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The most distant object that human explorers have ever visited in person is the Moon; which has a maximum distance from Earth of:
4.05 x 105 km
The next destination for human astronauts may be Mars, which has a minimum distance from Earth of:
5.46 x 107 km
Calculate how many times farther astronauts will have to travel than they've ever traveled before in order to reach Mars. When you write this number in scientific notation, what is the exponent?"