Question 1

Asteroid 2004 MN4 is predicted to strike Earth in 2029.

Accepted Answer

Asteroid 2004 MN4, also known as Apophis, was initially considered a potential threat due to its close approach to Earth in 2029. However, subsequent observations have ruled out the possibility of impact in 2029 or anytime in the foreseeable future.

Question 2

Once an object strikes Earth's surface, it is called a "meteor".

Accepted Answer

Once an object strikes Earth's surface, it is called a "meteorite." Before it hits the surface, it's referred to as a "meteoroid" in space and a "meteor" as it passes through the atmosphere.

Question 3

Earth is hit about once a week by meter-size asteroids.

Accepted Answer

This is a true statement. NASA estimates that Earth is hit by meteoroids larger than 1 meter about once a week, but most of them burn up before they reach the ground.

Question 4

Why is it easier to locate meteorites in Antarctica than anywhere else on Earth?
A) Antarctica is an easy location for humans to access.
B) More scientists are in the area to find meteorites.
C) When meteorites land, they melt a small crater on the ice.
D) Meteorites are easy to detect on top of the ice where there are no Earth rocks.
E) Meteorites fall most often through the ozone hole above the South Pole.

Accepted Answer

Meteorites are easier to locate in Antarctica because the white, icy background helps in spotting them, especially since there are few, if any, native rocks on the ice surface to be confused with. This contrast makes meteorites stand out, facilitating their detection and collection.

Question 5

Iron meteorites are easy to recognize because a magnet can stick to them.

Accepted Answer

Iron meteorites contain a high percentage of iron and nickel, which are magnetic, so a magnet can stick to them.

Question 6

Most meteors come from pieces of comets.

Accepted Answer

Most meteors come from debris left by asteroids or from the interplanetary dust particles that collide with Earth's atmosphere, not primarily from comets.

Question 7

Some astronomers speculate there are as many Trojan asteroids around Jupiter as asteroids in the asteroid belt.

Accepted Answer

Some astronomers speculate that there could be as many as 1 million Trojan asteroids sharing Jupiter's orbit, which would be comparable to the estimated number of asteroids in the asteroid belt.

Question 8

When you document the time and place of a meteorite as it streams through the atmosphere, it is considered a(n) ____.
A) fall
B) find
C) meteoroid
D) chondrite
E) impactor

Accepted Answer

When a meteorite is observed falling through the atmosphere, it is called a "fall." This distinguishes it from a "find," which is a meteorite that has been discovered on the ground without any associated observation of it falling. Meteoroid refers to the object that enters the Earth's atmosphere, while chondrite refers to a specific type of meteorite composition. Impactor refers to the object that hits the Earth's surface during an impact event, which may or may not be a meteorite.

Question 9

Comet dust particles that later encounter Earth are seen as meteors.

Accepted Answer

When Earth passes through the dust trail left by a comet, the dust particles enter Earth's atmosphere and create a streak of light called a meteor.

Question 10

The Barringer crater was formed 50,000 years ago by a comet.

Accepted Answer

The Barringer crater, also known as the Meteor Crater, was actually formed about 50,000 years ago by the impact of a meteorite, not a comet.

Question 11

Comets are solid objects.

Accepted Answer

The answer of Comets are solid objects....

Question 12

What do we learn by studying chondrites?
A) Earth's early composition
B) the history of comets from the Oort cloud
C) the different formations of the Terrestrial and Jovian planets
D) the steps in planetary differentiation
E) the conditions and processes from the early days of the solar nebula

Accepted Answer

Chondrites are some of the oldest and most primitive objects in our solar system, dating back to the early stages of the solar nebula. They can provide insight into the conditions and processes that occurred during the formation of our solar system, including the composition of the early solar nebula, the formation of planets and planetesimals, and the history of meteorite impacts. Chondrites can also provide information about the isotopic signatures of different elements and the formation of the first solid materials in the solar system.

Question 13

Some asteroids have moons.

Accepted Answer

Some asteroids have moons orbiting around them, such as the asteroid system of 243 Ida and its moon Dactyl.

Question 14

What do CAIs include?
A) carbon and aluminum
B) carbon and ammonium
C) calcium and argon
D) chlorine and argon
E) calcium and aluminum

Accepted Answer

CAIs (calcium-aluminum-rich inclusions) include calcium and aluminum.

Question 15

Stony meteorites are common among falls.

Accepted Answer

Stony meteorites, which are made primarily of silicate minerals, are the most common type of meteorite found among falls (i.e. meteorites that have been observed falling to Earth).

Question 16

Most asteroids are very regular in shape with bright surfaces.

Accepted Answer

Most asteroids are irregularly shaped and have dark surfaces. The few that are relatively round and bright are considered exceptions rather than the norm.

Question 17

On any clear night, you can see 3 to 15 meteors per hour.

Accepted Answer

This is true. On any clear night, you can see 3 to 15 meteors per hour depending on various factors such as location, time of year, and weather conditions. This is also known as the "meteor shower rate."

Question 18

What do the size and shape of Widmanstätten patters indicate?
A) the age of the meteorite
B) that the molten metal of the meteorite cooled very slowly
C) the metallic content of the core of the meteorite
D) the origination of the meteorite
E) the number of organic compounds found within the meteorite

Accepted Answer

The size and shape of Widmanstätten patterns indicate that the molten metal of the meteorite cooled very slowly. This slow cooling allowed the formation of unique patterns of interlocking crystals of iron-nickel alloys. The patterns are not related to the age, metallic content of the core, origination or organic compounds found within the meteorite.

Question 19

What is so special about the carbonaceous chondrites?
A) rich in hydrogen and helium
B) rich in organic compounds
C) rich in nitrogen
D) rich in oxygen
E) rich in rare metals, such as gold

Accepted Answer

Carbonaceous chondrites are rich in organic compounds, including amino acids and other building blocks of life. This makes them of great interest to astrobiologists studying the potential for life beyond Earth.

Question 20

Only about three comets per year plunge into the Sun and are destroyed.

Accepted Answer

Many more than three comets per year, often several hundred, are believed to plunge into the Sun or disintegrate in its outer atmosphere. These are mostly small comets that are not visible from Earth without the aid of a telescope. The SOHO (Solar and Heliospheric Observatory) satellite, for example, has observed thousands of such small comets, referred to as "sungrazers," since its launch.

Quiz 16: Meteorites Asteroids and Comets