Mars moon mystery as strange structures found in ‘terrifying’ Phobos
Europa’s Mars Express spacecraft has looked deeper than ever before into the subsurface of the Martian moon Phobos and found hints of unknown structures that could provide clues to the moon’s origin.
Mars Expressa 19-year veteran orbiting Mars, came within 51.6 miles (83 kilometers) of Phobos on September 22, 2022, and was able to probe beneath the lunar surface using upgraded software on his MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument.
Understanding the internal structure of Phobos could hold the key in solving the mystery of its origin. “We are still in the early stages of our analysis, but we have already seen possible signs of previously unknown features beneath the moon’s surface,” said Andrea Cicchetti, who is a member of the MARSIS science team at INAF, Italy’s MARSIS team. National Institute of Astrophysics, in a pronunciation (opens in new tab).
Related: How the Martian moon Phobos got its grooves
Mars has two moons, called Phobos and Deimos to the gods of ‘fear’ and ‘panic’ in Greek mythology. Unlike the big moons of our solar system, Phobos and Deimos are small, only 16.7 miles (27 kilometers) and 9.3 miles (15 kilometers) wide, respectively. They have a similar composition to C-type carbonaceous asteroids and have an irregular shape such as: asteroids also, leading to the suspicion that they are actually rogue states trapped by Mars’ gravity. However, the orbits of both Phobos and Deimos around the red planet are above Mars’ equator, and both orbits are extremely circular, suggesting they formed around Mars. If captured, they would be expected to have more elliptical orbits in different planes.
“Whether Mars’ two small moons are trapped asteroids or made of material ripped from Mars during a collision is an open question,” said Colin Wilson, a scientist on the European Space Agency’s Mars Express mission. in the same pronunciation (opens in new tab).
MARSIS includes a 40-meter antenna that beams low-frequency radio waves to the surface. Most radio waves are reflected directly from the surface, but some penetrate deeper, where they encounter transitions between layers of different composition and structure, and are reflected back from these boundaries. The stronger the reflection in the resulting ‘radargram’, the brighter the returning radio signal.
The narrow-track radargram on Phobos shows a bright line, split in two and labeled A–C and D–F, respectively. The A–C section was captured using the old MARSIS software to compare with DF, which uses the new software and shows much more detail. The main bright line is the reflection from the surface of Phobos, but below that there is evidence of fainter lines that could simply be interference or ‘junk’ from features on the surface, but they could also be caused by structures below the surface.
MARSIS was designed to survey the interior of Mars from an orbital distance of more than 155 miles (250 kilometers), but the recent software upgrade allows MARSIS to operate at much shorter distances, allowing it to be used during close proximity to the planet. moons fly.
Getting even closer to Phobos gives radargrams an even greater resolution than is achieved here. The plan for the coming years is to deploy MARSIS up to 40 kilometers (24.9 miles) from Phobos.
“Mars Express’s orbit has been refined to bring us as close as possible to Phobos during a handful of flybys between 2023 and 2025,” Cicchetti said.
Mars Express isn’t the only mission targeting Phobos. In September 2024, the Japanese Aerospace Exploration Agency (JAXA) plans to launch the Mars Moon Exploration (MMX) spacecraft. Just like JAXA’s Hayabusa2 mission to collect samples from near earth asteroid Ryugu, MMX will capture a minimum of 10 grams of regolith from the surface of Phobos. MMX will also have a small robber to the surface, before venturing to get a good look at Mars’ second moon, Deimosand then return to Earth with the precious Phobos samples that will be analyzed here in scientists’ labs Soil.
Follow Keith Cooper on Twitter @21stCenturySETI (opens in new tab). follow us on Twitter @Spacedotcom (opens in new tab) and further Facebook (opens in new tab).
#Mars #moon #mystery #strange #structures #terrifying #Phobos