Satisfying interfaces in Go using struct members and packages

main.go

package main

import "time"

type Time interface {
	Now() time.Time
}

type fakeTime struct {
	Now func() time.Time
}

func main() {
	// Why don't struct members staisfy interfaces?
	t := &fakeTime{
		Now: func() time.Time {
			return time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC)
		},
	}
	new(fakeTime).(Time)
	// ./main.go:20:15: invalid type assertion: new(fakeTime).(Time) (non-interface type *fakeTime on left)

	// Why don't packages satisfy interfaces?
	time.(Time)
	// ./main.go:24:6: use of package time without selector
}