Life On Other Planets Essay

1. Allie Hohmann
Science: 1A
Life on Other Planets Essay
Throughout our lives, scientists have been questioning whether or not Earth is the only planet,
or body in space, that contains intelligent life. There are many facts supporting both sides, but we still
do not know for sure whether we are the only humans out there. Many scientists believe that in order
for there to be life on a planet or moon, there has to be an existence of water; the life there may not be
humans, but plants or other intelligent life. One scientist, Robert Hazen, believes that since water exists
near the surface of the Earth, there is a possibility that life could be on Mars. Another scientist, Alan
Boss, says that the universe could be filled with rocky, earth-like planets containing water and possibly
life because there are already indications that such planets are going to be more common; Earth-like
planets probably occur around every solar-type star, or near them. Boss bases his hunch on the fact
that for nearby sun-like stars, about a third have turned up as 'super-earths'--planets five to ten times
more massive than Earth. Along with those theories, many scientists also believe that life of earth came
from other planets.
There are many places that are mainly thought to have life on them; some of those are Mars,
Europa, one of Jupiter's moons, and Enceladus, one Saturn's moons. The main reason why scientists
think that Mars could have intelligent life is because there is evidence that suggests that there had been
running water on its surface over one million years ago. There is also evidence of ice and liquid water on
this same planet. This evidence backs up scientists who believe that life existed on Mars, some of which
may still be around today. The discovery was made when a camera on NASA’s Mars Reconnaissance
Orbiter captured images of fan-shaped gullies on the planet’s surface. Scientists believe that they were
created by melting ice. Also, in May 2008, images from a robotic space craft showed what appeared to
be liquid droplets on the body which appeared to build during the space crafts time on Mars. Images
also showed some of these liquid droplets sliding down the space craft which some scientists compared
to melting ice. Another place that is thought to have life is one of Jupiter's moons, Europa. Some
scientists believe that there is a giant, salty ocean under its surface because the average temperature is
-260* and magnetic measurements taken by the Galileo space craft suggest that there is major activity
underneath its icy surface. Other signs of life on Europa include iceberg like formations on the surface,
which suggest that oceans once flowed on the planet before they froze. The third place that scientists
think that there is life is on one of Saturn's moons, Enceladus. There have been images from the Cassini
spacecraft which orbited Saturn a few years ago that showed ice particles out from the moon; these
images have raised the questions of whether liquid water exists on the space body. Along with those
images, there were also images that captured a tiger-stripe make on the ice surface, suggesting that
certain areas of the moon may not be as cold as once thought. Along with this evidence of different
space bodies, there has been one recent UFO sighting that has raised some more curiosity. Recently,
residents in Lincolnshire believed that they were visited by alien life forms when a turbine was damaged
over night with no apparent explanation. A local councilor even claimed to have seen ‘a round, white
light’ hovering nearby. This being just one of many UFO sightings.
While there are many reasons to believe in intelligent life on other planets, on contrast, there
are also some reasons that explain how extraterrestrial life wouldn't be possible. One of those is the
anthropic argument. This claims that extraterrestrial intelligence must be very rare because the time it
take for intelligent life to evolve is much longer that the portion of a star's existence that is conductive
to such life. Other reasons are that other planets in our solar system are either too hot or cold for
human life to be possible, and some rain harmful liquids; therefore it's unlikely that we could live on
them. The human body is very fragile and adaptive; we've spent billions of years adapting to and
surviving on Earth. Humans would need oxygen and temperatures that keep our bodies at a healthy 98

2. Allie Hohmann
Science: 1A
degrees meaning that adapting to other planets would be very hard. The atmosphere would also have
to be similar to Earth's.
Along with the idea of life on other planets in our solar system, there are speculations of life in
other solar systems. Currently, there are at least 150 red giant stars within 100 light-years of Earth and
many of them may have orbiting planets capable of supporting life. With those planets, dying red giant
stars may bring icy planets back from the dead. Lastly, once frozen planets and moos may provide a new
ground for life as their stars enter the last, and brightest, phase of their lives. There are many place that
could attain life, both in and out of our solar system.
I personally believe that it is possible for there to be life on other planets--not necessarily
intelligent life or humans. With the evidence of ice and water on the other space bodies, I think that is
evidence of possibility of plant life. Since plants need water and light to live, they could use the water,
and depending how close the planet is to a bright star, they could use the energy from that star to
survive. I don’t think there could be human life or any other intelligent life similar to ours because of the
certain temperatures on the planets--if the planet or moon was too hot, we would all burn, and if it
were too cold we would all freeze, making it impossible for humans to live there.