Pergunta 3 8 pts In astronomy, we define a \"habitable planet\" as a terrestrial
ID: 1790745 • Letter: P
Question
Pergunta 3 8 pts In astronomy, we define a "habitable planet" as a terrestrial planet with an atmosphere that can support liquid water on its surface. Which of the following are true statements about the three terrestrial planets in our Solar System that have atmospheres, as regards their habitability and the strength of the greenhouse effect in their atmospheres? You may wish to refer to the following table (see also Worksheet #5) Surface Temp Greenhouse Effect Actual Planet CO2 H20 Pressure No greenhouse Venus Earth Mars Energy 97% 38% 4% Temp 88 atm 0.0044 atm 0.006 atm +27 °C / 300 K | 462 °C / 735 K | +145% | | 18 °C / 255 K | 14 °C / 287 K | 65 °C / 208 K | -63 °C / 210 K | +12% +1% Venus and Mars look like relatively easy places for humans (e.g., astronauts) to visit and explore. A significant greenhouse effect is only observed in planets with atmospheres dominated by CO2, H20, and other greenhouse gases Mars experiences a greenhouse effect, but it is not strong enough at the present time to make the planet habitable It is not possible for a greenhouse effect to be so strong that it turns an otherwise-habitable planet uninhabitable Venus would be a habitable planet if not for the greenhouse effect of its atmosphere O If Venus had a much weaker greenhouse effect, as it likely had in the distant past, it could be a habitable planet. If Mars had a thicker atmosphere and stronger greenhouse effect, as it likely had in the distant past, it could be a habitable planet. O Earth is habitable thanks to the greenhouse effect of its atmosphereExplanation / Answer
The Earth's climate seems to be changing much more quickly than it used to do. We are altering one of our planet's natural 'temperature regulators' - the greenhouse effect. The greenhouse effect determines the flow of energy arriving at and leaving from Earth.
For a really strong greenhouse effect, we should look at Venus. Venus is similar to Earth in terms of size and mass, but its surface temperature is about 460 degrees Celsius. This is hot enough to melt lead! The Venusian atmosphere is mainly made up of carbon dioxide, a greenhouse gas. On Earth, carbon dioxide makes up only a tiny fraction of the atmosphere.
As a complete contrast to Venus, there is Mars. The Red Planet displays hardly any greenhouse effect. Mars does have some atmospheric carbon dioxide, but almost no atmosphere! The existing atmosphere is so thin that it cannot retain energy from the Sun. There are therefore extreme temperature contrasts between day and night and sun or shade. However, most scientists agree that Mars was much warmer in the past and even had oceans, which means that the atmosphere was also very different.
If mars had a thicker atmosphere and stronger greenhouse effect ,as it likely had in the past it coud be a habitable planet.