Space Assessment Prep
| # | Answer |
|---|---|
| 1 | A star produces its own light and energy through nuclear fusion, while a planet does not produce its own light and instead reflects the light of a star. |
| 2 | Mercury. |
| 3 | Orbit. |
| 4 | Gravity. |
| 5 | The Sun. |
| 6 | Distance. |
| 7 | The corona. |
| 8 | The Milky Way Galaxy. |
| 9 | A moon is a natural satellite that orbits a planet or dwarf planet. |
| 10 | Rotation is the spinning of an object on its axis, while revolution is the motion of an object around another object. |
| 11 | Because Earth rotates on its axis, causing different parts of the planet to face the Sun and then turn away from it. |
| 12 | Earth’s axial tilt as it orbits the Sun causes the seasons. |
| 13 | Saturn. |
| 14 | A meteor. |
| 15 | A meteorite. |
| 16 | A region of the solar system located between Mars and Jupiter that contains many asteroids. |
| 17 | Mars. |
| 18 | A planet that orbits a star outside our solar system. |
| 19 | Venus has a thick atmosphere rich in greenhouse gases that traps heat very effectively, making it hotter than Mercury. |
| 20 | Escape velocity is the minimum speed needed for an object to break free from a celestial body’s gravitational pull without further propulsion. |
| 21 | The average distance from Earth to the Sun, about 150 million kilometers. |
| 22 | We see different phases because the Moon orbits Earth, and we observe varying portions of its sunlit half from Earth. |
| 23 | A solar eclipse occurs when the Moon passes between Earth and the Sun, while a lunar eclipse occurs when Earth passes between the Sun and the Moon. |
| 24 | The Moon’s gravity pulls on Earth’s oceans, causing tidal bulges. |
| 25 | A galaxy is much larger than a solar system. |
| 26 | Planets orbit the Sun in elliptical paths, with the Sun at one focus of the ellipse. |
| 27 | A line joining a planet and the Sun sweeps out equal areas in equal intervals of time. |
| 28 | The square of a planet’s orbital period is proportional to the cube of the semi-major axis of its orbit. |
| 29 | Distance = speed × time = 20 km/s × 10 s = 200 km. |
| 30 | Because radio signals travel at the speed of light, and the large distance between Mars and Earth causes a significant time delay. |
| 31 | To observe distant objects in space without the distortion caused by Earth’s atmosphere. |
| 32 | Space telescopes avoid atmospheric distortion, weather, and light pollution, allowing clearer observations. |
| 33 | Its surface gravity would be about four times greater than Earth’s, since gravity at the surface is proportional to mass divided by radius squared. |
| 34 | Multiple stages reduce mass during flight, making it easier for the rocket to accelerate efficiently and reach space. |
| 35 | It is the region around a star where temperatures may allow liquid water to exist on a planet’s surface. |
| 36 | Liquid water is essential for many chemical reactions associated with life as we know it, so its presence increases the possibility of habitability. |
| 37 | The star is likely very far from Earth, because apparent brightness depends on both intrinsic brightness and distance. |
| 38 | Apparent brightness is how bright an object appears from Earth, while luminosity is the total energy a star emits each second. |
| 39 | The parallax angle is 0.1 arcseconds, since distance in parsecs is the reciprocal of parallax in arcseconds. |
| 40 | Its apparent brightness doubles. |
| 41 | Because during the main sequence it is steadily fusing hydrogen into helium in its core, which is the longest stable phase of stellar evolution. |
| 42 | A supernova is a powerful explosive event that occurs when a massive star ends its life or when a white dwarf undergoes a runaway thermonuclear reaction. |
| 43 | A neutron star or a black hole, depending on the mass of the collapsed core. |
| 44 | The event horizon is the boundary around a black hole beyond which nothing, not even light, can escape. |
| 45 | The probe’s velocity and the gravitational influences of nearby bodies, especially Earth, the Sun, and the asteroid. |
| 46 | Because carrying fuel adds mass, and a more efficient design allows the spacecraft to achieve the necessary velocity with less propellant. |
| 47 | It will move into a higher, less tightly bound orbit, and if the speed increase is large enough, the orbit may become more elliptical or even escape Earth’s gravity. |
| 48 | Geostationary satellites orbit far above Earth’s equator and appear fixed over one location, making them useful for communications and weather monitoring; low Earth orbit satellites are much closer to Earth and are often used for imaging, research, and the International Space Station. |
| 49 | The star is very hot, likely much hotter than the Sun, because blue-white stars have higher surface temperatures and strong hydrogen lines can be prominent in certain hot stellar types. |
| 50 | Three major challenges include entering Mars’ atmosphere and landing safely, designing systems that can survive cold temperatures and dust, and providing reliable power and communication for long-term operation on the surface. |