Galaxy Disco

Looks like a giant disco ball, remember them?

Instead, this is what NASA tells us.

How common are planetary systems like our own Solar System? In the twelve years previous to 2008, over 300 candidate planetary systems have been found orbiting nearby stars. None, however, were directly imaged, few showed evidence for multiple planets, and many had a Jupiter-sized planet orbiting inside the orbit of Mercury.

Last week, however, together with recent images of Fomalhaut b, the above picture was released showing one of first confirmed images of planets orbiting a distant Sun-like star. HR 8799 has a mass about 1.5 times that of our own Sun, and lies about 130 light years from the Sun — a distance similar to many stars easily visible in the night sky.

Pictured above, a 10-meter Keck telescope in Hawaii captured in infrared light three planets orbiting an artificially obscured central star. The 8-meter Gemini North telescope captured a similar image. Each planet likely contains several times the mass of Jupiter, but even the innermost planet, labelled d, has an orbital radius near the equivalent of the Sun- Neptune distance.

Although the HR 8799 planetary system has significant differences with our Solar System, it is a clear demonstration that complex planetary systems exists, systems that could conceivable contain an Earth-like planet.

What’s causing this unusual aurora over Saturn? No one is sure. Infrared images by the robotic Cassini spacecraft of the north pole of Saturn have uncovered aurora unlike any other seen previously in our Solar System.

The strange aurora are shown in blue in the above image, while the underlying clouds are shown in red. The previously recorded, also-strange hexagon cloud patterns are visible in red below the aurora. These Saturnian aurora can cover the entire pole, while auroras around Earth and Jupiter are typically confined by magnetic fields to rings surrounding the magnetic poles.

More normal auroral rings had been previously imaged around Saturn. The recently imaged strange auroras above Saturn’s north pole can change their global patterns significantly in only a few minutes. The large and variable nature of these auroras indicate that charged particles streaming in from the Sun are experiencing some type of magnetism above Saturn that was previously unexpected.