Provides for local solar eclipse: Moon Phobos orbits Mars. Graphic: GHMD / Wikimedia Cons / CC BY-SA 3.0
NASAThe Insight mission provides data from the surface Mars. Its seismometer, ETH, is equipped with electronics made in Zurich, it not only records the Mercury, but also reacts unexpectedly to solar eclipses. When the moon of Mars, Phobos, comes directly in front of the sun, the instrument gives tips slightly to one side. This miniature effect could help researchers determine the interior of the planet.
An observer standing on Mars will see the Earth’s lunar phobos crossing the sky from west to east every five hours. Its orbit passes once every year between Earth and any given point on Mars. Each time it does so, it causes one to seven solar eclipses within three days. One place where this happens is NASA’s Insight Lander site, located in the Elysium Planitia region since November 2018. In other words, the phenomenon is more frequent than that of the earth, when our moon crosses in front of the sun. “However, the Mars eclipse is short – it only lasts 30 seconds and it is never a complete eclipse,” explains Justin Simon Stahler, a seismologist at the ETH Zurich Institute Ge Geophysics. Photos taken by NASA’s two Mars rovers, Opportunity and Curiosity, also show sharp lumps against the background of the sun.
Photographs are not the only way to observe this transition. “When the Earth experiences a solar eclipse, the devices can detect a drop in temperature and a rapid gust of wind, as the atmosphere cools at a specific location and the air moves from that location.” Analysis of the data obtained from Insight should indicate that similar effects on Mars can also be detected.
Awaiting April 24, 2020
In April 2019, the first series of solar eclipses appeared from Insight’s landing site, but only some of the data recorded by it were preserved. Early indications of that data encouraged Stahler and the international research team to enthusiastically prepare for the next series of eclipses on April 24, 2020. They published findings from their observations in the journal Obust. Geographical research papers.
As expected, Insight’s solar cells recorded the transition. “When Phobos is in front of the sun, less sunlight reaches the solar cells and in turn it produces less electricity,” St સ્ટhler explains. “The reduction in exposure to light caused by Phobos’ shadow can be measured.” Indeed, the amount of sunlight decreased by 30 percent during the eclipse. However, Insight’s weather instruments did not indicate any atmospheric changes, and the wind did not change as expected. Other tools; Still, one surprise: both the seismometer and the magnetometer had an effect.
Abnormal signal from seismometer
The magnetometer signal is largely due to the reduction in the power of the solar cells, as Anna Mittholz, ETH was able to show the recent addition of the Mars team from Zurich. “But we didn’t expect this seismometer reading; This is an unusual signal, “says Stahler. In general, the instrument – equipped with electronics made on ETH – indicates an earthquake on the planet. The Ers. Intensity, as well as several hundred regional, shallow earthquakes have been reported.
If the lunar phobos obscures the sun, the seismometer tilts to the side, barely measurable, and thus registers the lunar transit against the sun. Credit: NASA / JPL
The surprising thing during the solar eclipse was that the seismometer tilted slightly in a certain direction. “This inclination is very small,” Stuhler notes. “The idea of the F-Frank coin; Now, push the two atoms of silver under one edge. That’s the trend we’re talking about: 10-8As easy as this effect was, it was still uncontrollable. “The clearest explanation would be the gravity of Phobos, similar to how the Earth’s lunar tides are caused,” says Stähler, “but we quickly judged it.” If that were the explanation, then the seismometer signal would be present for a long time and every five hours when Phobos was passing, not just during the eclipse. Researchers have identified possible causes of the tilt: “During an eclipse, the ground cools. “It develops unevenly, which bends the instrument,” said Martin van Drill, of the seismology and wave physics research group.
As it happens, an infrared sensor actually measured the Earth’s cooling on Mars by two degrees. Calculations revealed that within 30 seconds of the eclipse, the “cold front” could penetrate into the ground at a depth of only micro or millimeters, but the impact was enough to stretch the seismometer.
Experiments in old silver mines
Observations on Earth support St સ્ટhler’s theory. At the Black Forest Observatory, located in an abandoned silver mine in Germany, Rudolf Wiedemer-Schneiderig found a similar phenomenon: during a seismometer test, someone ignored the light rotation. The heat provided by the 60-watt bulb was apparently sufficient to heat the topmost layer of groundite beneath the ground, so that it expanded slightly and tilted the seismometer slightly to one side.
Scientists will be able to use a small tilt signal from Mars to map the orbit of Phobos with greater accuracy than before. Insight’s position is the most accurately measured position on Mars; If scientists know exactly when the transition through Phobos begins and ends here, they can accurately calculate its orbit. This is important for future space missions. For example, the Japanese space agency JXA Mars plans to send an investigation to the moon in 2024 and take samples back to Earth from Phobos. “To do that, they need to know exactly where they are flying,” says Stuhler.
What specific orbital data reveals
Accurate data on the orbit of Phobos can shed even more light on the internal structures of Mars. As our moon continues to gain angular momentum and is constantly moving away from Earth, Phobos is slowing down and slowly returning to Mars. In 30 to 50 million years, it will break on the planet’s surface. “We can use this slight recession to gauge how resilient and thus how warm the Martian interior is; Cold materials are always more resilient than hot ones, ‘M.T.H. Explains Aamir Khan of Geophysics at the Institute of Zurich. Ultimately, the researchers wanted to know if Mars was composed of the same material as Earth, or if the plate tectonics on Earth could explain why different elements, a ga ense atmosphere and life-supporting conditions – are the features that Mars lacks.
Reference:
S.C. Stähler, R. Wiedemer-Schneiderig, J.R. “A Geographical Overview of Phobos Transits by Insight” by Scholes, m. Van Drill, a. Mittholz, k. Hearst, CL Johnson, MT Lemon, RD Lorenz, p. Loganoni, NT Mલરller, l. Pau, a. Spiga, d. Benfield, s. Celine, c. Charlambos, j. Clinton, d. Giardini, F. Nimmo, m. Penning, W. J અનેrn and WB Benardt, 4 August Gust 2020, Geographical research papers.
DOI: 10.1029 / 2020GL089099
A. Bagheri, A. Khan, d. Al – Atar, o. Mars Recruitment Response by 29 Lab Gust 2019, “Laboratory-Based Viscoelastic Dispersion Models and Geophysical Data” by Crawford and De Giardini. JGR planets.
DOI: 10.1029 / 2019JE006015
