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Witnessing the blood-red fires of a volcanic eruption on Earth is memorable. But to see molten rock bleed out of a volcano on a different planet would be extraordinary. That is close to what scientists have spotted on Venus: two vast, sinuous lava flows oozing from two different corners of Earth\u2019s planetary neighbor.<\/p>\n
\u201cAfter you see something like this, the first reaction is \u2018wow,\u2019\u201d said Davide Sulcanese, a doctoral student at the Universit\u00e0 d\u2019Annunzio in Pescara, Italy, and an author of a study reporting the discovery in the journal Nature Astronomy, published on Monday.<\/p>\n
Earth and Venus were forged at the same time. Both are made of the same primeval matter, and both are the same age and size. So why is Earth a paradise overflowing with water and life, while Venus is a scorched hellscape with acidic skies?<\/p>\n
Volcanic eruptions tinker with planetary atmospheres. One theory holds that, eons ago, several apocalyptic eruptions set off a runaway greenhouse effect on Venus, turning it from a temperate, waterlogged world into an arid desert of burned glass.<\/p>\n<\/div>\n<\/div>\n
To better understand its volcanism, scientists hoped to catch a Venusian eruption in the act. But although the planet is known to be smothered in volcanoes, an opaque atmosphere has prevented anyone from seeing an eruption the way spacecraft have spotted them on Io, the hypervolcanic moon of Jupiter.<\/p>\n
In the 1990s, NASA\u2019s spacecraft Magellan used cloud-penetrating radar to survey most of the planet. But back then, the relatively low-resolution images made spotting fresh molten rock a troublesome task.<\/p>\n
By using modern software to peruse Magellan\u2019s data, scientists have now found two unambiguous lava flows: one tripping down the flank of Sif Mons, a broad shield volcano, and another winding its way across a western part of Niobe Planitia, a flat plain pockmarked with numerous volcanic mountains.<\/p>\n
Many planetary scientists reckoned Venus was effervescing with eruptions. \u201cBut it\u2019s one thing to strongly suspect it and quite another to know it,\u201d said Paul Byrne, a planetary scientist at Washington University in St. Louis who was not part of the new study.<\/p>\n
Venus lacks the plate tectonics of Earth. But its similarly rocky constitution and comparable size suggests that something must still be cooking inside the sun\u2019s second planet \u2014 and it should be volcanically active.<\/p>\n<\/div>\n<\/div>\n
There is indirect supporting evidence: Volcanic gases linger in Venus\u2019s skies, and the way that parts of the planet glow suggests they were painted over by lava in the recent geologic past.<\/p>\n
Direct evidence of volcanic fury finally, and surprisingly, emerged in 2023, when researchers caught sight of a volcanic vent doubling in size and possibly filling with lava in old Magellan data. Other scientists still yearned for signs of an unequivocal lava flow, an almost literal smoking gun.<\/p>\n
Mr. Sulcanese granted their wish. He found bright, riverlike patches on Sif Mons and Niobe Planitia in later Magellan survey images that weren\u2019t present in earlier data. After carefully ruling out other possibilities, including landslides, his team concluded that lava was the only reasonable explanation.<\/p>\n
\u201cMagellan is the gift that keeps on giving,\u201d said Stephen Kane, a planetary astrophysicist at the University of California, Riverside, who was not involved with the new study.<\/p>\n
Both lava flows are comparable in size to the output of the Kilauea volcano in Hawaii during its three-month paroxysm in 2018. And using these two eruptions, the study\u2019s authors estimate that there is considerably more eruptive activity than previously assumed \u2014 and that it\u2019s happening elsewhere on the planet in the present day.<\/p>\n<\/div>\n<\/div>\n
\u201cVenus is active,\u201d said Giuseppe Mitri, an astronomer also at the Universit\u00e0 d\u2019Annunzio and an author of the study.<\/p>\n
More important, volcanically speaking, Venus \u201cis Earth-like,\u201d said Anna G\u00fclcher, a planetary scientist at the California Institute of Technology who was not involved with the work.<\/p>\n
The result also complicates the tentative detection of phosphine in Venus\u2019s atmosphere; phosphine is a substance that is usually associated on Earth with living things. But other explanations for its possible presence on Venus couldn\u2019t be ruled out. Volcanic activity can also make phosphine, but rebuttals to that idea have suggested that Venus simply doesn\u2019t have sufficient volcanism to make it.<\/p>\n
\u201cWell, apparently there is,\u201d Dr. Kane said.<\/p>\n
The only way to find better answers \u2014 on phosphine, Venus\u2019s volcanic cadence, its cataclysmic transformation \u2014 is to revisit the planet. Fortunately, a fleet of new spacecraft is set to do just that in the 2030s.<\/p>\n
While we wait, Magellan\u2019s memories will continue to offer unexpected gifts.<\/p>\n
\u201cWe can start to think of Venus as a living, breathing world,\u201d Dr. Byrne said.<\/p>\n<\/div>\n<\/div>\n