Could a star far bigger than Earth's sun have a large enough range of 'life-sustaining distance'...

…for multiple planets orbiting it to fall within? In other words, could a very big star (scuse me having no idea how big that would be) potentially have more than one planet orbiting it at a distance that, with the right atmosphere, could create Earth-like conditions?

That could be…but there is a difficulty. Big stars have much shorter life-spans, and thus such planets might not have time to become earth-like, even if liquid water flows over its surface, from mountains to seas in streams.

There might be time for very primitive life to arise, but not for anything like the biodiversity we rejoice in. You’d have vast bacterial mud-flats, but not trees and animals.

Still, yes, the basic question is valid. A larger star would have a broader “goldilocks zone,” where planets could exist and liquid water could be found circulating.

The Sun itself has a large enough Goldilocks zone for multiple habitable planets. Mars could be habitable, with a thicker atmosphere, and there’s no inherent reason it couldn’t have one. It’d still be unpleasantly cold over most of the surface, but then, that’s true of a lot of inhabited areas of Earth.

What do the models say about planet formation around massive stars…If it’s just a handful of gas giants then that might rule out life (at least as we know it) for that reason?

There appear to be a huge number of planets. I just read that there are likely more rogue planets, those not even associated with a star, than there are stars. Each star probably has a decent number of planets to itself on average. There are pretty clearly many planets that are rocky and not gas giants.

Wikipedia has decent articles on things like exoplanets and rogue planets.

Disk formation has been observed in several large, young stars, sometimes with gaps suggestive of gas giant formation. But the dusty disks are blown away quickly, which means any planet would need to form quickly or not at all. Perhaps the lack of a dusty disk might inhibit gas giant migration, so a few terrestrial planets might slip through the net - but none have been detected yet.

The biggest problem would be the short duration of the habitable zone- a giant star changes brightness very quickly as it passes off the main sequence, and this means there wouldn’t be a stable habitable zone for long enough to allow the emergence of complex life. I’d prefer to look for multiple habitable planets around smaller stars - sunlike G-and F-type stars, with moderately large habitable zones and moderately long lifespans.

Yeah. I suspect that if Earth were in Mars’ location, it would be habitable.

Venus would be habitable if you could somehow get rid of its massively thick atmosphere and halt its runaway greenhouse effect. I’ve heard some people say that actually Venus is a better candidate for terraforming than Mars. It’s apparently easier to get rid of an atmosphere (reducing it to levels where the temperature would be human liveable) than create one from essentially nothing, in Mars case.

Hey; that gives me an idea!! If we could get a really, really long hose we could solve two planets’ atmosphere problems at once. :slight_smile:

This wiki https://en.wikipedia.org/wiki/Circumstellar_habitable_zone is pretty good on the issues and the calcs for our solar system.