This is today's edition of The Download , our weekday newsletter that provides a daily dose of what's going on in the world of technology.

Are we there yet? A reality check on six big tech promises

Some seemingly impossible feats are too good to give up on. Decoding a pet’s yowls and yips? Absolutely. Scrubbing the world of forever chemicals? Yes, please. Rocketing to Mars in a fraction of the time? Sounds great, but how close are we, really?

In the new Impossible issue of MIT Technology Review , we ran progress reports on six potentially transformative technologies and ideas that have been “just around the corner” for years, or even decades. From exercise in a pill to nuclear-powered spaceships, we asked experts what’s holding them back and how far they’ve come.

Check out our stories on how they all stacked up .

Over the coming days, we’ll unpack each of the six technologies in The Download.…