Why are we better off colonising space than other planets like Mars?
According to Jeff Bezos, there are a bunch of problems associated with colonizing other planets that do not exist when it comes to nearby outer space.
Other planetary [which we could attempt to colonize] aren't that big when compared to Earth, maybe a doubling of surface area at best. Considering how far they are, that's not that useful.
Round trip times are a significant logistical problem. Trips to Mars, for example, are on the order of years, and launch opportunities to Mars only occur once every 22 months.
Lastly, other planets are far enough away to do real time communications with Earth, limited by the speed of light.
Why is Blue Origin moon lander using liquid hydrogen for their fuel?
Liquid hydrogen fuel can be replenished using water from the Moon, thus enabling longer missions that don't require all the fuel to be packed ahead of time.
What are challenges and opportunities for Amazon's partnership with Blue Origin?
On one hand, it would be incredibly convenient for Amazon to use Blue Origin as a launch rocket for their upcoming satellite array. These satellites would enable Amazon to provide better services for their stream and cloud businesses, among other.
On the other hand, because Amazon is a public company, they have to make sure that Blue Origin doesn't just get a contract by default, thus enabling Bezos to stash money from his public company into his private venture.