Elon Musk reportedly talked about the colonization of Mars and boosting Earth’s birthrates during his keynote address at Allen & Co’s Sun Valley conference on Saturday, but he avoided discussing his attempt to withdraw from his $44bn bid to buy Twitter.

Musk’s talk to close out this year’s edition of the Idaho conference which annually draws tech, media and finance gurus became one of the hottest tickets after lawyers for the Tesla boss filed notice Friday that he was terminating his bid to acquire Twitter. The billionaire accused the social media firm of failing to provide information on bot accounts, among other things, making observers wonder whether he would address such complaints at his speech scheduled for the next day.

But Musk – who is also chief of the private rocket company SpaceX – declined to do so. Instead, he mused about how he viewed Mars as a “civilian life insurance” if a disaster ever wiped out Earth, Bloomberg reported, citing the recollections of multiple people at the closed-door speech.

The remarks on Mars echoed a tweet from him earlier this year that humans could land on the planet by 2029.

Reuters, who reported speaking with attendees as well, wrote that Musk also expressed concern over the decline of birthrates in wealthy countries. And, Bloomberg added, he also renewed complaints about how Twitter had banned Donald Trump after the former president’s supporters staged the deadly US Capitol attack in early January 2021.

It wasn’t immediately clear whether Musk was aware that Trump had called him a “bullshit artist” and his actions with Twitter “rotten” on Saturday while stumping for Republican political candidates in Alaska.

Trump’s insult came after Musk last month said he was mulling throwing his support behind Florida’s governor, Ron DeSantis, rather than Trump as the Republican challenger to the Democrats’ Joe Biden in the 2024 presidential election.

The chief executive officer of OpenAI, Sam Altman, reportedly moderated Musk’s talk Saturday.

Musk may be in for a lengthy legal battle after notifying the public of his intent to withdraw from buying Twitter.

Twitter chairperson Bret Taylor said the social media platform could sue Musk in a Delaware court to enforce the purchase deal they had struck with the world’s richest man. The agreement contained a provision that may force Musk to buy Twitter as long as he has financing in place, which the businessman said he had in May.

Musk could also be fined $1bn if he goes through with ditching the deal, though he is trying to avoid the penalty by alleging that Twitter breached “multiple provisions” of its sale agreement.