Mark Marley

@markmarley.bsky.social

Personal account. Substellar science since the 80s.

Scouting possible future names for model grids in our Sonora series (following Bobcat, Cholla, Diamondback, Elf Owl, Flameskimmer). G and H look good, I is a tough one, J and K are covered, and then we come to Lesser long-nosed bat...

My heart is so full! The “Charting Substellar Worlds” conference was a great success. Amazing science talks and community building. Conference organizing was so stressful, but so worth it in the end. Along with talks and we had s’mores, karaoke, and even some folks surfing 🏄🏾‍♂️.

It was great to see LPL grads and alums bringing planetary science perspective to brown dwarfs at the Charting Substellar Worlds workshop this week. Wonderful science and great setting.

Fuda NguyenBildBildBild

🔭 New paper day! 🪐 This time from Merle Schrader, a PhD student in the brown dwarf group at Trinity College Dublin. Today, they're publishing a fresh look at SIMP-0136, using principal component analysis, identifying the mechanisms driving its atmospheric variability. arxiv.org/abs/2607.26182

The JWST weather report: Unravelling the atmospheric variability of isolated worlds using principal component analysis

Brown dwarf variability directly probes atmospheric dynamics beyond the Solar System, and recent JWST time-resolved spectroscopy has opened a new window into these processes. Principal component analy...

arxiv.org

The first glimpse of the Martian surface was long anticipated. Bonestell's art dominated ideas of what Mars was like, basically the desert Southwest with most air absent. The idea of a dark blue sky on Mars persisted in space art until that morning. Here are those first looks at the Martian surface.

Top: the first view of the Martian surface, which appeared in slow steps left to right as the data came in. They wanted first thing to know if the lander was on solid ground and not too buried, sinking etc. The imaging sequence started 25 seconds after landing and continued for 5 minutes as the camera scanned a vertical line at a time moving to the right to scan the next. Having the orbiter relay the data took another 20 minutes. At left a brightening in the image can be seen that intensifies then fades, followed by a darkening that soon goes away. That represents a kind of record of the dust kicked up by the landing that brightened the field of view, then the shadow of the dust cloud briefly darkened the scene. The prominent angular rock near upper center is about 10 cm (4 inches) across. This first peek reassured everyone that the lander was on solid ground. A little dirt kicked up by the lander rockets can be seen pooled in the footpad.  

 Bottom: 6 minutes after landing  the second photo was obtained, a lower resolution 300 degree wide panorama of the surroundings taking in the scene in 9 minutes. At once the character of the scenery showed its distinctive nature, rocky and lightly even ground with small drifts and patches of lighter fine dust. The presence of dust in the atmosphere brought a brightness to it that was not anticipated, as an artist that was the major revelation I felt when looking over the scene. The atmospheric density was known to be like Earth's at 40 kilometers or 130,000 feet, so any noticeable blue sky brightness should only be evident near the horizon. In reality, the eternal presence of wind blown dust makes the sky a luminous version of the color of the ubiquitous surface dust, especially in the quarter of the sky near the Sun.

  Suddenly rendered dated were all those paintings by Bonestell, Pesek and others which were done between the times of the Mariner missions and the Viking landings, showing interpretations of known features but … I had my Polaroid SX-70 camera with me when just after the landing I was suddenly escorted from the press area into into the imaging team room, hastily badged and plopped in front of some of the many monitors in the area which steadily unveiled the first two looks at the Martian surface. No journalists were there dur to JPL PR department policy, but I got a few photos and a sound recording of the excited chatter of the geologists seeing Mars revealed. "Look at the exposure on that S_O_B" I remember hearing when the prominent rock appeared. Then the President called in his congratulations which went over the PA system. A highlight of my life, onr of several instances where I was in the Coolest Place in the world at that moment. My carefully obtained Polaroid from a monitor in the Imaging team area, at the conclusion of the introductory scanning of the first photo obtained of the surface of Mars.

There is an Arizona resident flex on introductions of saying how long your family has been here. I never initiate this but if someone else starts I always drop our 1885 arrival. In a very rare case I was beat by the initiator yesterday who goes back to 1870.

Today in 1959, a clogged coolant channel led to the meltdown of 30 percent of the fuel elements in the core of the uncontained 20-Megawatt Sodium Reactor Experiment nuclear reactor at the Santa Susana Field Laboratory, located about 30 miles northwest of downtown Los Angeles above Simi Valley.

A black and white photograph inside the Sodium Reactor Experiment building on September 19, 1958, during a tour for local public school science teachers. This photograph was published in the Valley Times newspaper with the caption, "Science teachers from Los Angeles City Schools view equipment for Sodium Reactor Experiment in Santa Susana Mountains, nuclear power project conducted by Atomics International. From left are Wesley W. Jones, of Atomics International, explaining operations to Averill M. Chapman, curriculum administrator, and Mrs. Archie Owen, science superintendent."A black and white photograph showing the Sodium Reactor Experiment building nestled among the rocks and hills above Simi Valley at the Santa Susana Field Laboratory in 1958, the year before the accident. The building is a three- or four-story boxy concrete structure with no windows.A color map showing the location of the Santa Susana Field Laboratory in relation to cities and communities in Southern California. Two circles denote a 10-mile and 25-mile radius from the site. Simi Valley, Thousand Oaks, and the San Fernando Valley are within a 10-mile radius. Malibu, Santa Monica, Beverly Hills, Burbank, and Hollywood are within a 25-mile radius.

Hear @offallingstars.bsky.social and LPL's Lori Huseby talk about our recent paper on UV irradiation of exoplanet haze analogs.

SETI Institute@setiinstitute.bsky.social · 4w ago

#ICYMI: On this week's #SETILive, @goastromo.bsky.social and her guests discussed the effects of UV radiation on an exoplanet's atmosphere, using both observations and lab testing, and why this work is important for the search for life. Watch the full interview: youtube.com/live/_Rnj_C7... 🧪 🔭 👩‍🔬

DPS has approved an LPL alumni and friends reception one evening. I asked for Tuesday or Thursday. I'll soon ask alums for photos we can show during the reception (finger food and a drink). The theme is celebrating 50 years since our first degree award to Wayne Slattery in 1976.

I need to know what the AZ exhibit is at the “state fair” on the Mall. From the Atlantic article, “Arizona is an immersive experience involving darkness, birdsong, and the scent of pine.” Is there an astronomy theme?