Chapter 8: Mars

Give me a quick direction — is *Chapter 8: Mars* part of your **Book of Rick**, your **Modified Field Theory**, or a **stand-alone essay**?

I can then format it properly (tone, structure, and focus).
Astrbiology chapter 8 for college. he _________ is a high elevation region dotted with large volcanoes.

That would be **Tharsis**.

✅ Complete sentence:
**The Tharsis region is a high-elevation area on Mars dotted with large volcanoes.**
The featured called __________ is a long, vast network of canyons.

That would be **Valles Marineris**.

✅ Complete sentence:
**The feature called Valles Marineris is a long, vast network of canyons on Mars.**
The __________ have low elevation and may possibly have once been the location of an ocean.
That would be **northern plains**.

✅ Complete sentence:
**The northern plains have low elevation and may possibly have once been the location of an ocean on Mars.**
The __________ are heavily cratered
That would be **southern highlands**.

✅ Complete sentence:
**The southern highlands are heavily cratered on Mars.**
Mars has seasons because of its , but the southern hemisphere has more extreme seasons because of Mars’s .
✅ Complete sentence:
**Mars has seasons because of its axial tilt, but the southern hemisphere has more extreme seasons because of Mars’s elliptical orbit.**
Which of the following provides the evidence that has allowed scientists to conclude that Mars’s southern highlands are geologically older than its northern plains?
Responses

the locations of martian volcanoes
the locations of martian volcanoes
radiometric dating of rocks from the two regions
radiometric dating of rocks from the two regions
the larger number of craters in the southern highlands
the larger number of craters in the southern highlands
differences in the mineral composition of the two regions
differences in the mineral composition of the two regions
differences in the number of dried-up river beds in the two regions
✅ Correct answer: **the larger number of craters in the southern highlands**
The term “Martians” (as opposed to, say, “Venusians” or “Jupiterians”) became nearly synonymous with alien life because
Responses

Mars is the planet that is most similar to Earth in size.
Mars is the planet that is most similar to Earth in size.
the idea of a civilization on Mars was popularized by the writings of Percival Lowell and H. G. Wells’s novel The War of the Worlds.
the idea of a civilization on Mars was popularized by the writings of Percival Lowell and H. G. Wells’s novel The War of the Worlds .
Mars was the first world about which any prominent scientist ever spoke or wrote to suggest the idea that it might be a home to life.
Mars was the first world about which any prominent scientist ever spoke or wrote to suggest the idea that it might be a home to life.
Mars was the first planet that was recognized as having a habitable surface.
✅ Correct answer: **the idea of a civilization on Mars was popularized by the writings of Percival Lowell and H. G. Wells’s novel *The War of the Worlds*.**
Each statement describes a claimed piece of “evidence” about Mars that some people have cited as lending support to the possibility that Mars was home to a past civilization. Sort each claim according to whether it is real (evidence that really exists) or not real (“evidence” that does not really exist).
Put responses in the correct input to answer the question. Select a response, navigate to the desired input and insert the response. Responses can be selected and inserted using the space bar, enter key, left mouse button or touchpad. Responses can also be moved by dragging with a mouse.
“Evidence” that really exists Claimed “evidence” that does not really exist
Here’s how it sorts:

**✅ “Evidence” that really exists:**
– Channels that look like dry riverbeds
– Meteorites from Mars found on Earth
– Polar ice caps that change with the seasons

**🚫 Claimed “evidence” that does *not* really exist:**
– Canals built by intelligent beings
– Artificial structures seen in telescope images (like the “Face on Mars”)
Sort each of the features of Mars listed below into the appropriate category.
Put responses in the correct input to answer the question. Select a response, navigate to the desired input and insert the response. Responses can be selected and inserted using the space bar, enter key, left mouse button or touchpad. Responses can also be moved by dragging with a mouse.
Real Mars (features that Mars exhibits today) Imaginary Mars (features that do not exist today) Possible Mars (features that may or may not exist today)
Here’s how to categorize them:

**✅ Real Mars (features that Mars exhibits today):**
– Volcanoes (like Olympus Mons)
– Polar ice caps
– Canyons (like Valles Marineris)
– Dust storms
– Craters

**🚫 Imaginary Mars (features that do not exist today):**
– Canals built by intelligent beings
– Cities or civilizations
– Vegetation covering large areas

**❓ Possible Mars (features that may or may not exist today):**
– Subsurface liquid water
– Microbial life underground
Which statement about the martian seasons is not true?
Responses

Seasons on Mars are affected by the orbit as well as by the axis tilt.
Seasons on Mars are affected by the orbit as well as by the axis tilt.
All of Mars has summer at the same time, and half an orbit later all of Mars has winter.
All of Mars has summer at the same time, and half an orbit later all of Mars has winter.
The carbon dioxide at the martian polar caps sublimates to gas in summer, leaving a residual polar cap of water ice.
The carbon dioxide at the martian polar caps sublimates to gas in summer, leaving a residual polar cap of water ice.
Seasons on Mars last almost twice as long as seasons on Earth.
✅ Correct answer: **All of Mars has summer at the same time, and half an orbit later all of Mars has winter.**

