blow (something) sky-high
1. Literally, to destroy something through an explosion. The tanks blew the enemy fortress sky-high.
2. To undermine or negate something completely. I thought I had finally discovered the problem with our experiment, but, when we tested it, the results blew my theory sky-high. Bob was considered for the promotion, but he blew that idea sky-high when he came in late to work each day this week.
1. Destroy by explosion, explode, as in Once the charge is set, get away fast or you'll be blown sky-high. [Early 1800s] Also see under blow up.
2. Refute completely, as in The lab report has blown your theory sky-high. [Mid-1800s]
blow somebody/something ˌsky-ˈhigh(informal) destroy somebody/something completely in an explosion: The explosives factory was blown sky-high when one of the workers lit a match.
blow sky-high, to
To refute completely, to explode a thesis or idea. While this expression has a modern sound, it is not so very new. Andrew Jackson, in a letter of 1845, wrote, “Put your veto on them both, or you and your Secretary will be blown sky-high.”