Untitled Deck

Question 1

Why are the minor bodies of the Solar System important to study?

Answer 1

They help us understand impact cratering, elemental abundances in the solar nebula, and processes in the Solar System’s formation.

Question 2

What is Kepler’s First Law of Planetary Motion?

Answer 2

Planets move in elliptical orbits with the Sun at one focus.

Question 3

Define perihelion and aphelion in an elliptical orbit.

Answer 3

Perihelion is the closest point to the Sun; aphelion is the farthest point.

Question 4

How does Kepler’s Second Law relate to orbital speed?

Answer 4

A line from the Sun to a planet sweeps out equal areas in equal times, meaning a planet moves faster when closer to the Sun.

Question 5

Write the mathematical form of Kepler’s Third Law.

Answer 5

P^2 = k a^3, where P is the orbital period and a is the semimajor axis.

Question 6

What is the semimajor axis of an orbit?

Answer 6

It is half the longest diameter of an ellipse, representing the average distance from the orbiting body to the Sun.

Question 7

What is orbital eccentricity?

Answer 7

It is a dimensionless measure of the shape of an orbit, ranging from 0 (circle) to 1 (elongated ellipse).

Question 8

What happens to a planet’s speed as it approaches perihelion?

Answer 8

The planet speeds up due to the Sun’s stronger gravitational pull.

Question 9

What are the perihelion and aphelion distances for a planet with a = 5 AU and e = 0.2?

Answer 9

Perihelion: q = 5(1-0.2) = 4 AU; Aphelion: Q = 5(1+0.2) = 6 AU.

Question 10

What is the significance of inclination in an orbit?

Answer 10

It measures the tilt of an orbit relative to the ecliptic plane, defined by Earth’s orbit.

Question 11

What are prograde and retrograde orbits?

Answer 11

Prograde orbits have inclinations between 0° and 90° (anticlockwise from above the north pole), while retrograde orbits have inclinations between 90° and 180° (clockwise).

Question 12

What is tidal heating?

Answer 12

A mechanism where gravitational interactions cause internal frictional heating, as seen on moons like Io.

Question 13

Why does Io remain volcanically active?

Answer 13

Orbital eccentricity causes gravitational interactions that lead to tidal heating within Io.

Question 14

What are Kirkwood Gaps?

Answer 14

Regions in the asteroid belt with few asteroids, caused by orbital resonances with Jupiter.

Question 15

What are Near Earth Asteroids (NEAs)?

Answer 15

Asteroids with orbits that bring them close to Earth.

Question 16

What are Potentially Hazardous Asteroids (PHAs)?

Answer 16

NEAs that have orbits crossing Earth’s path and could potentially collide with Earth.

Question 17

What is the composition difference between C-type and S-type asteroids?

Answer 17

C-type asteroids are carbonaceous and dark, while S-type asteroids are stony and more reflective.

Question 18

What is the Kuiper Belt?

Answer 18

A region beyond Neptune filled with icy bodies and dwarf planets like Pluto.

Question 19

What are Centaurs?

Answer 19

Minor bodies with unstable orbits between Jupiter and Neptune, thought to originate from the Kuiper Belt.

Question 20

What is unique about the Centaur Chariklo?

Answer 20

It is surrounded by two rings, the only known such object outside the giant planets.

Question 21

How do comets develop tails?

Answer 21

Sublimation of ices near the Sun releases gas and dust, forming ion and dust tails.

Question 22

What is the difference between ion and dust tails of comets?

Answer 22

Ion tails are gaseous and point away from the Sun due to solar wind; dust tails reflect sunlight and follow the comet’s orbit.

Question 23

What are long-period comets?

Answer 23

Comets from the Oort Cloud with semimajor axes of hundreds to thousands of AU and unpredictable appearances.

Question 24

What are short-period comets?

Answer 24

Comets with orbits confined to the planetary system, often originating from the Kuiper Belt.

Question 25

What is the Oort Cloud?

Answer 25

A distant spherical shell of icy bodies surrounding the Solar System, the source of long-period comets.

Question 26

Why are meteoroid streams formed?

Answer 26

Comets release dust particles into space, which continue orbiting the Sun along similar paths.

Question 27

What causes meteors (shooting stars)?

Answer 27

Meteoroids entering Earth’s atmosphere at high speeds vaporize, producing a streak of light.

Question 28

What is the zodiacal light?

Answer 28

A faint glow caused by sunlight scattering off interplanetary dust particles.

Question 29

How does radiation pressure affect small particles in space?

Answer 29

It pushes tiny particles outward from the Sun, acting like a solar wind.

Question 30

What is the Poynting–Robertson effect?

Answer 30

A process where dust particles spiral towards the Sun due to the braking effect of solar radiation.

Question 31

How are the orbits of Kuiper Belt objects classified?

Answer 31

Into Plutinos (3:2 resonance with Neptune), Classical objects, and Scattered Disc objects.

Question 32

What evidence supports the existence of the Kuiper Belt?

Answer 32

Discovery of objects like 1992 QB1 and over 1800 others with orbits beyond Neptune.

Question 33

What are binary asteroids?

Answer 33

Two asteroids orbiting each other, like Ida and its moon Dactyl.

Question 34

What is the main composition of cometary nuclei?

Answer 34

A mix of water ice, frozen gases (e.g., CO2, NH3), and dust particles.

Question 35

What is sublimation in the context of comets?

Answer 35

The process where ices turn directly into gas as the comet approaches the Sun.

Question 36

What are meteoroids?

Answer 36

Solid fragments from asteroids or comets, smaller than 1 mm to several meters in size.

Question 37

How does Jupiter influence comets and asteroids?

Answer 37

Its gravity perturbs orbits, creating phenomena like Kirkwood Gaps and influencing short-period comet paths.

Question 38

Why are asteroids in the asteroid belt irregularly shaped?

Answer 38

Frequent collisions prevent the formation of large, spherical bodies.

Question 39

What is the typical density of C-type asteroids?

Answer 39

Around 1200–1300 kg/m^3, indicating high porosity.

Question 40

What are the two main types of comet orbits?

Answer 40

Long-period (from the Oort Cloud) and short-period (from the Kuiper Belt).

Question 41

How can impacts influence the appearance of Kuiper Belt objects?

Answer 41

Impacts may expose subsurface ice, leading to transient atmospheres or changes in reflectance spectra.

Question 42

What is the purpose of the New Horizons mission?

Answer 42

To study Kuiper Belt objects and Pluto up close, providing insights into icy bodies.

Question 43

Why do some asteroids have moons?

Answer 43

Gravitational interactions during collisions or captures can create binary systems.

Question 44

What are Potentially Hazardous Asteroids (PHAs)?

Answer 44

NEAs that have orbits crossing Earth’s path and could potentially collide with Earth.

Question 45

What happens to comets after many perihelion passages?

Answer 45

They lose mass through sublimation and may fragment, eventually disintegrating.

Question 46

What is an example of an asteroid visited by a spacecraft?

Answer 46

Eros, visited by the NEAR mission, which even landed on its surface.

Question 47

What determines the reflectance spectrum of an asteroid?

Answer 47

Its surface composition and how it reflects sunlight at different wavelengths.