The Venus magnetic field is known to be incredibly weak. Scientists are still unsure why that is so. Venus is famously known in the astronomy economy as “Earth’s Twin” It has a similar size and relatively similar distance from the sun. It is also the only other planet of the inner solar system that has a significant atmosphere. However the lack of a strong magnetosphere points to marked differences between Earth and Venus.
Venus like the rest of the inner solar system is a rocky planet. Scientist don’t know much about the formation of these planets but based on data gathered from our planet as well as from space probes, they have been able to make some educated guesses. We do know that that the inner solar system was produced by the collision of planetessimals rich in iron and silicates. These collisions created the young planets which remained quite hot with liquid cores and fragile young crusts composed of silicates. However the big mystery lies in the development of the iron core.
We know that one of the reasons for Earth’s strong magnetic field is that its iron core works like a dynamo. This magnetic field is what shields our planet from strong solar radiation. However it seems that this phenomenon does not occur on Venus. It has led to interesting hypothesis to explain it. One is that the core has completely solidified. Earth core is still partially molten and it is thought that this trait allows for it to produce a magnetic field. Another theory is that it is due to the fact that is does not have plate tectonics like Earth.
When space probes passed Venus they discovered that the magnetic field of Venus was several times weaker then Earth’s However solar radiation was still being deflected. Scientists now believe that the field is actually a result of Venus’s ionosphere interacting with the solar wind. This would mean that it has an induced magnetic field. However it will take future missions to Venus to verify this hypothesis.
We have written many articles about Venus’ magnetic field for Universe Today. Here’s an article about the geology of Venus, and here’s an article about Venus compared to Earth.
If you’d like more information on Venus, check out Hubblesite’s News Releases about Venus, and here’s a link to NASA’s Solar System Exploration Guide on Venus.
We’ve also recorded an entire episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus.
Source:
UCLA
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