What is the purpose of ‘evolved Laser Interferometer Space Antenna (eLISA)’ project ?
Show answer
Answer: B. eLISA (evolved Laser Interferometer Space Antenna) is a European Space Agency mission concept. Three spacecraft flying millions of kilometres apart would use lasers to measure tiny changes in distance caused by passing gravitational waves. So its purpose is to detect gravitational waves from space (as of 2017; the mission is now called LISA, planned for launch in the 2030s).
Watch for: Watch for the word 'interferometer'; it links to LIGO-style gravitational wave detection, not neutrinos.
Why the other options are wrong
- A. Wrong because neutrinos are detected by underground detectors like IceCube or INO.
- C. Wrong because eLISA is a science mission, not a defence system.
- D. Wrong because solar flares are studied by solar observatories like SOHO or Aditya-L1.
Source to check: European Space Agency website (esa.int), LISA mission page; Department of Science and Technology note on LIGO-India
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.