Try this experiment in space-time travel for free:

Just step outside, into your backyard, even though it’s hot and humid out there now in early August, and imagine yourself in the middle of February in the Upper Midwest.

Think of thick ice on Lake Michigan and your knees turning to jelly as your boots crunch on the snow. You’re alone out there. The wind is full of threats. And that hard dry snow skittering across the ice tells you something as you cross a frozen river on a highway bridge.

It tells you to think of trying to build a fire and failing miserably like that idiot tenderfoot in the Jack London story who could not build a fire and was eventually ripped apart by hungry wolves.