Scientists have found the first evidence that briny water may flow on the surface of Mars during the planet's summer months, a paper published on Monday showed. (REUTERS)
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Scientists analysing data from Nasa’s spacecraft have said liquid water flows during the summer months on present-day Mars, raising the possibility that the planet long thought to be arid could support life.
Although the source and the chemistry of the water is unknown, the discovery announced on Monday will change scientists’ thinking about whether the planet that is most like Earth in the solar system hosts microbial life beneath its radiation-blasted crust.
On Tuesday, Rich Zurek, project scientist of Mars Reconnaissance Orbiter (MRO) and Leslie K Tamppari, deputy project scientist of MRO, answered questions posted by the public on a Reddit Ask Me Anything (AMA).
Here are 15 takeaways from the AMA:
1. What quantity of water are we talking about?
A. We think this is a very small amount of water, maybe just enough to wet the top layer of the surface of Mars. The streaks are 4-5 meters wide and 200-300 meters long.
2. Where does the water come from?
A. We don’t know where the water in these hydrated salts come from. That is the next mystery to solve! The leading hypotheses are that (1) the salts are sucking up the water from the atmosphere; (2) that the water is coming from the subsurface. There is certainly more to learn!
3. The water is referred to as “briny” and that it’s more fluid than it is water. What does that mean? Would this be something theoretically possible to drink or grow things with? Or would this be the kind of thing that would need purification before it could be used?
A. The salts in the water appear to be perchlorates, so I wouldn’t want to drink the water. To be a future resource for humans, you would want to remove the salts.
4. If the Mars rover were to travel to the site of the briny water, what would be the scientific procedure for determining if that water supports life?
A. The Curiosity rover does not have life detection instruments. It would look for confirmation that liquid water was present and how long during the day it was liquid.
5. What does the water taste like?
A. It would be salty, but considering that perchlorate is toxic to humans, you wouldn’t want to drink it.
Summary of the main points announced about the discovery of water on Mars. (AFP)
6. The gravity on mars is about 3.711 m/s. Want to know if this much gravity is enough to hold a large amount of water on its surface. What will happen if we pour 200 gallons of water on the surface? Will it evaporate?
A. If you pour pure water on the surface (depending on the time of day) it will either freeze or boil away into the atmosphere. The salts that were talked about in the press release today would keep the water liquid at much lower temperatures. Remember that the temperatures on Mars change by more than 100 degrees Celsius every day.
7. I read that the rover can’t approach specific areas (including where the streaks are located) due to risk of infection by Earth microbes. Why is that? What are some examples of microbes that could be living on the rover that you are concerned with infecting the surface of mars?
A. These features are on steep slopes, so our present rovers would not be able to climb up to them. Because liquid water appears to be present, these regions are considered special regions where we have to take extra precautions to prevent contamination by earth life. Our current rovers have not been sterilized to the degree needed to go to an area where liquid water may be present.
8. It was shown back in 2011 that salt water flows may be a seasonal occurrence. What was the final proof for the team that this was happening, and what was your initial reaction to the data?
A. With MRO, we were able
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