Research & Development World

  • R&D World Home
  • Topics
    • Aerospace
    • Automotive
    • Biotech
    • Careers
    • Chemistry
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Software
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
    • Semiconductors
  • R&D Market Pulse
  • R&D 100
    • Call for Nominations: The 2025 R&D 100 Awards
    • R&D 100 Awards Event
    • R&D 100 Submissions
    • Winner Archive
    • Explore the 2024 R&D 100 award winners and finalists
  • Resources
    • Research Reports
    • Digital Issues
    • R&D Index
    • Subscribe
    • Video
    • Webinars
  • Global Funding Forecast
  • Top Labs
  • Advertise
  • SUBSCRIBE

Comet dust: Mercury’s “invisible paint”

By R&D Editors | March 30, 2015

Impact material generated without the presence of carbon from complex organics, top left, is lighter than material generated with carbon, top right. Scanning electron microscope images, bottom row, show finer-scale structure and texture variations. Images: NASA/AmesA team of scientists has a new explanation for the planet Mercury’s dark, barely reflective surface. In a paper published in Nature Geoscience, the researchers suggest that a steady dusting of carbon from passing comets has slowly painted Mercury black over billions of years.

Mercury’s dark surface has long been a mystery to scientists. On average, Mercury is much darker than its closest airless neighbor, our moon. Airless bodies are known to be darkened by micrometeorite impacts and bombardment of solar wind, processes that create a thin coating of dark iron nanoparticles on the surface. But spectral data from Mercury suggests its surface contains very little nanophase iron, certainly not enough to account for its dim appearance.

“It’s long been hypothesized that there’s a mystery darkening agent that’s contributing to Mercury’s low reflectance,” said Megan Bruck Syal, a postdoctoral researcher at Lawrence Livermore National Laboratory who performed this research while a graduate student at Brown Univ. “One thing that hadn’t been considered was that Mercury gets dumped on by a lot of material derived from comets.”

As comets approach Mercury’s neighborhood near the sun, they often start to break apart. Cometary dust is composed of as much as 25% carbon by weight, so Mercury would be exposed to a steady bombardment of carbon from these crumbling comets. Using a model of impact delivery and a known estimate of micrometeorite flux at Mercury, Bruck Syal was able to estimate how often cometary material would impact Mercury, how much carbon would stick to Mercury’s surface and how much would be thrown back into space. Her calculations suggest that after billions of years of bombardment, Mercury’s surface should be anywhere from 3 to 6% carbon.

The next part of the work was to find out how much darkening could be expected from all that impacting carbon. For that, the researchers turned to the NASA Ames Vertical Gun Range. The 14-ft canon simulates celestial impacts by firing projectiles at up to 16,000 mph.

For this study, the team launched projectiles in the presence of sugar, a complex organic compound that mimics the organics in comet material. The heat of an impact burns the sugar up, releasing carbon. Projectiles were fired into a material that mimics lunar basalt, the rock that makes up the dark patches on the nearside of the Moon. “We used the lunar basalt model because we wanted to start with something dark already and see if we could darken it further,” said Peter Schultz, professor emeritus of geological sciences at Brown and a co-author of the new research.

The experiments showed that tiny carbon particles become deeply embedded in the impact melted material. The process reduced the amount of light reflected by the target material to less than 5%—about the same as the darkest parts of Mercury.

Importantly, spectroscopic analysis of the impact samples revealed no distinctive spectral fingerprints, again similar to flat spectral signatures from Mercury. “We show that carbon acts like a stealth darkening agent,” Schultz said. “From the standpoint of spectral analysis, it’s like an invisible paint.”

And that paint has been building up on Mercury’s surface for billions of years.

“We think this is a scenario that needs to be considered,” Schultz said. “It appears that Mercury may well be a painted planet.”

Source: Brown Univ.

Related Articles Read More >

Trump lifts 50-year supersonic ban, paving way for 3.5-hour New York–London trips
Europa’s lost decade: What happens to $5 billion‑plus in planetary R&D when missions die?
Artemis III Orion powers on at Kennedy, marking milestone for 2027 Moon-landing push
MIT’s new sodium fuel cell beats lithium three-to-one for regional aviation
rd newsletter
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest info on technologies, trends, and strategies in Research & Development.
RD 25 Power Index

R&D World Digital Issues

Fall 2024 issue

Browse the most current issue of R&D World and back issues in an easy to use high quality format. Clip, share and download with the leading R&D magazine today.

Research & Development World
  • Subscribe to R&D World Magazine
  • Enews Sign Up
  • Contact Us
  • About Us
  • Drug Discovery & Development
  • Pharmaceutical Processing
  • Global Funding Forecast

Copyright © 2025 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search R&D World

  • R&D World Home
  • Topics
    • Aerospace
    • Automotive
    • Biotech
    • Careers
    • Chemistry
    • Environment
    • Energy
    • Life Science
    • Material Science
    • R&D Management
    • Physics
  • Technology
    • 3D Printing
    • A.I./Robotics
    • Software
    • Battery Technology
    • Controlled Environments
      • Cleanrooms
      • Graphene
      • Lasers
      • Regulations/Standards
      • Sensors
    • Imaging
    • Nanotechnology
    • Scientific Computing
      • Big Data
      • HPC/Supercomputing
      • Informatics
      • Security
    • Semiconductors
  • R&D Market Pulse
  • R&D 100
    • Call for Nominations: The 2025 R&D 100 Awards
    • R&D 100 Awards Event
    • R&D 100 Submissions
    • Winner Archive
    • Explore the 2024 R&D 100 award winners and finalists
  • Resources
    • Research Reports
    • Digital Issues
    • R&D Index
    • Subscribe
    • Video
    • Webinars
  • Global Funding Forecast
  • Top Labs
  • Advertise
  • SUBSCRIBE