Weather report (8/10/23)

Good afternoon, and happy Thursday. The moon is waning just in time for us to catch the Perseid meteor shower, which has been trickling in bits and pieces since last month but which will reach its peak this weekend. Set that alarm early, wake up a few hours before dawn, and look up to the sky to catch the year’s hottest meteor shower.

Did someone forward you this email? Subscribe to Parallax here.

The Weather on Mars

Water once flowed across the surface of Mars. Telltale signs—riverbeds, lake beds—intertwine and pockmark the planet’s now-barren surface, and for more than two decades, researchers have been traversing these places with rovers to uncover its watery history.

Where that water came from, how much of it there might have been, and, importantly, whether or not it was part of a Martian weather cycle are all lingering mysteries for researchers studying the planet’s surface in hopes of discovering signs of past life.

In a study published this week in the journal Nature, a team of researchers from the University of Toulouse in France have investigated a strange hexagonal pattern stumbled upon by the Curiosity rover in Mars’ Gale Crater and determined that it is evidence of ancient weather cycles.

Curiouser and curiouser: Curiosity began its trek across the Martian surface twelve years ago as of this week, and its findings just keep getting stranger. When it came across a pattern of hexagons, each about 4 cm wide, left across a swath of ground in the Gale Crater, researchers back home recognized the signs.

The ridges delineating the hexagons were likely cracks in mud, which form at particular angles to create the pattern. They were likely once filled with minerals that would wash in with flooding, which the researchers estimate reached a depth of ~2 cm on a Mars-yearly cycle, potentially for millions of years.

• Similar patterns crop up on Earth where there is regular, low-level flooding, like in California’s Racetrack Playa.

“It’s the first time we can show that the climate sustained hydrological change seasonally, or wet and dry seasons,” William Rapin, lead author on the study, told New Scientist. “We knew the Earth had them, but we didn’t know of any other planets that did. Now we know Mars had seasons.”

Seasons of life: The fossilized ridges of salt hint at more than just seasons—they also hint at conditions that could have helped life to form on Mars.

First of all, they’re dated to ~3.6-3.8B years ago, roughly when life emerged on our home planet. Since there was enough time for life to form on Earth by then, then it’s more likely that there was enough time on the Red Planet, too.

Second, many complex molecules that are needed for life as we know it to form (specifically RNA) could have benefitted from regular flooding. The presence of different concentrations of component molecules at different times increases the likelihood of more complex molecules forming. Plus, RNA may need periods of dehydration to form from scratch.

Sponsored

The Nexus of the Space Ecosystem

Building our off-world future requires long-term thinking. Strategic planning and innovation will help us preserve space for future generations. ASCEND is the world’s premier outcomes-focused, interdisciplinary space event designed to accelerate building our sustainable off-world future.

Across three days in Las Vegas, ASCEND will feature 150 sessions spanning six space domain topics. We'll share bold ideas and perspectives for addressing the most important issues in space today:

• Space and Sustainability
• Space Exploration and Infrastructure
• Space Security and Protection
• Space Traffic Management
• Expanding and Evolving the Space Economy
• Education, Outreach, and Workforce

Be part of the cross-industry collaboration at 2023 ASCEND, October 23–25, in Las Vegas.

Other News from the Cosmos

• Chandrayaan-3, India’s Moon lander, has entered lunar orbit.

• Luna-25, Russia’s first lunar mission since 1976, is slated for launch tomorrow and could beat India’s craft to a landing.

• The geomagnetic field surrounding the Earth protects us from high-energy electron impacts.

• River “sinuosity,” or the amount they curve, has been affected by climate change on both Earth and Mars.

• Gamma rays coming from the Sun are more abundant than previously believed.

• Gas streamers feeding a triple-star system leave clues about how these types of systems form.

• Do not be afraid of the supermassive black hole.

The View from Space

JWST’s most recent target revealed details of Earendel, the farthest known star. The B-type star is more than a million times brighter than our own Sun and only about twice as massive. May it be a light for you in dark places, when all other lights go out.