Observations by NASA's Fermi Gamma-ray Space Telescope of several stellar eruptions, called novae, firmly establish these relatively common outbursts almost always produce gamma rays, the most energetic form of light.

"There's a saying that one is a fluke, two is a coincidence, and three is a class, and we're now at four novae and counting with Fermi," said Teddy Cheung, an astrophysicist at the Naval Research Laboratory in Washington, and the lead author of a paper reporting the findings in the Aug. 1 edition of the journal Science.

Does this galaxy make me look fat? Has Andromeda been taking skinny selfies?

It turns out the way some astrophysicists have been studying our galaxy made it appear that the Milky Way might be more massive than it's neighbor Andromeda. 

It isn't, says a study published in the journal Monthly Notices of the Royal Astronomical Society by an international group of researchers, including Matthew Walker of Carnegie Mellon University's McWilliams Center for Cosmology. In the paper, they outline a new, more accurate method for measuring the mass of galaxies. Using this method, the researchers have shown that the Milky Way has only about half the mass of its neighbor, the Andromeda Galaxy.  

New findings have resolved a decades-old puzzle about a fog of low-energy X-rays observed over the entire sky. Thanks to refurbished detectors first flown on a NASA sounding rocket in the 1970s, astronomers have now confirmed the long-held suspicion that much of this glow stems from a region of million-degree interstellar plasma known as the local hot bubble, or LHB. 

At the same time, the study also establishes upper limits on the amount of low-energy, or soft, X-rays produced within our planetary system by the solar wind, a gusty outflow of charged particles emanating from the sun. 

In June of 2013, an exceptional binary containing a rapidly spinning neutron star underwent a dramatic change in behavior never before observed - the pulsar radio beacon vanished and the system brightened fivefold in gamma rays, the most powerful form of light.

A binary consists of two stars orbiting around their common center of mass. This system, known as AY Sextantis, is located about 4,400 light-years away in the constellation Sextans. It pairs a 1.7-millisecond pulsar named PSR J1023+0038 -- J1023 for short -- with a star containing about one-fifth the mass of the sun. The stars complete an orbit in only 4.8 hours, which places them so close together that the pulsar will gradually evaporate its companion.

has been revealed as a transiting exoplanet with the longest known year - 704 days. For comparison, Mars orbits our Sun once every 780 days.

 The farther a planet is from its star, the less likely it is to transit the star from Earth's point of view. It has to line up just right, and most of the 1,800-plus exoplanets discovered so far are much closer to their stars and have much shorter orbital periods. The host star, Kepler-421, is located about 1,000 light-years from Earth in the direction of the constellation Lyra. 

A new discovery that many small galaxies throughout the universe do not 'swarm' around larger ones like bees but instead 'dance' in orderly disc-shaped orbits is a challenge to our understanding of how the universe formed and evolved.   

The universe contains billions of galaxies. Some, such as the Milky Way, are immense, containing hundreds of billions of stars. Most galaxies, however, are dwarfs, much smaller and with only a few billion stars.

For decades astronomers have used computer models to predict how these dwarf galaxies should orbit large galaxies. They had always found that they should be scattered randomly.

What creates the two gigantic donuts of radiation surrounding Earth called the Van Allen radiation belts? The Van Allen Probes launched in 2012 want to find out.

The inner Van Allen radiation belt is fairly stable, but the outer one changes shape, size and composition in ways that scientists don't yet perfectly understand. Some of the particles within this belt zoom along at close to light speed, but just what accelerates these particles up to such velocities? Recent data from the Van Allen Probes suggests that it is a two-fold process: One mechanism gives the particles an initial boost and then a kind of electromagnetic wave called Whistlers does the final job to kick them up to such intense speeds.

Sometimes we have to wonder in amazement about things found out in the universe. Case in point: a slinky string of pearls twisted into a corkscrew shape.

Nothing special about that. Except this string is 100,000 light years long.

The pearls in the string are superclusters of blazing, blue-white, newly born stars and the structure forms a bridge between two giant elliptical galaxies that are colliding. These young, blue "super star clusters" are evenly spaced along the chain at separations of 3,000 light-years from one another.

As every Boy Scout knows, friction generates heat. A new study finds that friction could be the key to survival for some distant Earth-sized planets traveling in dangerous orbits.

Earth-sized planets are becoming common in other star systems. Too close to a star, and heat can be a destructive force but for planets in the habitable zone, the right amount of friction, and therefore heat, can be helpful and perhaps create conditions for habitability.

Olber's Paradox asks why the sky is not a sheet of white. Since just the galaxy we are in has 50 stars for every person currently on earth traveling to us at all time, how can it ever get dark when there are billions of galaxies all containing stars? 

It isn't just a visible light mystery, something is amiss in the ultraviolet Universe also.  We can't explain all of the light in the cosmic budget.