University of Leicester researchers have captured stunning images of Saturn’s auroras as the planet’s magnetic field is battered by charged particles from the Sun.
The team’s findings provide a “smoking gun” for the theory that Saturn’s auroral displays are often caused by the dramatic collapse of its “magnetic tail”.
Just like comets, planets such as Saturn and the Earth have a “tail” – known as the magnetotail – that is made up of electrified gas from the Sun and flows out in the planet’s wake.
When a particularly strong burst of particles from the Sun hits Saturn, it can cause the magnetotail to collapse, with the ensuing disturbance of the planet’s magnetic field resulting in spectacular auroral displays. A very similar process happens here on Earth.
Curiosity watched on sol 713 as lumpy Phobos passed across the face of the Sun. There are 84 images in this animation, which runs faster than natural speed. A couple of sunspots are faintly visible. The animation is composed of raw JPEG images, so contains artifacts, particularly at the high-contrast areas at the edges of the Sun and Phobos.
NASA / JPL / MSSS / TAMU / Emily Lakdawalla (via Curiosity sees a Phobos transit, sol 713 | The Planetary Society)
Arp 188 and the Tadpole’s Tail
Why does this galaxy have such a long tail? In this stunning vista, based on image data from the Hubble Legacy Archive, distant galaxies form a dramatic backdrop for disrupted spiral galaxy Arp 188, the Tadpole Galaxy. The cosmic tadpole is a mere 420 million light-years distant toward the northern constellation Draco. Its eye-catching tail is about 280 thousand light-years long and features massive, bright blue star clusters. One story goes that a more compact intruder galaxy crossed in front of Arp 188 - from right to left in this view - and was slung around behind the Tadpole by their gravitational attraction. During the close encounter, tidal forces drew out the spiral galaxy’s stars, gas, and dust forming the spectacular tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper right. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail’s star clusters forming smaller satellites of the large spiral galaxy.
Image credit: Hubble Legacy Archive, ESA, NASA; Processing & copyright: Joachim Dietrich
Gravity wells -
A Gravity well or gravitational well is defined as “a conceptual model of the gravitational field surrounding a body in space.”
The more massive the body, the deeper and more extensive the gravity well associated with it. The Sun is very massive, relative to other bodies in the Solar System, so its gravity well appears “deep” and far-reaching.
(picture a very heavy object sinking deep into a bed mattress; the more mass the object has the deeper it sinks in and creates a deeper sinkhole; a deeper sink hole will pull in any nearby objects towards the centre object with greater influence. Objects of mass bend the fabric of spacetime this way also as the theory of general relativity explains)
Reid Wiseman is a national treasure.
from this view, we don’t seem so savage.
Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA).
Credit: NASA, Hubble, Mehdi Bozzo-Rey