Hubble Finds Oxygen Atmosphere On Jupiter's Moon Europa . Astronomers using NASA's Hubble Space Telescope (HST) have identified the presence of an extremely tenuous atmosphere of molecular oxygen around Jupiter's second moon, Europa . ... Europa's oxygen atmosphere is so tenuous that its surface pressure is barely one hundred billionth that of the Earth," said Principal Investigator Doyle Hall, of Johns Hopkins. ... The oxygen gas slowly leaks into space and must be replenished continuously. ...

... Galileo Images of Io . ... Galileo Finds Giant Iron Core in Jupiter's Moon Io . ... The temperature on Io's surface is about -143њ C (-230њ F); however, a large hot spot associated with a volcanic feature measured about 17њ C (60њ F). ... Io's rotation . ... This pair of Hubble images of Jupiter's volcanic moon Io shows the surprising emergence of a 320-kilometer (200-mile) diameter, large yellowish-white feature near the center of the moon's disk (photo on the right). ... Volcanic Plumes . ...

... A violent event of a different type occurred in March 1991, when a powerful interplanetary shock wave hit the Earth's magnetic field and created a new radiation belt. ... At 03:42 Greenwich time on March 24, 1991, the population of high-energy electrons and protons trapped in the Earth's magnetic field suddenly received huge reinforcements. ... The passage of the shock also left Earth with a new long-lived belt of high-energy protons. ... The horizontal axis measures distance from the Earth's center...

Cosmic Research, Vol. 42, No. 5, 2004, pp. 435­488. Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 5, 2004, pp. 453­508. Original Russian Text Copyright © 2004 by Veselovsky, Panasyuk, Avdyushin, Bazilevskaya, Belov, Bogachev, Bogod, Bogomolov, Bothmer, Boyarchuk, Vashenyuk, Vlasov, Gnezdilov, Gorgutsa, Grechnev, Denisov, Dmitriev, Dryer, Yermolaev, Eroshenko, Zherebtsov, Zhitnik, Zhukov, Zastenker, Zelenyi, Zeldovich, Ivanov-Kholodnyi, Ignat'ev, Ishkov, Kolomiytsev, Krasheninnikov, Kudela,