If you began to travel to the star nearest to us after ol' Sol, named Alpha Centauri, it takes about four light years.  

Now imagine there were instead 10,000 other stars crammed into that 25 trillion miles of space rather than none - that's the kind of density of a galaxy that was recently discovered.

New evidence suggests than no continental ice sheet formed during the Late Cretaceous Period more than 90 million years ago, when the climate was much warmer than it is today, though it has been commonly believed to have happened that way. 

Psychopathy is a personality disorder characterized by a lack of empathy and remorse, shallow affect, glibness, manipulation and callousness. Though less than one percent of the general population meet the criteria, the rate of psychopathy in prisons is around 23%. 

As you might suspect, psychopaths don't much care when people are in pain. 

A new paper using functional magnetic resonance imaging (fMRI) on the brains of 121 inmates of a medium-security prison in the USA finds that in psychopaths, the brain areas necessary for feeling empathy and concern for others fail to become active and be connected to other important regions involved in affective processing and decision-making. 

A new study finds that a 'microbial clock' may help forensic scientists who are attempting to determine the time of death in cases involving human corpses. 

The 'clock' in this instance is essentially the lock-step succession of bacterial changes that occur postmortem as bodies move through the decay process, much like estimates used to be made involving knowledge of rigor mortis.

Currently, investigators use tools ranging from the timing of last text messages and corpse temperatures to insect infestations on bodies and "grave soil" analyses, with varying results. And the more days that elapse following a person's demise, the more difficult it becomes to determine the time of death with any significant accuracy. 

Deep earthquakes occur where the oceanic lithosphere, driven by tectonics, plunges under continental plates – examples are off the coasts of the western United States, Russia and Japan.

Some new research is a step toward replicating the full power of these earthquakes to learn what sets them off and how they unleash their violence and was made possible only by the construction of a one-of-a-kind X-ray facility that can replicate high-pressure and high-temperature while allowing scientists to peer deep into material to trace the propagation of cracks and shock waves.

Galaxy Zoo 2, the second phase of a crowdsourcing effort to categorize galaxies in our universe, has leveraged more than 83,000 citizen scientists to obtain over 16 million galaxy classifications and information on more than 300,000 galaxies.

That's what you get when you ask the public for help in learning more about our universe.  Computers are good at automatically measuring properties such as size and color of galaxies, but more challenging characteristics, such as shape and structure, can only be determined by the human eye.

Rice containing a transgenic modification that makes it resistant to a common herbicide can pass that genetic trait to weedy rice, prompting powerful growth even without a weed-killer to trigger the modification benefit, new research shows. Previously, scientists have found that when a genetically modified trait passes from a crop plant to a closely related weed, the weed gains the crop's engineered benefit – resistance to pests, for example – only in the presence of the offending insects.

This new study is a surprising example of gene flow from crops to weeds that makes weeds more vigorous even without an environmental trigger, the researchers say.

An estimate finds that a northward shift of Earth's wind and rain belts could make a broad swath of regions drier, including the Middle East, American West and Amazonia, while making Monsoon Asia and equatorial Africa wetter.

Researchers have found reassuring evidence of the H1N1 influenza vaccine's safety during pregnancy. 

The national study, which was launched shortly after the pandemic H1N1 influenza outbreak of 2009 and funded by the U.S. Department of Health and Human Services Biomedical Advanced Research and Development Authority (BARDA), will be summarized in two Vaccine papers.

A survey of gun dealers and pawnbrokers in 43 U.S. states found nearly unanimous support for denying gun purchases for criminals and mentally ill people who have a history of violence or alcohol or drug abuse; conditions that might have prevented Washington Navy Yard shooter Aaron Alexis from legally purchasing a firearm.