Dr. James Pierce's

Favorite Quotes from Life in the Universe Essays:

— Planets —

Every term, each student in my Astronomy 115 course (Life in the Universe) was assigned to write an essay giving his or her opinion on the following question:

"Do extraterrestrial technical civilizations currently exist in our Galaxy?"

This group of quotes concerns planets. (The typos and misspellings are real, but they are not mine.) The material is presented here without comment; you will have to make up your own.

    Essay Quotes: Planets

  1. So basically, a planet that is going to properly hold an intelligent extraterrestrial species will most likely have to be living on a planet that is similar to Earth.

  2. Also, the atmosphere must consist of pressure for liquid water, a radiation shield, and most important oxygen.

  3. Their planet would also have to resemble the star that earth has.

  4. I believe that because Earth is the only planet with a liquid atmosphere and conditions able to support life makes our solar system unique.

  5. These elements do abundantly exist in the Universe, but no other technical civilization has been found other than ours that have such properties. Also, E.T. technical civilizations would also have to acquire a planet with an adequate water supply and a suitable atmosphere. As of today, humans are currently the only ones that have met these conditions.

  6. The most important part of this land mass would be it's atmosphere. This would help to control everything in side it's magnetic field and also repel every thing negative out.

  7. An atmosphere is also a vital key for life to maintain life.

  8. Since some planets are Jovial, which are not terrestrial because they're basically balls of gas inhabitable for life.

  9. Our planet has a gravitational belt that circles the earth protecting us from asteroids, comets, and anything else that could potentially destroy our entire planet. We don't know of any other planet that has this. I just don't think that we all came from one cell that multiplied into many. Then all of a sudden we have this planet that also came from a cell and then created a gravitation belt all on its own. It may just be hard to believe but it also doesn't seem probable to me.

  10. The planet would need to use the greenhouse effect to keep plants growing.

  11. I believe that earth has been placed in such a way and begin with the correct amount of elements that it is the only planet in the Milky Way to form life.

  12. The nine planets are spilt into two basic categories; jovial and earth-like or terrestrial planets.

  13. You can't have life without a planet to live it on.

  14. For intelligent life to exist the planet that they reside in needs to consist of the right elements, which would more than likely have to be similar to the genetic make-up of Earth.

  15. In our search for intelligent extraterrestrial life, humans have searched for planets with relative sizes to our planet.

  16. Large moons are most likely formed by random gigantic impacts and the Earth is just so lucky enough to be created around one of those impacts.

  17. Some argue that there are plenty of Earth like planets in our galaxy but we simply can't see them due to the obstruction of large jovian planets near by.

  18. We have tectonic plates and volcanic activity that keeps the earth from getting too hot in the center.

  19. For any extraterrestrial technical civilizations to currently exist, the plant in which they live on would have to the characteristics of: slow rotation, consist of a few moons, relatively small in size, and located close to the sun, made out of rocks and metals. ... The rotation needs to be relatively rapid in order to the proper amount of daylight and darkness needed each and every day, not only for terrestrials to survive, but also for plants and organisms currently present on Earth.

  20. Changes are against the odds for me and if life would have to be on a planet similar to ours then life cannot exist.

  21. After the big bang, how could these huge stars and planets have traveled billions of light years and be set-up so perfect that they orbit around the sun without colliding? Only because our planet's tilt is perfect enough to provide different seasons of earth.

  22. So if these elements came together to form life on earth, what would stop it from happing on another 'earth like' planet?

  23. The planet must also have something similar to our sun to give off heat and energy for the planet to stay alive and promote life. If you follow the Principle of Mediocrity then there must be some other plants out there with solar systems similar to ours.

  24. Our current atmosphere has a hole in it, which proves that atmospheres are not indestructible and unchangeable.

  25. Plate tectonics is what causes heat flow inside the earth. Plate tectonics is what gives us our electromagnetic field around the earth.

  26. Our solar system is made up of nine plants, moons numerous comets, meteoroids, and asteroids.

  27. Venus is the second planet closest from the Sun, whose surface temperature is 470 degrees Celsius or 878 degrees Fahrenheit. Liquid water would not be able to stay liquid with those types of temperatures, unlike Earth.

  28. It took 500 million to 1billion years for life to develop, so these planets must be at least that young.

  29. Mars is thought to have possibly supported life, but its atmosphere appears to have dried up.

  30. If our planet Earth were any bigger we would have longer days which would mean more hours of sunlight.

  31. There are other questions on whether life could exist on Jupiter because there is said to be a type of ocean under the icy surface.

  32. The principle of mediocracy tells us that Earth is actually not unique. This theory says that Earth is an average planet in an average solar system. Therefore, each planet that forms has the same probability to have the ability to support life as any other planet. I believe that this theory is partly correct and partly incorrect.

  33. We have searched our Galaxy and ocme to the conclusion that no planets, except for Mars, is capable of harboring life. The reason Mars is ruled out is because in 1996 NASA found a bacterial-like substance inside of a Martian meteor.

  34. The Moon is bombarded with craters made from impacts.

  35. For life to evolve on one of these stars, there first needs to be a planet orbiting around it.

  36. Evolution on other planets will not be dramatically different because, evolution is a long process.

  37. A planet is also necessary for life to develop on and would be necessary.

  38. The greenhouse effect also bounces back infrared rays keeping us safe from radioactivity.

  39. Liquid is vital for life, there are only four places that liquid could exist; Venus, Mercury, Mars, and Earth.

  40. The factors are vast for life to be able to thrive on a planet similar to our own.

  41. The raw materials, atmosphere, and distance from the sun our planet has sure seems like luck.

  42. Even if a planet was close enough in all aspects of what it would take to create intelligent life, I doubt that another planet would, given the sensitive way Earth had to create life.

  43. Even though our solar system is typical of other solar systems, there are a lot of very sensitive qualities a planet would need to produce intelligent life.

  44. What kind of planetary environment will give way for the possibility of life?

  45. Now I could go on and talk about our planet in how it has plate tectonics and the core of the Earth and how it has hot lava releasing up to the core through volcanoes.

  46. We also have planets like Venus and Mars that are similar to Earth, they are just located in poor positions relative to the sun for life to develop. However, one can't jump to conclusions and say that if given a more suitable position in our solar system that either planet could not host a technical civilization.

  47. Theoretically, the planet would have to have air held in by an atmosphere, and a large abundance of water in order to sustain intelligent life.

  48. Our atmosphere is our biggest asset. It provides us a source of oxygen along with trees and plants.

  49. We'd imagine in order for a planet to inhabit life forms it would need to have an atmosphere, water source, and located in a habitable zone.

  50. The second point that I want to bring up is that not every plant can support life.

  51. I believe that Mars, at some time, could have had life on it that suffered a catastrophe which killed off the life on it as well as all its resources.

  52. There are many reasons extraterrestrial life would not be able to survive in our galaxy. Some reasons consist of a stable planet, including the environment and the atmosphere dealing with elements.

  53. The reason why the planets are categorized is because there is correlation between the planets.

  54. The planet must have the proper mass, luminosity, stable variability and high metallicity.

  55. As the moon and other planets will show, without our specific atmosphere, planets have enormous creators created by asteroids that would completely wipe out life on a planet.

  56. These planets also need to be a PoP I star with a high metal content for life to exist and evolve.

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Created May 12, 2013; last modified March 19, 2021
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