As the sun rises over the rim of Jezero Crater, two main reasons stand out to me as why the landing of @NASAPersevere later today is so important:

(1) the geology, and (2) the future.

As they say, a thread.

(1) THE GEOLOGY. Jezero Crater is going to be spectacular! Even from orbit, we can identify at least 8 unique lithologies (rock types). Each will have its own story to tell about the history of Mars. (2/18)

The delta mudstones will tell us about low energy deposition in a lake. Hydrated silica could tell us about hydrothermal activity. The mafic floor will tell us about igneous processes. (3/18)

All of these will help answer the big science questions. Like, how did the martian climate evolve? What is the potential for biosignatures? Was there ever life on Mars?! (4/18)

In situ science is always going to tell us new things. The way we have explored Mars has, by necessity, been backwards – we started with global, low-resolution, data, and have gradually got closer. Grab your hard hat, we’re all field geologists now. (5/18)

Each small, high-resolution, local study can now be joined together, to form a new global perspective. This is how we figured out the Earth – we didn’t start with satellites! (6/18)

So, even though @NASAPersevere will look at the local geology, the implications will be global in importance. Which brings me onto the second reason… (7/18)

(2) THE FUTURE. This is the start of returning samples from Mars back to Earth. This has never been done before. The samples collected and cached will, later this decade, be picked up by another rover, delivered to a small rocket, and returned to Earth. (8/18)

It is no understatement to say that these Mars rocks will be among the most important samples ever studied in planetary science. (9/18)

Although we do have some small pieces of Mars in the form of meteorites, ejected in huge impact events over the last 20 million years or so, we don’t know exactly where they come from on the planet. They tell us lots about Mars, but context (and selection) is key. (10/18)

For example, the age of every planetary surface in the Solar System is extrapolated from counting the size and density of impact craters. So far, we only have the returned Apollo and Luna Moon samples for calibration. (11/18)

The igneous rocks in particular at Jezero will offer a crucial second set of calibration points, applicable across the Solar System. (12/18)

And we all know that extraordinary claims require extraordinary evidence. Finding life is almost certainly going to be one of those claims. And so, the sensitivity of instruments and laboratories on Earth are going to be key. (13/18)

It is easy, and I think fair, to say that these samples will be studied for decades to come. Advances mean that new techniques can be used when available. We do this still with the Apollo samples to this day, 50 years later! (14/18)

It is about a century since the grand age of exploration on Earth. Many of the samples from expeditions such as Beagle, Discovery, Endeavour, and Challenger, are studied as part of the collection of @NHM_London. (15/18)

It is incredibly exciting to think that samples from another planet will soon represent this new era of exploration. (16/18)

And so younger people watching this landing today can know that it will be them that study the samples eventually returned. In the meantime, we’re going to have years of spectacular science from a fantastic geology field site. (17/18)

“It is in our nature to explore, to reach out into the unknown.” Who knows what we’ll find? Good luck @NASAPersevere ! (18/18)