What is the purpose of ‘evolved Laser Interferometer Space Antenna (eLISA)’ project?
Answer & explanation
Answer: (b) To detect gravitational waves
eLISA was planned as a space-based observatory to detect gravitational waves, the ripples in space-time caused by events such as merging black holes. It works as a laser interferometer in space, so its purpose is gravitational-wave detection.
- ✓ (b) The name gives it away: a Laser Interferometer Space Antenna is a laser-based gravitational-wave detector in space, the space counterpart of ground detectors such as LIGO.
- ✗ (a) Neutrinos are detected by large underground or under-ice detectors, not by a laser interferometer in space.
- ✗ (c) A missile-defence test has nothing to do with this science mission.
- ✗ (d) Solar flares are studied by solar observatories and space-weather missions, not by an interferometer built for gravitational waves.
- • Since then The eLISA concept is now the European Space Agency's LISA mission, described as the first space-based observatory for gravitational waves, with launch planned for 2035.
Remember · eLISA/LISA = laser interferometer in space to detect gravitational waves. Ground-based cousin: LIGO, which India is joining.
📘 Read it in NCERT: Class 11 Knowledge Traditions and Practices of India, Part I, Ch 5 (practise this chapter)
Sources
- European Space Agency: LISA, first gravitational wave detector in space ↗ “ESA's Laser Interferometer Space Antenna (LISA) will be the first space-based observatory dedicated to studying gravitational waves”
- NCERT Class 11 · Knowledge Traditions and Practices of India, Part I, Chapter 5 “LIGO is a large-scale experiment to detect cosmic gravitational waves and to develop them as an astronomical tool”
Question and answer: UPSC's official GS Paper I (2017, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·