As CEO of Amazon, Jeff Bezos has his hands in just about every tech trend and innovation as they sweep entire industries. To put that into its proper perspective: When he last appeared onstage at Recode's Code Conference eight years ago -- as he did again on Tuesday evening in Los Angeles -- the hot new thing was e-readers like Amazon's then-novel Kindle.

You could say this year his thoughts were bigger: Artificial intelligence, saving planet Earth, and free speech all came up in the tech titan's conversation with Recode editor-at-large Walt Mossberg.

Here are some highlights from the conversation.

Saving the planet

How do you protect planet Earth? "By going into outer space," Bezos told Mossberg Tuesday. What he meant was something "slightly more measured" than Elon Musk's idea of building colonies on Mars, as Recode noted in a post about Bezos's comments.

The executive who started his business selling books said activities that require the most energy should be performed in space, in order to leave Earth clean and habitable for humans.

"Earth will be zoned residential and light industrial. You shouldn't be doing heavy energy on Earth. We can build gigantic chip factories in space," he said.

Artificial intelligence

Bezos thinks you should believe the hype on this one. Natural language processing, AI, machine learning -- however you cut it, "I think it's gigantic."

"It's probably hard to overstate how big of an impact it's going to have on society over the next 20 years," he said.

Voice interfaces won't replace screens (people like to use their eyes and fingers), but we will be interacting with computers in ways predicted in science-fiction novels, he says. Plus, algorithms and computing power are improving.

"I think we're on the edge of a golden era," he said.

Billionaires battling media

That Bezos thinks billionaires should let the press do its thing unencumbered is not surprising. The Amazon CEO also owns The Washington Post, and has himself been the target of vitriol from billionaire Donald Trump over the paper's coverage of the Republican candidate's presidential campaign.

Still, the executive had some strong words for high-profile folks who don't like the stories journalists report about them. He was careful to say he was speaking generally, and not specifically about venture capitalist Peter Thiel's funding of Hulk Hogan's lawsuit against Gawker -- though the Gawker suit was the subject of the original question from Mossberg.

"The best defense to speech that you don't like about yourself as a public figure is to develop a thick skin. It's really the only effective defense, because you can't stop it," he said. "If you're doing anything interesting in the world, you're going to have critics. If you absolutely can't tolerate critics, then don't do anything new or interesting."

"It's the ugly speech that needs protection," he pointed out. And if you don't like someone's ugly speech -- well, Bezos advised, "you don't have to invite those people to your dinner parties."

Privacy

Bezos believes it's okay to use customers' information as long as you're transparent about how you're doing it. He said Amazon does this by greeting consumers by name when they log on to the site, indicating that purchases are not anonymous. Tracking purchases allows Amazon to make recommendations for future purchases - -something the CEO asserts customers enjoy.

Still, handling this information can be sensitive. "You have to figure out ways to be kind of obviously clear," he said.

Shipping

Amazon sells everything from books to groceries to electronics the company makes itself, offering customers the option of receiving items as soon as just a few hours after they order. You would think the company was trying to put the U.S. Postal Service out of business, especially considering the tech giant's investment in drone delivery.