Download Grade 9 Academic Science – Space

Grade 9 Academic Science – Space
Chances of Survival
We have talked about human’s living on Mars. It seems plausible, and the movies make it seem possible…if not
romantic (…if we can only avoid the aliens that use our bodies to reproduce…). Yet, it seems Earth is unique in our
Solar System. It is the only planet that, we think, supports life. NOTE: Research into the possibilities of conditions
for life on Mars (e.g., water, carbon) is underway as you read. We also imagine life is possible elsewhere in the
Universe (…think of the scale, size, plus the number of galaxies, stars and other objects that could support other life
forms). Next, we believe we could engineer an atmosphere on another planet that would allow you and I (…okay,
maybe just you…) to survive. It would be a big task, but as with any engineering, it is theoretically possible and fun to
image.
Table 1. Planet Temperature and Atmosphere Chart
Planet
Distance
to Sun
(AU)
Temperature
Range
Amount of
Atmosphere
(bars)*
Atmospheric Conditions
Mercury
0.39
-170OC to 662OC
(832OC range)
~0.000000000000010
(Trace)
42% oxygen (O2)
29% sodium (Na)
22% hydrogen (H2)
6% helium (He)
0.5% potassium (K)
Possible trace amounts of argon (Ar),
carbon dioxide (CO2), water (H2O),
nitrogen (N2), xenon (Xe) , krypton
(Kr) and neon (Ne)
Venus
0.75
constant
460OC
92
96.5% CO2
3.5% N2
0.0020% H2O
trace amounts of sulfur dioxide (SO2),
Ar, carbon monoxide (CO), He and
Ne
Earth
1
-50OC to 45OC
(95OC range)
1 (sea level)
Our Moon
NA
-153OC to 134OC
(728OC range)
0
Mars
1.52
-111OC to 26OC
137OC range)
0.0061
78% N2
21% O2
0.035% CO2
1 to 4% H2O
300 Dobson Units ozone (O3)
0.002% methane (CH4)
0.9% Ar
trace amounts of He, Kr and H2
No atmosphere
95.32% CO2
2.7% N2
1.6% Ar
0.13% O2
0.08% CO
0.0210% H2O
trace amounts of nitrogen oxide (NO),
Ne, Kr, Xe and
hydrogen-deuterium-oxygen (HDO)
* 1 bar is the average atmospheric pressure at sea level on Earth
Source: NASA. http://astroventure.arc.nasa.gov/teachers/pdf/AV-Atmoslesson-3.pdf
Why can we not just move to another planet? Well for starters, life on Earth has needed 4.5 billion years to evolve
and adapt to the living conditions on Earth. Evolution is a randomly slow process. You and I cannot change
suddenly to live in different conditions.

Our bodies evolved under the pressure of Earth’s atmosphere. If we go to a planet or moon with less
pressure, we will explode. If the pressure is too high, we implode.

We are influenced and constrained physically by the pull of Earth’s gravity. If gravity is too strong, we are
unable to move. If gravity is too weak, our muscles waste away (THINK of astronaut Chris Hadfield in the
space station right now)

Temperature is another factor. You and I have to maintain an internal body temperature of about 37OC to
be healthy. If the air temperature around us is a few degrees colder, we experience hypothermia. If it is
only a few degrees warmer, hyperthermia occurs.

Finally, we need a breathable atmosphere. That is, we need oxygen. In a low oxygen concentration, we die
of hypoxia. If the atmosphere has too much oxygen, we die of oxygen toxicity.
Could you and I survive on any of the planets or moons listed in Table 1? Provide reasons for your decision
for each case.
The search for Earth-like planets …or exoplanets… is underway. NASA’s Kepler satellite will orbit our Sun for four
years while searching distant stars for signs or indications of exoplanets. After Kepler, NASA will send the Terrestrial
Planet Finder (…a huge telescope being built in space…) to search even more galaxies. NASA is seeking a planet
in the “habitable zone” - the region around a star within which it is theoretically possible for a planet with
sufficient atmospheric pressure to maintain liquid water on its surface. This planet is referred to as a
“Goldilocks planet.” To date, 54 Goldilocks planets have been mapped. Interesting question: What are the
Kepler satellite and the Terrestrial Planet Finder telescope looking at as they conduct their searches? The
bigger problem is getting to these inhabitable planets. They could be many light-years away, and with today’s
technology, we have not yet traveled to Mars (about 0.5 AU away from Earth. FYI: 1 AU = 150 000 000 km or 1.5 X
108 km while 1 LY = 9 460 000 000 000 km or 9.46 X 1012 km). Other planets are, at present, too far away.
So, another solution would be to engineer or terraform the atmosphere on Mars, our nearby neighbour. Sound
simple, right? All we need to do is add oxygen to the atmosphere so we can breathe. Not so fast…it is not easy.
What do you think we would need to do to Mars to terraform it for our survival?