Happy New Year – from Mars. It is always something special to think about the passage of time from different perspectives than we know best. So let’s celebrate that our slightly colder red cousin has done another lap around the sun. The 36th year of Mars began on February 7th with a noticeable lack of fireworks or people singing Auld Lang Syne.
Despite the lack of festivals on the planet’s surface (maybe Curiosity Auld Lang Syne could play for herself?) The Friends of the Planet at ESA have compiled a list of fun facts about the Martian year. Here are some highlights.
Every 26 months, Mars faces the sun in our night sky. Since 1995 Mars has been in such “opposition” with the Sun seven times. In this mosaic, a color composite was put together from each of the seven observations made by the Hubble opposition to demonstrate the beauty and splendor of the red planet. This mosaic of all seven Martian globes shows relative differences in the apparent angular size of Mars over the years. Mars was closest in 2003 when it was within 56 million kilometers of the earth. The part of Mars sloping towards the earth also shifts over time, which leads to a change in the visibility of the polar caps. Clouds and dust storms as well as the size of the ice caps can change the appearance of Mars on time scales of days, weeks and months. Other features of Mars, such as some of the great dark markings, have remained unchanged for centuries.
Photo credit: NASA / ESA
The 36th year may seem a little young since the planet is a few billion years old. This is because people with our anthropomorphic inclinations arbitrarily chose to count the Martian years in the human year 1955. Each year it takes approximately 687 Earth days, which brings us to the 36th Mars year beginning this month.
An important question is at what point in Mars’ rotation around the Sun does its year actually begin. Astronomers have decided that the northern equinox marks the beginning of a new Martian year. This point is the beginning of spring in the northern hemisphere and autumn in the southern hemisphere. That makes at least more sense than the arbitrary date after the start of winter, which our species has chosen for at least most of the western hemisphere to start a new year.
UT video about the Martian weather and how the atmosphere can be rebuilt.
The choice of this date could be due in part to another fun fact about the Martian year – the seasons aren’t all the same length. Mars has a highly elliptical orbit compared to Earth, which means that the spring of its northern hemisphere (194 days) is much longer than its autumn (142 days). This path is predictably having a major impact on the red planet’s weather. Increasing luminosity when the sun is closer (in the summer and spring of the southern hemisphere) leads to large dust storms that cover the planet almost annually, as in the first Mars year with the aptly named “great dust storm of 1956”.
These dust storms aren’t the only annual weather events, however – another interesting event is the Arsia Mons Elongated Cloud, a 1,800 km long cloud of ice crystals that appears at least 80 Mars days (“sols”) per year and then disappears. Like many other features of Mars, it shows how dynamic and changing the planet is, even though it appears to be just a ball of rock with hardly any atmosphere.
Image of the elongated cloud of Arsia Mons – a 1800 km long cloud of ice particles that appears annually on Mars.
Photo credit: ESA / GCP / UPV / EHU Bilbao
As we learn more about our sometimes closest neighbor, we will no doubt find more annual phenomena taking place there. But even now we can see that time passes differently depending on how you look at it. If nothing else, you can tell your co-workers that you are at least 53% of your Earth age on Mars.
Learn more :
ESA: Happy New Year on Mars
UT: How long is a year on Mars?
OUT: Mars rotation
ScienceAlert: Happy New Year Mars. Here’s why it’s such a crucial week
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