There was a professor Frank Brown from Northwestern University who during the 1970’s wanted to send potatoes into space. He had previously observed that potatoes have metabolic rates that were in sync with the moon. If you moved potatoes from the east coast to the west coast those potatoes would retain the metabolic cycle for their old location and only gradually change to the new. Changes in latitude; changes in attitude.
It was his speculation that Humans were similarly in sync with the sun and moon and moving out of range of the moon may have profoundly negative effects on our bodies. Humans quite possibly will wither and die if moved too far from our homes. Dr. Hawking’s conclusions may be based on incomplete data...
Oh no, certainly. There is talk these days of all sorts of exoplanets, like Gliese 581-C. Some of these planets orbit blue stars, or red stars or all manner of star that is different from ours. Folks that live on Earth, in Alaska for example, literally go crazy from periods of long darkness. Just the amount of light can drive us loopy. I know from experience that you can take a houseplant that is thriving in a particular area, and move it two feet to the left and it will wither and die. You never know. That being said, of course we could adapt and build shelters and bring light and such with us, but yes, finding Earth equivalents is going to be rare if not impossible and we will have to make do. Some, I’m sure, will even speak of gene-altering but then again, this is science fiction and we can’t even get back to the moon.
Many of Hawkings conclusions are in fact based on incomplete date. For example his recent reversal on decades long insistance that black holes do not absorb information . While not all his work, he adheres to the Lamda Cold Dark Matter model, which is full of incomplete and downright fictional math.