Best Space Photos of the Week
Black Hole Blows
Black holes are often depicted as cosmic vacuum cleaners, devouring everything in their path. However, researchers have discovered that they are actually quite messy eaters. As black holes feed, they expel some of the infalling matter via powerful winds of radiation.
These winds can have far-reaching effects. Most mature galaxies harbor supermassive black holes at their cores. A recent study using two X-ray telescopes found that the winds from a particularly bright galaxy with an active black hole called PDS 456 are blowing across most of the galaxy. This suggests that the winds may be pushing out the gases needed for new stars to form, potentially regulating the growth of the host galaxy.
Montana Aurora
On February 18, the skies over northern Montana were ablaze with a spectacular aurora display. The show was visible even beyond the Arctic Circle. Earth was passing through a stream of solar particles, which collided with air molecules in our atmosphere to create the brilliant light show.
The main display was likely happening over Canada, where observers would have witnessed the more common green ribbons of light created by solar particles striking oxygen molecules lower in the atmosphere. However, from a distance in Montana, observers could see the brilliant reds of aurora activity much higher in the sky.
Frozen Volcano
On February 16, a volcano in the Kuril Islands roared to life for the first time in seven years. The Chikurachi volcano spewed plumes of ash up to 25,000 feet high, carried westward by winds over the snow-covered landscape. Despite being a hotbed of volcanic activity, the Kuril island chain is inhabited and has been at the center of a 60-year-old territory dispute between Japan and Russia.
Dawn Approaches
Ceres is the only official dwarf planet that resides in the main asteroid belt between Mars and Jupiter. Since September 2014, NASA’s Dawn spacecraft has been getting closer to this tiny target and is now providing even better images than the Hubble Space Telescope.
Recent shots taken on February 12 show two sides of Ceres as the object rotates, revealing craters and a scattering of bright spots that have astronomers puzzled. Dawn is expected to start orbiting Ceres on March 6, and its close-up views will hopefully resolve the mystery.
Dark Merger
Dark matter, an invisible and mysterious substance, appears to play a guiding role in the growth of supermassive black holes. Galaxies have supermassive black holes at their centers, and astronomers have long believed that the size of the black hole must be linked to the number of stars in the galaxy.
However, galaxies are also embedded in haloes of invisible dark matter, which outweighs all their visible matter. A recent study has found a tight relationship between the mass of supermassive black holes and the mass of their dark matter haloes in 3,000 elliptical galaxies. This suggests that dark matter, not light, governs the size of black holes.
This relationship may be related to the way elliptical galaxies form—via the merger of two smaller galaxies. When two galaxies become one, the dark matter halo grows, setting a galaxy-wide “gravitational blueprint” that somehow triggers the black hole to bulk up.
