Universe

The line connecting a planet and the Sun covers equal areas in equal intervals of time

Step 1: Kepler proposed three laws of planetary motion based on Tycho Brahe's careful observations. Step 2: Kepler's Second Law, also called the Law of Equal Areas, describes the speed variation of a planet. Step 3: When a planet is closer to the Sun, it moves faster; when farther, it moves slower — but always sweeping equal areas in equal time. Step 4: Option A describes a circle, but Kepler's First Law says orbits are elliptical. Option C is Kepler's Third Law (Law of Harmonies). Option D is incorrect because planetary speed varies.

7613 m/s

Step 1: Write down the formula: v = √(GM / (R+h)). Step 2: Substitute values — G = 6.673 × 10⁻¹¹, M = 5.972 × 10²⁴ kg, R = 6,371,000 m, h = 500,000 m. Step 3: Calculate R + h = 6,871,000 m. Step 4: Numerator = 6.673 × 10⁻¹¹ × 5.972 × 10²⁴ ≈ 3.985 × 10¹⁴. Step 5: v = √(3.985 × 10¹⁴ / 6.871 × 10⁶) = √(5.798 × 10⁷) ≈ 7613 m/s or 7.613 km/s. Option A is too low (escape velocity from Moon), and 11200 m/s is Earth's escape velocity.

It orbits Earth at approximately 400 km and its core construction was completed by 2011

Step 1: The ISS is a large spacecraft that serves as a space laboratory and home for astronauts. Step 2: Its first part was placed in orbit in 1998 and core construction was completed by 2011. Step 3: It orbits at approximately 400 km above Earth in low Earth orbit. Step 4: It is managed by five space agencies — NASA, Roskosmos, ESA, JAXA, and CSA — representing 16 countries. At any given time, at least six humans are present. It IS visible from Earth with the naked eye — it is the largest man-made object in space.

2062

Step 1: Halley's Comet is a periodic comet that appears roughly every 76 years. Step 2: It was last seen in the year 1986. Step 3: Add 76 years to 1986: 1986 + 76 = 2062. Step 4: Therefore, Halley's Comet will next be visible in 2062. Comets travel in highly elliptical orbits around the Sun, which gives them very long periods of revolution.