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Frame-dragging (Lense-Thirring effect) was confirmed by which satellite experiment?
- Gravity Probe B
- LAGEOS
- MICROSCOPE
- GOCE
Answer: Gravity Probe B
Gravity Probe B (2004-2011) measured frame-dragging via gyroscope precession, confirming general relativity prediction within ~20% accuracy.
Jupiter's magnetosphere is primarily powered by which energy source?
- Solar wind
- Planetary rotation
- Tidal heating
- Internal heat
Answer: Planetary rotation
Jupiter's rapid rotation (9.9 hr) drives magnetospheric dynamics via centrifugal forces and Io plasma torus coupling, unlike solar-wind-dominated Earth.
The Sachs-Wolfe effect describes CMB temperature fluctuations caused by which phenomenon?
- Doppler shift
- Gravitational redshift/blueshift
- Thomson scattering
- Synchrotron emission
Answer: Gravitational redshift/blueshift
Photons climbing out of potential wells lose energy (redshift); falling in gain energy (blueshift), imprinting primordial density perturbations on CMB.
The NEO Surveyor mission will detect potentially hazardous asteroids using which wavelength?
- Visible
- Infrared
- Ultraviolet
- Radio
Answer: Infrared
NEO Surveyor uses infrared detectors to find dark asteroids missed by optical surveys, identifying PHAs >140 m within 5 years of launch.
Fast Radio Bursts (FRBs) are millisecond-duration radio pulses originating from which type of source?
- Supernovae
- Magnetars
- Active galactic nuclei
- Pulsar glitches
Answer: Magnetars
FRB 200428 linked to Galactic magnetar SGR 1935+2154 confirmed magnetars as FRB sources, though extragalactic FRBs may have diverse origins.
Earth trojan asteroids occupy which Lagrange points relative to Earth-Sun system?
- L1 and L2
- L3 only
- L4 and L5
- L1, L2, L3
Answer: L4 and L5
Earth trojans librate around L4 (leading) and L5 (trailing) points; 2010 TK7 (L4) and 2020 XL5 (L4) are confirmed examples.
ISRO's POEM platform repurposes which spent stage for microgravity experiments?
- PSLV fourth stage
- GSLV cryogenic stage
- LVM3 core stage
- SSLV terminal stage
Answer: PSLV fourth stage
PSLV Orbital Experimental Module (POEM) uses depleted PS4 stage as stabilized platform hosting payloads for weeks/months post-primary mission separation.
Gamma-ray bursts (GRBs) are classified into short and long duration based on which threshold?
- 1 second
- 2 seconds
- 10 seconds
- 60 seconds
Answer: 2 seconds
Short GRBs (<2 s) originate from compact object mergers; long GRBs (>2 s) from collapsars/massive star deaths, differing in progenitors and host galaxies.
Voyager 1 crossed the heliopause into interstellar space in which year?
- 2004
- 2012
- 2018
- 2021
Answer: 2012
Voyager 1 crossed the heliopause on Aug 25, 2012, becoming the first human-made object to enter interstellar space, confirmed by plasma density jump.
Adaptive optics in ground-based telescopes corrects atmospheric distortion using which component?
- Corrector plates
- Deformable mirrors
- Filter wheels
- Charge-coupled devices
Answer: Deformable mirrors
Deformable mirrors adjust shape hundreds of times per second based on wavefront sensor data, compensating for atmospheric turbulence in real-time.
NASA's Parker Solar Probe uses which planet's gravity assists to approach the Sun?
- Mercury
- Venus
- Earth
- Mars
Answer: Venus
Parker Solar Probe performs multiple Venus flybys to shrink its orbit and reduce perihelion distance, eventually reaching within 6.2 million km of the Sun.
What specific impulse range do Hall-effect thrusters typically achieve compared to chemical rockets?
- Lower (<300 s)
- Similar (300-450 s)
- Higher (1000-3000 s)
- Much higher (>10,000 s)
Answer: Higher (1000-3000 s)
Hall thrusters achieve 1000-3000 s specific impulse versus 300-450 s for chemical rockets, enabling efficient station-keeping and orbit raising despite low thrust.
Which ESA mission will study Jupiter's icy moons Europa, Ganymede, and Callisto?
- JUICE
- Europa Clipper
- Laplace
- JIMO
Answer: JUICE
JUICE (JUpiter ICy moons Explorer) launched April 2023, arriving 2031 to study habitability of Ganymede, Europa, and Callisto.
Which mission studied Pluto and its moons up close in 2015?
- Voyager 1
- New Horizons
- Cassini
- Juno
Answer: New Horizons
NASA's New Horizons conducted the first Pluto flyby on July 14, 2015, revealing glaciers, mountains, and atmospheric haze on the dwarf planet.
Which mission returned the first samples from the Moon since Luna 24 in 1976?
- Chang'e 5
- Artemis I
- Hayabusa2
- OSIRIS-REx
Answer: Chang'e 5
China's Chang'e 5 returned 1.7 kg of lunar regolith in December 2020, the first lunar sample return in 44 years, from Oceanus Procellarum.
Which mission mapped Venus's surface through clouds using radar in the 1990s?
- Venera 13
- Magellan
- Akatsuki
- Pioneer Venus
Answer: Magellan
NASA's Magellan orbiter (1990-1994) used synthetic aperture radar to map 98% of Venus's surface, revealing volcanic plains, tectonic features, and impact craters.
Which space telescope discovered the first confirmed exoplanet orbiting a sun-like star (51 Pegasi b)?
- Hubble
- Kepler
- Ground-based ELODIE spectrograph
- TESS
Answer: Ground-based ELODIE spectrograph
51 Pegasi b was discovered in 1995 using radial velocity method with ground-based ELODIE spectrograph at Observatoire de Haute-Provence, not a space telescope. Note: Question tests precision—no space telescope made this discovery.
Which mission performed the first asteroid deflection test by kinetic impact in 2022?
- OSIRIS-APEX
- DART
- Lucy
- Psyche
Answer: DART
NASA's DART (Double Asteroid Redirection Test) successfully impacted Dimorphos in September 2022, altering its orbit around Didymos, proving planetary defense capability.
Hawking radiation predicts that black holes can slowly lose mass and eventually evaporate.
- True
- False
Answer: True
Stephen Hawking theorized that quantum effects near the event horizon cause black holes to emit thermal radiation, leading to gradual mass loss over immense timescales.
What is the orbital period of a satellite in Medium Earth Orbit (MEO) typically used for navigation constellations like GPS?
- 90 minutes
- 12 hours
- 24 hours
- 48 hours
Answer: 12 hours
Navigation satellites in MEO (e.g., GPS at ~20,200 km altitude) have an orbital period of approximately 12 hours, ensuring global coverage with multiple overlapping orbits.