Maryland: Volcanoes on Venus Are Still Active

[bystander]

Scientists Discover Volcanoes on Venus Are Still Active
Computer, Mathematical, and Natural Sciences | University of Maryland | 2020 Jul 20

New 3D model provides evidence that Venus is churning inside

The 3D rendition above shows two coronae observed on the surface of Venus. The
ring-like structures are formed when hot material from deep inside the planet rises
through the mantle and erupts through the crust. (Image courtesy Laurent Montési)

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A new study identified 37 recently active volcanic structures on Venus. The study provides some of the best evidence yet that Venus is still a geologically active planet. ...

“This is the first time we are able to point to specific structures and say ‘Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead,’” said Laurent Montési ... “This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes.”

Scientists have known for some time that Venus has a younger surface than planets like Mars and Mercury, which have cold interiors. Evidence of a warm interior and geologic activity dots the surface of the planet in the form of ring-like structures known as coronae, which form when plumes of hot material deep inside the planet rise through the mantle layer and crust. This is similar to the way mantle plumes formed the volcanic Hawaiian Islands.

But it was thought that the coronae on Venus were probably signs of ancient activity, and that Venus had cooled enough to slow geological activity in the planet’s interior and harden the crust so much that any warm material from deep inside would not be able to puncture through. In addition, the exact processes by which mantle plumes formed coronae on Venus and the reasons for variation among coronae have been matters for debate. ...

Corona Structures Driven by Plume-Lithosphere Interactions
and Evidence for Ongoing Plume Activity on Venus ~ Anna J. P. Gülcher et al

• Nature Geoscience (online 20 Jul 2020) DOI: 10.1038/s41561-020-0606-1

[neufer]

Venus interacts with the solar wind.

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<<Venus is known not to have a magnetic field; Venus only has an induced magnetosphere formed by the Sun's magnetic field carried by the solar wind(; i.e., field lines wrapping around an obstacle—Venus). The induced magnetosphere of Venus has a bow shock, magnetosheath, magnetopause and magnetotail with the current sheet. At the subsolar point the bow shock stands 1900 km above the surface of Venus. This distance was measured in 2007 near the solar activity minimum. Near the solar activity maximum it can be several times further from the planet. The magnetopause is located at the altitude of 300 km. The upper boundary of the ionosphere (ionopause) is near 250 km. Between the magnetopause and ionopause there exists a magnetic barrier—a local enhancement of the magnetic field, which prevents solar plasma from penetrating deeper into the Venusian atmosphere, at least near solar activity minimum. The magnetic field in the barrier reaches up to 40 nT. The magnetotail continues up to ten radii from the planet. It is the most active part of the Venusian magnetosphere. There are reconnection events and particle acceleration in the tail. The energies of electrons and ions in the magnetotail are around 100 eV and 1000 eV respectively.

Due to the lack of the intrinsic magnetic field on Venus, the solar wind penetrates relatively deep into the planetary exosphere and causes substantial atmosphere loss. The loss happens mainly via the magnetotail. Currently the main ion types being lost are O⁺, H⁺ and He⁺. The ratio of hydrogen to oxygen losses is around 2 (i.e. almost stoichiometric) indicating the ongoing loss of water.

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Atmosphere of Venus
..............................
Carbon dioxide	96.5 %
Nitrogen	3.5 %
Sulfur dioxide	150 ppm
Argon		70 ppm
Water vapor	20 ppm
Carbon monoxide	17 ppm
Helium		12 ppm

http://asterisk.apod.com/viewtopic.php? ... 57#p303931

[BDanielMayfield]

So, wouldn't the venusan atmosphere be obtaining it's great heat from both solar and internal sources?

[neufer]

So, wouldn't the venusan atmosphere be obtaining it's great heat from both solar and internal sources?

• Io has a lot more volcanism and its surface temperature is 110 K.

<<Earth's energy budget accounts for the balance between the energy that Earth receives from the Sun, and the energy the Earth radiates back into outer space. Earth is very close to being in radiative equilibrium, the situation where the incoming solar energy is balanced by an equal flow of heat to space; under that condition, global temperatures will be relatively stable. Globally, over the course of the year, the Earth system—land surfaces, oceans, and atmosphere—absorbs and then radiates back to space an average of about 340 watts of solar power per square meter.

The geothermal heat flux from the Earth's interior is estimated to be 47 terawatts and split approximately equally between radiogenic heat and heat leftover from the Earth's formation. This comes to 0.087 watt/square metre, which represents only 0.027% of Earth's total energy budget at the surface, which is dominated by 173,000 terawatts of incoming solar radiation.>>

[BDanielMayfield]

So, wouldn't the venusan atmosphere be obtaining it's great heat from both solar and internal sources?

• Io has a lot more volcanism and its surface temperature is 110 K.

<<Earth's energy budget accounts for the balance between the energy that Earth receives from the Sun, and the energy the Earth radiates back into outer space. Earth is very close to being in radiative equilibrium, the situation where the incoming solar energy is balanced by an equal flow of heat to space; under that condition, global temperatures will be relatively stable. Globally, over the course of the year, the Earth system—land surfaces, oceans, and atmosphere—absorbs and then radiates back to space an average of about 340 watts of solar power per square meter.

The geothermal heat flux from the Earth's interior is estimated to be 47 terawatts and split approximately equally between radiogenic heat and heat leftover from the Earth's formation. This comes to 0.087 watt/square metre, which represents only 0.027% of Earth's total energy budget at the surface, which is dominated by 173,000 terawatts of incoming solar radiation.>>

Thanks for your help on this Art.

Bruce