When did the rovers send pictures from mars to earth?

Answer 1

To simply find out more about the Martian planet. Before the Martian probes were launched, much was of course known about Mars- that it had not supported life for hundreds of thousands of years, that the so-called 'canals' were a geographical feature and not artificially made, and so on.

But Scientists from Earth were curious- warranted, the 'canals' were not made by intelligent life, and all evidence supported the theory that Mars is a dead planet. BUT- had it once, maybe, held water? Nobody for a minute imagined that life- even vegetation- existed on Mars, but PERHAPS, it might at one point in the past have had water on it, which MAY have given rise to primitive lichens, and maybe bacterial forms of life. Probes (both orbital and landers) can give the answers to these questions.

And this is indeed what they are currently finding out- the Mars Orbiter suggests that there may indeed be a residue of underground water left on Mars, that appears at some seasons of the year. If any life- even at microscopic level- ever existed there, they would be long dead by now, but their fossilised remains MIGHT exist in ancient rocks, which would indicate that eons ago, Mars may have been closer to the Sun than it is now, which would allow organic life to develop.

The other reason that probes were sent there, was simply to find out what it looked like. Nobody knew what Mars looked like before 1969, when the first probe succesfully landed- and even then, it only transmitted pictures for about 15 seconds. The first truly succesful probe was Mariner 1 in 1976, which broadcast pictures of the Martian surface- it's true that she landed on the South-East of the planet, which is not the best place to go, so all she got was a view of a red desert covered in rocks. Other probes since then have taken pictures of a more interesting geography, with hills, small valleys and variable soil, as well as analysing the content of the atmopshere, but even so the fact remains that Mars cannot, and has not supported, life for many Millenia.

Maybe in Centuries to come, humankind will be able to travel to Mars, and then much further along, even modify it's atmosphere so that people can breathe normally on it without the need of space-suits. But this is a long way off- such things will not happen in the lifetime of anyone alive today! It's quite possible that this will happen ONE day, but not for a VERY long time.