For those West of the Eastern US time zone, today is perihelion day - when the Earth is at its closest approach to the Sun. The hour and minute is 05:15 UT, so 00:15am on January 2nd here in New Jersey. We will be going as fast as the Earth travels orbiting the Sun, so enjoy the thrill.
Something to celebrate
The furthest point out in our orbit will take place early in the morning on July 5th …. the exact times vary from year to year given the mismatch of our calendar system to our orbit.
The apparent size difference of the Sun's disk is readily apparent if you want to take photos of the Sun and compare them (about 7% difference in area)