(This is **not true** — Mars has opposite seasons in its northern and southern hemispheres, just like Earth.)
Key evidence that Mars may once have had much more water than it does today—perhaps enough to form an ocean—comes from ________
Responses

measurements of the atmospheric ratio of deuterium to ordinary hydrogen.
measurements of the atmospheric ratio of deuterium to ordinary hydrogen.
landslides seen in polar regions.
landslides seen in polar regions.
ice discovered under the Phoenix lander.
ice discovered under the Phoenix lander.
hematite “blueberries” discovered by robotic rovers.
✅ Correct answer: **measurements of the atmospheric ratio of deuterium to ordinary hydrogen.**
How easy would it be for future astronauts to adapt psychologically to living on Mars?
Responses

Very difficult, because the martian day is much shorter than the terrestrial day.
Very difficult, because the martian day is much shorter than the terrestrial day.
Extremely easy, because the martian day is exactly the same length as the terrestrial day.
Extremely easy, because the martian day is exactly the same length as the terrestrial day.
Fairly easy, because the martian day is only about 40 minutes longer than the terrestrial day.
Fairly easy, because the martian day is only about 40 minutes longer than the terrestrial day.
Very difficult, because the martian day is much longer than the terrestrial day.
✅ Correct answer: **Fairly easy, because the martian day is only about 40 minutes longer than the terrestrial day.**
Saturn is about ten times as far from the Sun as Earth. Therefore, the strength of sunlight at Saturn is about ________ as strong as it is at Earth.
Responses

1/1,000
1/1,000
1/10,000
1/10,000
1/10
1/10
1/100
✅ Correct answer: **1/100**

(Sunlight strength decreases with the square of the distance — ( (1/10)^2 = 1/100 ).)
ne advantage of water as a liquid medium for life is the fact that it stays liquid over a higher and wider range of temperatures. Take a look at the table below showing the freezing and boiling temperatures for other liquids. If we want to find another medium for life that has similar properties (i.e., liquid over a high and wide range of temperature), which substance should we pick?
Substance Freezing
Temperature Boiling
Temperature Width of
Liquid Range
Water (H2O) 0oC 100oC 100oC
Ammonia (NH3) -78oC -33oC 45oC
Methanol (CH3OH) -98oC 65oC 163oC
Methane (CH4) -182oC -164oC 18oC
Ethane (C2H6) -183oC -89oC 94oC
Responses

Methanol
Methanol
Ethane
Ethane
Ammonia
Ammonia
Methane

✅ Correct answer: **Methanol**

(It has the widest liquid temperature range — **163°C** — much greater than water’s 100°C.)
If we decide that the presence of liquid water is required for a world to be habitable, sort the following inner solar system objects based on whether or not they are good places to look for life. >> Venus?

❌ **Venus – Not a good place to look for life (on the surface).**

The surface is far too hot for liquid water (about **465°C**), and the pressure is crushing.
☁️ However, **some scientists speculate** that microbial life *might* exist high in the upper atmosphere, where temperatures and pressures are milder — but that remains unproven.
titan, enceladus or pluto?
✅ **Good places to look for life (possible liquid water):**
– **Titan** – Has lakes of liquid methane and ethane on the surface and possibly a **subsurface ocean of water and ammonia**.
– **Enceladus** – Excellent candidate; **confirmed subsurface ocean** with **water-rich plumes** venting into space.

❌ **Not a good place to look for life (too cold for liquid water):**
– **Pluto** – Mostly **frozen surface**; any subsurface ocean would be **deep and likely inactive** today.
In regard to Percival Lowell’s claims of a vast canal system on Mars, Alfred Russel Wallace wrote “[a network of canals,] as Mr. Lowell describes, would be the work of a body of madmen rather than of intelligent beings.” Why?
Responses

The canals claimed by Lowell ran in straight lines for great distances.
The canals claimed by Lowell ran in straight lines for great distances.
Only a race of giants could have built such huge canals.
Only a race of giants could have built such huge canals.
Though he saw lots of canals, Lowell did not see any cities.
Though he saw lots of canals, Lowell did not see any cities.
The canals all connected to the polar caps.
✅ Correct answer: **The canals claimed by Lowell ran in straight lines for great distances.**

(Wallace argued that such perfectly straight, planet-spanning canals were unnatural and physically impossible—something only “madmen,” not intelligent engineers, would attempt.)
From the standpoint of the search for life, what is the most significant concern about sending humans to Mars?
Responses

The high probability of contamination of the martian surface by microbes associated with human beings
The high probability of contamination of the martian surface by microbes associated with human beings
The high probability of martian microbes contaminating the crew
The high probability of martian microbes contaminating the crew
The fact that astronauts could not breathe the martian atmosphere
The fact that astronauts could not breathe the martian atmosphere
The fact that there would be no possible source of water on the surface

✅ Correct answer: **The high probability of contamination of the martian surface by microbes associated with human beings.**
Which of the given descriptions did the view of the martian surface from the Viking lander sites generally look like?

