CalculationTime · Mars Loop 2027

Mars draws a loop

From January to April 2027, Mars stops against the stars of Leo, runs backwards for twelve weeks, then carries on. Earth is overtaking it on the inside track. Here is the loop, drawn live from the ephemeris, on both faces of the sky.

 

Southern face Cropped from the clock face looking south. Turn round to face north near midnight in February and Mars' loop sits in your sky this way up.
Northern face Cropped from the clock face looking north. Turn round to face south near midnight in February and the loop sits this way up for you.
 

Why it runs backwards

Earth circles the Sun in a year. Mars takes 687 days. Every 26 months Earth catches up and passes Mars on the inside, like a faster car on the inner lane.

Watch the line of sight from Earth through Mars to the distant stars. Most of the time it sweeps forward. As Earth draws level, the line swings back for a few weeks. That backwards swing is the loop. Mars itself never reverses.

The loop opens up and down because Mars' orbit is tilted about 1.8° to ours, so it sits a few degrees north of the Sun's road during the pass.

View from

Milestones

    Where to look

    The next loops

    OppositionInClosestBrightest

    Positions from Astronomy Engine (Don Cross, MIT), geocentric, in your own time zone: the same ephemeris as the Twin Clocks and the Wanderers' Lane. Heights above and below the Sun's road are magnified so the loop is readable; the scale is printed on each view. Brightness is magnitude, where lower is brighter.