Exam 9: Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Kirkwood gaps in the asteroid belt occur at distances where

If a major asteroid collision in the asteroid belt occurs, on average, 1 time in 100,000 years, then how many major collisions have occurred over the approximately 4 billion year history of the solar system?

Describe some ways in which a meteorite can be distinguished from a terrestrial rock.

When a comet passes near the Sun, part of it takes on the appearance of a large, bright ball from which the tail extends. This part is called _.

If all the asteroids were gathered into a single object, it would make an object

Refer to the following scenario for the questions below. Lost in the Solar System: You have been abducted by an alien being. After performing experiments on you, the alien gives you a "life- support belt", allowing you to survive in any environment, and dumps you somewhere in the solar system. Each question below gives a brief description of a place where you were left by the alien. Identify your location. Be as specific as possible. Include a brief explanation for your answer. -It is very cold, but otherwise comfortable. You breathe deeply. Although there is no oxygen, the air pressure is quite tolerable and seems almost Earth- like (because it is mostly nitrogen). Your vista includes the breathtaking sights of an ocean of liquid methane and methane- snow- capped mountains (although the atmosphere is very smoggy, and the visibility is limited). Your solar day is about 16 Earth days long. A large, ringed object seems to hang in your sky, never rising or setting; however, it does go through phases from new to full and back to new again with the same 16- day period as the rising and setting of the Sun.

Which of the following statements is not true?

The impact of a 100 meter asteroid could kill many people if it struck a major city. Suppose the probability of such an impact in any single year is 1 in 1,000, and suppose we know (somehow)that it has been 1200 years since the last impact. What would that tell us?

Pluto is different from the Jovian planets in all of the following ways except which one?

All meteorites collected on Earth come from asteroids or comets.

Suppose there were no solar wind. How would the appearance of a comet in our inner solar system be different?

Can rocks fall from the sky? Many astronomers resisted the idea that rocks could fall from the sky until undeniable eyewitness testimony was available. (The tide turned in 1803 when several thousand stone fragments fell to the ground near L'Aigle, France, in the presence of hundreds of witnesses). Suppose that, for whatever reason, no meteorite falls could ever be witnessed. Would it still be possible to make the scientific case that some rocks on the Earth had to have fallen from interplanetary space? How would you make this case?

Why was the Shoemaker- Levy 9 impact so important to astronomers?

No spacecraft has ever visited an asteroid or comet.

What is Eris?

Why do we sometimes observe asteroids at the distances of the gaps in the asteroid belt?

A spacecraft traveling through the asteroid belt has a high risk of being destroyed through a collision.

All comets orbit the Sun in the same direction as the planets.

Describe the Deep Impact and Stardust missions and what they were designed to achieve.

Why is the Kuiper belt flat but the Oort cloud spherical?