Mercury and Venus are the closest together because of there size
they are also the smallest planets
The two mainland, state capitals that are closest together are Providence, Rhode Island and Boston, Massachusetts. The distance between the two is about 50 miles.
Bratislavia & Vienna
Hull FC and Hull KR.
The four inner planets are closest together: Mercury, Venus, Mars & Earth
The centromere. It where the two identical sister chromatids come closest in contact.
Manchester and Salford touch for miles. Leeds and Bradford (i think) or it could be Preston and Blackburn (which do not touch at all)
Mercury and Earth are the two planets closest to Venus.
Adelaide, capital of South Australia, and Melbourne, capital of Victoria, are the two closest capitals on the mainland. Other capital cities on the mainland include Perth, Darwin, Brisbane, and Sydney. Canberra is the capital of Australia.
The magnetic field lines are closest together at the poles of a magnet. This is where the magnetic field is strongest and the lines are most concentrated.
Water molecules are closest together in the liquid phase.
Australia is made up of one large island and four smaller ones. The two capitals that are the closest together on the mainland are Adelaide and Melbourne.
Mercury and Venus The distance between planets is changing constantly (because they're moving) , but Mercury and Venus come closest together. As a general rule the further from the Sun you go the further apart planets are spread.