Studying Venus poses significant challenges due to its thick atmosphere, which obscures its surface. Researching the planet requires the utilization of radar and specialized observation techniques.
Jean-Luc Margot, a scientist at the University of California, Los Angeles, along with his colleagues, tracked Venus from 2006 to 2020 using the Goldstone Solar System Radar System in California to examine the planet using radio waves.
Following this, the research team employed both the aforementioned radar and the Green Bank Telescope in West Virginia, situated around 3,000 km away, to monitor the echoes of radio waves reflecting back to Earth. This method is referred to as radar sounding.
Through this technique, even the slightest alterations in Venus’s movement can be detected by researchers.
The research team determined the length of Venus’s day, which is nearly equivalent to 243 Earth days, fluctuating by 21 minutes over a span of 15 years of observation.
Additionally, the researchers uncovered that Venus’s axis experiences subtle oscillations according to a model that predicts a recurring pattern every 29,000 years. The slight axial wobble is influenced by the Sun’s gravitational pull, while the oscillations in the length of the day are a consequence of Venus’s dense atmosphere exerting pressure on and pulling its surface.
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A computer simulation depicts the entirety of Venus’s surface, observed from the northern hemisphere.
Image: NASA.
Nonetheless, scientists suspect that another factor contributing to this motion is the influence of Venus’s core. The research team employed data to compute the required size of the core to account for these oscillations.
“We estimate a preliminary value of around 3,500 km (for the radius of Venus’s core),” remarked scientist Margot. The research team cannot definitively ascertain whether Venus’s core is solid or liquid. However, prior theoretical studies indicate that Venus’s core primarily comprises iron and nickel, akin to Earth’s.
Nevertheless, the scientific community remains uncertain as to “whether Venus possesses a solid core internally and a liquid core externally, akin to Earth, or if it consists entirely of liquid or solid material,” stated expert Margot.
While the estimations align with previous models regarding the size of Venus’s core, obtaining an actual measurement will facilitate more accurate research about Venus in the future. Understanding the size and density of the core could prove invaluable in unraveling the histories of planets across the universe, as highlighted by New Scientist.
“Most aspects of a planet’s evolution are determined by the size of its core. Gaining insight into a planet’s internal structure is truly challenging until we acquire a comprehensive understanding,” added Jean-Luc Margot.