Andromeda’s Bright X-Ray Source


The Andromeda galaxy is our nearest neighboring large galaxy. It has a mysterious dominant source of high-energy X-ray emission called Swift J0042.6+4112. Recent observations by the NuSTAR (Nuclear Spectroscopic Telescope Array) mission have pinpointed a pulsar that is for this high-energy radiation. A pulsar is the dense remnant of a dead star that is highly magnetized and spinning. The strong pulsar in Andromeda is likely in a binary system in which material from a stellar companion gets pulled onto the pulsar. X-rays are radiated by the material as it heats up.

The highest energy x-rays are color code blue in the NuSTAR image above, and the pulsar is shown as a blue dot. It appears brighter in high-energy X-rays than anything else in the galaxy.

Image Credit: NASA

Flying Through Cas A


This animation shows what it might be like to fly through of Cas A based on a 3-D model derived from Chandra X-ray and Spitzer IR data. It opens with an artists rendition of the neutron star remains of the original exploded star detected by Chandra. The green region is mostly iron observed in X-rays; the yellow region is mostly argon and silicon seen in X-rays and in visible and infrared light; the red region is cooler debris seen in the infrared and the blue region is the outer blast wave, most prominent in X-rays.

Video Credit: NASA

The Changing Face of Comet 67P


A 30-m wide boulder with a mass of almost 13,000 tonnes was found to have moved about 140 m across the face of Comet 67P/Churyumov–Gerasimenko in the months before the comet reached perihelion in August, 2015. That was when the when the comet’s activity was at its highest. In both images above, an arrow points to the boulder; in the right-hand image, the dotted circle outlines the original location of the boulder for reference. The rock was probably moved by jets of material outgassing from the comet.

Image Credit: ESA

A Stellar Death Spiral


Roughly 290 million years ago, a star more or less like the Sun got too close to the central black hole of its galaxy. Intense tides tore the star apart and the resulting outburst of visible, ultraviolet and X-ray light first reached Earth in 2014. Observations from the Swift satellite have mapped out how and where these different wavelengths were produced as the shattered star’s debris circled the black hole. This animation illustrates how debris from a tidally disrupted star collided with itself, creating shock waves that emit ultraviolet and visible light. According to the Swift observations, that debris then took about a month to fall back to the black hole, where they produced changes in its X-ray emission that correlated with the earlier UV and visible light bursts.

Video Credit: NASA

The Equinox


The 2017 Spring Equinox for the Northern Hemisphere (and Autumn in the South) will occur a few minutes after this post goes up. At an equinox, the Earth’s terminator—the dividing line between day and night—is at a right angle to the equator and connects the north and south poles. This time-lapse video show a view of a year on Earth in twelve seconds as seen from geosynchronous orbit by the Meteosat satellite. The video starts at the September, 2010, equinox. As the Earth revolves around the Sun, the terminator tilts in a way that provides less daily sunlight to the northern hemisphere during winter in the north. The March, 2011, equinox arrives halfway through the video, followed by the terminator tilting the other way during summer in the north. The year ends with the September, 2011, equinox.

Video Credit: NASA

The Orion Nebula in False Color


This false color image of the Orion Nebula was generated using visible light and infrared data from two of the instruments onboard the Hubble Space Telescope. The image shows a segment of the sky about 0.002° wide. That works out to around 3.4 light-years at the nebula which is 1,500 light-years away.

Image Credit: Nasa / ESA / STScI