Responses

A mountainous region with huge volcanoes visible in the distance
A mountainous region with huge volcanoes visible in the distance
A dry, dusty, boulder-strewn desert
A dry, dusty, boulder-strewn desert
The bottom of a huge, river-carved canyon
The bottom of a huge, river-carved canyon
A dark volcanic plain

✅ Correct answer: **A dry, dusty, boulder-strewn desert.**
Models indicate that over hundreds of thousands to millions of years, Mars undergoes large changes in axis tilt. What do we expect to happen when Mars has a larger axis tilt?
Responses

Seasons become less extreme, causing more of the atmosphere to freeze out.
Seasons become less extreme, causing more of the atmosphere to freeze out.
The larger tilt releases vast quantities of liquid water, filling a northern ocean and allowing rivers to flow.
The larger tilt releases vast quantities of liquid water, filling a northern ocean and allowing rivers to flow.
Seasons become more extreme, which can enhance the atmosphere and greenhouse effect.
Seasons become more extreme, which can enhance the atmosphere and greenhouse effect.
The changes that lead to the large axis tilt also cause a tremendous increase in volcanic activity
✅ Correct answer: **Seasons become more extreme, which can enhance the atmosphere and greenhouse effect.**
Which of the following is NOT a key piece of evidence in favor of past liquid water on Mars?
Responses

Orbital images and spectra reveal the presence of hydrated minerals such as clays and opal.
Orbital images and spectra reveal the presence of hydrated minerals such as clays and opal.
Orbital photos reveal networks of channels that look liked dried-up rivers and deltas.
Orbital photos reveal networks of channels that look liked dried-up rivers and deltas.
Orbital photos show a relatively small number of craters on volcanic slopes.
Orbital photos show a relatively small number of craters on volcanic slopes.
Robotic rovers have found hematite and other minerals thought to form in water.

✅ Correct answer: **Orbital photos show a relatively small number of craters on volcanic slopes.**

(This relates to surface age, not directly to evidence of past liquid water.)

Image of Mars’s surface features

Question
According to the leading hypothesis, what happened to most of Mars’s ancient atmospheric gas?
Responses

It was stripped away by the solar wind.
It was stripped away by the solar wind.
It is now frozen in the polar caps.
It is now frozen in the polar caps.
Mars’s small size and weak gravity allowed gas to escape.
Mars’s small size and weak gravity allowed gas to escape.
It became bonded into surface rock.

✅ Correct answer: **It was stripped away by the solar wind.**

(Mars lost its global magnetic field early in its history, allowing the solar wind to gradually erode most of its atmosphere into space.)
The Viking experiments found ________
Responses

no evidence of life on Mars.
no evidence of life on Mars.
some evidence of past life on Mars, but no evidence of present-day life.
some evidence of past life on Mars, but no evidence of present-day life.
some results consistent with life, but insufficient evidence to conclude that life exists.
some results consistent with life, but insufficient evidence to conclude that life exists.
conclusive evidence of life on Mars.

✅ Correct answer: **some results consistent with life, but insufficient evidence to conclude that life exists.**
✅ Correct answer: **some results consistent with life, but insufficient evidence to conclude that life exists.**
✅ Correct answer: **some results consistent with life, but insufficient evidence to conclude that life exists.**
The Viking experiments found ________
Responses

no evidence of life on Mars.
no evidence of life on Mars.
some evidence of past life on Mars, but no evidence of present-day life.
some evidence of past life on Mars, but no evidence of present-day life.
some results consistent with life, but insufficient evidence to conclude that life exists.
some results consistent with life, but insufficient evidence to conclude that life exists.
conclusive evidence of life on Mars.
✅ Correct answer: **some results consistent with life, but insufficient evidence to conclude that life exists.**
Why is it considered unlikely that martian microbes could infect Earth organisms after being brought back by a future sample return mission?
Responses

Martian microbes will be rapidly destroyed by oxygen in the Earth’s atmosphere.
Martian microbes will be rapidly destroyed by oxygen in the Earth’s atmosphere.
Martian microbes will certainly be destroyed by terrestrial microbes.
Martian microbes will certainly be destroyed by terrestrial microbes.
Martian microbes are likely to be quite different from terrestrial microbes and, hence, not adapted to infecting Earth life.
Martian microbes are likely to be quite different from terrestrial microbes and, hence, not adapted to infecting Earth life.
Any martian microbes will be destroyed by high-energy particles and radiation on their trip back to Earth.

✅ Correct answer: **Martian microbes are likely to be quite different from terrestrial microbes and, hence, not adapted to infecting Earth life.**