On January 5, 2020 at 7:47 a.m. Greenwich Time, the Earth comes closest to the Earth in its yearly trek. This is called Perihelion. At Perihelion the Earth is about 147 million kilometers from the sun as opposed to 152 million kilometers in July. Solstice, on the other hand, refers to the tilt of the Earth to or from the Sun. The fact that they occur with two weeks of each other is pure coincidence. (As far as we know.)
The date of Earth’s Perihelion drifts as the centuries pass. The December Solstice and Perihelion happened at the same time in 1246 AD. As the centuries continue to pass, these events will drift even farther apart. On the average, one revolution of the Earth relative to Perihelion is about 25 minutes longer than one revolution relative to the December solstice. Perihelion advances one full calendar date every 60 or so years. Earth’s Perihelion – or closest point to the sun – will happen at the same time as the March equinox in about 6000 AD.
Future and past aphelion and perihelion dates and times are available at astropixels.