Last week NASA scientists confirmed what they had been hoping to announce since Mars rovers Spirit and Opportunity were first conceived: Yes, Mars once had wet, liquid water on its surface.

Scientists have known since the 1970s – based on telescope observations from Earth and photographs from NASA’s Viking orbiters – that Mars has polar ice caps and a small amount of water vapor in its atmosphere. But since the late 1800s when astronomer Percival Lowell described Martian “canals” and hypothesized the existence of thriving Martian cities, modern scientists have been itching for a liquid explanation for Mars’ dry canyons, “river beds” and “shorelines.”

NASA’s watery discovery has sparked a slew of speculation as to whether Mars ever harbored life. Water is considered fundamental to the development of primitive life forms as we know them – but therein lies a flaw: “as we know them.”

Who is to say extraterrestrial life forms must use the same building blocks to evolve that earthly life uses? Living things on Earth possess DNA that codes for the proteins life is made of. What are the chances that an identical system – or even a similar one, with the same environmental requirements as earthly life – will evolve on another planet?

Finding that Mars once had water is exciting. It gives us an idea that the planet might have been warmer and “more hospitable,” maybe even with little Martian microbes.

But who is to say little Martian microbes – completely different from any of our terrestrial microbes – could not exist as the planet is now?

Perhaps the most exciting thing about Martian liquid water isn’t the possibility of extraterrestrial life but the idea that Mars just became a little more familiar to humans. Besides opening up many more opportunities for studying the Red Planet, if humans ever make their way there, they might be able to imagine it a little more like home.