Planet Business: Musk dreams of golden future on red planet

In numbers: the King of Golf

$6,000

The late Arnold Palmer’s annual earnings at around the time he became the first client of sports marketing agency IMG in 1960.

$500,000

His annual earnings within two years of shaking hands with IMG’s founder, king of sports marketing Mark McCormack. Palmer went on to become the first player to make $1 million from the game.

$52.9 million

Wealth attributed to US golfer Phil Mickelson, who made eighth place in Forbes’s list of the highest paid athletes in 2016.

Image of the week: Astronomical ambition

Elon Musk, of SpaceX fame, has been unveiling his plans to colonise Mars, giving a keynote at a Mexico conference on the subject of Making Humans a Multiplanetary Species . Musk said he envisaged a Mars colonial fleet, of about 1,000 passenger ships, flying en masse to Mars, and that this would be "kind of like Battlestar Galactica". Then he also suggested the first Mars-bound spacecraft might be called the Heart of Gold, which is a reference to The Hitchhiker's Guide to the Galaxy. So, by this reckoning, the future is either a clone-filled dystopia in which no one can find mythical planet Earth, or a surreal universe in which Earth has been destroyed to make way for an intergalactic bypass and nothing seems to make much sense. Either way, this is science fiction.

Photograph: Susana Gonzalez/Bloomberg

The lexicon: Backpacker tax

Dubbed “ridiculous” by the Australian tourism industry when it was announced last year, “backpacker tax” is the shorthand for Australia’s plan to introduce a new income tax regime for overseas visitors on working holiday visas. The new Australian government has now softened the measure, slashing the rate from the proposed 32.5 per cent to 19.5 per cent, but while the tax won’t be as heavy as it could have been, it’s still a new burden as it replaces a system of tax-free earnings for backpackers on the first 18,200 Australian dollars they earned. The other bad news is that, in order to fund the “compromise” rate, Australia’s “departure tax” has been hiked $5 to $60. It’s hard to know whether it wants people to come or go.

Getting to know: David Kittos

David Kittos is a British-based photographer who has been in the news lately for a reason he could probably never have predicted in his wildest dreams. Six years ago, he posted a picture to photo-sharing site Flickr of a bowl of skittles, labelling it all rights reserved. Enter Donald Trump jnr, who thought Kittos’s image might be just perfect to use as a visual analogy for his take on the “Syrian refugee problem”. (In case you missed it, this went: “If I had a bowl of Skittles and I told you just three would kill you, would you take a handful?”) The image has now been removed from Twitter “following a report from the copyright holder”, aka Kittos via his newly hired lawyer. The thing is, Kittos was once a refugee himself, leaving Cyprus in 1974 after Turkey invaded. And not surprisingly, he does not approve of Trump one little bit.

The list: Twitter suitors

Twitter is reported to be entertaining conversations with a string of suitors about its possible sale, and its future as a standalone company is now shortening by the day. But which one of them will put a ring on it?

1. Walt Disney: the Star Wars franchise owner could be the one to give Twitter a happy ending of sorts.

2. Microsoft: "At the moment, Microsoft has nothing to share," was the company's non-denial denial.

3. Verizon: the US telecoms giant that bought AOL could be coming back to the acquisitions table for more.

4. Salesforce. com: it's hard to get enthused about what a business software maker might do with Twitter if it got its hands on it.

5. Google: parent company Alphabet could be tempted to pick up Twitter. It has already stopped trying to make Google+ happen.