Why are so many people believing this one? Maybe it's because there's an image with the story (left) that appears to come from NASA which all but proves the hoax. But just because it looks real, doesn't mean that it is. Let's consider how easy it is to make a fake tweet. In less than a minute via LemmeTweetThatForYou.com you can make a fake tweet and then save the image. Bet you didn't know it was so easy to put words in someone else's mouth!
So that's how this hoax got started. Put out a fake story and paste an image on it that makes it look like it's verified by a legitimate organization.
Sorry to break it to you that we won't go weightless on Sunday.
And another word to the wise: before you go sharing and retweeting things online, consider doing some homework first. Can you answer the question "Is this inforamtion coming from a legitimate news site?" If you're still unsure, do a quick Google search. If your homework makes you go "Wow!" then by all means share and RT.
And make sure to #beready for internet hoaxes in the future because they're looking even more real these days.