Astronomy

The active asteroid discovered near Jupiter is named 2019 LD2. It is notable for exhibiting comet-like activity while orbiting near Jupiter, distinguishing it from typical asteroids.

The first active asteroid-type body discovered near Jupiter's orbit is the centaur-comet hybrid P/2019 LD2, found in 2019. It exhibits comet-like activity such as a dust and gas tail while orbiting near Jupiter's Trojan asteroids. This discovery is notable because such active objects had not been observed in that region for billions of years, and Jupiter's strong gravity influences their orbit. The object was discovered by the University of Hawaii's ATLAS survey telescopes and confirmed with Hubble observations, marking the first comet-like active asteroid near Jupiter's orbit.

Sagittarius A*, the supermassive black hole at the center of the Milky Way Galaxy, is approximately 26,000 light-years away from Earth. This distance is widely accepted in astronomical measurements, and the closest option provided is 25,500 light-years (option A), which is an acceptable approximation for educational purposes.

Venus is the only planet in the solar system whose rotation period (day) is longer than its orbital period (year). It takes about 243 Earth days to rotate once on its axis but only about 225 Earth days to orbit the Sun.

Canopus is the second brightest star in the night sky as seen from Earth, after Sirius. Betelgeuse and Vega are bright stars but not as bright as Canopus. 'None of these' is incorrect because Canopus is indeed the second brightest.

UY Scuti is currently considered one of the largest known stars by radius, making it the biggest star in the Universe among the options listed. The other stars, Rigel, Canopus, and Arcturus, are large but smaller in comparison.

The Alpha Centauri system is the closest star system to our Sun, located about 4.37 light-years away. It includes the stars Alpha Centauri A, Alpha Centauri B, and Proxima Centauri, the latter being the closest individual star to the Sun.

The Andromeda Galaxy is classified as a spiral galaxy, characterized by its distinct spiral arms. It is one of the closest spiral galaxies to the Milky Way and is well-studied in astronomy.

NASA scientists have detected water vapor on Europa, one of Jupiter's moons, which is known for its subsurface ocean beneath an icy crust. This discovery supports the possibility of habitable conditions there.

Water vapor has been detected in the atmosphere of the potentially habitable super-Earth K2-18b, making it the correct answer. The other options have no confirmed water detection.