In earlier iterations of D&D you could use the "Silence 15' Radius" spell to target items (say a coin) and much like the light spell carry it with you or toss it toward foes.  It doesn't specify in the spell, but wanted to make sure.  Current language for Silence on DnDBEYOND site: 

"For the duration, no sound can be created within or pass through a 20-foot-radius sphere centered on a point you choose within range. Any creature or object entirely inside the sphere is immune to thunder damage, and creatures are deafened while entirely inside it. Casting a spell that includes a verbal component is impossible there."

The Target: just 120' range / 20' radius.

Thanks Nerds.

signed, a Nerd.

The sphere is centered on a point you choose within range, so since it doesn't say it can be cast on a creature or object and move with it, it can't.

I suppose so. I feel it is an oversight vs a planned development by the writers however.  The predecessor "Silence 15' Radius' acted as such:

"This spell could be cast on an object, a creature, or into the air. If cast upon a creature, it had a chance to resist the spell and, if successful, the center of effect was placed one foot (30 cm) behind the creature. All sounds were stopped at the source and no sound entered or exited the area of effect. Spells with verbal components could not be cast within the sphere of silence and sonic attacks such as a harpy's song were ineffective. 

and since the spells Light and Darkness still maintain the ability to be cast on objects, people or in open spaces (check that Light now can only be on an object), it stands to reason why limit this spell as such... it just feels like an oversight.

I don't think it's an oversight but rather purposefully designed this way. 

If it interest you, the Devs have answered this question;

@RevLouisBrenton Can the 5E Silence spell be cast on a person or object, or only on a point in space?

@mikemearls only on a point – prevents it from making Stealth much less useful 

@JeremyECrawford The silence spell is centered on a point in space, not on a creature or an object. #DnD 

Considering they specifically call out that the spells Light and Darkness can be cast on objects and they altered Silence to not include it, when earlier editions did, points that it was a deliberate design choice. 

They also made Silence a ritual. Having it on a mobile object would be a bit much.