Question 1

If we identified a large object on a collision course with Earth,what would be the best approach to minimize the hazard,given today's technology?

Accepted Answer

Attempting to deflect the object onto a different orbital path would be the best approach to minimize the hazard. This can be done using a kinetic impactor, which is essentially a spacecraft that collides with the object, changing its trajectory. NASA already has plans in place to test this technique with the Double Asteroid Redirection Test (DART) mission, scheduled to launch in 2021. Blowing the object apart with weapons can create additional debris that could still pose a threat to Earth, and evacuation may not be possible or practical for large areas. Doing nothing is not an option since the potential danger is too great.

Question 2

Bombardment of planet Earth by asteroids and comets was severe about 4.6 billion years ago,but has now ceased completely.

Accepted Answer

While the frequency of asteroid and comet impacts has decreased over time, they have not completely ceased. Small meteoroids still enter Earth's atmosphere every day, but they burn up before reaching the surface. Larger asteroids or comets could potentially impact Earth in the future, although the likelihood is low and efforts are being made to detect and prevent such events.

Question 3

The meteorite impact at the K-T boundary vaporized lots of sulphur-bearing limestone rocks.What was the effect on climate due to this vaporization?

Accepted Answer

The vaporization of sulphur-bearing limestone rocks at the K-T boundary led to the production of sulphuric acid in the atmosphere. This resulted in acid rain, which can have negative effects on the climate and ecosystems.

Question 4

Asteroids are only found in the Oort Cloud.

Accepted Answer

Asteroids are found in the Oort Cloud as well as the Kuiper Belt, which is a region of the solar system beyond Neptune. Some asteroids can also be found in the asteroid belt between Mars and Jupiter.

Question 5

Where is the crater that caused the mass extinction 65 million years ago located?

Accepted Answer

The mass extinction event 65 million years ago was caused by the impact of a large asteroid or comet on Earth, creating the Chicxulub crater. This crater is located on the Yucatan Peninsula in Mexico.

Question 6

The Kuiper belt contains comets and asteroids.

Accepted Answer

The Kuiper belt is a region of the outer solar system beyond the orbit of Neptune, and it is known to contain many comets and asteroids.

Question 7

An impact or an airburst from an object several kilometres in diameter

Accepted Answer

An impact or airburst from an object several kilometers in diameter would have global consequences, affecting climate and ecosystems worldwide, similar to the event that led to the extinction of the dinosaurs.

Question 8

The cause of the most recent mass extinction identified in Earth's history is

Accepted Answer

The most recent mass extinction, known as the Holocene or Anthropocene extinction, is primarily attributed to human activities such as habitat destruction, pollution, and climate change.

Question 9

If there was an asteroid of the same size as the one at the K-T boundary,would it mean a mass extinction that includes humans? Choose the best answer.

Accepted Answer

A similar-sized asteroid impact could cause significant environmental changes, disrupting ecosystems and food chains, which could threaten human survival.

Question 10

At present,what is the smallest sized asteroid that we are able to detect and track?

Accepted Answer

The answer of At present,what is the smallest sized asteroid...

Question 11

Is the risk of disaster from asteroid impacts high or low? Choose the best answer.

Accepted Answer

The risk of disasters from asteroid impacts is relatively high because even though they are rare, they can cause catastrophic effects such as mass extinction.

Question 12

Structurally,what is the primary difference between a simple impact crater and a complex impact crater?

Accepted Answer

The primary difference between a simple impact crater and a complex impact crater is that a simple impact crater does not have an uplifted center, while a complex impact crater does have an uplifted center. Simple impact craters are typically smaller in size and have a circular shape with a bowl-like depression, but they lack the central peak formation. Complex impact craters, on the other hand, have a central peak or uplifted mound that is formed due to the rebound of the rock beneath the impact point.

Question 13

The Chelyabinsk Meteor in 2013 in Russia caused over 300 deaths,making it the deadliest airburst ever.

Accepted Answer

The Chelyabinsk Meteor in 2013 did not cause any deaths, but did result in injuries to over 1,000 people due to shattered glass and other debris from the airburst.

Question 14

The earliest mass extinction event identified in the geologic record occurred about 446 million years ago at the end of the Ordovician Period.Which of the following situations/events coincided with this mass extinction?

Accepted Answer

The end of the Ordovician Period mass extinction is associated with a significant glaciation event that led to a drop in sea levels and a corresponding reduction in habitable shallow marine environments, which were crucial for many organisms at the time.

Question 15

Comet Shoemaker-Levy 9 collided with Jupiter in 1993.If a comet of similar size strikes Earth

Accepted Answer

The answer of Comet Shoemaker-Levy 9 collided with Jupiter in...

Question 16

Which of the following solar system features is farthest from the sun?

Accepted Answer

The Oort cloud is a hypothesized cloud of icy objects that is thought to extend to roughly halfway to the nearest star, making it much farther from the sun than any of the other options listed.

Question 17

A Tunguska-like event would cause catastrophic damage

Accepted Answer

A Tunguska-like event would cause catastrophic damage if it happened over an urban area due to the high population density and infrastructure, leading to significant loss of life and property.

Question 18

Scientific acceptance of the idea that asteroids could strike Earth and wreak havoc is relatively recent.What event made this possibility become nearly universally accepted?

Accepted Answer

The observation of comet Shoemaker-Levy 9's collision with Jupiter in 1994 provided a dramatic and visible demonstration of the potential for celestial bodies to impact planets, leading to widespread acceptance of the possibility of similar events occurring on Earth.

Question 19

What does it mean for an asteroid to be "differentiated"?

Accepted Answer

When an asteroid is said to be "differentiated", it means that it has undergone igneous processes that have caused it to become layered, with different materials like iron, nickel, and silicates settling into distinct layers based on their densities. This is similar to how the Earth has heavier iron in its core and lighter silicates in its crust.

Question 20

The Tunguska event in Siberia in 1908 produced a crater about 1 km in diameter.

Accepted Answer

The Tunguska event in 1908 did not produce a crater, but rather flattened trees over an area of about 2,000 square kilometers.

Quiz 15: Meteorite Impacts and Extinctions