Romain Tilhac

Geochemist | CNRS researcher at Géosciences Montpellier | Climber and caver, passionate about mountains, travelling and photography

[Geologia - Universidad de Oviedo @geologiaoviedo]

La Univ. de Oviedo acogió entre el 30-sep. y el 4-oct. el 7th Orogenic Lherzolite Meeting, organizado por Marco A. López y Sergio Llana. Del 30 de sep. al 1 de oct., tuvo lugar una excursión a la zona de Cabo Ortegal.

Enhorabuena a los organizadores y gracias a los asistentes

[Romain Tilhac @romaintilhac]

🤩Excited to lead the #lherzolite2024 field trip to the mantle section of the Cabo Ortegal Complex in just a month! Here's a teaser of one the outcrops we'll see, Galician weather allowing... ⛰️🌦️

Check out a light version of the Metashape 3D model on https://t.co/WXsr2Cl52M.

[Bon Pote @BonPote]

119 mm de pluie en 24 heures à l'aéroport de Dubaï. C'est 1,5 fois plus que ce qu'il tombe en un an.

L’impression qu’il y a un problème plus important que les activistes climat qui bloquent 5 min les routes..

[Nahel Belgherze @WxNB_]

The earthquake that struck Japan’s Noto peninsula on Monday was so strong that the coastline has moved up to 250 meters offshore due to significant land uplift.

[Brian O’Driscoll @BODriscollEarth]

New layered intrusion review paper….
Layered intrusions: Fundamentals, novel observations and concepts, and controversial issues - ScienceDirect https://t.co/MMzQLb7P7R

[AstroDude @__AstroDude]

An amazing timelapse of Earth's rotation.

[Romain Tilhac @romaintilhac]

@DJCManns I’d imagine (assuming enough degassing occurred) buoyancy to drop indeed and also viscosity to increase, intuitively delaying eruption, but not sure in which direction that would play upon further replenishment and mixing.

[jasonloxton.bsky.social @jason_loxton]

The science says human births cause volcanoes. Prove me wrong.

[Romain Tilhac @romaintilhac]

Definitely a term I may use in future peer reviews…

[Romain Tilhac @romaintilhac]

That got me to read more about the fascinating cargo cult, and its metaphor in coding, scientific thinking, politics, etc 🤔

[Dr Milan Milanović @milan_milanovic]

𝗛𝗼𝘄 𝗮 𝗦𝗶𝗻𝗴𝗹𝗲 𝗟𝗶𝗻𝗲 𝗢𝗳 𝗖𝗼𝗱𝗲 𝗕𝗿𝗼𝘂𝗴𝗵𝘁 𝗗𝗼𝘄𝗻 𝗔 𝗕𝗶𝗹𝗹𝗶𝗼𝗻 𝗗𝗼𝗹𝗹𝗮𝗿 𝗥𝗼𝗰𝗸𝗲𝘁

On June 4, 1996, the European Space Agency (ESA) launched the Ariane 5 rocket for the first time, marking a significant moment in the history of space exploration. This mission was not without difficulty, though, as 𝗮 𝘀𝗶𝗻𝗴𝗹𝗲 𝗹𝗶𝗻𝗲 𝗼𝗳 𝗰𝗼𝗱𝗲 𝗿𝗲𝘀𝘂𝗹𝘁𝗲𝗱 𝗶𝗻 𝗮 𝗰𝗮𝘁𝗮𝘀𝘁𝗿𝗼𝗽𝗵𝗶𝗰 𝗳𝗮𝗶𝗹𝘂𝗿𝗲 and the loss of the entire cargo, which was worth almost half a billion euros.

Two communication satellites were intended to be transported into geostationary transfer orbit by the Ariane 5. Up until the rocket deviated off track and burst 37 seconds into the flight, the launch was going smoothly. 𝗔 𝘀𝗼𝗳𝘁𝘄𝗮𝗿𝗲 𝗳𝗹𝗮𝘄 𝗶𝗻 𝘁𝗵𝗲 𝗴𝘂𝗶𝗱𝗮𝗻𝗰𝗲 𝘀𝘆𝘀𝘁𝗲𝗺, which was in charge of regulating the rocket's course, was found to be the root of the disaster. The Ariane 5 launch is acknowledged as one of the most expensive software failures in history. The destruction of the scientific satellites delayed scientific research into the workings of the Earth's magnetosphere for almost 4 years.

