectroscopy to confirm its spiral nature. The exact designation A1689B11 is repeated across these sources. The slight difference in spacing (A1689B11 versus A1689 B11) in various formats does not change the identity of the object. None of the other letter-and-number combinations listed in the options is associated with this well-known galaxy in the literature.
Why Other Options Are Wrong:
A1689 B01 is incorrect because this designation does not correspond to the specific ancient spiral galaxy widely reported as existing 11 billion years ago.
A1689 B10 is wrong for the same reason; it is a distractor that changes the final digits of the known designation.
A1689 B20 is also incorrect; while it looks similar, it is not the reported name of the ancient spiral galaxy described in the question.
Common Pitfalls:
Because the options look very similar, students may answer based on a vague memory of the pattern without noticing the exact final digits. This is a classic example of a recall-based question where attention to detail is crucial. A good strategy for such questions is to memorise not just the general format but the specific digits of well-known objects, especially when they are highlighted in textbooks or news. In this case, remembering that the last two digits are "11" in A1689B11 helps you avoid mixing it up with similar-looking catalogue numbers.
Final Answer:
The most ancient spiral galaxy described in the question is designated A1689 B11.
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