이오, 지구 전체 발전소 6배 에너지의 화산

태양계 5번째 행성인 목성에 딸린 위성에서 엄청난 규모의 화산 폭발이 관측됐다. 폭발력이 지구에 있는 전체 발전소에서 나오는 에너지의 무려 6배로 측정됐다.

지난달 말 미국 항공우주국(NASA)은 목성 위성 ‘이오’에서 강력한 화산 폭발을 확인했다고 밝혔다. 이오는 지름이 3642㎞로, 달(3474㎞)보다 약간 큰 천체다.

NASA는 지난해 10월 무인 탐사선 ‘주노’를 통해 이오 표면 사진을 찍었다. 그런데 사진 판독 과정에서 이상한 현상이 확인됐다. 10월22일까지는 별일 없던 이오 표면에서 돌연 10월27일 길게 뻗은 검은 연기 같은 모습이 관찰됐다. 일주일도 안 되는 사이 이오에 심상치 않은 변화가 생긴 것이다.

연기의 정체를 파악하기로 한 NASA는 같은 해 주노에 “12월27일 적외선(열) 감지 장비를 켠 채 이오에 접근해 비행하라”는 명령을 내렸다.

관측 결과는 놀라웠다. NASA는 “이오 관측 역사상 가장 강력한 화산 폭발이 확인됐다”고 밝혔다. 폭발은 이오 남극 근처에서 발생했다.

특히 주목할 것은 폭발력이었다. 전기 에너지로 환산했더니 무려 80조W(와트)였다. NASA는 “지구에 존재하는 모든 발전소 전기 생산용량의 6배에 이르는 수치”라고 설명했다.

이런 엄청난 폭발의 원천은 이오가 공전하는 목성의 강한 중력(물체를 잡아당기는 힘)이다. 이오는 목성에서 멀어졌다가 가까워지는 일을 반복하는 타원형 궤도를 42.5시간마다 한 바퀴 도는데, 목성이 바짝 다가오면 이오의 땅은 무려 100ｍ나 부풀어 오른다. 목성 중력 때문에 이오의 평평한 들판이 산으로 바뀌는 셈이다.

목성의 쥐락펴락하는 힘에 반복적으로 노출되는 이오의 지하에서는 높은 마찰열이 생기지 않을 수 없다. 이오 땅속에서 화산의 ‘연료’인 뜨거운 마그마가 다량 생성되는 이유다. 실제로 이오에는 활동 중인 화산이 400개나 있다.

NASA는 “다음달 3일 주노를 통해 이오를 재차 관측할 계획”이라며 “화산 분출이 있는 지역에서 경관 변화가 있는지를 확인할 것”이라고 설명했다.

실제로 이오의 다른 화산은 분화구에서 각종 암석과 마그마를 내뿜으며 지표면을 변화시킨다. 특히 화산에서 분출되는 화학 물질인 황과 이산화황으로 인해 퇴적물이 생긴다. 이오의 표면 사진이 피자처럼 알록달록한 이유도 이 때문이다. NASA는 “이오에서 이번에 폭발이 확인된 화산을 지구 표면 망원경으로 관측하는 활동도 병행할 것”이라고 밝혔다.

 

 

 

 

A huge volcanic eruption was observed on a satellite attached to Jupiter, the fifth planet of the solar system. The explosive power was measured at six times the energy generated by the entire power plant on Earth.

Late last month, the U.S. National Aeronautics and Space Administration (NASA) said it confirmed a powerful volcanic eruption on Jupiter's moon Io. Io is 3,642 kilometers in diameter and slightly larger than the moon (3474 kilometers).

NASA took photos of the surface of the Io in October last year through an unmanned probe called Juno. However, a strange phenomenon was confirmed during the photo review process. On October 27, a long, black smoke-like appearance was suddenly observed on the Io surface, which was nothing until October 22. In less than a week, the Io has experienced an unusual change.

NASA, which decided to determine the identity of the smoke, ordered Juno to "flight close to Io with infrared (thermal) detection equipment on on December 27."

The observations were astonishing. NASA said, "We have identified the strongest volcanic eruption in the history of this observation." The eruption occurred near the Io Antarctic.

Especially noteworthy was the explosive power. When converted into electricity, it was 80 trillion watts. NASA said that the figure is six times the amount of electricity produced by all power plants on Earth.

The source of such massive explosion is the strong gravity (the force that pulls objects) of Jupiter that Io orbits around. Io orbits around an elliptical orbit every 42.5 hours, which repeats moving away and getting closer to Jupiter, and when Jupiter gets closer, Io's land swells up to 100 meters. In other words, the gravity of Jupiter turns Io's flat field into a mountain.

In the underground of Io, which is repeatedly exposed to Jupiter's rattling force, high frictional heat is inevitable. This is why a large amount of hot magma, the 'fuel' of volcanoes, is produced in the Io land. In fact, Io has 400 active volcanoes.

NASA said, "We plan to observe Io again through Juno on the 3rd of next month," adding, "We will check whether there are any changes in the landscape in the area where the volcanic eruption occurs."

In fact, other volcanoes in Io emit various rocks and magma from craters and change the surface of the earth. In particular, sulfur and sulfur dioxide, chemicals that are released from volcanoes, cause sediments. This is why Io's surface photos are as colorful as pizza. NASA said, "We will also observe the volcano, which has been confirmed to have erupted in Io, with an Earth surface telescope."