Science & Exploration

Venus is alive – geologically speaking

08/04/2010 5956 views 16 likes
ESA / Science & Exploration / Space Science / Venus Express

ESA’s Venus Express has returned the clearest indication yet that Venus is still geologically active. Relatively young lava flows have been identified by the way they emit infrared radiation. The finding suggests the planet remains capable of volcanic eruptions.

It has long been recognised that there are simply not enough craters on Venus. Something is wiping the planet’s surface clean. That something is thought to be volcanic activity but the question is whether it happens quickly or slowly? Is there some sort of cataclysmic volcanic activity that resurfaces the entire planet with lava, or a gradual sequence of smaller volcanic eruptions? New results suggest the latter.

“Now we have strong evidence right at the surface for recent eruptions,” says Sue Smrekar, a scientist at NASA's Jet Propulsion Laboratory in California.

The volcanic peak Idunn Mons
The volcanic peak Idunn Mons

That strong evidence comes in the form of compositional differences compared to the surrounding landscape in three volcanic regions. The data were collected by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on ESA’s Venus Express spacecraft, which has been orbiting the planet since April 2006.

VIRTIS records the brightness of surface rocks, providing an estimate of ‘emissivity’. In 2008, Jörn Helbert and Nils Müller, Institute of Planetary Research, German Aerospace Center, Berlin and co-authors on this new work, published a map of the variation of infrared emissivity across the southern hemisphere of Venus.

Dr Smrekar and her colleagues targeted three regions that geologically resemble Hawaii, well known for its active volcanism. They show that the regions on Venus have higher emissivities than their surroundings, indicating different compositions.

On Earth, lava flows react rapidly with oxygen and other elements in the atmosphere, changing their composition. On Venus, the process should be similar, though more intense because of the hotter, denser atmosphere, chiefly of carbon dioxide.

Artist's impression of  Venus Express spacecraft
Artist's impression of Venus Express spacecraft

The researchers interpret the fact that the lava flows appear to have different compositions from their surroundings as being evidence of a lack of surface weathering, indicating that the flows erupted relatively recently. They estimate that the flows are possibly as geologically recent as 2 500 000 years – and likely much less, possibly even currently active. “This is a significant result,” says Håkan Svedhem, ESA Venus Express Project Scientist.

Whilst the gradual resurfacing scenario might not be the most spectacular, it does make Venus look a little more Earth-like.

“There are some intriguing models of how Venus could have completely covered itself in kilometres of volcanic lava in a short time, but they require that the interior of Venus behaves very differently from Earth. If volcanism is more gradual, this implies that the interior may behave more like Earth, though without plate tectonics,” says Dr Smrekar.

Related Links

Science & Exploration

Venus Express finds planetary atmospheres such a drag

07/10/2010 2447 views 4 likes
Read
Venus in the ultraviolet
Science & Exploration

Was Venus once a habitable planet?

24/06/2010 17677 views 37 likes
Read
Science & Exploration

Venus is alive – geologically speaking

08/04/2010 5956 views 16 likes
Read
Science & Exploration

New map hints at Venus' wet, volcanic past

14/07/2009 4721 views 4 likes
Read
Atmospheric investigations by Venus Express
Science & Exploration

Watching Venus glow in the dark

24/02/2009 2128 views 2 likes
Read
Mars Express
Science & Exploration

ESA extends missions studying Mars, Venus and Earth’s magne…

10/02/2009 1653 views 0 likes
Read
Interaction between Venus and the solar wind
Science & Exploration

Where did Venus’s water go?

18/12/2008 11896 views 18 likes
Read
Venus in the ultraviolet
Science & Exploration

Venus comes to life at wavelengths invisible to human eyes

03/12/2008 2415 views 1 likes
Read
Earth atmosphere’s molecules detected by Venus Express
Science & Exploration

Venus Express searching for life – on Earth

10/10/2008 3203 views 5 likes
Read
Wind circulation on Venus
Science & Exploration

How windy is it on Venus? Venus Express answers

18/09/2008 6112 views 9 likes
Read
Artist's impression of Venus Express
Science & Exploration

Closing in on Venus

17/07/2008 980 views 0 likes
Read
Southern hemisphere of Venus in the ultraviolet
Science & Exploration

New details on venusian clouds revealed

30/05/2008 2526 views 2 likes
Read
Hydroxyl detected in the Venusian atmosphere
Science & Exploration

Key molecule discovered in Venus’s atmosphere

15/05/2008 2598 views 0 likes
Read
Science & Exploration

Notes for editors

07/10/2010 364 views 0 likes
Read