News for hackers. Stuff that matters.
Re:Space colonies of the future as imagined by NASA in the 1... by politician on Tuesday November 23, 2021 @12:15PM (#29320357)
Don’t metals spontaneously weld in vacuum?
Re:Space colonies of the future as imagined by NASA in the 1... by ortusdux on Tuesday November 23, 2021 @01:07PM (#29321017)
Yes, under certain circumstances. Two pieces of identical metal, with no surface coatings or oxides, will directly bond if placed in intimate contact. Done properly, the weld would be as strong as the metal. As Feynman put it, the atoms have no way of knowing they are in different pieces.

Similar results can be reliably recreated on earth. Ultrasonic welding rubs two pieces of metal together until the oxide breaks apart leaving pure metal to fuse. Explosive welding creates a plasma that strips off the oxide layer, and then propels the metals into each other. This method has the benefit of bonding dissimilar metals, and usually produces bonds that are as strong as the weakest metal.

Re:Space colonies of the future as imagined by NASA in the 1... by rtkwe on Tuesday November 23, 2021 @12:40PM (#29320682)
It's not perfect and you wouldn't want to trust it for a habitat. It requires the surfaces to be pretty meticulously clean and it's not as strong as traditional welds.
Re:Space colonies of the future as imagined by NASA in the 1... by wnkrshm on Tuesday November 23, 2021 @02:53PM (#29322483)
They also become brittle due to cosmic particles, if one e.g. wants to think about interstellar travel.