This is big news for all Mars enthusiasts and everyone else. Strong evidence of flowing water has been seen on Mars by the Orbiter, which has been deputed to scan the Martian surface. This is bigger than the discovery of frozen ice-caps. Flowing water supports life on Earth and could have done so on Mars too.
This is the strongest hint that liquid water may still be present on the Martian surface. This is a good place to remind everyone that liquid water has not been physically found, though. Alfred McEwan, a planetary geologist at Arizona University, says:
We have this circumstantial evidence of water flowing on Mars. We have no direct detection of water.
The Discovery and its implications
The discovery comes via the Mars Reconnaissance Orbiter (MRO) and was announced by NASA yesterday (i.e. on the 4th of August). The discovery of such signs was made at lower latitudes, where the temperature is much warmer than at the poles and liquid water can exist.
Biochemists are also excited, apart from the obvious bunch of astrobiologists. This opens up a whole new world of chemical processes, some of which could be those of life as we know it. As far as we know about the composition of Mars, it could support primitive life forms identical to the ones we have on earth. Specifically, it could (or still can) support life-forms like Archea.
The signs of flowing water are what we would expect on Earth. There are fine marks of leeching and long drawn tendrils, separated from each other by a few meters. (See figure below). These are identical to the marks left on eroding soil, when water gently thaws away the underlying layers of soil and erodes. It is highly improbable that anything other than a liquid flow caused these marks and the only liquid that can possibly exist on such a scale is water.
The possibility of this being salty water is even more enticing. Salt lowers the melting point of water and, thus, water can remain liquid even at much higher latitudes. Further, we know of several kinds of salt-loving (or halophilic) microbes living on saline water on Earth. There is no reason why creatures similar to these cannot arise on Mars.
The Mars rover, Curiosity, to be launched later this year, should tell us more. There is no fear of a War of the Worlds scenario, the author of this article assures you.