Τα ηφαίστεια της Ιούς βρίσκονται σε λάθος θέση, Scientists to Io: Your Volcanoes Are in the Wrong Place

This is a montage of New Horizons images of Jupiter and its volcanic moon Io, taken during the spacecraft's Jupiter flyby in early 2007. The image shows a major eruption in progress on Io's night side, at the northern volcano Tvashtar. Incandescent lava glows red beneath a 330-kilometer (205-mile-high) volcanic plume, whose uppermost portions are illuminated by sunlight. The plume appears blue due to scattering of light by small particles in the plume. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Goddard Space Flight Center

Τα εκατοντάδες ηφαίστεια στο φεγγάρι του Δία Ιώ, δεν βρίσκονται εκεί που υποτίθεται ότι θα έπρεπε να είναι, λένε οι επιστήμονες.

Μια ακολουθία πέντε διαδοχικών εικόνων των γιγαντιαίων νεφών του ηφαιστείου Tvashtar στον δορυφόρο του Δία, Ιώ. Οι φωτογραφίες λήφθηκαν από την αποστολή New Horizons της NASA. This five-frame sequence of images from NASA's New Horizons mission captures the giant plume from Io's Tvashtar volcano. Snapped by the probe's Long Range Reconnaissance Imager (LORRI) as the spacecraft flew past Jupiter in 2007, this first-ever movie of an Io plume clearly shows motion in the cloud of volcanic debris, which extends 330 km (205 miles) above the moon's surface. Only the upper part of the plume is visible from this vantage point. The plume's source is 130 km (80 miles) below the edge of Io's disk, on the far side of the moon. Io's hyperactive nature is emphasized by the fact that two other volcanic plumes are also visible off the edge of Io's disk: Masubi at the 7 o'clock position, and a very faint plume, possibly from the volcano Zal, at the 10 o'clock position. Jupiter illuminates the night side of Io, and the most prominent feature visible on the disk is the dark horseshoe shape of the volcano Loki, likely an enormous lava lake. Boosaule Mons, which at 18 km (11 miles) is the highest mountain on Io and one of the highest mountains in the solar system, pokes above the edge of the disk on the right side. The five images were obtained over an 8-minute span, with two minutes between frames, from 23:50 to 23:58 Universal Time on 1 March 2007. Io was 3.8 million km (2.4 million miles) from New Horizons. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Η σημαντική ηφαιστειακή δραστηριότητα της Ιούς συγκεντρώνεται 30 έως 60 μοίρες ανατολικότερα από εκεί που υπολόγιζαν οι επιστήμονες της ΝΑSA λαμβάνοντας υπόψη τα μοντέλα προσομοίωσης της εσωτερικής θερμότητας του πλανήτη. «Το εξωτικό, ηφαιστειακό φεγγάρι του Δία Ιώ είναι ακόμα πιο μυστηριώδες από ό,τι οι ερευνητές θεωρούσαν μέχρι σήμερα» λέει η ΝΑSA αφού ολοκλήρωσε την επεξεργασία στοιχείων που συνέλεξε το διαστημικό όχημα της «Νέοι Ορίζοντες».

This is a map of the predicted heat flow at the surface of Io from different tidal heating models. Red areas are where more heat is expected at the surface while blue areas are where less heat is expected. Figure A shows the expected distribution of heat on Io's surface if tidal heating occurred primarily within the deep mantle, and figure B is the surface heat flow pattern expected if heating occurs primarily within the asthenosphere. In the deep mantle scenario, surface heat flow concentrates primarily at the poles, whereas in the asthenospheric heating scenario, surface heat flow concentrates near the equator. Credit: NASA/Christopher Hamilton

«Κάτι λείπει από την κατανόησή μας για την Ιώ» δήλωσε ο επικεφαλής της μελέτης Κρίστοφερ Χάμιλτον, καθηγητής από το Πανεπιστήμιο του Μέριλαντ.

Η Ιώ είναι ο πιο ηφαιστειογενής πλανήτης στο ηλιακό μας σύστημα. Διαθέτει δραστηριότητα 25 φορές πολλαπλάσια αυτής της Γης.

Μια σύνθεση εικόνων της Ιούς και της Ευρώπης (επίσης δορυφόρου του Δία) που λήφθηκαν στις 2 Μαρτίου του 2007 από το διαστημικό σκάφος New Horizons. This is a composite image of Io and Europa taken March 2, 2007 with the New Horizons spacecraft. Here Io (top) steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-kilometer (190-mile) high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are also visible: that from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and from the volcano Amirani, seen between Prometheus and Tvashtar along Io's terminator (the line dividing day and night). The Tvashtar plume appears blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume. This image was taken from a range of 4.6 million kilometers (2.8 million miles) from Io and 3.8 million kilometers (2.4 million miles) from Europa. Although the moons appear close together in this view, a gulf of 790,000 kilometers (490,000 miles) separates them. Io's night side is lit up by light reflected from Jupiter, which is off the frame to the right. Europa's night side is dark, in contrast to Io, because this side of Europa faces away from Jupiter. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Αυτή η έντονη δραστηριότητα παράγεται από τις βαρυτικές έλξεις του Δία, με την υποβοήθηση από το κοντινά φεγγάρια Ευρώπη και Γανυμήδη.

Η Ιώ ολοκληρώνει δύο τροχιές για κάθε μία της Ευρώπης, και κάθε τέσσερις του Γανυμήδη.