If a meteorite hit the earth, could life be blown onto other planets?

You need to travel at 11 metres per second to escape form Earth's gravity. It is much harder to blow things off the Earth than it is Mars, although it is potentially possible to go from Earth to Mars. Humans might even be doing it accidentally when we send satellites up into space: sometimes they get hit with things and things like paint might flake off. However, once above the atmosphere, everything we send up is sterilised by radiation. And space scientists do as much as they can to prevent space becoming contaminated.