Сиэтл Выбрать
$ 57.09 67.30

Active Volcanoes of Our Solar System

05.04.2017
Тип статьи:
  • Авторская
Volcanoes Are Not Confined to EarthEvidence of past volcanic activity has been found on most planets in our solar system and on many of their moons. Our own moon has vast areas covered with ancient lava flows. Mars has Olympus Mons and Tharsis Rise, the largest volcanic features in our solar system. The surface of Venus is covered with igneous rocks and hundreds of volcanic features.Most of the volcanic features discovered within our solar system formed millions of years ago — when our solar system was younger and the planets and moons had much higher internal temperatures. Geologically recent volcanic activity is not as widespread.Based upon observations from Earth and from space vehicles, only four bodies in the solar system have confirmed volcanic activity. These are 1) Earth; 2) Io, a moon of Jupiter; 3) Triton, a moon of Neptune; and, 4) Enceladus, a moon of Saturn.What is an Active Volcano?The term «active volcano» is used mainly in reference to Earth's volcanoes. Active volcanoes are ones that are currently erupting or that have erupted at some time in human history.This definition works fairly well for volcanoes on Earth because we can observe some of them easily — but many are located in remote areas where small eruptions could go unnoticed, or below remote parts of the oceans where even large eruptions might not be detected.Beyond Earth, our abilities to detect volcanic eruptions did not begin until the invention of powerful telescopes and made a great leap when space vehicles were able to carry telescopes and other sensing devices close to other planets and their moons.Today a number of telescopes are available to detect these eruptions — if they are large enough and facing in the proper direction. However, small eruptions might not be noticed because there are not enough telescopes to watch all areas of the solar system where volcanic activity might occur.Although only a few extraterrestrial eruptions have been detected, much has been learned about them. Perhaps the most interesting discovery has been the cryovolcanoes in the outer region of the solar system.What is a Cryovolcano?Most people define the word «volcano» as an opening in Earth's surface through which molten rock material, gases, and ash escape. This definition works well for Earth; however, some bodies in our solar system have a significant amount of gas in their composition.Planets near the sun are rocky and produce silicate rock magmas similar to those seen on Earth. However, planets beyond Mars and their moons contain significant quantities of gas in addition to silicate rocks. The volcanoes in this part of our solar system are usually cryovolcanoes. Instead of erupting molten rock, they erupt cold or frozen gases such as water, ammonia, or methane.For more you can check: Expense Management VideoExpense Management Video Examples


Автор: David Hill

Комментарии

Нет комментариев. Ваш будет первым!
Наверх