Mars - The Summary So Far
Before the Summary, some Justification
At this stage you might feel inundated with information on Mars. And we'll visit Mars again in each of the remaining modules of this course. Are we overdoing it? We hope not because we believe that there are some strong justifications for spending so much time on a relatively small planet. Most of those reasons are quite obvious:- Mars will be the first planet to be visited by humans.
- Mars is the best candidate for human colonization.
- Mars is amongst the best candidates for finding extraterrestrial life in the Solar system.
- Mars is the only candidate for terraforming (creating earth-like conditions) in the solar system.
The bottom line is that if we want to pursue a long-term human presence on Mars, we need to understand it quite thoroughly. On a more personal level, by providing you with a good background on Mars, we hope that you will be better able to understand future Martian headlines that will no doubt be making the news in the upcoming years. And there will be many more. Because even though we do know quite a bit about the planet, there are many areas we do not fully understand. To give you a better understanding of our level of ignorance, please check this 2 page abstract linked to here. It comes from a big planetary science conference held in March of 2016. In it, 2 well known researchers outline a large number of "unanswered questions" about the geological evolution of the planet. For many we think we have partial answers, but that is a long way from fully understanding it. Some of the questions are very important if we, as a species, plan to set up colonies there. Such questions include:
What is the history of water on Mars, its total abundance, and its acquisition accretion, degassing) and loss with time? What was the nature of the hydrological cycle with time? How was water partitioned into the atmosphere, surface water, altered minerals, cryosphere and groundwater, and how did this change with time?
When did Mars become characterized by a global cryosphere and how much groundwater remains today in the subsurface? How has the thickness and latitudinal distribution of the cryosphere changed with time?
Finally, the Summary so far
In this section of module 3 we have documented how the surface of Mars has been shaped by a number of processes. We have demonstrated a variety of tectonic and volcanic features that cover much of the Martian surface. But ultimately, Mars could not escape the fate of small planets in that it cooled relatively rapidly and became tectonically dead after a relatively short period of tectonic activity that never did evolve into the full blown plate tectonics that has been active on Earth for over 4 billion years. The large craters that were produced during its earliest history are still clearly visible on its surface, which means that the surface has not changed significantly since its early history. Earth was similarly bombarded by large objects in its early history but most of the craters have long been lost to tectonic and atmospheric processes that are not active on Mars. That stationary crust affected the volcanism and produced some very large volcanoes. And even though we have evidence of recent (geologically speaking) volcanic activity, most volcanism is in its distant past. Similarly, the most Earth-like water related features, the valley-networks, are largely confined to the oldest rocks. After that early period of activity, we primarily find evidence of episodic releases of water.And so the picture that emerges is of a planet that would have been very active early on in its history. Following the formation of the dichotomy, approximately 4.1 billion years ago, Mars had its "heyday" of activity which lasted until about 3 billion years ago. After that, the level of geological activity dwindled and a lengthy, calm period on Mars was punctuated by episodic events. Today, wind is one of the predominant forces on Mars, slowly eroding the rocks and creating large dune fields that actively migrate. We'll examine the state of water on Mars in more detail next and we'll look at the possibility of life on Mars in the last module.
So please keep in mind that when we finally set up shop on Mars, we'll be there long after the big geological "party" has ended. And that's likely a good thing. 3.5 billion years ago, an active Mars with widespread volcanism and active atmosphere and hydrosphere would have been a much more difficult exploration target.
Update Feb 21, 2019 - Now, get your Martian weather report right here!
As stated on the official Mars InSight Mission site:
No matter how cold your winter has been, it's probably not as chilly as Mars. Check for yourself: Starting today, the public can get a daily weather report from NASA's InSight lander.
This public tool includes stats on temperature, wind and air pressure recorded by InSight. Sunday's weather was typical for the lander's location during late northern winter: a high of 2 degrees Fahrenheit (-17 degrees Celsius) and low of -138 degrees Fahrenheit (-95 degrees Celsius), with a top wind speed of 37.8 mph (16.9 m/s) in a southwest direction. The tool was developed by NASA's Jet Propulsion Laboratory in Pasadena, California, with partners at Cornell University and Spain's Centro de Astrobiología. JPL leads the InSight mission.
Through a package of sensors called the Auxiliary Payload Subsystem (APSS), InSight will provide more around-the-clock weather information than any previous mission to the Martian surface. The lander records this data during each second of every sol (a Martian day) and sends it to Earth on a daily basis. The spacecraft is designed to continue that operation for at least the next two Earth years, allowing it to study seasonal changes as well.
"It gives you the sense of visiting an alien place," said Don Banfield of Cornell University, in Ithaca, New York, who leads InSight's weather science. "Mars has familiar atmospheric phenomena that are still quite different than those on Earth."
This is the link to the full description, and here is the link to the weather directly. Note that the default is in F, but if you click on the C, all data is switched to Celsius. Enjoy!
