Mars, Cancer, and the Beehive Cluster

The scientific community has been intently focused on Mars for the past couple months.  Every 26 months, our planets align in a way that shortens the time from Earth to Mars down to about 9 months, and as more countries develop space programs, more robotic explorers are sent to the red planet during this window.  In 2021, the UAE orbiter Hope arrived on February 9^th, China’s Tianwen-1 entered orbit on February 10^th, and the NASA Perseverance rover touched down February 18^th.  Perseverance carried with it the Ingenuity helicopter, which has spent the last month proving the first powered flight on another world, and on May 14^th, Tianwen-1 released the Zhurong rover which became only the second country to successfully land a rover on the Martian surface.

Mars is easily identifiable with the naked eye, having a deep red hue due to high levels of oxidized iron in its crust – basically the whole planet has rusted over the last couple billion years.  The arrivals of the orbiters and landers in February signaled a (relatively) close approach of our two planets, as they have spent most of 2021 pulling further distant from one another, and lower and dimmer in our night sky.  Sinking closer to the setting sun, Mars enters the constellation Cancer on June 8^th.  As the moth wanes, you may be able to catch one last conjunction with Mars passing just 0.5 arcminutes from the Beehive Cluster M44 on June 23^rd, just minutes after sunset, low in the western sky.

The Beehive Cluster – or Messier 44 – is one of the nearest open clusters to Earth.  Ptolemy referred to it as the “nebulous mass in the breast of Cancer”, proving how easily identifiable it is with the naked eye.  Galileo resolved 40 stars within the cluster, though we now count at least 1000 stars across 39 light years, which are close enough to be gravitationally bound to each other.  At least 3 exoplanets are known to orbit stars within the Beehive Cluster.  If you are lucky enough to catch the conjunction of this open cluster and our neighboring planet, both should easily fit within the field of view of your telescope or binoculars.  With the right magnification, one can resolve some nebulosity from the Beehive Cluster and the polar ice cap of Mars.