Bio-signatures are any substance or element such as an atom, molecule, or phenomenon that provides scientific evidence of past or present life. If we were in a classroom we would show that life exists by looking at the board for handwriting, book bags, and possibly lunchboxes from the students. These would all be examples of life in the room if we had to prove there was life. People are changing the Earth’s atmosphere everyday by polluting and by breathing, because when humans are breathing inhaling oxygen, they are exhaling carbon dioxide. Animals and other living things like bacteria produce gases besides oxygen and carbon dioxide. Methane is four hydrogen atoms bound to a carbon atom, which is the main component of natural gases on Earth. One of the most natural causes of methane is cow gases (belching and farts) and and also different types of bacteria let out methane. Methane is not stable in the Earth’s atmosphere, because it is easily destroyed by UV light from the Sun. The fact that methane is easily destroyed makes it a good bio-signature because if you find methane, then it implies that it was recently produced. For an example, if I had candy sitting out in a crowded room and people were actively eating it, I would expect it to be gone rapidly. If every time I went back into the room and there was still a full bowl of candy I could predict someone was refilling it.
The figure below shows where methane is located and where the red spots are is where there is a lot of methane located, but as you notice there is also green spots that mean that there is methane, but not as much. Because, methane on Earth comes from cows and bacteria, this discovery shows that there is a possibility that Mars is still alive. Though, you should not get too excited about alien life because there are multiple things that can produce methane. The press exaggerated when they said it was a sign of life on Mars. Astrobiologists are not sure what the origin of methane is because geological processes like oxidation of iron also release methane. Methane can also be produced by volcanoes, but volcanoes usually release other gases that were not detected.
This picture shows that where the red is there is a high amount of methane:
Just because there are rough conditions on Mars does not mean that there cannot be life, it would just be very difficult for animal life, but bacterial life could survive in tougher conditions. The reason I am saying bacterial life can survive in tougher conditions is because bacteria live in the strangest places on Earth proving that they can survive in tougher conditions. There could possibly be life on Mars in the future or current life there now, scientist are not still sure because methane can come from anywhere. We will have to wait and see if the methane on Mars came from current life on Mars (like bacteria), chemical processes, or volcanoes.
1. Based on the graph above, how much of the planet’s atmosphere shows methane signatures?
2. How do people contribute to changing earth’s atmosphere?
3. Do you think or believe that there could be current life or future life on Mars? Why or Why not?