Venus is volcanically active just like Earth

By Mark Waghorn via SWNS

Venus is volcanically active - just like Earth, scientists discovered after a lava lake was found on the fiery second planet from the sun.

Analysis of images taken more than three decades ago revealed a volcanic vent measuring almost one square mile in size.

The molten lake was detected by researchers examining pictures of the volatile planet taken by NASA during the 1990s - shedding fresh light on its mysterious geology.

This lava lake was found to have changed in shape and grew over eight months.

On Earth, the phenomenon is linked with eruptions or movement of magma beneath the surface - causing expansion due to the collapse of the walls.

The digital evidence was captured by NASA's Magellan space probe. Until recently, it would have taken too much time to search the data for feature formation.

Professor Robert Herrick, of the University of Alaska Fairbanks and a lead author of the study, said: "It is really only in the last decade or so that the Magellan data has been available at full resolution, mosaicked and easily manipulable by an investigator with a typical personal workstation."

The U.S. team focused on an area containing two of Venus' largest volcanoes, Ozza and Maat Mons.

Prof. Herrick said: "Ozza and Maat Mons are comparable in volume to Earth's largest volcanoes but have lower slopes and thus are more spread out."

The north face of a domed shield of Maat Mons contains the expanded vent.

Comparing two shots from February and October 1991 showed it had turned from a circular pattern of just under a square mile to an irregular one of about 1.5 square miles.

The walls became shorter, perhaps only a few hundred feet high, and the vent was nearly filled to its rim.

The researchers speculate a lava lake formed. It's not known if the contents were liquid or cooled and solidified.

They don't believe a "venusquake" was responsible. Vent collapses of this scale on Earth have always been accompanied by nearby volcanic eruptions.

Magma withdraws from beneath the vent because it is going somewhere else.

The surface of Venus is geologically young, especially compared to all the other rocky bodies except Earth and Jupiter's moon Io.

Prof Herrick added: "However, the estimates of how often eruptions might occur on Venus have been speculative, ranging from several large eruptions per year to one such eruption every several or even tens of years."

He contrasts the lack of information about Venusian volcanism with what is known about Jupiter’s moon Io and about Mars.

Prof. Herrick said: "Io is so active that multiple ongoing eruptions have been imaged every time we've observed it."

On a geological time scale, relatively young lava flows indicate Mars remains volcanically active.

Prof. Herrick said: "However, nothing has occurred in the 45 years that we have been observing Mars.

"Most scientists would say that you'd probably need to watch the surface for a few million years to have a reasonable chance of seeing a new lava flow."

The study in Science adds Venus to the small pool of volcanically active worlds in our solar system.

Prof. Herrick said: "We can now say Venus is presently volcanically active in the sense there are at least a few eruptions per year.

"We can expect the upcoming Venus missions will observe new volcanic flows that have occurred since the Magellan mission ended three decades ago and we should see some activity occurring while the two upcoming orbital missions are collecting images."

Venus is Earth's "sister" planet. The hellish world may even have harbored life two billion years ago.

Although similar in size and mass, it does not have plate tectonics. The boundaries of Earth's moving surface plates are the primary locations of volcanic activity.

There is currently renewed interest in the exploration of Venus. NASA and the European Space Agency have approved three new spacecraft missions.

They will acquire observations of the planet’s surface at much higher resolution than Magellan.

Venus is the hottest planet in the solar system, with a surface temperature of 932 degrees Fahrenheit — high enough to melt lead.

It may have harbored oceans for a billion years of its history. There is even a region of the planet's thick atmosphere where microbial life could survive - floating among the clouds.