Steam No Man's Sky on Mac?

I have downloaded Steam on my Mac, will I be able to buy No Man's Sky?

I am reading that it is only available for the PC, if so I am gutted

Buy? Yes. Even if the Steam client won't let you buy the game because your OS is not supported, you can always use your browser to buy the game.

However, if you want to play the game, that is a different issue. According to Steam and GoG, these are the minimum system requirements for No Man's Sky:

MINIMUM:
OS: Windows 7/8.1/10 (64-bit versions)
Processor: Intel Core i3
Memory: 8 GB RAM
Graphics: nVidia GTX 480, AMD Radeon 7870
Storage: 10 GB available space

As you can see, OSX is not supported. So no, you can't play the game on a Mac (yet).

However, assuming your Mac is relatively modern, you can install Windows on it (using Boot Camp). Therefore you won't need a new PC to play the game.

To be honest, macOS probably wouldn't handle the game too well. Unless you have a Mac Pro, you will probably be left running the game (if it is ported or if you run it in Bootcamp or Wine*) on low graphics settings.

I played it today with a 980ti graphics card and it was kind of choppy even with a 6-core i7-5820k at stock 3.3 Ghz.

I have no idea if it will run on Wine, it's just a possible solution for those who use Windows Apps on Mac. If you have never heard of Wine, I suggest you stay away from this as it can be technical, especially since the developer stated that VCRedist 2010 is needed to run the game, managing software dependencies for the casual gamer is difficult in Wine.