Indonesian volcanic eruption: Mount Sinabung forces evacuations

Indonesians look at the volcanic ash spewing up into the air from Mount Sinabung as it erupts in Karo, North Sumatra, on January 1, 2014

An Indonesian volcano that has erupted relentlessly for months shot volcanic ash into the air 30 times on Saturday, forcing further evacuations with more than 20,000 people now displaced, an official said.

Mount Sinabung on the western island of Sumatra sent rivers of lava flowing through an evacuation zone and columns of volcanic cloud up as high as 4,000 metres (13,000 feet), National Disaster Mitigation Agency (BNPB) spokesman Sutopo Purwo Nugroho said.

"Hot lava spewed from the volcano some 60 times, reaching up to five kilometres (three miles) southeast of the crater. This outpour is the biggest we've seen in all the recent eruptions," Nugroho said.

Authorities had already told residents in a five-kilometre radius of the volcano to evacuate, and Nugroho said an expanded evacuation zone may be considered.

The number of people who have now fled the rumbling volcano since it began erupting in September last year has risen to 20,331, Nugroho said.

Mount Sinabung is one of dozens of active volcanoes in Indonesia that straddle major tectonic fault lines, known as the Ring of Fire.

It had been quiet for around 400 years until it rumbled back to life in 2010, and again in September last year.

In August, five people were killed and hundreds evacuated when a volcano on a tiny island in East Nusa Tenggara province erupted.

NASA Spitzer Image: Galaxy's Ring of Fire

How many rings do you see in this new image of the galaxy Messier 94, also known as NGC 4736? 

While at first glance one might see a number of them, astronomers believe there is just one. 

This image was captured in infrared light by NASA's Spitzer Space Telescope. 

Credit: NASA/JPL-Caltech

The singer Johnny Cash may have preferred this galaxy's burning ring of fire to the one he sang about falling into in his popular song.

The "starburst ring" seen at centre in red and yellow hues is not the product of love, as in the song, but is instead a frenetic region of star formation.

The galaxy, a spiral beauty called Messier 94, is located about 17 million light-years away. In this image from NASA's Spitzer Space Telescope, infrared light is represented in different colours, with blue having the shortest wavelengths and red, the longest.

Starburst rings like this can often be triggered by gravitational encounters with other galaxies but, in this case, may have instead been caused by the galaxy's oval shape.

Gas in the ring is being converted into hot, young stars, which then warm the dust, causing it to glow with infrared light.

The outer, faint blue ring around the galaxy might be an optical illusion. Astronomers think that two separate spiral arms appear as a single unbroken ring when viewed from our position in space.

Solar Dynamics' Observatory: Ring of Fire

This new image from the SDO: Solar Dynamics Observatory’s Atmospheric Imaging Assembly (AIA) shows in great detail a solar prominence taken from a March 30, 2010 eruption. The twisting motion of the material is the most noticeable feature.

Launched on Feb. 11, 2010, SDO is the most advanced spacecraft ever designed to study the sun.

Click on the image to see more detial of the SDO Instruments

During its five-year mission, it will examine the sun's magnetic field and also provide a better understanding of the role the sun plays in Earth's atmospheric chemistry and climate.

Since launch, engineers have been conducting testing and verification of the spacecraft’s components. Now fully operational, SDO will provide images with clarity 10 times better than high-definition television and will return more comprehensive science data faster than any other solar observing spacecraft.