Spring on Earth can be a seditious affair as plants come to life again and small and big creatures prepare to mate. Of course, this does not happen on Mars.
But even in a cold world like Mars, spring brings with it changes, though you have to take a closer look to see them.
Fortunately, there are spacecraft orbiting Mars with high-resolution cameras, and we can follow images of the beginning of the Martian spring.
When winter arrives in the polar regions of Mars, a thin layer of ice is placed on the surface of the planet. It is not water ice, but carbon dioxide ice. When spring comes, as in May 2019 in the northern polar region of Mars, this CO2 ice sublimates and changes directly from solid to vapor, without passing through a liquid phase.
On the dune fields of Mars this sublimation takes place from the cheers. This is because the winter grains that compose the layer become almost transparent, and sunlight lets the ice melt from below. That catches gas between the ice below and the sand above.
As the warming proceeds, the ice breaks and releases the trapped gas violently.
As it explodes through the ice, it carries dark sand. You can see these dark spots in the picture below.
 The ESA / RosCosmos ExoMars trace gas orbiter will be on Mars in October 2016 has arrived and has been investigating the planet ever since.
Part of its instrument payload is the Color and Stereo Surface Imaging System (CaSSIS), which among other things creates detailed digital elevation models of the Martian surface.
CaSSIS is a high-resolution camera that captured a picture of melting CO2 in the northern polar region of Mars in May 2019.
The picture also shows various types of dunes that form on the planet. While the left side of the picture looks like dunes, as most people imagine, the right side does not look that way.
These are called Barchan Dunes or Crescent Dunes. These dunes can grow larger and connect to barchanoids. The dunes of Barchan tell us in which direction the prevailing wind blows: The curved peaks point against the wind.
The CaSSIS instrument on the trace gas orbiter also recorded images of spring in the southern polar region in May 2018, but this time in a crater.
The same kind of spring sublimation is present in this image, where geysers or explosions of buried CO2 ice burst through the surface ice and carry sand along with it. In this dune field the sand is carried over the face of the dunes.
The axial inclination of Mars is about 25 degrees, just over 23.4 degrees Earth. The seasons on Mars do not move in step with the earthly seasons. One Martian year is approximately 687 Earth days, but unlike Earth, the seasons of Mars do not occupy every quarter of the year. That's because of his orbit.
While Earth's orbit is nearly circular and moves around the sun at a steady speed, Mars does not. The orbit is more elliptical and the speed varies. As the seasons of the earth change year by year on the same dates, the seasons of Mars do not change.
Here is an excerpt from a table from The Planetary Org that shows the seasons of Mars. There are several ways to measure and mark seasons on Mars, but some scientists use this method.
From left to right: spring equinox, summer solstice, autumn equinox, winter solstice. Click here to see the whole picture.
The European Planetary Science Congress will meet this week, to discuss, among other things, results and images of the Trace Gas Orbiter.
This article was originally published by Universe Today. Read the original article.