President Andres Manuel Lopez Obrador sparked puzzlement and intrigue when he posted the image up on Twitter.
Dark energy could be the key to understanding a cyclical universe that contracts and expands over and over again.
Black holes may be the long-sought source of the mysterious dark energy that makes up most of the universe.
Three unidentified objects have now been downed by fighter jets over North America and we still don't know what they are.
Astronomers have identified a very unusual galaxy that could help improve our understanding of dark matter.
Despite a few technical hiccups, the mission succeeded in further cementing America's dominance in the space race.
This remarkable new robot was inspired by dandelion seeds and requires only a light source to power it up.
Archaeologists excavating a car park off the coast of Northumberland, England have unearthed seven skeletons.
The enormous snake was recently captured on camera when Everglades visitor Kymberly Clark came across it.
Saturday marked the 75th anniversary of the death of pilot Thomas Mantell who crashed while pursuing a UFO.
Back in 1992, two friends had been traveling in South Lanarkshire, Scotland when they encountered something terrifying.
Treasure hunters will soon be scouring the Dutch countryside for a cache of riches buried by German soldiers during WWII.
Dozens of witnesses took to social media to post photographs and video clips of the unusual aerial phenomenon.
Social media was awash on Friday with reports of strange objects, vapor trails and colored lights over the country.
The European Space Agency is working on a new mission to track down dark matter and find out what it is made of.
The alleged entity was picked up on camera on a dark woodland path in Clumber Park, Nottinghamshire.
This hellish world was photographed in remarkable detail during one of the probe's recent flybys.
Dating back one million years, the remarkably intact skull has been hailed as an important find by palaeoanthropologists.
The unattached appendage had been found floating in the scalding-hot water by park staff earlier this year.
The end of the spacecraft's current mission was marked by a series of sonic booms over Florida on Saturday.