Light Years and Observing Cosmic Time — NEET Biology
📚 Practice ConceptWhen we look at stars on a clear night sky we are, in a way, looking back in time. Stellar distances are measured in light years. What we see today is an object whose emitted light started its journey millions of year back and from trillions of kilometres away and reaching our eyes now. However, when we see objects in our immediate surroundings we see them instantly and hence in the present time. Therefore, when we see stars we apparently are peeping into the past.
Assertion (A): Light from distant objects takes time to reach us, affecting our perception of time. Reason (R): When we see stars we apparently are peeping into the past, unlike nearby objects which we see instantly.
View solution & NCERT explanation
Correct answer: A — If both assertion and reason are true and the reason is the correct explanation of the assertion.
Both statements are true from NCERT. NCERT states “when we see objects in our immediate surroundings we see them instantly and hence in the present time. Therefore, when we see stars we apparently are peeping into the past.” The Reason explains WHY light affects our time perception - distant starlight shows us the past while nearby objects appear in present time.
What does NCERT say about When we look at?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.