Can Venus show us more about Earth?

Lava flows are stud­ied as glimpses into our planet’s past, maybe young plate tec­ton­ics.

Los Angeles Times - - THE NATION - By Amina Khan amina. khan@ latimes. com Twit­ter: @am­i­nawrite

Hid­den be­neath a thick at­mos­phere, vol­ca­noes may still be erupt­ing on the sur­face of Venus, a new study finds.

The find­ings, de­scribed in the jour­nal Geo­phys­i­cal Re­view Letters, re­veal that our near­est plan­e­tary neigh­bor could be far more ac­tive than pre­vi­ously thought.

Sci­en­tists of­ten look to our neigh­bor­ing plan­ets to learn more about Earth’s past. Just next door, Mars is thought to have had wa­ter and per­haps an at­mos­phere thick enough to sup­port life; tiny, sun- scorched Mer­cury still has a liq­uid outer core that pow­ers a mag­netic field, rather like Earth’s.

Venus, our clos­est plan­e­tary com­pan­ion, could pro­vide in­sights of its own, but it’s shrouded in thick clouds of sul­fu­ric acid that block out vis­i­ble light.

And that’s too bad, said study coau­thor James Head, a plan­e­tary geo­sci­en­tist at Brown Univer­sity in Rhode Is­land, be­cause in many ways it would be the best planet to study to learn more about Earth and its history.

“Venus — in terms of its size, its den­sity, po­si­tion in the so­lar sys­tem — is lit­er­ally the most Earth- like planet,” Head said. “And I think that if we could see what was go­ing on in the for­ma­tive years of Earth, that would be re­ally in­cred­i­ble.”

Rus­sian lan­ders in the 1970s and ‘ 80s noted some fa­mil­iar ter­rain, in­clud­ing plateaus and fea­tures that re­sem­bled moun­tain belts. But they saw sur­pris­ingly few craters.

The ter­rain in­di­cated that the sur­face had been ac­tive, un­der­go­ing the kind of geo­phys­i­cal churn seen on Earth.

Venus, like Mars, had clearly had vol­canic ac­tiv­ity in the dis­tant past — but could it be con­tin­u­ing to­day?

“Peo­ple were think­ing, ‘ Well, is it like the Earth, which is very ac­tive, or is it like the moon and Mars, which are like a bunch of craters?’ ” Head said.

Data from NASA’s Mag­el­lan space­craft, which en­tered Venu­sian or­bit in 1990, seemed to say that Venus was geo­phys­i­cally dead.

But if it had been in­ac­tive for a very long time, then it should be heav­ily cratered.

To get at that ques­tion, the sci­en­tists turned to the Euro­pean Space Agency’s Venus Ex­press space­craft, us­ing data from its Venus Mon­i­tor­ing Cam­era to look for bright spots that sig­naled lo­cal lava f lows.

They fo­cused on the planet’s rift zones, with the idea that any hot spots of ge­o­logic ac­tiv­ity would be there.

Sure enough, the sci­en­tists found bright spots that in­di­cate tem­per­a­ture spikes caused by f low­ing lava, a sign that Venus is still ac­tive. These spots don’t cover the planet but pop up only along the rift lines cross­ing the planet’s sur­face.

The rift zones with these hot spots are some­what rem­i­nis­cent of the East African rift zone on Earth, Head said.

While the dy­nam­ics on Venus are clearly very dif­fer­ent than the ones on Earth to­day, Venus’ cur­rent ac­tiv­ity could hint at what Earth looked like be­fore its tec­tonic plates were formed.

“That’s why Venus is so im­por­tant. ... Maybe this is what the Earth looks like be­fore plate tec­ton­ics got started,” Head said. “Maybe we’re look­ing at the be­gin­ning of plate tec­ton­ics on Venus.”

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