• Luke

Mars


In the south west sky there is a bright distinctly red spot of light that comes out fairly quickly in the twilight. I’m sure you’ve guessed already this is the planet Mars! This year Mars has been particularly bright red for a few reasons.


Location of Mars looking south from Boulder Colorado

Mars takes 2 years to go around the Sun where it takes the Earth 1 year. This means about every 3 years we catch up with mars and pass by it. When this happens it is called ‘opposition’. Opposition means an alignment of the Sun the Earth and one of the outer planets (outer planets are planets that are further from the Sun than us: Mars, Jupiter, Saturn, Uranus, Neptune). You can see when this happens by watching the Sun set, because the Sun, Earth and another planet is in alignment the planet is on the opposite side of the of the sky from the Sun. After you watch the Sun set in the west, turn around and see the planet that is in opposition rise in the east, for that night that planet will be as above the eastern horizon as the Sun is below the western horizon (the same phenomenon can be seen at full moon too). This happened on July 27th 2018 for Mars so it is no longer rising as the Sun sets (you will see it fairly high in the sky during twilight). However because that happened this year that means we are still closer to mars then we will be for another ~3 years.



Mars was in opposition on July 27th of 2018.


In addition to being closer to Mars there has been a dust storm on Mars making it extra red for the passed few months. This dust storm is actually threatening the Opportunity rover by blocking out the sun so that the solar panels can not provide the power the rover needs to operate. Currently the dust storm is over but NASA still hasn’t been able to contact the Opportunity rover. NASA suspects that dust has accumulated on rover's solar panels during the storm preventing them from charging the rover. There's still hope that with some wind gust the solar panels might clear and power up the rover once again. We’re all pulling for the little rover which has been on mars for over 14 years and has broke many records and made some amazing discoveries in that time. The Curiosity rover however has been operational this entire time as it relies on a nuclear power source.



A penny the Curiosity rover uses to calibrate its camera. On the right is a photo from about a month after it landed and on the left is a picture 6 years from when it landed, just after the dust storm.


Mars has also been in the news lately thanks to the successful landing of NASA's InSight lander. the InSight lander will be placing instruments on the surface of mars using a robotic arm that will probe the interior of the planet and give us a better understanding of mars and the other terrestrial planets (Earth, Venus, and Mercury). InSight is also powered by solar panels so it will have to battle the martian dust.



a NASA illustration of insight on mars

It has long set now but but there is a star Anterries in the constellation Scorpio as the red heart of the scorpion. I bring Anterries up as Anterries is Arabic and means ‘rival to mars’, this is because like mars it too is red. The rivalry comes when comparing the brightness between Mars and Anterries Mars is truly winning the rivalry currently but this is not always true. Actually usually Mars loses the rivalry 2 years out of 3 (when mars is further away, or on the other side of the Sun, as Anterries is always the same brightness). People will often come to me and point to Anterries or Aldebaran (a red star that makes up the eye of Taurus the bull which should be appearing just above the eastern horizon in the evening) or Betealgeuse (the red star you might be familiar with in Orion, currently appearing in our sky late at night) and ask if it is mars and I have to tell them no… This year is different because we are passing close to mars and because the dust storm on mars, Mars is truly winning the rivalry and being the brightest red point on the ecliptic.


In a telescope or a good pair of binoculars mars appears as a red disk, where any of the red stars will still be just a point of light. If you have a good telescope you might be able to see the white ice cap (which is tented red after the dust storm). With a good telescope and trick called occulting where you block out the light of mars you might be able to see mars's two faint moons Phobos and Deimos. Phobos and Deimos are small and irregularly shaped leading us to think they are most likely captured asteroids.



Mars in my best telescope.


Mars has captured our imaginations a lot in modern times by being the site of many scifi novels, movies, and arts. This is owed to a wealthy and influential astronomer Percival Lowell who in 1906 claimed to see canals on mars that were so straight they must of been engineered. Lowell wished to find life on mars so much that he started to. This hallucination was contagious and many other astronomers picked up on the canals. the story took off and inspired two generations of scifi writers and artist (Burroughs, Bradbury, Weinbaum, to name a few) who created works that went on to be inspirations for many artists to this day (Andy Weir, Kim Stanley Robinson, David Bowie and countless more). Lowell's observation was before photography when all astronomy was done by eye which leads many to say the canals were in the eye of the beholder as the drawings Lowel produced resemble retina of the human eye. We know now that there are no canals on mars but it wasn't until the Viking and Mariner probes of the 60s and 70s that hopes of canals on mars was finally put to rest.



Martian canals depicted by Percival Lowell.


Even without canals Mars is still an amazing place that captivates the imagination. Valles Marineris which is a system of naturally formed canyons that reaches 4 miles deep and would stretch across mainland United States if it was on earth. If human eyes ever see Valles Marineris up close I’m sure it will be a jaw dropping sight putting the grand canyon to shame. Mars is also home to Olympus Mons an extinct volcano reaching 72,000ft making it the largest mountain in our solar system (there is a case to be made for Rheasilvia a mountain on the asteroid Vela to be bigger). With science supporting the idea of frozen carbon dioxide (dry ice) snow storms some have thought about skiing down Olympus Mons and getting lots of air with Mars’s low gravity (about a third of the gravitational force we have on earth). Along with volcanoes and canyons mars also has many impact craters that scar its surface. Mars is home to the greatest diversity of impact crater types of any planet in the Solar System.



Olympus Mons

Hope you enjoy observing Mars this evening. If you want to see it up close in my telescope I will be holding a tour on the 14th of December. Be sure to catch the special commit show I will hold on the week of the 16th (more details to come soon).

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