Mr . (NAME STARTS WITH E, SCIENCE TEACHER)'s Theory

During a certain science class by the above stated teacher, I was told by the teacher that some scientists had theorized that when absolute zero is reached, the atom that experiences it will collapse, and so will all of the matter around it, and a black hole might possibly form. So heres my question: Why are some scientists still trying to reach absolute zero without more data to back up the idea that they aren't simply going to kill themselves and everyone else???? Also, does it really make sense that NASA makes absolutely sure that there is virtually no risk in an astronaut dying, while other scientists are trying to do something that risks killing us all???? This doesn't make much sense to me, someone please enlighten me....