𝗪𝗵𝗮𝘁 𝘄𝗮𝘀 𝘁𝗵𝗲 𝗰𝗮𝘂𝘀𝗲?

A dead part of code from the last Ariane 4 mission, which began almost ten years prior, contained a simple and fixable programming error. The rocket used a method known as the 𝗵𝗼𝗿𝗶𝘇𝗼𝗻𝘁𝗮𝗹 𝗯𝗶𝗮𝘀, sometimes known as the BH value, to identify whether it was pointing up or down. This was represented using a 64-bit floating-point variable, which the guidance system used to convert to 16 16-bit signed integers. A 64-bit variable can represent billions of values, while a 16-bit can represent only 65,535 values.

We know that integers are represented with the first bit used to store signs, and 16-bit integers can then be from -32,768 to 32,767. Yet, floating-point numbers are made to track a broader range of numbers, using the same numbers of bits between -1.8e+308 and -2.2e-308. If you try to store one into a 16-bit integer, it will be much out of the bound of a signed integer. So, what happened is a well-known 𝗶𝗻𝘁𝗲𝗴𝗲𝗿 𝗼𝘃𝗲𝗿𝗳𝗹𝗼𝘄.

One more contributing factor to the disaster was user requirements that Ariane 5 use a much steeper trajectory than previous ones, which resulted in a more incredible vertical velocity.

What are some takeaways from the disaster? 𝗮 𝗰𝗼𝗽𝘆-𝗽𝗮𝘀𝘁𝗶𝗻𝗴 𝗰𝗼𝗱𝗲 𝘄𝗶𝘁𝗵𝗼𝘂𝘁 𝘂𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱𝗶𝗻𝗴 𝗶𝘁 (Cargo-cult) is a significant issue. Another is the omission of proper exception handling, neglecting changed user requirements, and the absence of appropriate tests.

#technology #softwareengineering #programming #techworldwithmilan #softwaredesign

[Prof. Eliot Jacobson @EliotJacobson]

Holy crap ...

"we call for an IPCC special report that focuses on the perilous climate feedback loops, tipping points, and—just as a precaution—the possible but less likely scenario of runaway or apocalyptic climate change."

https://t.co/aUTqcZ4VT3

[nature @Nature]

Falling behind: postdocs in their thirties tire of putting life on hold.

Read the results of Nature’s second global survey of postdoctoral researchers https://t.co/jYxKuLT3B9

[Romain Tilhac @romaintilhac]

@LeonSimons8 Perhaps a silly question but I wonder why did the emitted thermal radiation also significantly increased around 2014?

[Matthew Tarling @RocksbyDefault]

I'm so excited to share with you "Viewing the Rock World", an outreach project based on a 3D-printable thin section viewer that anyone can make! Looking for teachers, educators, student groups, anyone interested in participating! Check out https://t.co/PMPvvQsfu7 for more info.

[Dr. Lucky Tran @luckytran]

A wise person once said that you will experience climate change through a series of increasingly wild videos, until you are the one taking the video.

[Romain Tilhac @romaintilhac]

📣For mantle lovers dealing with melt percolation and chromatography out there, you are probably familiar with the good old "plate model" from the 90's... I have a Matlab code available online that does it all, and we can always adjust it to your needs!

https://t.co/vPE9Fbv6g7

[Juan Carlos Afonso @JuanAfonso12]

Numerical modellers!, you may be interested in the capabilities of this new hybrid FV method for modelling fluids, including systems of #geodynamic and #geophysical interest. The main advantage? Simple, versatile and fast! Codes available. https://t.co/awARrK9Cmf

[Romain Tilhac @romaintilhac]

For those at @goldschmidt2023 in Lyon, join us in half an hour for the start of our mantle heterogeneities session (2f) in the R4 room!

[Romain Tilhac @romaintilhac]

Unbelievable fieldwork in the Bay of Island ophiolite complex, Newfoundland 🤩