If Earth is a car, and we now look out of the rear window, we see the Moon. It isn’t, however, chasing us like a cop, but is crossing over the road (our orbit) behind us.
And apparently walking backward across the traffic: it’s moving from right to left, but with its D-shaped face it looks westward at the Sun.
All this merely means that it is at its First Quarter position. The actual moment was near the beginning of this date, 4:19 by Universal Time, which was from 5 to 8 hours earlier in the time zones of the contiguous U.S.A. So for America it was nearer to the sunset of the 3rd than of the 4th.
Looking at Mars and Venus in our space-diagram of the planets at the end of January, Rick Scheithauer wondered whether Mars, which happened then to be at the point where ecliptic crosses equator, was also near the direction from which Earth had traveled.
This direction is the opposite of what we have called informally the EDOT or “Earth’s direction of travel,” known in astronomical literature as the Apex of Earth’s Way. So the behind-direction is the Antapex of Earth’s Way. It’s not easy to think of a homelier term; “rearview point” isn’t too good, so until you suggest something cute I’ll call it antapex.
It has to be roughly (though not exactly) 90° from the Sun, tangent to Earth’s not-quite-circular orbit. Mars, however, has an elongation from the Sun of 51° on Jan. 30, 50° on Feb. 4, so the antapex is considerably out east from it. I’ve now worked it into my programming, and this is just the time to show it. There it is, near the First Quarter Moon. At that phase the Moon’s longitude is 90° from the Sun, so it would have passed exactly through the antapex, but for its latitude, which at present has it cruising south of the ecliptic.
A planet’s position when it is 90° from the Sun is called “quadrature.” Mars does not reach either east or west quadrature this year, because it never gets far enough from being behind the Sun. Mercury and Venus are never as far out as quadrature; the outer planets pass through both quadratures almost every year (Jupiter for example was at west quadrature, out in the morning sky, on Jan. 12).
There is also such a thing as the Apex of the Sun’s Way, and I’ll return to that.