NASA scientists studying Mars announced this week that life was very likely possible in the planet’s infancy, according to this article:
The first era began with the planet's formation about 4.6 billion years ago and lasted for about 600 million years. Rock from this period lies exposed on the planet's surface due to meteorite strikes, erosion and underground shifts that formed cracks or faults in the planet's crust.
This ancient Mars terrain contains clay minerals, such as chamosite and nontronite, which form when water is abundant, temperatures are moderate and acidity is low, conditions that may have been suitable for life.
However, Mars underwent significant changes somewhere between 4 billion and 3.6 billion years ago—right about when life on our own planet was beginning to form. So, did Mars have a head start on us, and was there any life during that small window? For now, who knows.
Meanwhile, some other NASA scientists are looking forward rather than back. The Cassini space craft, which has been studying Saturn for the last couple of years, has found some intriguing data surrounding the small moon Enceladus, which contains “simple organic molecules, water and heat, the ingredients for life,” according to Dr. Rob Brown, a member of the Cassini team. Cassini did a flyby of Enceladus in July of 2005, and the results are astounding:
From this flyby came confirmation that the moon has an atmosphere, and strong evidence that the gases which make up the atmosphere are coming from cracks in the surface, nick-named "tiger stripes", near the south pole.
It appears that the gases are being forced through the surface, as they emerge in jets which shoot upwards for hundreds of kilometres before dispersing, eventually forming Saturn's E-ring.
Most of the gas is water vapour, suggesting strongly that liquid water lies under the moon's icy surface.
Its tiger stripes amount to a "water volcano", the only one seen in the solar system other than on Earth.
Among our neighbours, it is the only known geophysically active world other than Jupiter's moon Io.
Of course, it'll be another two years before Cassini attempts another flyby of Enceladus. Hopefully NASA is at work on getting further research done, as the article hints.