Why does Obama oppose Elon Musk's Mars colony proposal?  

Former President Barack Obama has been out of the White House for over seven years.  

But, on occasion, he generates headlines and sparks controversy.  

Obama recently spoke out at a renewable energy conference in Paris, criticizing billionaires, particularly Elon Musk and his SpaceX company's plans to colonize space.  

"But when I hear some of the people talk about the plan to colonize Mars because the [Earth's] environment may become so degraded that it becomes unliveable, I look at them like, what are you talking about?"  

Obama also claimed that even after a nuclear war or the devastation of climate change, Earth would be more hospitable than Mars.   

He argued that Mars lacks oxygen, which is required for human survival.  

"I would rather us invest in taking care of this planet here," he stated. He proposed that space travel should be limited to "gathering knowledge and discovery."  

Obama's tone on getting to Mars was different 14 years ago.  

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