Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

Hot Lava Flows discovered on Venus

  • 25-06-2015 10:58am
    #1
    Registered Users, Registered Users 2 Posts: 413 ✭✭


    http://www.esa.int/Our_Activities/Space_Science/Venus_Express/Hot_lava_flows_discovered_on_Venus

    Hot Lava Flows Discovered on Venus
    European Space Agency
    18 June 2015

    ESA's Venus Express has found the best evidence yet for active volcanism
    on Earth's neighbour planet.

    Seeing the planet's surface is extremely difficult due to its thick
    atmosphere, but radar observations by previous missions to Venus have
    revealed it as a world covered in volcanoes and ancient lava flows.

    Venus is almost exactly the same size as Earth and has a similar bulk
    composition, so is likely to have an internal heat source, perhaps due
    to radioactive heating. This heat has to escape somehow, and one possibility
    is that it does so in the form of volcanic eruptions.

    Some models of planetary evolution suggest that Venus was resurfaced in
    a cataclysmic flood of lava around half a billion years ago. But whether
    Venus is active today has remained a hot topic in planetary science.

    ESA's Venus Express, which completed its eight-year study of the planet
    last year, conducted a range of observations at different wavelengths
    to address this important question.

    Volcanic activity on Venus?

    In a study published in 2010, scientists reported that the infrared radiation
    coming from three volcanic regions was different to that from the surrounding
    terrain. They interpreted this as coming from relatively fresh lava flows
    that had not yet experienced significant surface weathering. These flows
    were found to be less than 2.5 million years old, but the study could
    not establish whether there is still active volcanism on the planet.


    An additional piece of evidence was reported in 2012, showing a sharp
    rise in the sulphur dioxide content of the upper atmosphere in 2006-2007,
    followed by a gradual fall over the following five years. Although changes
    in wind patterns could have caused this, the more intriguing possibility
    is that episodes of volcanic activity were injecting vast amounts of sulphur
    dioxide into the upper atmosphere.

    Now, using a near-infrared channel of the spacecraft's Venus Monitoring
    Camera (VMC) to map thermal emission from the surface through a transparent
    spectral window in the planet's atmosphere, an international team of
    planetary scientists has spotted localised changes in surface brightness
    between images taken only a few days apart.

    Brightness changes in Ganiki Chasma

    "We have now seen several events where a spot on the surface suddenly
    gets much hotter, and then cools down again," says Eugene Shalygin from
    the Max Planck Institute for Solar System Research (MPS) in Germany, and
    lead author of the paper reporting the results in Geophysical Research
    Letters this month.

    "These four 'hotspots' are located in what are known from radar
    imagery to be tectonic rift zones, but this is the first time we have
    detected that they are hot and changing in temperature from day to day.
    It is the most tantalising evidence yet for active volcanism."

    The hotspots are found along the Ganiki Chasma rift zone close to the
    volcanoes Ozza Mons and Maat Mons. Rift zones are results of fracturing
    of the surface, which is often associated with upwelling of magma below
    the crust. This process can bring hot material to the surface, where it
    may be released through fractures as a lava flow.

    "These observations are close to the limits of the spacecraft's capabilities
    and it was extremely difficult to make these detections with Venus'
    thick clouds impairing the view," says co-author Wojciech Markiewicz.
    "But the VMC was designed to make these systematic observations of
    the surface and luckily we clearly see these regions that change in temperature
    over time, and that are notably higher than the average surface temperature."

    Because VMC's view is blurred by the clouds, the areas of increased
    emission appear spread out over large areas more than 100 km across, but
    the hot regions on the surface below are probably much smaller. Indeed,
    for the hotspot known as "Object A", the team calculate that the feature
    may only be around 1 square kilometre in size, with a temperature of 830
    degrees C,
    much higher than the global average of 480 degrees C.

    The Ganiki Chasma rift zone was already considered to be one of the most
    recently geologically active regions on the planet, and as the new analysis
    suggests, it is still active today.

    "It looks like we can finally include Venus in the small club of volcanically
    active Solar System bodies," says Hakan Svedhem, ESA's Venus Express
    project scientist.

    'Our study shows that Venus, our nearest neighbour, is still active
    and changing in the present day - it is an important step in our quest
    to understand the different evolutionary histories of Earth and Venus."

    Notes for editors

    "Active volcanism on Venus in the Ganiki Chasma rift zone," by E.V.
    Shalygin et al is published in Geophysical Research Letters.

    For more information, please contact:

    Markus Bauer
    ESA Science and Robotic Exploration communication officer
    Tel: +31 71 565 6799
    Mob: +31 61 594 3 954
    Email: markus.ba...@esa.int

    Eugene Shalygin
    Max Planck Institute for Solar System Research, Germany
    Email: shaly...@mps.mpg.de

    Wojciech Markiewicz
    VMC principal investigator
    Max Planck Institute for Solar System Research, Germany
    Email: ma...@mps.mpg.de

    Hakan Svedhem
    ESA Venus Express project scientist
    Email: hakan.sved...@esa.int


Advertisement